COMMISSION J: Radio Astronomy (November 2004 – October 2007)
Edited by Hideyuki Kobayashi
J1@Overview of Japanese radio astronomy
activity
J2 Observatory report
J2.1 National Astronomical Observatory of
J2.1.1 Nobeyama@Radio Observatory
With continuing the open use of 45-m telescope,
NMA (Nobeyama Millimeter Array), and RAINBOW (the combined interferometer of
NMA and the 45-m telescope) and also supporting the
J2.1.2 Mizusawa VERA observatory
Mizusawa VERA observatory is
carrying out VERA project and Japanese VLBI network project. And as a research project, we have the
optical fiber linked VLBI experiment.
VERA project aims to make the 3-D map of the galaxy and reveal the
kinematic field of the Galaxy. We
suppose it will show the distribution of mass in the Galaxy, especially the
distribution of the dark matter. In
order to make precise astrometry measurements, VERA is equipped with 2-beam
observation system for the complete phase referencing VLBI observations. It can simultaneously observe two
objects within 2.2 degree separations.
VERA aims trigonometric parallax measurements with 10 micro-arc-second
accuracy.
VERA got construction funds at 2000 and
2001. They covered the construction
of four 20-m radio telescopes, receivers, digital equipments, recorders,
control system and other related equipments. At the end of March 2001, constructions
of basic hardware system was completed.
In 2003, VERA succeeded usual one-beam VLBI observations and feasibility
was confirmed. In 2004, we started
the test of 2-beam observations and succeeded to make a continuum map with
phase referencing.
In 2005, geodesy observations were
started with the GSI 32-m VLBI station.
The position of GSI VLBI station is well determined on the world
coordinate. VERA stations are
referred to the GSI station. And
remote operation system from Mizusawa had started. Then observation time increased from
1,500 hours per year to 3,000 hours per year. Moreover Japanese VLBI network with
Usuda 64-m, Yamaguchi 32-m, Tsukuba 32-m, Kashima 34-m and
In 2006, VERA succeeded to measure the
trigonometric parallaxes of S269 and Orion-KL. And around 10 sources were started to
measure the precise trigonometric parallaxes and proper motions. The common use observations were
internationally opened. And
five VLBI stations; Usuda 64-m, Yamaguchi 32-m, Tsukuba 32-m, Kashima 34-m and
In 2007, some papers related to VERA
observations were published.
Especially the S269 observation is the furthest determination of the
trigonometric parallax. Also VERA has succeeded the distance measurements of
Orion-KL with 2% error, which is competitive for the most accurate measurements
of VLBA. And around 10 sources were
started to measure the precise trigonometric parallaxes and proper
motions. The common use
observations were internationally opened. And five VLBI stations; Usuda
64-m, Yamaguchi 32-m, Tsukuba 32-m, Kashima 34-m and
Mizusawa VERA observatory also organizes
the Japanese VLBI network, which has 11 VLBI stations including VERA. We collaborate universities; Hokkaido
University, Tsukuba University, Ibaraki University, Gifu University, Osaka
Prefecture University, Yamaguchi University and Kagoshima University. Also
J2.1.3
The Atacama Large Millimeter/submillimeter Array (ALMA), an
international astronomy facilityCis a partnership among
Europe, Japan, and North America, in cooperation with the Republic of
Chile. ALMA is funded in Europe by
the European Organization for Astronomical Research in the Southern HemisphereCin Japan by the National lnstitutes of Natural Sciences(NINS) in
cooperation with the Academia Sinica in Taiwan, and in North America by the
U.S. National Science Foundation (NSF) in cooperation with the National
Research Council of Canada (NRC).
ALMA@construction and operations are led on be half of Europe by ESOCon behalf of Japan by the National Astronomical 0bservatory of Japan
(NAOJ), and on behalf of North America by the National Radio Astronomy
Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI)D
The mission of the ALMA project at NAOJ is to conduct the following
activities in collaboration with the international partners to achieve the
scientific goals of ALMAF
ljDesign, develop, build and
deliver ALMA subsystems
The major subsystems assigned to Japan areF
iajthe Atacma Compact Array(ACA) that is composed of 16 antennas, a dedicated
correlator, and
ibjthe receiver Cartridges for Band 4,8, and 10 that are integrated
into the receiver front end subsystem and mounted on every ALMA antennasD
Softwares needed for these subsystems are also developed and integrated
in the ALMA software systemD
2jContribution to the cost
of common infrastructure
Contribute proper shares to the costs of site development, the
permanent power supplyDand other infrastructureD
3jSystem integration and
verification
Participate in the joint activities of Assembly, Integration and
Verification(AIV) and Commissioning and Science Verification (CSV) to finish
ALMA as a scientific instrumentD
4jPreparation for the
scientific operations
Set up the East Asian ALMA Regional Center (EA-ARC), one of the
three ARCs in the world, to interface
5jScientific operations and
maintenance
Operate ALMA throughout its lifetime(at least 30years) with an
appropriate maintenance and improvements in various magnitudesDServe the science community through EA-ARC by providing not only the
observing opportunity with ALMA according to proposals but also the archival
data from observations in the past to promote science with
We have started the construction of the Atacama Large
Millimeter/submillimeter ArrayiALMA) as an international collaboration projectCAfter a tough negotiation, agreement was signed in 2004 that
established the trilateral structure of North AmericaCEurope, and Japan @(and Taiwan).
At the end of December 2007, we had
delivered three 12-m antennas and the correlator for the ACA system at the
J2.1.4 ASTE
ASTE (Atacama Submillimeter Telescope
Experiment) is a 10-m submillimeter telescope operating since 2002 in the
Atacama Desert in northern
The ASTE antenna has an excellent
performance with its surface accuracy adjusted to 19 microns r.m.s., and its
pointing accuracy of 2 arc-minutes r.m.s.
Two main receiver systems were used for the observing run for the resent
years, which are SIS receiver at 345 GHz for spectroscopy, and a bolometer
camera "AzTEC" for continuum imaging.
The SIS receiver employs a cartridge
type plug-in cryogenics at 4 K, where we can use the common cryogenic system
for several receiver cartridges. The initial stage of the observation was done
by a receiver cartridge called "SC345", which is a double side-band
receiver at 345 GHz developed mainly by the
AzTEC is a 144 element semiconductor
bolometer camera at 270 GHz developed by
We have been working on technical
developments for the future as well.
The SC345 SIS receiver is to be upgraded to a side-band separating (2SB)
receiver (CATS345), and a wide band F-FX type auto-correlator (WHSF) which
covers a wide bandwidth of 8 GHz in total is showing up. A superconductive imaging submillimeter-wave
camera with nine-element SIS photon detectors at 650 GHz (SISCAM-9), has been
tested on the telescope to receive its first light from the moon. (H. Ezawa)
J2.1.5 Lunar exploration
Japanese Lunar
Explorer (KAGUYA) was launched successfully on Sep. 14, 2007 and has been
continuously observing the whole moon. Two radio-metric experiments were
performed in the KAGUYA mission to measure the precise lunar gravity
field. One is a 4-way Doppler experiment using a relay sub-satellite
(Rsar) for the direct measurement far-side lunar gravity. Another is a
differential VLBI experiment with the two sub-satellites (Rstar and Vstar)
which transmit three carrier waves at S band and one carrier wave at X band.
Both experiments have been done successfully. World-first precise
far-side lunar gravity map has been produced. In the multi-wavelength
differential VLBI experiment, removal of the phase ambiguity was attained and
pico-second order accuracy was confirmed through the same-beam observation
using VERA network of NAOJ. VLIB observation of KAGUYA by VERA stations
and four oversea stations (
J2.1.6 Nobeyama Solar Radio Observatory
Nobeyama Solar Radio Observatory (NSRO) carries out solar radio
observations and researches on solar physics by multi-wavelength analyses
including radio. We observed the Sun routinely with the Nobeyama
Radioheliograph (NoRH) and Radio Polarimeters (NoRP). By combining the radio
data with data taken from sattellites and from the ground, we study solar
activity, especially particle acceleration processes in solar flares. Obtained
data are opened to scientists in solar and related field. Through these
activities, NSRO serves as international center for solar data analyses and
research.
We have operated NoRH and NoRP and observed data are archived and opened
to scientists in the world for common use. We invited large number of Japanese
and foreign scientists and provided data for common use and collaboration.
Scientific research of NSRO is highly biased to collaboration with outer users
rather than own research. We organized an international symposium "Solar
Physics with the Nobeyama Radioheliograph" in 2004 and published the
proceedings book and a special issue in PASJ journal.
J2.2 Japan Aerospace Exploration Agency (JAXA)
J2.2.1 Space VLBI VSOP and VSOP-2
The first VLBI
dedicated satellite, HALCA for the VSOP (VLBI Space Observatory Programme)
mission, was operated in 1997-2005. Almost 800 observations at 1.6 and 5.0 GHz
were conducted to study the compact cores and the parsec-scale jets of
extragalactic radio sources and other objects.
Following the success of the first space
VLBI mission VSOP, JAXA and NAOJ started the next generation Space VLBI
project, VSOP-2 (ASTRO-G) since 2007. The nominal launch epoch is the fiscal
year 2012 with H2A rocket. The orbit of the ASTRO-G satellite will be 25,000km
apogee and 1,000 km perigee with the inclination of 31 degree. The observing
bands are 8, 22 and 43 GHz. The 35,000 km baseline between ASTRO-G and the
ground radio telescopes at 43 GHz, provides the angular resolution of about 40
micro arcseconds to observe innermost regions of AGN jets and astronomical
masers.
To achieve more sensitive VLBI
observation, the 9.3m large deployable reflector, the attitude control system
with fast switching and the pointing accuracy for 43 GHz observation, a cooled
mm-wave receiver by Stirling cycle refrigerator, giga-bit data transmission,
and high accuracy orbit determination are the main technical challenges in the
ASTRO-G development.
This project is also planned as a wide
international collaboration for ground radio telescopes, correlators, link
stations, and the science operation, as we did in VSOP (HALCA) mission. (M.Tsuboi&Y.Murata)
J2.2.2 Usuda and Uchinoura
Usuda 64-m antenna is mainly used for the
tracking of spacecrafts, Hayabusa (MUSES-C), Kaguya (SELENE) and Geotail, for
which S and X band receivers are installed. It was also used for a ground VLBI
station for VSOP (HALCA) project, and supported VSOP L and C band
observations. C-band receiver was
modified to observable 6.7GHz methanol line. We use K4 and K5 VLBI terminals to join
the Japanese VLBI network observations.
Uchinoura 34-m antenna is mainly used for the operation of near-earth
satellites. We installed both K4 and K5 VLBI terminal system to 34m, and
started S/X-band VLBI observations.
These telescopes are also used for the spacecraft orbit determination
using VLBI technique. (N.Mochizuki)
J2.3 National Institute of Information and Communication Technology
(NICT)
National Institute of Information and Communication Technology
(NICT) is@operating 34-m and 11-m radio telescopes at Kashima and another 11-m
radio@telescope at Koganei. They are mainly used for geodetic and
astronomical VLBI observations and pulsar timing observations. As one of the
Technical Development Centers of International VLBI Service for Geodesy and
Astrometry@(IVS), NICT has been developing two types of disk-based data
acquisition systems. One is Gbps-class VLBI observing systems (K5/VSI) with
digital filtering function [Takeuchi et al. 2006] and the other is multi
channel VLBI system (K5/VSSP)[Kondo et al. 2006; Koyama et al. 2006]. Software correlator programs which@run on multiple PC systems for distributed processing are under
development@as the correlator part of the K5 system. Application of VLBI
technique for spacecraft navigation has been studied for spacecraft Nozomi
[Sekido et al. 2004] and Hayabusa. A compact VLBI system is under the
development with combination of small-size telescope and K5 wide-band sampler
for certification of accurate 10km baseline Ishii et al. 2007]. Accurate
ionospheric delay modeling and estimation of ionospheric total electron
contents with VLBI has been studied [Hobiger et al., 2006, 2007a, 2007b]. As
single dish observations, Kashima 34m radio telescope has been used for regular
pulsar timing observation. Additionally, spectral line observations with 22GHz
receiver have been performed under collaboration with
J2.4 60-cm Telescope of the U.
The radio astronomy group at
J3 Solar System Radio Astronomy (2004.11-2007.10)
Dynamics of Jupiter's radiation belt (JRB) has been investigated by
observing the synchrotron radiation (JSR) using single dish radio telescopes of
Tohoku University (325 and 785MHz), Nagoya University (327MHz) and National
Institute of Information and Communications Technology (2300MHz), Japan, and a
radio interferometer named Giant Metrewave Radio Telescope (GMRT, 610MHz),
India. Long-term monitoring of JSR at 327MHz for 1995 - 2004 showed that
variations of JRB electrons of about 5MeV are roughly 4 times larger than those
of higher energy electrons (- 15MeV) and have been controlled by solar wind dynamic
pressure or solar UV/EUV flux when these parameters are large values [Nomura et
al., 2006, 2007]. A multi-frequency JSR observation at 325 - 2300MHz had been
made in May to June, 2007 simultaneously with an interferometer observation
using the GMRT. The campaign observation suggested that short term variations
with the time scale of days to weeks were larger at lower energy JRB electrons
and the variations of lower energy electrons might not be induced by solar
activities which are considered to be a main promoter at higher energy
electrons, but induced by some Jupiter's inner processes [Misawa et al., 2007;
Tsuchiya et al., 2007; Imai et al., 2007].
An interferometer at the lunar
surface has been studied to realize high sensitivity and high resolution
observations at a low frequency below 15MHz which is impossible from the ground
due to the ionospheric shielding effect. This study has been made for the
purpose of investigating solar system bodies, interstellar matter,
extra-galaxies and initial cosmic structure. A goal of this study is
construction of a low frequency array on the lunar far-side where man-made and
natural noises from the Earth can be always avoided and radio bursts from the
Sun can be shielded during the lunar night. As the first step of this
project, feasibility of an Earth-Moon baseline interferometer at 25MHz has been
examined for revealing source size and generation processes of Jupiter's
decameter wave and for making fundamental measurements of the lunar surface
environment [Iwata et al., 2006; Noda et al., 2006; Kawano et al., 2007].
Investigating the constituents and the isotope ratios of planetary
atmosphere is key to understanding the physical and chemical environment and
the evolutionary processes of the solar planetary system. The
The interplanetary scintillation (IPS) method using radio sources
distributed over the sky can observe the dynamics and structure of the solar
wind in three dimensions with a relatively short time cadence. Because of this
advantage over in-situ measurements, the Solar-Terrestrial Environment
Laboratory (STEL) of the
To improve a spatial resolution of the IPS observations,
construction of a new radiotelescope dedicated for IPS observations started in
2006 at Toyokawa. The new radiotelescope, called the Solar Wind Imaging
Facility (SWIFT), is a meridian-transit-type cylindrical parabolic antenna with
a physical aperture of 106 m NS X 38 m EW and an illumination efficiency of 91
% (a design value), and it will enable to observe twice as many IPS sources as
the existing IPS antennas can. An observation frequency is 327 MHz which is the
same as the existing one. The feed system of the SWIFT consists of 192 (NS) ~ 2
(EW) phased-array dipoles, which forms a single steerable beam in the meridian
plane between S 60 deg to N 30 deg with respect to the zenith. An overall test
of the SWIFT is underway to check and optimize the system performance.
Three-dimensional (3D) structure and radial evolution of coronal
mass ejection (CME) in the interplanetary space (beyond the field-of-view of
the coronagraph) are poorly understood despite their importance in the space
weather research. STEL IPS observations were analyzed to elucidate these
enigmas of CME. A series of interplanetary disturbances associated with intense
CMEs were clearly detected from STEL IPS observations during October to
November 2003, and some important aspects have been revealed from detailed
analysis of IPS data for this period. A loop-shaped high-density structure has
been determined from the model fitting analysis of IPS observations for the
2003 October 28 halo CME event, which is the most prominent one among the
Halloween storms. This reconstructed feature has been compared with 3D
distribution of the solar wind density reconstructed from Solar Mass Ejection
Imager (SMEI) observations, and as the result, they are found to be in good
agreement (correlation coefficient ~0.6). It is also found that the loop
structure is roughly aligned to the direction of the magnetic flux rope inferred
from cosmic ray modulation data and in situ solar wind data. Consequently, the
loop structured identified from the IPS observations is considered to represent
the coronal ejecta confined within the magnetic flux rope. Another noteworthy
point disclosed from STEL IPS observations is large-scale reduction in the
solar wind density after occurrence of the 2003 October 28 CME event (Tokumaru
et al., 2005, 2007; Jackson et al., 2007). Here, it should be noticed that
there is a variety of global features determined for interplanetary CME events.
Some CMEs are associated with loop-shaped interplanetary disturbances, and
others are associated with shell-shaped high density structures. For example,
STEL IPS observations for the 1999 September 20 CME event suggest that an
interplanetary counterpart of this CME has a shell-shaped distribution. This
distribution is consistent with in situ measurements by the gNozomih
spacecraft, which is the Mars mission of
One of the main issues of solar wind research is the mechanism of
solar wind acceleration. Recent studies reveal that the solar wind speed (V)
correlates with corona magnetic parameters (B/f) during the solar activity
minimum, where the B and f represent photospheric magnetic field and magnetic
flux expansion rate, respectively. To verify this relationship, solar wind IPS
data from 1995 to 2005 were analyzed. As result, it was found that V linearly
depended on B/f through the solar cycle, and also found that the proportional
coefficient peaked at the solar activity minimum and reached its lowest level
at the solar activity maximum (Fujiki et al., 2005; Hakamada et al., 2005; Kojima
et al., 2007).
Phase scintillation measurements of the gNozomih spacecraft X-band
waves taken during the solar occultation between 2000 December and 2001 January
have been used to investigate the density turbulence in the near-Sun plasma for
an unprecedentedly wide frequency range. The scintillation spectra obtained
within 20 solar radii show a three-part structure; the Kolmogorov turbulence at
<0.5 Hz, a local flattening between 0.5 and 3 Hz, and a steep fall at higher
frequencies (Imamura et al., 2005). (M.Tokumaru)
References
and Abstracts
l
Abada-Simon, M., J. Casares, A. Evans, S. Eyres, R.
Fender, S. Garrington, O. de Jager, N. Kuno, I. G. Martíez-Pais, D. de Martino, H. Matsuo, M. Mouchet, G. Pooley, G. Ramsay, A. Salama,
and B. Schulz [2005a], "First Detections of the Cataclysmic Variable AE
Aquarii in the Near to Far Infrared with ISO and IRAS: Investigating the
Various Possible Thermal and Non-Thermal Contributions," Astron.
Astrophys., vol.433, pp.1063-1077.
Ø
We have
used ISO to observe the Magnetic Cataclysmic Variable AE Aquarii in the
previously unexplored range from 4.8 Źm up to 170 Źm in the framework of a
coordinated multi-wavelength campaign from the radio to optical wavelengths. We
have obtained for the first time a spectrum between 4.8 and 7.3 Źm with ISOCAM
and ISOPHOT-P: the major contribution comes from the secondary star spectrum,
with some thermal emission from the accretion stream, and possibly some
additional cyclotron radiation from the post-shock accretion material close to
the magnetised white dwarf. Having reprocessed ISOPHOT-C data, we confirm AE
Aqr detection at 90 Źm and we have re-estimated its upper limit at 170 Źm. In
addition, having re-processed IRAS data, we have detected AE Aqr at 60 Źm and
we have estimated its upper limits at 12, 25, and 100 Źm. The literature shows
that the time-averaged spectrum of AE Aqr increases roughly with frequency from
the radio wavelengths up to ~ 761 Źm; our results indicate that it seems to be
approximately flat between ~761 and ~ 90 Źm, at the same level as the 3Š upper
limit at 170 Źm; and it then decreases from ~ 90 Źm to ~ 7 Źm. Thermal emission
from dust grains or from a circum-binary disc seems to be very unlikely in AE
Aqr, unless such a disc has properties substantially different from those
predicted recently. Since various measurements and the usual assumptions on the
source size suggest a brightness temperature below 109 K atÉ3.4 mm,
we have reconsidered also the possible mechanisms explaining the emission
already known from the submillimetre to the radio. The complex average spectrum
measured from ~ 7 Źm to the radio must be explained by emission from a plasma
composed of more than one gpure'' non-thermal electron energy distribution
(usually assumed to be a power-law): either a very large volume (diameter 80
times the binary separation) could be the source of thermal bremsstrahlung
which would dominate from ~ 10 Źm to the ~millimetre, with, inside, a
non-thermal source of synchrotron which dominates in radio; or, more probably,
an initially small infrared source composed of several distributions (possibly
both thermal, and non-thermal, mildly relativistic electrons) radiates
gyro-synchrotron and expands moderately: it requires to be re-energised in
order to lead to the observed, larger, radio source of highly relativistic
electrons (in the form of several non-thermal distributions) which produce
synchrotro.
l
Abada-Simon,
M., J. Casares, A. Evans, S. Eyres, R. Fender, S. Garrington, O. de Jager, N.
Kuno, I. G. Martíez-Pais, D. de Martino, H. Matsuo, M. Mouchet, G. Pooley, G.
Ramsay, A. Salama, and B. Schulz [2005b], "AE Aquarii Emission Processses
from Radio to Infrared," Proc. of "The Astrophysical of Cataclysmic
Variables and Related Objects", eds. J. M. Hameury and J. P. Lasotu, ASP Conf.
Ser. vol.330, pp.341-342.
Ø
AE
Aquarii is a Magnetic Cataclysmic Variable (MCV) flaring at all wavelengths.
The origin emission from radio to 10 Źm is thought to be magneto-bremsstrahlung
from both thermal and non-thermal electron energy distributions.
l
Akabane,
K., and
Ø
The
luminosity of the central star of the compact HII regions of NGC 7538 was
estimated from the solid angle of the IR sources subtended relative to the
central star, and was found to be 5~ 10 times as intense as that of IR sources.
Under the single central star approximation, the luminosity gives a stellar UV
photon rate NU(*) (s-1) of ~3.0 ~ 1048, ~1.5 ~
1049, ~5.1 ~ 1049, and ~1.7 ~ 1047 for the compact HII
regions of NGC 7538-IRS1(A/2), B, IRS2, and IRS3, respectively. NU
(*) and the observed electron density, ne, provide the dust opacity
of the ionizing photon, ŃSd, for the optical path out to the Str
mgren sphere radius rS, assuming a gas with standard dust content.
Ionizing photon opacity over the same optical path but with the actual dust
content ŃSda is also derived from ri / rS,
where ri is the radius of the ionized sphere, which is estimated
from NU(*) and the observed volume emission measure ne2
(4Īri 3/3) (Spitzer 1978). An observational trend of Į{NU(*)
/ 4Īri2 1/2 ~ constant, where Į = Sda
/ Sd}, was obtained for the 4 compact HII regions of the NGC
7538(N). Fourteen selected compact HII regions from data catalogued by VLA
observations were examined for this trend, and a similar result was obtained. A
limit of Į as 15 Į 0.1 was given for the 14 selected sources. The size of the
dust-depleted cavity of the NGC 7538(N) suggested by Chini et al. (\cite{Chini1986})
coincides with that of the ionized sphere of the IRS2 of the region.
l
Ao, Y.,
J. Yang, K. Sunada, and K. Tatematsu [2006], "CS J=2-1 Observations
towards Massive Dense Cores," Proc. of the IAU Symp. vol.231,
"Astrochemistry Throughout the Universe: Recent Successes and Current
Challenges," eds. by Dariusz C. Lis, Geoffrey A. Blake & Eric Herbst,
2005, poster presentation, Session I.03.
Ø
We
present the results of CS J=2-1 map observations towards 17 massive forming regions
selected from the previous CO line survey cold IRAS sources along the Galactic
plane (Yang et al. 2002). All sources were detected in CS J=2-1 and showed the
existence of CS cores around the associated IRAS sources. The average values
for core radius R, average line width ?V, CS column density NCS, volume density
n, virial mass MVIR and CS abundance log
X(CS) are 0.40 pc, 2.31 km s-1, 1.3 x 1014 cm-2,
5.5 x 104 cm-3, 620 Msol and -8.93,
separately. We examined the archival VLA radio continuum data for all sources,
with 4 additional sources from the previous work (Ao, Yang, & Sunada 2004).
Extended HII regions were found towards 12 sources and UCHII regions were
associated with 5 sources. 4 remaining sources with high far-infrared
luminosities without radio continuum emission were classified as the candidates
of high-ass protostellar objects (HMPOs), which were found to be characterized
by low LFIR/MV IR ratios.
l
Aoki,
W., I. Iwata, K. Ohta, N. Tamura, M. Ando, M. Akiyama, G. Kiuchi, and K.
Nakanishi [2007], "Balmer Absorption Lines in FeLoBALs," Proc. of the
"The Central Engine of Active Galactic Nuclei", eds. Luis C. Ho and
Jian-Min Wang, ASP Conf. Ser., vol.373, pp.337-338.
Ø
We
discovered non-stellar Balmer absorption lines in two many-narrow-trough FeLoBALs
(mntBALs) by the near-infrared spectroscopy with Subaru/CISCO. Presence of the
non-stellar Balmer absorption lines is known to date only in the Seyfert galaxy
NGC 4151; thus our discovery is the first cases for quasars. Since all known
active galactic nuclei with Balmer absorption lines share similar
characteristics, it is suggested that there is a population of BAL quasars
which have unique structures at their nuclei or unique evolutionary phase.
l
Argon,
A. L., L. J. Greenhill, J. M. Moran, M. J. Reid, K. M.Menten, and M. Inoue
[2004], "The IC 133 Water Vapor Maser in the Galaxy M33: A Geometric
Distance," Astrophys. J., vol.615, pp.702-719.
Ø
We
report on the results of a 14 yr long VLBI study of proper motions in the IC
133 H2O maser source in the galaxy M33. The method of ordered motion
parallax was used to model the three-dimensional structure and dynamics of IC
133 and to obtain a distance estimate, 800}180 kpc. Our technique for
determining the distance to M33 is independent of calibrations common to other
distance indicators, such as Cepheid period-luminosity relations, and therefore
provides an important check for previous distance determinations.
l
Ariyoshi,
S., H. Matsuo, C. Otani, H. Sato, H. M. Shimizu, K. Kawase, and T. Noguchi
[2005], "Characterization of an STJ-Based Direct Detector of Submillimter
Waves," IEEE Trans, Appl. Superconductivity, vol.15, pp.920-923.
Ø
We have
developed submillimeter-wave direct detectors employing niobium-based
superconducting tunnel junctions (STJs), with broadband spectral response, high
sensitivity and imaging capability. Spectral response peaked at 650 GHz with a
fractional bandwidth of 14 percent, which firs one of the important atmospheric
windows for an astronomical project. We also confirmed the linearity of the
detector response in the dynamic range greater than 106. The measured coupling
efficiency was about 0.2, which was lower than the expected value of 0.5. The
measured noise current of the detector was 10fA/ćHz, which agreed with the shot
noise from the residual leakage current of 100 pA at 0.3 K. Resultant noise
equivalent power (NEP) is 1.6 10-16 W / ćHz, that is less than the
background photon fluctuation limit for ground-based submillimeter-wave
observations.
l
Asada,
K., and M. Inoue [2004a], "A Follow-Up RM Observation for Helical Magnetic
Field in 3C273," Proc. of the 7th symposium of the European VLBI Network
on New Developments in VLBI Sciences and Technology, eds. R. Bachiller, F.
Colomer, J.-F. Desmurs, and P. de Vicente, pp.65-68.
Ø
We
present results of our follow-up observation for a gradient of Faraday Rotation
Measure (RM) across 3C 273 jet. We have found RM gradient across 3C 273 jet,
and it may reveals a presence of a helical magnetic field which has been
suggested to be related to the formation and collimation of jets by
magneto-hydrodynamic models. However, regime we could reveal a distribution of
RM was very limited, since 3C 273 was observed as a calibrator. In order to
reveal further distribution of RM, we made follow-up observation. We detected
gradient of RM across the jet and it continues more than 20 pc in projected
distance. In addition, the distribution of the RM shows a significant proper
motion. Coincidentally, its apparent proper motion of 5.25 c corresponds to
that of the relativistic emitting plasma of 5.26 c.
l
Asada,
K., M. Inoue, Y. Uchida, and S. Kameno [2004b], "Detection of the
Direction of the Rotation of the Accretion Disk or Spinning Black Hole,"
Proc. of the "Coevolution of Black Holes and Galaxies, 2004", ed. L.
C. Ho, Carnegie Observatory Astrophysics Ser., vol. 1.
Ø
We show
the direction of accretion disk around the possible super massive black hole of
3C 273 or spinning supermassive black hole itself as clockwise based on the
observed 3D structure of magnetic field in the jet of 3C 273. Using VLBA
polarimetry, we derived distributions of Faraday Rotation Measure (RM) and
projected magnetic field of 3C 273 jet. Based on a systematic gradient across
the jet of RM and the projected magnetic field, the helical magnetic field is
revealed, which is suggested by MHD models. The sign of RM indicates the
direction of the twist of the helical magnetic field as a right hand screw. If
the observed helical magnetic field is wound up by the accretion disk around
possible super-massive black hole, we can see the direction of the rotation.
l
Asada,
K., M. Inoue, S. Kameno, and H. Nagai [2005], "A Helical Magnetic Field in
3C 273," Proc. of the "Future Directions in High Resolution
Astronomy: A Celebration of the 10th Anniversary of the VLBA", eds. J. D.
Romney, and M. J. Reid, ASP Conf. Ser. vol.340, pp.168-170.
Ø
Using
VLBA polarimetry, we derived distributions of Faraday Rotation Measure (RM) and
projected magnetic field of 3C 273 jet. Based on a systematic gradient across
the jet of RM and the projected magnetic field, the helical magnetic field is
revealed, which is suggested by MHD models. The sign of RM indicates the
direction of the twist of the helical magnetic field as a right hand screw. If
the observed helical magnetic field is wound up by the accretion disk around
possible super-massive black hole, we can see the direction of the rotation.
l
Asada,
K., S. Kameno, Z.-Q. Shen,
Ø
The
expansion and inner proper motions of a young radio lobe associated with the
bright radio source 3C 84 in the Seyfert galaxy NGC 1275 have been detected by
VSOP observations. These proper motions are consistent with the evolution
scenario of classical double radio sources. The apparent expansion velocity is
(0.50 } 0.09) c. The age of the radio lobe is estimated to be (45.7 } 8.9)yr in
2001, which is in agreement with the age previously estimated by Romney et al.
(1982). The total flux density at 5GHz increased at the end of the 1950's,
marked several peaks in the middle of the 1980's, and is presently in a decay
phase. The decay of the total flux density can naturally be explained by an
adiabatic cooling due to expansion of the radio lobe, and previously measured
spectral indices suggest that the emission comes from the surface of the radio
lobe.
l
Asada,
K., M. Inoue, H. Nagai, and S. Kameno [2007], "Further Evidence of Helical
Magnetic Field," Proc. of the "The Central Engine of Active Galactic
Nuclei", eds. Luis C. Ho and Jian-Min Wang, ASP Conf. Ser., vol.373,
pp.211-212.
Ø
Based on
multi-frequency polarimetry towards 0333+321 using VLBA, we reveal both the
distributions of the projected magnetic field and Faraday rotation measure in
order to discuss the 3D configuration of the magnetic field. There is a
systematic gradient in the distribution of rotation measure, and the sign of
its rotation measure is different at both sides of jet respect to the jet axis.
It strongly supports that the helical magnetic field in the jet is responsible
to the RM gradient, since the sign of the rotation measure can be changed only
by changing the direction of the magnetic field.
l
Asai,
A., K. Ichimoto, K. Shibata, R. Kitai, and H. Kurokawa [2004a], "The
Red-Asymmetry Distribution at Hæ Flare Kernels Observed in the 2001 April 10
Solar Flare," American Geophysical Union, Fall Meeting 2004, abstract
#SH13A-1134.
Ø
We
report a detailed examination about the evolution of the Halpha flare kernels
during an X2.3 solar flare which occurred on 2001 April 10. The Halpha
red-asymmetry, that is, the red-shifted Halpha emission, is observed at almost
all Halpha flare kernels, during the impulsive phase of the flare. At Halpha
kernels nonthermal particles and/or thermal conduction precipitate into the
chromospheric plasma, and this is thought to lead the downward compression of
the chromospheric plasma, which is observed as the reddening of Halpha emission
(e.g. Ichimoto & Kurokawa 1984). We examined the evolution of the flare
kernels inside the flare ribbons by using the Halpha images obtained with the
Domeless Solar Telescope at Hida Observatory,
l
Asai,
A., T. Yokoyama, M. Shimojo, and K. Shibata [2004b]. "Downflow as a
Reconnection Outflow," Proc. of the 5th Solar-B Science Meeting, "The
Solar-B Mission and the Forefront of Solar Physics : Dedicated to the Memory of
Yutaka Uchida", ASP Conf. Ser., vol.325, pp.361-366.
Ø
We
present a detailed examination about the evolution of TRACE downflow motions
(sunward motions) seen above post-flare loops. We found that the times when the
downflow motions are seen correspond to those of the bursts of nonthermal
emissions in hard X-rays and microwave. These results mean that the downflows
occurred when strong magnetic energy was released, and that they are, or at
least correlated with, the reconnection outflows. We also propose an
observation of downflows as the reconnection outflows by Solar-B.
l
Asai,
A., T. Yokoyama, M. Shimojo, S. Masuda, and K. Shibata [2004c], "Flare
Ribbon Expansion and Energy Release Rate," Proc. of the IAU Symp. 223,
"Multi-Wavelength Investigations of Solar Activity", ed. A. V. Stepanov, E. E. Benevolenskaya, and
A. G. Kosovivhev, pp.443-444.
Ø
We
report a detailed examination about the relationship between the evolution of
the Halpha flare ribbons and the released magnetic energy during an X2.3 solar
flare which occurred on 2001 April 10. We successfully evaluated the released
energy quantitatively, based on the magnetic reconnection model. We measured
the photospheric magnetic field strengths and the separation speeds of the
fronts of the Halpha flare ribbon, and estimated the released magnetic energy
at the flare by using those values. Then, we compared the estimated energy
release rates with the nonthermal behaviors observed in hard X-rays and
microwaves. We also estimated the magnetic energy released during the flare.
The estimated energy release rates in the Halpha kernels associated with the
hard X-ray sources are locally large enough to explain the difference between
the spatial distribution of the Halpha kernels and the hard X-ray sources.
Furthermore, we reconstructed the peaks in the nonthermal emission by using the
estimated energy release rates.
l
Asai,
A., H. Nakajima, M. Shimojo, S. M. White, and H. Hudson [2005a], "Preflare
Nonthermal Emission Observed in Microwaves and Hard X-Rays," Proc. of the
9th Asian-Pacific Regional IAU Meeting, pp.46-47.
Ø
We
present a detailed examination on the nonthermal emissions during the preflare
phase of the large X4.8 solar flare which occurred on 2002 July 23. The
microwave data obtained with Nobeyama Radioheliograph, at Nobeyama Solar Radio
Observatory, NAOJ, and the hard X-ray data taken with Reuven Ramaty High Solar
Spectroscopic Imager obviously showed nonthermal features. We found a faint
ejection associated with the flare in the EUV images taken with the Transition
Region and Coronal Explorer. Then, we examined the temporal, and spectroscopic
features on the emission sources, and found the loop-top sources during the
preflare phase both in hard X-rays and in microwaves.
l
Asai,
A., M. Shimojo, T. T. Ishii, H. Kurokawa, and K. Shibata [2005b], "Solar
Flares/CMEs and Space Weather," Proc. of the Second Japanese CAWSES
Workshop, p.20.
Ø
Coronal
mass ejections (CMEs) are the physically same phenomena as solar flares. They
are different from flares on one point that they are observed in different
aspects. Even in the case of CMEs that are not associated with any so-called
solar flares, they often show flare-like phenomena that are accompanied by
energy release on the solar surface. In this talk we would like to review their
contribution to the weather research on each aspect.
l
Asai,
A., H. Nakajima, M. Shimojo, S. M. White, H. Hudson, and R. P. Lin [2006a],
"Preflare Nonthermal Emission Observed in Microwaves and Hard
X-Rays," Publ. Astron. Soc. Japan, vol.58, pp.L1-L5.
Ø
We
present a detailed examination on nonthermal emissions during the preflare
phase of the X4.8 flare that occurred on 2002 July 23. The microwave (17GHz and
34GHz) data obtained with the Nobeyama Radioheliograph at Nobeyama Solar Radio
Observatory and the hard X-ray data taken with the Reuven Ramaty High Energy
Solar Spectroscopic Imager obviously showed nonthermal features in the preflare
phase. We also found a faint ejection associated with the flare in the EUV
images taken with the Transition Region and Coronal Explorer. We discuss the
temporal and spatial features of the nonthermal emissions in the preflare
phase, and their relation with the ejection.
l
Asai,
A., T. T. Ishii, K. Shibata, and
Ø
Introduction:
We report the evolution and the coronal features of an active region NOAA
10798, and the related magnetic storms. Method: We examined in detail the
photospheric and coronal features of the active region by using observational
data in soft X-rays, in extreme ultraviolet images, and in magnetogram obtained
with GOES,
l
Asai,
A., T. Yokoyama, M. Shimojo, S. Masuda, and K. Shibata [2006c], "Flare
Ribbon Expansion and Energy Release," J. Astrophys. Astr., vol.27,
pp.167-173.
Ø
We
report a detailed examination about the relationship between the evolution of
the Hæ flare ribbons and the released magnetic energy during the April 10 2001
flare. In the Hæ images, several bright kernels are observed in the flare
ribbons. We identified the conjugated foot-points, by analyzing the lightcurves
at each Hæ kernels, and showed their connectivities during the flare. The,
based on the magnetic reconnection model, we calculated quantitatively the
released energy by using the photospheric magnetic field strengths and
separation speeds of the Hæ flare ribbons. Finally, we examined the downward
motions which are observed at the Hæ kernels. We found that the stronger the
red-asymmetry tends to be associated with the brighter the Hæ Kernel.
l
Asai,
A., H. Nakajima, M. Shimojo, and S. M. White [2006d], "Preflare Features
in Microwaves and in Hard X-Rays," Advances in Geosciences, eds. W.-H. Ip,
and M. Duldig, vol.2, pp.33-41.
Ø
Not
Available
l
Asai, A.
[2006e], "Flare Associated Oscillations Observed with NoRH," Proc. of
Nobeyama Symposium 2004, "Solar Physics with the Nobeyama
Radioheliograph", pp.33-38.
Ø
We
present an examination of the multi-wavelength observation of a C7.9 flare
which occurred on 1998 November 10. This is an imaging observation of the
quasi-periodic pulsations (QPPs) obtained with Yohkoh/HXT and Nobeyama
Radioheliograph (NoRH). We found that the Alfven transit time along the flare
loop was almost equal to the period of the QPP. We therefore suggest that
variations of macroscopic magnetic structures, such as oscillations of coronal
loops, affect the efficiency of particle injection/acceleration. We also report
other QPP events observed with NoRH, and review some works on these
flare-associated oscillations.
l
Asai,
A., H. Nakajima, M. Oka, K. Nishida, and Y. T. Tanaka [2007a], "Loop Top
Nonthermal Emission Sources Associated with an Over-the-Limb Flare Observed
with NoRH and RHESSI," Adv. Space Res., vol.39, pp.1398-1401.
Ø
We
studied the M3.7 class flare which occurred on 2005 July 27, in the active
region NOAA 10792. This flare is an over-the-limb flare, and the footpoints are
entirely occulted by the solar disk. The microwave and the hard X-ray images
obtained with the Nobeyama Radioheliograph and the RHESSI satellite,
respectively, clearly showed emission sources above the post-flare loop system.
We examined the emission sources in detail spatially, temporally, and
spectroscopically. As a result, one of the hard X-ray emission sources and the
microwave emission sources are nonthermal.
l
Asai,
A., T. Yokoyama, M. Shimojo, S. Masuda, and K. Shibata [2007b], "Evolution
of Hæ Kernels and Energy Release in an X-Class Flare," Proc. of the
"New Solar Physics with Solar-B Mission", eds. Shibata, Kazunari,
Nagata, Shin'ichi, and Sakurai, T., ASP Conf. Ser., vol.369, pp.461-468.
Ø
The
investigation on the evolution of Hæ kernels allows us to derive some key
information on the energy release processes and the particle acceleration
mechanisms during a flare. We report a detailed examination on the relationship
between the evolution of the Hæ flare ribbons and the released magnetic energy
during an X2.3 solar flare which occurred on 2001 April 10. In the Hæ images,
several bright kernels were observed in the flare ribbons. We identified the
conjugated footpoints, by analyzing the light curve at each Hæ kernel, and
showed their connectivities during the flare. Then, based on the magnetic
reconnection model, we calculated quantitatively the released energy by using
the photospheric magnetic field strengths and the separation speeds of the
fronts of the Hæ flare ribbons. We confirmed that the estimated energy release
rate corresponds to the nonthermal emission light curves at the strong emission
sources. Finally, we examined the downward motions at the Hæ kernels. The
"red-asymmetry" features, generated by the precipitation of the
nonthermal particles and/or thermal conduction into the chromospheric plasma,
were observed for all the flare ribbons. We also found that the stronger the
redasymmetry tends to be associated with the brighter Hæ kernel.
l
Asaki,
Y., H. Sudou, Y. Kono, A. Doi, R. Dodson, N. Pradel, Y. Murata, N. Mochizuki,
P. G. Edwards, T. Sasao, and E. B. Fomalont [2007], "Verification of the
Effectiveness of VSOP-2 Phase Referencing with a Newly Developed Simulation
Tool, ARIS," Publ. Astron. Soc. Japan, vol.59, pp.397-418.
Ø
The
next-generation space VLBI mission, VSOP-2, is expected to provide unprecedented
spatial resolution at 8.4, 22, and 43 GHz. In this report, phase referencing
with VSOP-2 is examined in detail based on a simulation tool called ARIS. The
criterion for successful phase referencing was set to keep the phase errors
below one radian. Simulations with ARIS reveal that phase referencing achieves
good performance at 8.4 GHz, even under poor tropospheric conditions. At 22 and
43 GHz, it is recommended to conduct phase referencing observations under good
or typical tropospheric conditions. The satellite is required to have an
attitude-switching capability with a one-minute or shorter cycle, and an orbit
determination accuracy higher than 10 cm at apogee; the phase referencing
calibrators are required to have a signal-to-noise ratio larger than four for a
single scan. The probability to find a suitable phase referencing calibrator
was estimated by using VLBI surveys. From the viewpoint of calibrator
availability, VSOP-2 phase referencing at 8.4 GHz is promising. However, the
chance of finding suitable calibrators at 22 and 43 GHz is significantly
reduced; it is important to conduct specific investigations for each target at
those frequencies.
l
Baan, W.
A., Y. Hagiwara, and P. Hofner [2007], "HI and OH Absorption toward NGC
6240," Astrophys. J., vol.661, pp.173-184.
Ø
VLA
observations of large-scale H I and OH absorption in the merging galaxy of NGC
6240 are presented with 1" resolution. H I absorption is found across
large areas of the extended radio continuum structure with a strong concentration
toward the double nucleus. The OH absorption is confined to the nuclear region.
The H I and OH observations identify fractions of the gas disks of the two
galaxies and confirm the presence of central gas accumulation between the
nuclei. The data clearly identify the nucleus of the southern galaxy as the
origin of the symmetric superwind outflow and also reveal blueshifted
components resulting from a nuclear starburst. Various absorption components
are associated with large-scale dynamics of the system including a foreground
dust lane crossing the radio structure in the northwest region.
l
Beuther,
H., T. K. Sridharan, and M. Saito [2005], "Caught in the ACT: The of
Massive Star Formation," Astrophys. J. (Letters), vol.634, pp.L185-L188.
Ø
Combining
mid-infrared data from the Spitzer Space Telescope with cold gas and dust
emission observations from the Plateau de Bure Interferometer, we characterize
the infrared dark cloud IRDC 18223-3 at high spatial resolution. The millimeter
continuum data reveal a massive ~184 Msolar gas core with a projected size of
~28,000 AU that has no associated protostellar mid-infrared counterpart.
However, the detection of 4.5 mum emission at the edge of the core indicates
early outflow activity, which is supported by broad CO and CS spectral
line-wing emission. Moreover, systematically increasing N2H+(1-0)
line width toward the millimeter core center can be interpreted as additional
evidence for early star formation. Furthermore, the N2H+(1-0)
line emission reveals a less massive secondary core that could be in an
evolutionary stage prior to any star formation activity.
l
Bieging,
J. H., W. L. Peters, B. Vila-Vilaro, K. Schlottman, and C. Kulesa [2007],
"Sequential Star Formation in the Sh 254-258 Molecular Cloud: HHT Maps of
CO J=3-2 and 2-1 Emission," Proc. of the IAU Symp, 237, "Triggered
Star Formation in a Turbulent Interstellar Medium", eds. B. G. Elmegreen
& J. Palous, p.396.
Ø
The
molecular cloud associated with the Sh 254-258 group of 5 small H II regions
appears to be forming a (late)-
l
Borders,
T., L. Sjouwerman, M. Messineo, H. Habing, M. Honma, and H. Imai [2004],
"43 GHz SiO Masers and Astrometry with VERA in the Galactic Center,"
American Astronomical Society Meeting 205, #176.04.
Ø
We are
using the Very Large Array (VLA) to monitor 24 strong circumstellar 43 GHz SiO
masers in the inner Galaxy, located within 2.5 degrees of Sgr A*, for
estimating 43 GHz SiO maser light curves. The periods and accurate
interferometric positions derived in this program will enable VLBI astrometry
with the new Japanese VLBI Exploration of Radio Astrometry (VERA) array in the
l
Borovik,
V. N., V. V. Grechnev, O. I. Bugaenko, S. A. Bogachev, I. Y. Grigorieva, S. V.
Kuzin, S. V. Lesovoi, M. A. Livshits, A. A. Pertsov, G. V. Rudenko, V. A.
Slemzin, A. I. Stepanov, K. Shibasaki, A. M. Uralov, V. G. Zandanov, and I. A.
Zhitnik [2005], "Observations of a Post-Eruptive Arcade on October 22,
2001 with CORONAS-F, other Spaceborne Telescope, and in Microwaves," Proc.
of the IAU Symp. 226, "Coronal and Stellar Mass Ejections", eds. K.
Dere, J. Wang, and Y. Yan,
pp.108-111.
Ø
Using
multi-spectral data, we estimate plasma parameters in the post-eruptive arcade
observed on October 22, 2001 at 100 Mm above the limb: the temperature is 6 MK
and the plasma density is (5-9) \cdot 109 cm-3. We state
a problem of the long-term equilibrium of the hot top of the arcade high in the
corona: either the magnetic field surrounding the arcade well exceeds that one
extrapolated in the potential approximation, or beta > 1 both inside and
outside the arcade. A downflow observed in soft X-rays can contribute to the
equilibrium.
l
Butner,
H. M., S. Takakuwa, S. B. Charnley, S. D. Rodgers, and J. V. Buckle [2007],
"Chemical Differentiation in B5: H13CO+ and CH3OH
Fine Scale Variations," Proceedings in "Protostars and Planets
V", LPI contribution no. 1286, p.8470.
Ø
Not
Available
l
Byun,
D.-Y., B.-C. Koo, K. Tatematsu, and K. Sunada [2006], "Interaction Between
the Supernova Remnant HB 21 and Molecular Clouds," Astrophys. J., vol.637,
pp.283-295.
Ø
We have
carried out 12CO J=1-0 observations toward the mixed-morphology
supernova remnant (SNR) HB 21 using the SRAO 6 m telescope. The whole area of
the SNR was covered using full-beam grid spacing (2') and partly using
half-beam spacing (1'). We discovered shocked clouds with broad (Deltav>~10
km s-1) emission lines in the north, northwest, and center of the
SNR. The large (~20') cloud in the northwest has a bow-shaped morphology and
enhanced radio emission along the cloud boundary. Toward the central, X-ray-bright
area of the remnant, sensitive CO observations have revealed small broad-line
clouds. They are probable candidates for the evaporating clouds, which may be
responsible for the enhanced thermal X-rays in the central area. Shocked clouds
have also been discovered in the northern V-shaped radio structure. Our results
suggest that the unusual radio features and the central thermal X-ray
enhancements of HB 21 might be the result of an interaction with molecular
clouds. High-resolution mappings of two shocked, 1' sized clumps were made with
the NRO 45 m telescope. For the U-shaped clump in the north, we have found that
temperature and density increase near the bottom of the U-shape. The observed
features coincide with the theoretical expectation for a cloud swept by a shock
wave propagating from the south to the north. For the other shocked clump in
the south, the central velocity systematically changes with a gradient of 11 km
s-1 pc-1. We suggest 1.7 kpc as the distance to HB 21 by
considering all available distance estimates.
l
Cai,
H.-B., Z.-Q. Shen, H. Sudou, L.-L. Shang,
Ø
We
present the results of six-epoch Very Long Baseline Array (VLBA) observations
of 3C 66A. The high-resolution Very Long Baseline Interferometer (VLBI) maps
obtained at multi-frequency (2.3, 8.4, and 22.2 GHz) simultaneously enabled us
to identify the brightest compact component with the core. We find that the
spectrum of the core can be reasonably fitted by the synchrotron
self-absorption model. Our VLBA maps show that the jet of 3C 66A has two
bendings at about 1.2 and 4 mas from the core. We also give possible
identifications of our jet components with the components in previous VLBA
observations by analysing their proper motions. We find consistent differences
of the position from the core in one component between different frequencies at
six epochs.
l
Cameron,
P. B., P. Chandra, A. Ray, S. R. Kulkarni, D. A. Frail, M. H. Wieringa, E.
Nakar, E. S. Phinney, A. Miyazaki, M. Tsuboi, S. K. Okumura, N. Kawai, K. M.
Menten, and F. Bertoldi [2005], "Detection of a Radio Counterpart to the
27 December 2004 Giant Flare from SGR 1806-20," Nature, vol.434,
pp.1112-115.
Ø
It was
established over a decade ago that the remarkable high-energy transients known
as soft gamma-ray repeaters (SGRs) are located in our Galaxy and originate from
neutron stars with intense (1015G) magnetic fields-so-called Ōmagnetars'. On 27 December 2004, a giant flare with a fluence
exceeding 0.3ergcm-2 was detected from SGR 1806-20. Here we report
the detection of a fading radio counterpart to this event. We began a
monitoring programme from 0.2 to 250GHz and obtained a high-resolution 21-cm
radio spectrum that traces the intervening interstellar neutral hydrogen
clouds. Analysis of the spectrum yields the first direct distance measurement
of SGR 1806 - 20: the source is located at a distance greater than 6.4kpc and
we argue that it is nearer than 9.8kpc. If correct, our distance estimate
lowers the total energy of the explosion and relaxes the demands on theoretical
models. The energetics and the rapid decay of the radio source are not
compatible with the afterglow model that is usually invoked for gamma-ray
bursts. Instead, we suggest that the rapidly decaying radio emission arises
from the debris ejected during the explosion.
l
Chen,
Xi, Zhi-Qiang, H. Imai, and R. Kamohara [2006], "Inward Motions of the
Compact SiO Masers around VX Sagittarii," Astrophys. J., vol.640,
pp.982-994.
Ø
We
report Very Long Baseline Array (VLBA) observations of 43 GHz v=1, J=1-0 SiO
masers in the circumstellar envelope of the M-type semiregular variable star VX
Sgr at three epochs during 1999 April-May. These high-resolution VLBA images
reveal a persistent ringlike distribution of SiO masers with a projected radius
of ~3 stellar radii. The typical angular size of 0.5 mas for individual maser
features was estimated from two-point correlation function analysis of maser
spots. We found that the apparent size scale of maser features was distinctly
smaller than that observed in the previous observations by comparing their
fractions of the total power imaged. This change in the size scale of maser
emission may be related to stellar activity that caused a large SiO flare
during our observations. Our observations confirmed the asymmetric distribution
of maser emission, but the overall morphology has changed significantly, with
the majority of the maser clustering to the northeast of the star compared to
the majority of the masers lying in the southwest in 1992. By identifying 42
matched maser features appearing in all three epochs, we determined the
contraction of an SiO maser shell toward VX Sgr at a proper motion of
-0.207}0.069 mas yr-1, corresponding to a velocity of about 4 km s-1
at a distance of 1.7 kpc to VX Sgr. Such a velocity is on the order of the
sound speed and can be easily explained by the gravitational infall of material
from the circumstellar dust shell.
l
Chifor,
C., H. E. Mason, D. Tripathi, H. Isobe, and A. Asai [2006], "The Early
Phases of a Solar Prominence Eruption and Associated Flare: a Multiwavelength
Analysis," Astron. Astrophys., vol.458, pp.965-973.
Ø
Aims. We
aim to examine the precursor phases and early evolution of a prominence
eruption associated with a M4-class flare and a partial halo coronal mass
ejection (CME) observed on 2005 July 27. Our main goal is to investigate the
precursor eruption signatures observed in EUV, X-ray and microwave emission and
their relation to the prominence destabilisation.
Methods: We perform a multi-wavelength study of the prominence morphology and
motion using high-cadence and spatial resolution EUV 171 Å images from the
TRACE satellite. The high-temperature flare radiative emission in soft and hard
X-rays are analysed through imaging and spectral modeling with RHESSI.
Complementary microwave images (17 GHz and 34 GHz) from NoRH are also
investigated. Results: The activation of the filament proceeds from one
anchored footpoint. We observe "pre-eruption" brightenings in X-ray
and EUV images, close to the erupting footpoint of the prominence, being
temporally correlated to the point when the prominence first enters a slow-rise
phase, and then an accelerated fast-rise phase. The brightness temperature (Tb)
of the prominence at 34 GHz is increasing during the eruption. We also find
very good correlation between the prominence height-time profile and the
spatially integrated soft X-ray (SXR) emission. Conclusions: We discuss the
observed precursor brightenings with respect to possible mechanisms that might
be responsible for the prominence destabilisation and acceleration. Our
observations suggest that reconnection events localised beneath the erupting
footpoint may eventually destabilise the entire prominence, causing the
eruption.
l
Cho,
S.-H., H.-G. Kim, Y.-S. Park, C.-H.
Choi, and
Ø
We
present the first astronomical detection of 28Si18O maser
emission toward Orion KL by using the laboratory-measured line frequencies of 28Si18O.
The simple model of a 28Si18O maser condition adopting a
line overlap mechanism leads us to confirm a maser action in spite of its
lowest relative abundance, i.e., 28Si16O/28Si18O
~ 500. Mow the 28Si18O lines can be used to investigate
interstellar physics and chemistry, especially when the depths of the spectral
lines of the main species are high.
l
Choi,
M., T. Kamazaki, K. Tatematsu, and J.-F. Panis [2004], "Structure of the
Dense Molecular Gas in the NGC 1333 IRAS 4 Region," Astrophys. J.,
vol.617, pp.1157-1166.
Ø
The NGC
1333 IRAS 4 region was observed in the HCN and HCO+ J=1Ø0 lines
using a single-dish telescope and in the 2.1 mm continuum and the H2CO
JK-1K+1=212Ø111 line using an interferometer. The
single-dish maps show that there are at least two velocity components in
emission: one at VLSR=6.7 km s-1 associated with the IRAS
4 core, and the other at ~8 km s-1 associated with a cloud extended
from the SVS 13 complex. In addition, there is a foreground cold layer at ~8 km
s-1 that causes absorption over most of the mapped area. The cloud
structure suggests that the blue-skewed line profile of IRAS 4A/B may not be a
sign of protostellar collapse. Examinations of both single-dish and
interferometric maps suggest that the dip previously seen in the
interferometric spectra toward IRAS 4A/B may be caused mostly by the
large-scale foreground layer and partly by missing short-spacing flux.
Absorption by an infalling envelope with an unusual velocity profile cannot be
ruled out. The HCO+ map revealed other molecular cores, one
associated with SK 1, and the other with SK 10/14. They are probable sites of
star formation.
l
Choi,
M., K. Tatematsu, G. Park, and M. Kang [2007], "Ammonia Imaging of the
Disks in the NGC 1333 IRAS 4A Protobinary System," Astrophys. J.
(Letters), vol.667, pp.L183-L186.
Ø
The NGC
1333 IRAS 4A protobinary was observed in the ammonia (2, 2) and (3, 3) lines
and in the 1.3 cm continuum with a high resolution (about 1.0"). The
ammonia maps show two compact sources, one for each protostar, and they are
probably protostellar accretion disks. The disk associated with IRAS 4A2 is seen
nearly edge-on and shows an indication of rotation. The A2 disk is brighter in
the ammonia lines but dimmer in the dust continuum than its sibling disk, with
the ammonia-to-dust flux ratios different by about an order of magnitude. This
difference suggests that the twin disks have surprisingly dissimilar
characters, one gas-rich and the other dusty. The A2 disk may be unusually
active or hot, as indicated by its association with water vapor masers. The
existence of two very dissimilar disks in a binary system suggests that the
formation process of multiple systems has a controlling agent lacking in the
isolated star formation process and that stars belonging to a multiple system
do not necessarily evolve in phase with each other.
l
Deguchi,
S., J. Nakashima, and
Ø
The
bipolar nebula IRAS 19312+1950 is a unique SiO maser source exhibiting both
properties of young and evolved objects. To clarify the nature of this object,
we made molecular line observations with the Nobeyama 45-m radio telescope. We
detected emission from O-bearing (HCO+, SiO, SO, and SO2),
C- and N-bearing molecules (CN, CS, HCN, HNC, NH3, N2H+,
CH3N, H2CS, and CH3OH), and their isotopic
species (C17O, 13C18O, and C34S).
The line profiles consist of weak broad (¢~
30 kms-1) and/or strong narrow (¢<=
5 kms-1) components, depending on the molecular species. Strong time
variations of H2O and SiO masers were also observed. Numerical
modeling of the envelope with the LVG-code resulted in a good fit of the model
with a mass loss rate of 2.6 x 10-4 M⦿yr-1 to
the observed intensities for the broad-component lines. On the other hand,
non-O-bearing molecules, which only have narrow profiles, were found to have
abundances typical of those in cool dust clouds. No isotopic enrichment was
found, indicating little evidence of the narrow cool component being ejecta of
the central AGB star or a possible companion. These facts compelled us to
conclude that IRAS 19312+1950 is an exotic mass-losing evolved star embedded in
a low-mass (~ 20M⦿) dark cloud.
l
Deguchi,
S., N. Matsunaga, and H. Fukushi [2005a], "Detection of SiO Maser Emission
in V838 Mon," Publ. Astron. Soc. Japan, vol.57, pp.L25-L28.
Ø
We
report on the detection of 43GHz SiO maser emission in V838 Mon, a prototype of
a new class of eruptive variables, in which a red supergiant was formed after a
nova-like eruption in 2002. The detection of SiO masers indicates that the star
formed after the eruption is indeed a kind of cool mass-losing object with
circumstellar masers. The measured radial velocity and the intensity of maser
emission are consistent with the object being located at a distance of about
7kpc from the sun. It also suggests that a considerable percentage of SiO
masing objects in the Galaxy are formed by the same mechanism as that which
created V838 Mon.
l
Deguchi,
S., J. Nakashima, T. Miyata, and Y. Ita [2005b], "Observations of Stellar
Maser Sources with No IRAS Counterpart," Publ. Astron. Soc. Japan, vol.57,
pp.933-949.
Ø
We
investigated stellar maser sources with no IRAS counterpart at the radio,
middle-infrared, and near-infrared wavelengths. A 43GHz SiO maser search for
120 2MASS/MSX objects, and 10 OH 1612MHz sources with no or a very faint MSX
counterpart, resulted in 43 SiO detections: one OH 1612MHz source, 2
near-infrared stars, and 40 MSX sources. Additional near-infrared J-, H-, and
K-band observations of the OH 1612MHz sources detected 5 near-infrared
counterparts. Furthermore, middle-infrared imaging observations at 8.8, 9.7,
12.4, and 24.5mum with the Subaru 8.2-m telescope found counterparts for 2
near-infrared stars with SiO masers, and counterparts for 6 OH 1612MHz sources.
However, 4 OH 1612MHz sources were not detected in the sensitive near- and
middle-infrared searches; three of these are relatively strong OH maser sources
for which the positions were known accurately. We conclude that one of these
(OH 028.286i-01.801) must be a young object in a star-forming region.
l
Deguchi,
S., A. Miyazaki, and Y. Chol Minh [2006], "HOCO+ toward the
Ø
We have
identified a weak thermal line, U42.767, which has been detected only in the
directions toward Sgr A and Sgr B2, as the HOCO+ 202-101
transition. Because of the proximity of this line to the SiO maser line at
42.821 GHz ( J=1-0 v=2), it was observable simultaneously in ~ 43 GHz SiO maser
searches at Nobeyama. From the past data of SiO maser surveys of infrared
objects in the Galactic center, we created a map of emission distribution of
HOCO+ in the Sgr A molecular cloud as well as maps of the 29SiO
J = 1-0 v = 0 thermal emission and H53æ emission. The emission distribution of
HOCO+ was quite similar to that of 29SiO emission. This
suggests that an enhancement of the HOCO+ abundance in the galactic
center is induced by shock activities,which release CO2 molecules
frozen on grains into gases.
l
Deguchi,
S., J. Nakashima, N. Koning, and
Ø
Some
stellar maser sources at preplanetary stage have very thick circumstellar
envelopes, for which no near-infrared identifications have been made. We
investigated such stars at radio/NIR/MIR wavelengths using the NRO 45-m, ANU
2.2-m, UH 2.2-m, and SUBARU 8.2-m telescopes. Furthermore, using the Spitzer/Glimpse
survey of the Galactic plane, we found counterparts in the 3.6 micron band for
all of the OH/IR objects without previous NIR identification. One of the most
interesting objects among these is IRAS 18450-0148 (W43A) with collimated
outflows. Their spectra indicate that they have massive thick disks.
l
Deguchi,
S., T. Fujii, Y. Ita, H. Imai, H. Izumiura, O. Kameya, N. Matsunaga, A.
Miyazaki, A. Mizutani, Y. Nakada, J. Nakashima, and A. Winnberg [2007b],
"An SiO Maser Search off the Galactic Plane," Publ. Astron. Soc.
Japan, vol.59, pp.559-587.
Ø
We
searched for the SiO J=1-0 v= 1 and 2 maser lines at ~ 43 GHz in 277
2MASS/MSX/IRAS sources off the Galactic plane (|b|> 3), which resulted in
119 (112 new) detections. Among the new detections, are two very faint objects
with MSX 12 Źm flux densities below 2 Jy. These are likely to be O-rich
AGB-stars associated with dwarf-galaxy tidal tails. The sample also includes
medium bright MSX objects at moderately high Galactic latitudes
(3<|b|<5) and in the IRAS gap at higher latitudes. A signature of a
warp of the inner Galactic disk is found for a disk subsample. This warp
appears relatively strongly in the area of 0<l<45 and 3<|b|<5.
We also found a group of stars that does not follow to the Galactic rotation. This
feature appears in the Galactic disk at l~ 27, and extends more than 15 in
Galactic latitude, like a stream of tidal debris from a dwarf galaxy.
l
Deguchi,
S., N. Matsunaga, and H. Fukushi [2007c], "SiO Maser Emission in V838
Mon," Proc. of the "The Nature of V838 Mon and its Light Echo",
eds. R. L. M. Corradi and U. Munari, ASP Conf. Ser. vol.363, pp.81-86.
Ø
We
present further radio observations of V838 Mon in the SiO and several other
molecular lines after 2005 April. The detection of SiO masers in this object
indicates that the star formed after eruption is indeed a cool mass-losing
object with circumstellar masers. Further observations of SiO masers found a
sudden increase within a few months and succeeding flattening of maser
intensities, suggesting a sudden slow onset of mass-loss from the central star
after the 2002 eruption. A detection of CO emission 30" north of the star
is also reported. A possible implication for stellar evolution in related
objects is given.
l
Deguchi,
S., J. Nakashima, S. Kwok, and
Ø
Using
the 3.6, 4.5, 5.8, and 8.0 mum images with 1.2" pixel resolution of the Spitzer/GLIMPSE
survey, we investigated 23 masing and 18 very red objects, which are extremely
faint in the near-infrared bands. We found the counterpart for all of the
selected objects on the GLIMPSE images. Color indices in these IR bands suggest
the presence of a high-extinction layer of more than a few tenths of a solar
mass in front of the central star. Furthermore, radio observations in the SiO
and H2O maser lines found characteristic maser-line spectra of the
embedded objects, e.g., the SiO J=1-0 line intensity in the v=2 state is
stronger than that of the v=1 state, or very thick circumstellar matter, some
of which cannot be ascribed to the AGB wind of the central star. Individually
interesting objects are discussed, including two newly found water fountains
and an SiO source accompanying a nebulosity.
l
DeLuca,
E. E., M. A. Weber, A. L. Sette, L. Golub, K. Shibasaki, T. Sakao, and R. Kano
[2005], "Science of the X-Ray Sun: The X-Ray Telescope on Solar-B,"
Adv. Sp. Res., vol.36, pp.1489-1493.
Ø
The
X-Ray Telescope (XRT) on Solar-B is designed to provide high resolution, high
cadence observations of the X-ray corona through a wide range of filters. The
XRT science team has identified four general problems in coronal physics as the
primary science goals for our instrument. Each of these goals will require
collaborative observations from the other Solar-B instruments: EUV Imaging
Spectrograph (EIS) and Solar Optical Telescope Focal Plane Package (SOT). We
will discuss the science goals and observations needed to address those goals.
l
Dobashi,
K., H. Uehara, R. Kandori, T. Sakurai, M. Kaiden, T. Umemoto, and F. Sato
[2005], "Atlas and Catalog of Dark Cluds Based on Digitized Sky Survey
I," Publ. Astron. Soc. Japan, vol.57, S1-S386.
Ø
We
present a quantitative atlas and catalog of dark clouds derived by using the
optical database gDigitized Sky Survey I''. Applying a traditional star-count
technique to 1043 plates contained in the database, we produced an AV map
covering the entire region in the galactic latitude range |b|≤40. The map was
drawn at two different angular resolutions of 6' and 18', and is shown in
detail in a series of figures in this paper. Based on the AV map, we identified
2448 dark clouds and 2841 clumps located inside them. Some physical parameters,
such as the position, extent, and optical extinction, were measured for each of
the clouds and clumps. We also searched for counterparts among already known
dark clouds in the literature. The catalog of dark clouds presented in this
paper lists the cloud parameters as well as the counterparts.
l
Dobashi,
K., H. Uehara, R. Kandori, T. Sakurai, M. Kaiden, T. Umemoto, and F. Sato
[2007], "Atlas and Catalog Dark Clouds Based on Digitized Sky Survey
I," Proceedings in "Protostars and Planets V", LPI contribution
no. 1286, p.8137.
Ø
Not
Available
l
Doi, A.,
S. Kameno, and M. Inoue [2005a], "Radio Spectra of the Low-Luminosity
Active Galactic Nucleus NGC 266 at Centimetre-to-Submillimetre
Wavelengths," Mon. Not. R. Astron. Soc., vol.360, pp.119-124.
Ø
We
report multi-frequency and multi-epoch radio continuum observations with
multi-spatial resolution for the low-luminosity active galactic nucleus (LLAGN)
NGC 266. In the centimetre regime, we find diffuse components with Very Large
Array (VLA) observations, and a variable compact core with a rising spectrum
with Very Long Baseline Array (VLBA) observations. Although the spectral index
of the rising spectrum is consistent with the prediction of the simple
advection-dominated accretion flow (ADAF) model, the observed radio power is
slightly high compared with that of the model prediction. A spectral break at
centimetre-to-millimetre wavelengths is inferred from the upper limits of flux
densities from Nobeyama Millimetre Array (NMA) and James Clerk Maxwell
Telescope (JCMT) data at millimetre and submillimetre wavelengths,
respectively. More complicated considerations are required for the theoretical
model to interpret such observed radio properties.
l
Doi, A.,
Ø
We
investigate the high-frequency radio spectra of 20 low-luminosity active
galactic nuclei (LLAGNs) with compact radio cores. Our millimetre survey with
the Nobeyama Millimetre Array (NMA) and analyses of submillimetre archival data
that had been obtained with the Submillimetre Common User Bolometer Array
(SCUBA) on the James Clerk Maxwell Telescope (JCMT) reveal the following
properties. At least half of the LLAGNs show inverted spectra between 15 and 96
GHz; we use the published data at 15 GHz with the Very Large Array (VLA) in a
0.15-arcsec resolution and our measurements at 96 GHz with the NMA in a
7-arcsec resolution. The inverted spectra are not artificially made due to
their unmatched beam sizes, because of little diffuse contamination from dust,
HII regions, or extended jets in these LLAGNs. Such high-frequency inverted
spectra are apparently consistent with a `submillimetre bump', which is predicted
by an advection-dominated accretion flow (ADAF) model. We find a strong
correlation between the high-frequency spectral index and low-frequency core
power measured with very-long-baseline-interferometry (VLBI) instruments. The
inverted spectra are found exclusively in low-core-power sources, while steep
spectra are in high-core-power ones with prominent pc-scale jets. This suggests
that the ADAF and non-thermal jets may coexist. The flux ratios between disc
and jet seem to be different from LLAGN to LLAGN; disc components can be seen
in nuclear radio spectra only if the jets are faint.
l
Doi, A.,
K. Fujisawa, A. Habe, M. Honma, N. Kawaguchi, H. Kobayashi, Y. Murata, T.
Omodaka, H. Sudou, and H. Takaba [2006a], "Bigradient Phase
Referencing," Publ. Astron. Soc. Japan, vol.58, pp.777-785.
Ø
We
propose bigradient phase referencing (BPR), a new radio-observation technique,
and report on its performance using the Japanese
vely-long-basline-interferometry network (JVN). In this methods, a weak source
is detected by phase-referencing using a primary calibrator, in order to play a
role as a secondary calibrator for phasa-referencing to a weal target. We will
be given the opportunity to select a calibrator from of milli-Jansky sources,
one of which may be located at a position closer to the target. With such a
smaller separation, high-quality phase-referencing can be achieved. A
subsequent more-sophisticated calibration can relocate the array's focus to a
hypothetical point much closer to the target; a higher quality of phase
referencing is available. Our demonstrative observations with strong radio
sources have proved the capabilities of the BPR in terms of the image dynamic
ranges and astrometric reproducibility. The image dynamic range on a target has
been improved by a factor of about six compared to that of normal
phase-referencing; the resultant position difference of the target's emission
between two epochs was only 62}50 miroarcsecond, even with less than 2300-km
baselines at 8.4 GHz and fast-switching between a target-calibrator pair
separated by 2. 1.
l
Doi, A.,
H. Nagai, K. Asada, S. Kameno, K. Wajima, and M. Inoue [2006b], "VLBI
Observations of the Most Radio-Loud, Narrow-Line Quasar SDSS
J094857.3+002225," Publ. Astron. Soc. Japan, vol.58, pp.829-834.
Ø
We observed
the narrow-line quasar SDSS J094857.3+002225, which is known to have the
highest radio loudness in the narrow-line Seyfert 1 galaxies (NLS1s), at
1.7-15.4 GHz with the Very Long Baseline Array (VLBA). This is the first
very-long-baseline interferometry (VLBI) investigation of a radio-loud NLS1. We
independently discovered (1) very high brightness temperatures from its
compactness in a VLBA image and (2) flux variation among the VLBA observation
and our other observations with the VLBA and the Very Large Array (VLA). A
Doppler factor larger than 2.7-5.5 was required to meet an intrinsic limit of
brightness temperature in the rest frame. This is evidence for highly
relativistic nonthermal jets in an NLS1. We suggest that the Doppler factor is
one of the most important parameters in the determination of the radio loudness
of NLS1s. The accretion disk of SDSS J094857.3+002225 is probably in a very
high state, rather than the high/soft state, by analog with X-ray binaries with
strong radio outbursts and superluminal jets, such as GRS 19156105.
l
Doi, A.,
S. Kameno, and M. Inoue [2006c], "Radio Spectra and Radio-Loudness of
Low-Luminosity AGNs," J. Physics: Conference Series, vol.54, pp.335-341.
Ø
We
investigated the empirical relation between black hole mass (mBH),
Eddington ratio (Lbol/LEdd), and radio loudness (RRL a
ratio of radio to optical luminosity) of nearby low-luminosity active galactic
nuclei (LLAGNs). A best-fit plane was found in the three-dimensional space
using a sample of 48 nearby LLAGNs: RRL = mBH0.52}0.14(Lbol/LEdd)
-0.39}0.08. This suggests that spectral energy distributions of LLAGNs
are controlled by both the black hole mass and accretion rate.
l
Doi, A.,
K. Fujisawa, M. Inoue, K. Wajima, H. Nagai, K. Harada, K. Suematsu, A. Habe, M.
Honma, N. Kawaguchi, F. Kawai, H. Kobayashi, Y. Koyama, H. Kuboki, Y. Murata,
T. Omodaka, K. Sorai, H. Sudou, H. Takaba, K. Takashima, K. Takeda, S. Tamura,
and K. Wakamatsu [2007], "Japanese VLBI Network Observations of Radio-Loud
Narrow-Line Seyfert 1 Galaxies," Publ. Astron. Soc. Japan, vol.59,
pp.703-709.
Ø
We
performed phase-reference very long baseline interferometry (VLBI) observations
on five radio-loud narrow-line Seyfert 1 galaxies (NLS1s) at 8.4 GHz with the
Japanese VLBI Network (JVN). Each of the five targets (RXS J08066+7248, RXS
J16290+4007, RXS J16333+4718, RXS J16446+2619, and B3 1702+457) in milli-Jansky
levels were detected and unresolved in milli-arcsecond resolutions, i.e., with
brightness temperatures higher than 107 K. The nonthermal processes of active
galactic nuclei (AGN) activity, rather than starbursts, are predominantly
responsible for the radio emissions from these NLS1s. Out of the nine known
radio-loud NLS1s, including the ones chosen for this study, we found that the
four most radio-loud objects exclusively have inverted spectra. This suggests a
possibility that these NLS1s are radio-loud due to Doppler beaming, which can
apparently enhance both the radio power and the spectral frequency.
l
Egusa,
F., Y. Sofue, and H. Nakanishi [2004], "Offsets between Hæ and CO Arms of
a Spiral Galaxy, NGC 4254: A New Method for Determining the Pattern Speed of
Spiral Galaxies," Publ. Astron. Soc. Japan, vol.56, pp.L45-L48.
Ø
We
examined the offsets between H II regions and molecular clouds belonging to
spiral arms of a late-type spiral galaxy, NGC 4254 (M99). We used a
high-resolution 12CO (J = 1-0) image obtained by Nobeyama Millimeter
Array (NMA) and an Hæ image. We derived angular offsets (Ę) in the galactic
disk, and found that they show a linear dependence on the angular rotation
velocity of the gas (¶G). This linear relation can be expressed by
the equation Ę = (¶G - ¶P) tHæ, where ¶P
and tHæ are constant. Here, ¶P corresponds to the pattern
speed of the spiral arms and tHæ is interpreted as being the
timescale between the peak compression of the molecular gas in the spiral arms
and the peak of massive star formation. We could thus determine ¶P
and tHæ simultaneously by fitting a line to our Ę-G plot, if we
assume they are constant. From the plot for NGC4254, we obtained tHæ
= (4.8}1.2) x 106 yr and ¶P = 26+10-6
km s-1 kpc-1, which are consistent with previous studies.
We suggest that this Ę-¶G plot can be a new tool to determine the
pattern speed and the typical timescale needed for star formations.
l
Egusa,
F., Y. Sofue, and H. Nakanishi [2006], "Determination of Star Formation
Timescale and Pattern Speed of Spiral Galaxies," International
Astronomical Union XXVIth General Assembly, Pragua, 14-25 August, 2006,
abstract book, p.123 (S237-106 Poster).
Ø
We
developed a method to determine the star formation timescale and pattern speed
in spiral galaxies. Though they are important and fundamental parameters, it
has been difficult to derive their value directly from observations. Our method
utilizes azimuthal offsets between arms of HII regions and molecular clouds for
the determination. Assuming a circular rotation, a plot of offsets versus
angular rotation velocities should be fitted with a line, whose gradient is
star formation timescale and abscissa intercept is pattern speed. We have
succeeded in deriving these two parameters for three nearby spiral galaxies so
far, by the use of CO and H-alpha images from the literatures. Results are
listed in Table 1. The derived values of pattern speed are of course different
for galaxies, star formation timescales, however, fall into a narrow range:
about 4 to 7 Myr. since this value is consistent to a typical teimscale for
molecular clouds to collapse gravitationally, global star formation in spiral
arms might be mainly triggered by the gravitational collapse of molecular gas.
l
Endo,
A., K. Kohno, B. Hatsukade, K. Ohta, N. Kawai, Y. Sofue, K. Nakanishi, T.
Tosaki, B. Vila-Vilaro, N. Kuno, T. Okuda, and K. Muraoka [2007], "A
Revised Estimated of the CO (J=1-0) Emission from the Host Galaxy of GRB 030329
Using the Nobeyama Millimeter Array," Astrophys. J., vol.659,
pp.1431-1437.
Ø
A
sensitive observation of the CO J=1-0 molecular line emission in the host
galaxy of GRB 030329 (z=0.1685) has been performed using the Nobeyama
Millimeter Array to detect molecular gas and hidden star formation. No sign of
CO emission was found, which invalidates our previous report of the presence of
molecular gas. The 3Š upper limit on the CO line luminosity (L'CO)
of the host galaxy is 6.9x108 K km s-1 pc2.
The lower limit to the host galaxy's metallicity is estimated to be
12+log(O/H)~7.9, which yields a conversion factor from CO line luminosity to H2
of æCO=40 Msolar (K km s-1 pc2)-1.
Assuming this factor, the 3Šupper limit on the molecular gas mass of the host
galaxy is 2.8x1010 Msolar. Based on the Schmidt law, the
3 sigma upper limit on the total star formation rate (SFR) of the host galaxy
is estimated to be 38 Msolar yr-1. These results
independently confirm inferences from previous observations in the optical,
submillimeter, and X-ray bands, which regard this host galaxy as a compact
dwarf and not a massive, aggressively star-forming galaxy. Finally, the SFRs of
GRB host galaxies, estimated using various techniques immune to dust
obscuration, including our CO luminosity measurements, are compared with the
SFRs of the same galaxies estimated using extinction-corrected optical/UV
tracers. We show that most of the SFRs measured in extinction-free wavelengths,
including positive detections and upper limits, are larger by from 1 to a few
orders of magnitude compared with the SFRs of the same galaxies measured by
optical/UV tracers.
l
Ezawa,
H., and the ASTE team [2005a], "Progress and Current Status of the Atacama
Submillimeter Telescope Experiment (ASTE)," Proc. of the 9th Asian-Pacific
Regional IAU Meeting, pp.278-279.
Ø
The
Atacama Submillimeter Telescope Experiment (ASTE) is a project to operate a 10
m submillimeter telescope at the high altitude site in the Atacama desert of
northern
l
Ezawa,
H., R. Kawabe, K. Kohno, S. Yamamoto, and the ASTE team [2005b], "ASTE:
The Atacama Submillimeter Telescope Experiment," Proc. at the XXVIIIth
General Assembly of the URSI, October 2005,
Ø
Not
Available
l
Fujii,
T., S. Deguchi, Y. Ita, H. Izumiura, O. Kameya, A. Miyazaki, and Y. Nakada
[2006], "SiO Maser Survey of the Inner Bar of the Galactic Bulge,"
Publ. Astron. Soc. Japan, vol.58, pp.529-561.
Ø
We
surveyed 291 MSX/2MASS infrared objects in the 7x 2 area of the galactic
center in the 43GHz SiO J = 1-0 Ė = 1 and 2 mass lines, obtaining accurate
radial velocities of 163 detected objects. The surveyed area is the region
where the IRAS catalog is incomplete due to contamination by high source
density. The objects in the present MSX/2MASS sample were chosen to have similar
infrared characteristics to those of the previous SiO-maser-survey samples
based on the color-selected IRAS sources. The sampling based on the 2MASS
catalog causes a bias to the foreside objects of the bulge due to heavy
obscuration by interstellar dust; the detections considerably leaned on the Vlsr
< 0 side. The l=V diagram reveals two conspicuous feature, which were not present or
tenuous with |l| < 1.5, which is likely to be associated with the inner
bar, and the other feature having considerably eccentric velocities, more then
those of the normal x1 -orbit family feature. The
extinction-corrected K magnitudes (if used as a distance modulus) tend to show
a sequential deposition of these objects along the line of sight toward the
galactic center, depending on their radial velocities. The tendency that
appeared in the distance measures is consistent with the bulge-bar dynamical
model utilizing the periodic orbit families in the bar potential.
l
Fukushi,
H., N. Matsunaga, T. Tanabe, Y. Nakada, S. Deguchi, A. Ishihara, N. Kusakabe,
M. Tamura, and IRSF/SIRPOL team [2007], "Near-IR Scattered Light in V838
Monocerotis," Proc. of the "The Nature of V838 Mon and its Light
Echo", eds. R. L. M. Corradi and U. Munari, ASP Conf. Ser. vol.363, pp.181-183.
Ø
A J-band
polarimetric image was taken for V838 Monocerotis with the imaging polarimeter
SIRPOL on the IRSF 1.4-m telescope at the South African Astronomical
Observatory. A diffuse nebulosity is seen in the north-east and the south-west
directions of the central star in the PI image. The polarization vectors reveal
a circular feature indicating that the nebulous light is the scattered light
from the central star. The polarization degree reaches up to 40-percent in the
outer part of the nebula.
l
Furuya,
R. S., R. Cesaroni, S. Takahashi, M. Momose, L. Testi, H. Shinnnaga, and C.
Codella [2005a], "Relative Evolutionary Timescale of Hot Molecular Cores
with Respect to Ultracompact HII Regions," Astrophys. J., vol.624,
pp.827-831.
Ø
Using
the
l
Furuya,
R. S., Y. Kitamura, A. Wootten, M. J. Claussen, and R. Kawabe [2005b],
"Proper Motion of H2O Masers in IRAS 20050+2720 MMS1: an AU
Scale Jet Associated with an Intermediate-Mass Class 0 Source," Astron.
Astrophys., vol.438, pp.571-583.
Ø
We
conducted a 4 epoch, 3 month, VLBA proper motion study of H2O masers
toward an intermediate-mass class 0 source IRAS 20050+2720 MMS1 (d = 700 pc).
The region of IRAS 20050+2720 contains at least 3 bright young stellar objects
at millimeter to submillimeter wavelengths and shows three pairs of CO outflow
lobes: the brightest source MMS1, which shows an extremely high velocity (EHV)
wing emission, is believed to drive the outflow(s). From milli-arcsecond (mas)
resolution VLBA images, we found two groups of H2O maser spots at
the center of the submillimeter core of MMS1. One group consists of more than ~
50 intense maser spots; the other group consisting of several weaker maser
spots is located at 18 AU south-west of the intense group. Distribution of the
maser spots in the intense group shows an arc-shaped structure which includes
the maser spots that showed a clear velocity gradient. The spatial and velocity
structures of the maser spots in the arc-shape did not significantly change
through the 4 epochs. Furthermore, we found a relative proper motion between
the two groups. Their projected separation increased by 1.13}0.11 mas over the
4 epochs along a line connecting them (corresponding to a transverse velocity
of 14.4 km s-1). The spatial and velocity structures of the intense
group and the relative proper motions strongly suggest that the maser emission
is associated with a protostellar jet. Comparing the observed LSR velocities
with calculated radial velocities from a simple biconical jet model, we
conclude that the most of the maser emission is likely to be associated with an
accelerating biconical jet that has large opening angle of about 70. The large
opening angle of the jet traced by the maser would support the hypothesis that
poor collimation is an inherent property of luminous (proto)stars.
l
Furuya,
R. S., Y. Kitamura, and H. Shinnaga [2006], "The Initial Conditions for
Gravitational Collapse of a Core: An Extremely Young Low-Mass Class 0 Protostar
GF 9-2," Astrophys. J., vol.653, pp.1369-1390.
Ø
We
present a study of the natal core harboring the low-mass Class 0 protostar GF
9-2 in the filamentary dark cloud GF 9 using the Nobeyama 45 m and CSO 10.4 m
telescopes and the OVRO millimeter array. GF 9-2 is unique in the sense that it
show H2O masers, a clear signpost of protostar formation, but dose
not have a high-velocity large-scale outflow. These facts indicate that the GF
9-2 core is early enough after star formation that it still retains some
information of initial conditions for collapse. Our 350 mum dust continuum
image identified a protostellar envelope with an extent of ≅5400 AU in the center of the molecular
core ≅0.08 pc
in size. The envelope mass is estimated to be ≅0.6 Msolar from the 350 mum flux density, while the
LTE mass of the core is ≅3 Msolar from molecular line. We found that the
core has a radial density profile of rho(r)~r-2 for the 0.003
<~r/pc<~0.08 region and that the velocity width of the core gas increases
inward, while the outermost region maintains a velocity dispersion of a few
times the ambient sound speed. If we interpret the broadened velocity width as
infall, the core collapse can be well described by an extension of the
Larson-Penston solution for the period after formation of a central star. We
derived the mass accretion rate of ≅3 x 10-5 Msolar yr-1 from
infall velocity of ≅0.3 km s-1 at r 7000 AU. Furthermore, we found
evidence that a protobinary is being formed at the core center. All of the results
suggest that the GF 9-2 core has been undergoing gravitational collapse for
<~5000 yr since the protostar formation and that the unstable state
unitiated the collapse ≅2 x 105 yr (the free-fall time) ago.
l
Gelfreikh,
G. B., K. Shibasaki, E. Yu. Nagovitsyna, andYu. A. Nagovitsyn [2004],
"Analysis of Quasi-Periodic Oscillations of Position and Brightness of
Details of the Radio Sources of the Solar Active Regions Based on Observations
Made with the Radio Heliograph Nobeyama," Proc. of the IAU Symp. 223,
"Multi-Wavelength Investigations of Solar Activity", eds. A. V. Stepanov, E. E. Benevolenskaya, and
A. G. Kosovivhev, pp.245-246.
Ø
As based
on analysis of radio maps at the wavelength of 1.76 cm obtained from
observations at the radio heliograph Nobeyama the parameters of oscillation
processes in solar active regions were studied. As a technique for data
processing wavelet analysis was used. The inherent periodicity in oscillations
submits the existence of a resonance structure for some kinds of MHD waves in
the plasma of the solar atmosphere.
l
Golub,
L., E. DeLuca, G. Austin, J. Bookbinder, D. Caldwell, P. Cheimets, J. Cirtain,
M. Cosmo, P. Reid, A. Sette, M. Weber, T. Sakao, R. Kano, K. Shibasaki, H.
Hara, S. Tsuneta, K. Kumagai, T. Tamura, M. Shimojo, J. McCracken, J.
Carpenter, H. Haight, R. Siler, E. Wright, J. Tucker, H. Rutledge, M. Barbera,
G. Peres, and S. Varisco [2007], "The X-Ray Telescope (XRT) for the Hinode
Mission," Solar Phys., vol.243, pp.63-86.
Ø
The
X-ray Telescope (XRT) of the Hinode mission provides an unprecedented
combination of spatial and temporal resolution in solar coronal studies. The
high sensitivity and broad dynamic range of XRT, coupled with the spacecraft's
onboard memory capacity and the planned downlink capability will permit a broad
range of coronal studies over an extended period of time, for targets ranging
from quiet Sun to X-flares. This paper discusses in detail the design,
calibration, and measured performance of the XRT instrument up to the focal
plane. The CCD camera and data handling are discussed separately in a companion
paper.
l
Grechnev,
V. V., A. M. Uralov, V. G. Zandanov, G. V. Rudenko, V. N. Borovik, I. V.
Grigorieva, V. A. Slemzin, S. A. Bogachev, S. V. Kuzin, I. A. Zhitnik, A. A.
Pertsov, K. Shibasaki, and M. A. Livshits [2006a], "Plasma Parameters in a
post-Eruptive Arcade Observed with CORONAS-F/SPIRIT, Yohkoh/SXT, SOHO/EIT, and
in Microwaves," Publ. Astron. Soc. Japan, vol.58, pp.55-68.
Ø
The SPectroheliographIc
X-Ray Imaging Telescope (SPIRIT) aboard the CORONAS-F spacecraft sometimes
observes in the Mg XII 8.42Å line (Tmax ~ 9 MK) large, bright
features existing for many hours high in the corona. This fact suggests that
plasma beta there might not be small. We identify such a feature observed on
2001 October 22 at a height of 100Mm with a hot part of a post-eruptive arcade.
Using multi-spectral data and radio astronomy methods, we estimate the plasma
parameters in the arcade and reveal the coronal magnetic configuration. Several
hours after the eruption, the temperature in the arcade was 6-8MK, and the
plasma density was (5-10) \cdot 109 cm-3. We confirm the
results by the accord of the quantities obtained from different observations
using different methods and by the extrapolation of the photospheric
magnetograms into the corona, from which we have obtained a magnetic field
strength of about 7G at that height. Hence, indeed beta ≥ 1 in the
post-eruptive arcade. The high-beta possibility had previously been stated,
e.g., by Ichimoto et al. (1994), but still not investigated. We address this
issue in terms of the gstandard flare modelh elaborated by Shibata and
Yokoyama. During this event, Yohkoh/SXT observed McKenzie-Hudson dark moving
features. Those features are filled with cold material, if they are not empty,
and may affect the arcade.
l
Grechnev,
V. V., A. M. Uralov, V. G. Zandanov, N. Y. Baranov, and K. Shibasaki [2006b],
"Observations of Prominence Eruptions with Two Radioheliographs, SSRT, and
NoRH," Publ. Astron. Soc. Japan, vol.58, pp.69-84.
Ø
We
address simultaneous observations of eruptive prominences with two
radioheliographs, SSRT at 5.7GHz and NoRH at 17 and 34GHz. Three events are
presented: 1997 September 27, 2000 September 4, and 2001 January 14. We analyze
them using images observed in microwaves, Halpha, images from Extreme
ultraviolet Imaging Telescope on board Solar and Heliospheric Observatory
(SOHO), and white-light images from Large Angle and Spectrometric Coronagraph
(SOHO/LASCO). We address three stages of the eruptive process: 1) pre-eruptive
ascent, 2) rapid acceleration, 3) free expansion, and the overall kinematics of
the ejecta. We estimate the densities and kinetic temperatures of prominences,
and also the velocities and accelerations of ejecta. The main body of a
prominence is surrounded by low-density cool extensions mixed with the coronal
plasma, but the transition from the cool prominence to the hot plasma is sharp.
From microwave and LASCO observations with overlapping fields of view we
identify a radio prominence and a core of a coronal mass ejection (CME). Their
temperature remains at about 5000K, while the brightenings observed in extreme
ultraviolet are probably due to only skin-heating. We discuss the observations
in terms of our Dual-Filament CME initiation model.
l
Haba,
A., S. Kameno, S. Sawada-Satoh, and N. Sato [2004], "The H2O
Maser from the AGN of NGC 1052," Proc. of the 7th symposium of the
European VLBI Network on New Developments in VLBI Sciences and Technology, eds.
R. Bachiller, F. Colomer, J.-F. Desmurs, and P. de Vicente, pp.153-154.
Ø
We
report observations of H2O maser emission from the AGN of NGC 1052.
The velocity range of the maser emission is 1450 ≤ VLSR
≤ 1850 km s-1, the most redshifted ever seen from this
source. We detected a narrow component with a FWHM of 21 km s-1 in
the maser spectrum profile for the first time. The peak flux density of the
narrow feature is 47 mJy at VLSR = 1787 km s-1. Over a
short time interval of 3 x 105 sec, the peak flux density and the
velocity width of the narrow feature appeared to change by 16 } 9% and -30 }
12%, respectively, with the peak flux density of the continuum emission
simultaneously varying by 21 %. We assume that the new narrow component is located
within 0.05 pc of the AGN. The increasing of the peak flux density and the
narrowing of the velocity width of the narrow component imply an increase in
the gain of the maser through the excited molecular cloud. Since the continuum
and the narrow components brightened simultaneously, the continuum are regarded
as the seed photon of the maser, running behind the excited molecular gas. The
masers are generated through the XDR where the knots of the continuum jet are
amplified. Another possible interpretation is the interaction between the jet
from the AGN and the molecular gas.
l
Hachisuka,
K., A. Brunthaler, Y. Hagiwara, M. K. Menten, H. Imai, M. Miyoshi, and T. Sasao
[2004], "Distance of W3(OH) by VLBI Annual Parallax Measurement,"
Proc. of the 7th symposium of the European VLBI Network on New Developments in
VLBI Sciences and Technology, eds. R. Bachiller, F. Colomer, J.-F. Desmurs, and
P. de Vicente, pp.317-320.
Ø
The most
powerful tool for measuring distances within our Galaxy is the annual parallax.
We carried out phase-referencing VLBI observations of H2O masers in
the star forming region W3(OH) with respect to the extragalactic continuum
source ICRF 0244+624 to measure their absolute proper motions. The measured
annual parallax is 0.484 } 0.004 milli-arcseconds which corresponds to a
distance of 2.07+0.01-0.02 kpc from the sun. This
distance is consistent with photometric and kinematic distances from previous
observations.
l
Hachisuka,
K., N. Mochizuki, Y. Asaki, M. Miyoshi, and S. Horiuchi [2005], "Towards
an Understanding of the Dynamics of the Milky Way," Proc. of the
"Future Directions in High Resolution Astronomy: A Celebration of the 10th
Anniversary of the VLBA", eds. J. D. Romney, and M. J. Reid, ASP Conf.
Ser. vol.340, p.520.
Ø
We
report on the proper motions of Galactic water masers relative to an adjacent
extragalactic continuum source measured by VLBA multi-epoch phase referencing
observations for two interstellar regions. We estimated the distance to these
Galactic maser sources by their proper motions. The distance to W3(OH) are 2.05
} 0.23 and 2.26 } 0.09 kpc by annual parallax of each maser feature, and IRAS
21008+4700 is 5.26 kpc by the rms deviation from the least squares method
fitting for its proper motion. These results provide us a first step of an
understanding of the dynamics of the Milky Way.
l
Hachisuka,
K., A. Brunthaler, K. M. Menten, M. J. Reid, H. Imai, Y. Hagiwara, M. Miyoshi,
S. Horiuchi, and T. Sasao [2006], "Water Maser Motions in W3(OH) and a
Determination of Its Distance," Astrophys. J., vol.645, pp.337-344.
Ø
We
report phas-referencing VLBA observations of H2O masers near the
star-forming region W3(OH) to measure their parallax and absolute proper
motions. The measured annual parallax is 0.489}0.017 mas (2.04}0.07 kpc), where
the error is dominated by a systematic atmospheric contribution. This distance
is consistent with photometric distances from previous observations and with
the distance determined from CH3OH maser astrometry presented in a
related paper. We also find that the source driving the H2O outflow,
the "TW-object," moves with a three-dimensional velocity of > 7 km
s-1 relative to the ultracompact HII region W3(OH).
l
Hagiwara,
Y., W. A. Baan, and P. Hofner [2007a], "HI and OH Absorption toward NGC
6240," New Astron. Rev., vol.51, pp.58-62.
Ø
We
present results of HI and OH absorption imaging of the merging galaxy of NGC
6240 using the very large array at 1 arcsec resolution. HI absorption is found
across the extended radio continuum structure with a significant concentration
towards the two nuclei, while the OH absorption is confined mostly between the
nuclei. The OH velocity gradients around the nuclei confirm earlier results of
radio molecular emission lines in defining the central gas peak between the
nuclei and the kinematics of the nuclear region. The HI velocity gradients
might trace remnants of the two interacting galaxies and the characteristics of
a symmetric superwind outflow. The absorbing gas provides a key to solve
kinematics of two merging galaxies.
l
Hagiwara,
Y. [2007b], "Low-Luminosity Extragalactic Water Masers toward M82, M51,
and NGC 4051," Astron. J., vol.133, pp.1176-1186.
Ø
Subarcsecond
observations using the Very Large Array (VLA) are presented for low-luminosity
H2O maser emission in M82, M51, and NGC 4051. New maser features
have been detected within the M82 starburst complex. They are largely
associated with star-forming activity such as optically identified
starburst-driven winds, HII regions, or the early phase of star formation in
the galaxy. The H2O maser M51 consists of blueshifted and redshifted
features relative to the systemic velocity of the galaxy. The redshifted
features are measured to the northwest of the nuclear radio source, while the
location of the blueshifted counterpart is displaced by ~2" from the radio
source. A small velocity gradient closely aligned with the radio jet is
detected from the redshifted features. The redshifted maser most likely
amplifies the background radio continuum jet, while the blueshifted counterpart
marks off-nuclear star formation in the galaxy. All of the detected maser
features in the narrow-line Seyfert 1 galaxy NGC 4051 remain unresolved by new
VLA observations. Due to the low luminosity of the maser. the maser excitation
is not directly related to the active galactic nucleus.
l
Hanada,
H., T. Iwata, N. Namiki, N. Kawano, K. Asari, T. Ishikawa, F. Kikuchi, Q. Liu,
K. Matsumoto, H. Noda, J. Ping, S. Tsuruta, K. Iwadate, O. Kameya, S. Kuji, Y.
Tamura, X. Hong, Y. Aili, and S. Ellingsen [2005a], "Gravimetric Missions
in Japanese Lunar Explorer, SELENE," Proc. at the XXVIIIth General
Assembly of the URSI, October 2005, India. (CD-ROM : J05-P.4)
Ø
SELENE
(SElenological and Engineering Explorer), is a mission preparation for launch
in 2007 by JAXA (Japan Aerospace Exploration Agency), it carried 15 emissions,
two of which (RSAT and VRAD) are gravimetric experiments using radio waves. The
RSAT (Relay Satellite Transponder) mission will undertake 4-way Doppler
measurements of the main orbiter through the Rstar sub-satellite. This is in
addition to 2-way Doppler and ranging measurements of the satellite and will
realize the first direct observation of the gravity fields on the far side of
the Moon. The VRAD (Differential VLBI Radio Source) emission involves observing
the trajectories of Rstar and Vstar using differential VLBI with both a
Japanese network (VERA), and an international network. We have already finished
development of the onboard instruments and are carrying out proto-flight tests
under various conditions. We have also performed test VLBI observations of
orbiters with the international network.
l
Hanada,
H., T. Iwata, N. Namiki, N. Kawano, K. Asari, T. Ishikawa, F. Kikuchi, Q. Liu,
K. Matsumoto, H. Noda, and S. Tsuruta [2005b], "Gravimetric Missions by
VLBI and Doppler in SELENE," American Geophysical Union, Fall Meeting,
abstract #G51A-0809.
Ø
SELENE
is a mission in preparation for launch in 2007 by JAXA (Japan Aerospace
Exploration Agency). It execute 15 experiments, two of which (RSAT and VRAD)
are gravimetric experiments using radio waves. RSAT (Relay Satellite
Transponder) mission will undertake 4-way Doppler measurements of the main
orbiter through the Rstar sub-satellite. This is in addition to 2-way Doppler
and ranging measurements of the satellites and will realize the first direct
observation of the gravity fields on the far side of the Moon. VRAD
(Differential VLBI Radio Source) mission involves observing the trajectories of
Rstar and Vstar sub-satellites using differential VLBI with both a Japanese
network (VERA), and an international network. We have already finished
development of the onboard instruments and are carrying out proto-flight tests
under various conditions. We have also performed test VLBI observations of
orbiters with the international network.
l
Handa,
T., M. Sakano, S. Naito, M. Hiramatsu, and M. Tsuboi [2006a], "Thermal SiO
and H13CO+ Line Observations of the Dense Molecular Cloud G0.11-0.11 in the
Ø
We
obtained the first view in H13CO+ J=1-0 and a
high-resolution map in thermal SiO lines of G0.11-0.11, which is a molecular
cloud situated between the
l
Handa,
T., M. Sakano, S. Naito, M. Hiramatsu, and M. Tsuboi [2006b], "An
Extremely Large Density Cloud G0.11-0.11 in the Galactic Center Region,"
J. Physics: Conference Series, vol.54, pp.47-51.
Ø
We
obtained the detail map in H13CO+ and in thermal SiO lines
of G0.11-0.11, which is a molecular cloud located between the Galactic Center
Arc and Sgr A. From line intensity rotios we found H13CO+
line is optically thin, whereas the thermal SiO lines are optically thick for
this cloud. The cloud has a large column density up to N(H2)=(6-7) x
1023 cm-2, which corresponds to about 640-740 mag in Av
or 10-12 mag in A25mum. This is the largest known even in the
l
Hatsukade,
B., K. Kohno, A. Endo, T. Tosaki, K. Ohta, S. Sakamoto, N. Kawai, J. R. Corets,
K. Nakanishi, T. Okuda, K. Muraoka, T. Sakai, P. M. Vreeswijk, H. Ezawa, N.
Yamaguvhi, K. Kamegai, and R. Kawabe [2007a], "A Search for CO (J = 3-2)
Emission from the Host Galaxy of GRB 980425 with the Atacama Submillimeter
Telescope Experiment," Publ. Astron. Soc. Japan, vol.59, pp.67-72.
Ø
We
report on a deep search for 12CO (J=3-2) line emission from the host
galaxy GRB 980425 with the Atacama Submillimeter Telescope Experiment (ASTE).
We observed five points of the galaxy, covering the entire region. After
combining all of the spectra we obtained a global spectrum with a rms noise
level of 3.3 mK in the Tmb scale at a velocity resolution of 10 km s-1.
No significant emission was detected, though we found a marginal emission
feature in the velocity range corresponding to the redshift of the galaxy. We
derived 3 Š upper limits on the global properties: the velocity-integrated CO
(3-2) intensity of ICO (3-2) < 0.26 K km s-1, by
adopting a velocity width of 67 km s-1; an H2 column
density of N(H2) < 3 x 1020 cm-2; a
molecular gas mass of M(H2) < 3 x 108 M⦿, by assuming a CO
line luminosity to H2 molecular gas mass conversion factor of XCO
= 5.0 x 1020 cm-2 (K km s-1)-1; and
a star-formation rate of SFR < 0.1 M⦿ yr-1, based on the
Schmidt law. The SFR is consistent with the previous results of Hæ and mid-IR
observations, thereby suggesting that there is a variety of significant
obscured star formation in the host galaxy of GRB 980425. This result implies
that there is a variety of GRB hosts with regard to the presence of obscured
star formation.
l
Hatsukade,
B., K. Kohno, A. Endo, T. Tosaki, K. Ohta, S. Sakamoto, N. Kawai, J. R. Cortes,
K. Nakanishi, T. Okuda, K. Muraoka, T. Sakai, H. Ezawa, N. Yamaguchi, K.
Kamegai, and R. Kawabe [2007b], "A Possible Detection of CO (J=3-2)
Emission from the Host Galaxy of GRB 980425 with Atacama Submillimeter Telescope
Experiment," Proc. of the IAU Symp. 235, "Galaxy evolution across the
Hubble Time", eds. F. Combes & J. Palous, p.312.
Ø
Long-duration
gamma-ray bursts (GRBs) are considered to be due to the death of massive stars.
Therefore, GRBs are closely associated with the star formation of host
galaxies. Since GRBs can be detected at cosmological distances, they are
expected to be probes of the star formation history of the Universe. In order
to determine the use of GRBs, it is essential to understand the star formation
of their hosts. Multi-wavelength observations have shown that the star
formation rates (SFRs) of GRB hosts derived from submillimeter/radio
observations are generally higher than those from optical/UV observations
(Berger et al. 2003). This implies that GRB hosts have a large amount of
molecular gas and massive star formation obscured by dust. In order to solve
this problem, it is necessary to derive the SFRs in a method which is
independent of existing methods and not affected by dust extinction. We observed
12CO (J = 3-2) line emission from the host galaxy of GRB 980425
using the Atacama Submillimeter Telescope Experiment (ASTE). Five points were
observed covering the entire region of the galaxy, and we find possible
emission features (S/N ~ 3Š) at the velocity range corresponding to the
redshift of the galaxy. By combining all spectra of five points, we obtain a
global spectrum with a ~4Š emission feature. If the features are real, this is
the first detection of CO among GRB hosts. We derive the total gas mass of M(H2)=7
} 2 x108M⦿ assuming a
l
Haupt,
C., R. Stramek, and K.-I. Morita [2006], "System Engineering in the ALMA
Project," Proc. of the SPIE, vol.6271, pp.62710E.
Ø
The
Atacama Large Millimeter and Submillimeter Array (ALMA) is a
submillimeter-wavelength radio telescope under construction in northern
l
Hayakawa,
T., M. Hiramatsu, K. Kamegai, K. Tatematsu, A. Mizuno, T. Onishi, and T.
Hasegawa [2007], "350GHz Band Emission Lines OBservations of Chamaeleon
Star Forming Regions," Proceedings in "Protostars and Planets
V", LPI contribution no. 1286, p.8591.
Ø
Not
Available
l
Hirabayashi,
H., Y. Murata, P. G. Edwards, Y. Asaki, N. Mochizuki, M. Inoue, T. Umemoto, S.
Kameno, and Y. Kono [2004], "On the Near-Term Space VLBI Mission
VSOP-2," Proc. of the 7th Symposium of the European VLBI Network on New
Developments in VLBI Science and Technology, eds. R. Bachiller, F. Colomer,
J.-F. Desmurs, and P. de Vicente, pp.285-288.
Ø
A second
generation near-term space VLBI mission, VSOP-2, is being planned for a launch
in 2010 or soon after. The scientific objectives are very high angular
resolution imaging of astrophysically exotic regions, including the cores,
jets, and accretion disks of active galactic nuclei (AGN), water maser emissions,
micro-quasars, coronae of young stellar objects, etc. A highest angular
resolution of about 40Ź as is achieved in the 43 GHz band. Engineering
developments are in progress for the deployable antenna, antenna pointing, high
data rate transmission, cryogenic receivers, accurate orbit determination,
etc., to realize this mission. International collaboration will be as important
as it has been for VSOP.
l
Hirabayashi,
H., Y. Murata, P. G. Edward, Y. Asaki, N. Mochizuki, M. Inoue, T. Umemoto, S.
Kameno, L. I. Gurvits, and A. P. Lobanov [2006], "Design of the Near-term
Next Generation Space-VLBI Mission VSOP-2," ESO Astrophysics Symposia,
"Exploring the Cosmic Frontier: Astrophysical Instruments for the 21st
Century", eds. A. P. Labonov, J. A. Zensus, C. Cesarsky, and P. J.
Diamond, pp.37-38.
Ø
A second
generation space VLBI mission, VSOP-2, is being planned for a launch in 2010 or
soon after. The scientific objectives are very high angular resolution imaging
of astrophysically exotic regions, including the cores, jets, and accretion
disks of active galactic nuclei (AGN), water maser emissions, micro-quasars,
coronae of young stellar objects, etc. A highest angular resolution of about 40
muas is achieved in the 43 GHz band. Engineering developments are in progress
for the deployable antenna, high data rate transmission, cryogenic receivers,
antenna pointing, accurate orbit determination, etc., to realize this mission.
International collaboration will be as important as it has been for VSOP.
l
Hiramatsu,
M., K. Kamegai, T. Hayakawa, K. Tatematsu, T. Onishi, A. Mizuno, and T.
Hasegawa [2007a], "ASTE Submillimeter Observations of a YSO Condensation
in Cederblad 110," Proc. of the IAU Symp, 237, "Triggered Star
Formation in a Turbulent Interstellar Medium", eds. B. G. Elmegreen &
J. Palous, p.426.
Ø
Outflow-cloud
interaction is an important issue in discussions about star formation in
clusters because it could generate turbulence and restrain star formation
activities, as well as it causes outflow-triggered star formation.
l
Hiramatsu,
M., T. Hayakawa, K. Tatematsu, K. Kamegai, T. Onishi, A. Mizuno, N. Yamaguchi,
and T. Hasegawa [2007b], "ASTE Submillimeter Observations of a Young
Stellar Object Condensation in Cederblad 110," Astrophys. J., vol.664,
pp.964-974.
Ø
We
present results of submillimeter observations of a low-mass young stellar
object (YSO) condensation in the Cederblad 110 region of the Chamaeleon I dark
cloud with the Atacama Submillimeter Telescope Experiment. Our HCO+(J=4-3)
map reveals a dense molecular gas with an extent of ~0.1 pc, which is a complex
of two envelopes associated with class I sources Ced 110 IRS 4 and IRS 11 and a
very young object Cha-MMS 1. The other two class I sources in this region, IRS
6 and NIR 89, are located outside the clump and have no extended HCO+
emission. HCO+ abundance is calculated to be 2.6x10-10
for MMS 1 and 3.4x10-9 for IRS 4, which are comparable to the
reported value for other young sources. Bipolar outflows from IRS 4 and IRS 6
are detected in our 12CO(J=3-2) map. The outflow from IRS 4 seems to
collide with Cha-MMS 1. The outflow has enough momentum to affect gas motion in
MMS 1, although no sign has been detected to indicate that a triggered star
formation has occurred.
l
Hirota,
T., H. Maezawa, and S. Yamamoto [2004a], "Molecular Line Observations of
Carbon-Chain-Producing Regions L1495B and L1521B," Astrophys. J., vol.617,
pp.399-405.
Ø
We
present the first comprehensive study of physical and chemical properties of
quiescent starless cores L1495B and L1521B, which are known to be rich in
carbon-chain molecules like the cyanopolyyne
l
Hirota,
T., and VERA Project Team [2004b], "Observations of H2O maser
sources in Orion-Monoceros Molecular Clouds with VERA," Proc. of the 7th
Symposium of the European VLBI Network on New Developments in VLBI Science and
Technology, eds. R. Bachiller, F. Colomer, J.-F. Desmurs, and P. de Vicente,
pp.201-202.
Ø
We
present results of phase-referencing VLBI observations of H2O maser
sources in Orion-Monoceros Molecular Clouds with VERA (VLBI Exploration of
Radio Astrometry), which is newly constructed Japanese VLBI network. Main
topics of this poster are (1) the aim of one of the first scientific projects
for VERA "3-Dimensional Structure and Kinematics of Orion-Monoceros
Molecular Cloud Complex"; (2) current status (sensitivity and astrometric
accuracy) of phase-referencing VLBI observations with VERA; and (3) results of
VLBI observations of H2O maser sources in Orion-Monoceros Molecular Clouds with
VERA.
l
Hirota, T.,
and S. Yamamoto [2006], "Molecular Line Observations of Carbon-Chain-Rich
Core L492," Astrophys. J., vol.646, pp.258-268.
Ø
We
report on molecular abundances and distributions in a starless dense core,
L492. We have found that the abundances of carbon-chain molecules such as CCS,
C3S, HC3N, HC5N, and HC7N are
comparable to those in chemically young dark cloud cores called
"carbon-chain-producing regions," such a L1495B, L1521B, L1521E, and
TMC-1. This is the first dark cloud core extremely rich in carbon-chain
molecules that is found outside the Taurus in carbon-chain-producing regions,
being significantly lower than those in the evolved prestellar cores such as
L1498 and L1544. On the other hand, the abundances of NH3 and N2H+
are systematically higher than those in carbon-chain-producing regions. Our
mapping observations reveal that the central hole of molecular distributions,
which were reported for CCS and C34S in evolved prestellar cores, is
not significant in L492, indicating that the depletion factor of molecules is
not very high. Furthermore, L492 is dynamically more evolved than
carbon-chain-producing regions, and the protostellar collapse has started like
in L1498 and L1544. Therefore, it is likely that the chemical and dynamical
evolutionary stage of L492 is intermediate between carbon-chain-producing
regions (L1495B, L1521B, L1521E, and TMC-1) and evolved prestellar cores (L1498
and L1544).
l
Hirota,
T., T. Bushimata, Y. K. Choi, M. Honma, H. Imai, K. Iwadate, T. Jike, S.
Lameno, O. Kameya, R. Kamohara, Y. Kan-ya, N. Kawaguchi, M. Kijima, M. K. Kim,
H. Kobayashi, S. Kuji, T. Kurayama, S. Manabe, K. Maruyama, M. Matsui, N.
Matsumoto, T. Miyaji, T. Nagayama, A. Nakagawa, K. Nakamura, C. S. Oh, T.
Omodaka, T. Oyama, S. Sakai, T. Sasao, K. Sato, M. Sato, K. M. Shibata, M.
Shintani, Y. Tamura, M. Tsushima, and K. Yamashita [2007], "Distance to
Orion KL Measured with VERA," Publ. Astron Soc. Japan, vol.59, pp.897-903.
Ø
We
present the initial results of multiepoch VLBI observations of 22 GHz H2O
masers in the Orion KL region with VERA (VLBI Exploration of Radio Astrometry).
With the VERA dual-beam receiving system, we carried out phase-referencing VLBI
astrometry, and successfully detected the annual parallax of Orion KL to be
2.29}0.10 mas, corresponding to a distance of 437}19 pc from the Sun. The
distance to Orion KL was determined for the first time with the trigonometric
parallax method in these observations. Although this value is consistent with
that previously reported, 480}80 pc, which was estimated from a statistical
parallax method using the proper motions and radial velocities of the H2O
maser features, our new results provide a much more accurate value with an
uncertainty of only 4%. In addition to the annual parallax, we detected an
absolute proper motion of the maser feature, suggesting an outflow motion
powered by the radio source I along with the systematic motion of source I
itself.
l
Hofner,
P., W. A. Baan, and
Ø
We
report Very Large Array CnB- and A-configuration observations of the 22 GHz H2O
maser line toward the starburst galaxy NGC 253. We detect a broad, highly
blueshifted (VLSR=120.5 km s-1) H2O line
coincident with the continuum source TH4, which is believed to be a supernova
remnant. The H2O maser emission arises from an area whose size is
smaller than 0.9 pc. A weaker feature at VLSR=60.0 km s-1
is also seen at the same position. We also detect the extended 1.3 cm continuum
along the galactic disk of NGC 253, as well as the two central continuum
sources TH2 and TH4.
l
Honma,
M., T. Bushimata, I. K. Choi, T. Fujii, T. Hirota, K. Horiai, H. Imai, N.
Inomata, J. K. Ishitsuka, K. Iwadate, T. Jike, O. Kameya, R. Kamohara, Y.
Kanya, N. Kawaguchi, N. Kobayashi, S. Kuji, T. Kurayama, S. Manabe, T. Miyaji,
A. Nakagawa, K. Nakashima, R. Nagayoshi, T. Omodaka, T. Oyama, M. Rioja, S.
Sakai, S. Sakakibara, K. Sato, T. Sasao, K. M. Shibata, R. Shimizu, K. Sora, H.
Suda, Y. Tamura, and K. Yamashita [2004a], "Studying Black Holes with
VERA," Proc. of the "Stellar-Mass, Intermediate-Mass, and
Supermassive Black Holes", eds. S. Mineshige and K. Makishima, Porg.
Theore. Phys. Supple., No.155, pp.339-340.
Ø
In this
paper we discuss the potential use of VERA (VLBI exploration of radio
astrometry) to study black holes based on phase-referencing VLBI astrometry.
First we present a brief overview of the project, from system design to
scientific targets, and then we discuss the possibilities to investigate black
holes and other high energy phenomena that are possibly linked to black holes.
l
Honma,
M., T. Bushimata, Y. K. Choi, T. Fujii, T. Hirota, K. Horiai, H. Imai, N.
nomata, J. Ishitsuka, K. Iwadate, T. Jike, O. Kameya, R. Kamohara, Y. Kan-Ya,
N. Kawaguchi, H. Kobayashi, S. Kuji, T. Kurayama, S. Manabe, T. Miyaji, A.
Nakagawa, K. Nakashima, T. Omodaka, T. Oyama, S. Sakai, K. Sato, T. Sasao, K.
M. Shibata, R. Shimizu, K. Sora, H. Suda, Y. Tamura, and K. Yamashita, [2004b], "Astrometry of W49N -
OH43.8-0.1 H2O maser pair with VERA," Proc.of the 7th Symposium
of the European VLBI Network on New Developments in VLBI Science and
Technology, Edited by R. Bachiller, F. Colomer, J.-F. Desmurs, and P. de
Vicente, pp.203-204.
Ø
We
present the results of multi-epoch VERA observations of W49N@OH43.8-0.1 H2O maser pair. Based on the dual-beam
VLBI observation with VERA, we successfully obtained the phase-referenced maps
of OH43.8-0.1 with respect to the W49N reference spot for 3 epochs with a time
span of 6 months. The maps were in good agreement with previous studies
obtained with a single-beam VLBI, and were also consistent with each other with
an accuracy of about 0.2 mas. Moreover, there are systematic, rather linear
displacements of maser feature positions, which may be the relative proper
motions of maser features caused by the Galactic rotation as well as internal
motions of individual maser features.
l
Honma,
M., T. Bushimata, Y. K. Choi, T. Fujii, T. Hirota, K. Horiai, H. Imai, N.
Inomata, J. Ishitsuka, K. Iwadate, T. Jike, O. Kameya, R. Kamohara, Y. Kan-ya,
N. Kawaguchi, M. Kijima, H. Kobayashi, S. Kuji, T. Kurayama, S. Manabe, T.
Miyaji, A. Nakagawa, K. Nakashima, C. S. Oh, T. Omodaka, T. Oyama, M. Rioja, S.
Sakai, K. Sato, T. Sasao, K. M. Shibata, R. Shimizu, K. Sora, H. Suda, Y.
Tamura, and K. Yamashita [2005a], "Multi-Epoch VERA Observations of H20
Masers in OH 43.8-0.1," Publ. Astron. Soc. Japan, vol.57, pp.595-603.
Ø
We
report on multi-epoch observations of H2O maser emission in the
star-forming region OH 43.8-0.1, carried out with VLBI Exploration of Radio
Astrometry. The large-scale maser distributions obtained by single-beam VLBI
mapping reveal new maser spots scattered over the area of 0''.7x1''.0, in addition
to a `shell-like' structure with a scale of 0''.3x0''.5, which was mapped
previously. Proper motions were also obtained for 43 spots based on 5-epoch
monitoring with a time span of 281 days. The distributions of the proper
motions show a systematic outflow in the north-south direction with an
expansion velocity of ~ 8 km s-1. The overall distributions of the
maser spots as well as the proper motions are better represented by a bipolar
flow plus a central maser cluster with a complex structure, rather than a shell
with uniform expansion, such as those found in Cep A R5 and W75N VLA2. The
distance to OH 43.8-0.1 was also estimated based on the statistical parallax,
yielding D = 2.8 } 0.5 kpc. This distance is consistent with a near kinematic
distance, and rules out a far kinematic distance (~ 9kpc). Also, the radial
velocity of the OH 43.8-0.1 combined with the distance provides a constraint on
the flatness of the galactic rotation curve, indicating that there is no
systematic difference in the rotation speeds at the Sun and at the position of
OH 43.8-0.1, which is located at a galacto-centric radius of ~ 6.3 kpc.
l
Honma,
M., T. Bushimata, T. Fujii, T. Hirota, K. Horiai, H. Ishitsuka, K. Iwadate, T.
Jike, O. Kameya, R. Kamohara, Y. Kan-ya, N. Kawaguchi, H. Kobayashi, S. Kuji,
T. Kurayama, S. Manabe, T. Miyaji, A. Nakagawa, K. Nakashima, T. Omodaka, T.
Oyama, M. Rioja, S. Sakai, S. Sakakibara, K. Sato, T. Sasao, K. M. Shibata, R.
Shimizu, H. Suda, and Y. Tamura [2005b], "The VERA Project," Baltic
Astronomy, vol.14, pp.455-457.
Ø
VERA
(VLBI Exploration of Radio Astrometry) is the first VLBI array dedicated to
phase-referencing astrometry. The construction of the VERA array has been
started in 2000 and completed in 2002 April; currently it is the system
evaluation phase. In this paper, we present a brief overview of the system and
report the recent status of the project.
l
Honma,
M., T. Bushimata, T. Fujii, T. Hirota, K. Horiai, H. Ishitsua, K. Iwadate, T.
Jike, O. Kameya, R. Kamohara, Y. Kan-ya, N. Kawaguchi, H. Kobayashi, S. Kuji,
T. Kurayama, S. Manabe, T. Miyaji, A. Nakagawa, K. Nakashima, T. Omodaka, M.
Rioja, S. Sakai, S. Sakakibara, K. Sato, T. Sasao, K. M. Shibata, R. Shimizu,
H. Suda, and Y. Tamura [2005c], "Dual-Beam Phase Referencing with
VERA," Proc. of the "Future Directions in High Resolution Astronomy:
A Celebration of the 10th Anniversary of the VLBA", eds. J. D. Romney, and
M. J. Reid, ASP Conf. Ser. Vol.340, pp.569-571.
Ø
We
present the recent results of phase-referencing observations with VERA's
dual-beam system. Since the first fringe detection with the dual-beam system in
May 2002, several observations have been made to check the system performance
and in particular to test how the VERA's dual-beam system works in
phase-referencing observation. Among these observations, we mainly focus on the
observations of a pair of strong maser sources W49N and OH43.8-0.1, and discuss
the phase-referencing capability as well as potential astrometric accuracy of
VERA.
l
Honma,
M., T. Bushimata, Y. K. Choi, T. Hirota, H. Imai, K. Iwadate, T. Jike, O.
Kameya, R. Kamohara, Y. Kan-ya, N. Kawaguchi, M. Kijima, H. Kobayashi, S. Kuji,
T. Kurayama, S. Manabe, T. Miyaji, T. Nagayama, A. Nakagawa, C. S. Oh, T.
Omodaka, T. Oyama, S. Sakai, K. Sato, T. Sasao, M. Shintani, H. Suda, Y. Tamura,
M. Tsushima, and K. Yamashita [2007], "Astrometry of Galactic Star-Forming
Region Sharpless 269 with VERA: Parallax Measurements and Constration on Outer
Rotation Curve," Publ. Astron Soc. Japan, vol.59, pp.889-895.
Ø
We have
performed high-precision astrometry of H2O maser sources in the
Galactic star-forming region Sharpless 269 (S269) with VERA. We successfully
detected a trigonometric parallax of 189}8 Ź as, corresponding to a source
distance of 5.28+0.24-0.22 kpc. This is the smallest
parallax ever measured, and the first one detected beyond 5 kpc. The source
distance as well as the proper motions were used to constrain the outer
rotation curve of the Galaxy, demonstrating that the difference of rotation
velocities at the Sun and at S269 (which is 13.1 kpc away from the Galaxy's
center) is less than 3%. This gives the strongest constraint on the flatness of
the outer rotation curve, and provides a direct confirmation of the existence
of a large amount of dark matter in the Galaxy's outer disk.
l
Huang,
G., and H. Nakajima [2005], "Location and Parameters of a Microwave
Millisecond Spike Event," Astrophys. Sp. Sci., vol.295, pp.423-442.
Ø
A
typical microwave millisecond spike event on November 2, 1997 was observed by
the radio spectrograph of National Astronomical Observatories (NAOs) at
2.6--3.8 GHz with high time and frequency resolution. This event was also
recorded by Nobeyama Radio Polarimeters (NoRP) at 1 35 GHz and Radio Heliograph
(NoRH) at 17 GHz. The source at 17 GHz is located in one foot-point of a small
bright coronal loop of YOHKOH SXT and SOHO EIT images with strong photospheric
magnetic field in SOHO MDI magnetograph. It is assumed that the electron
cyclotron maser instability and gyro-resonance absorption dominate,
respectively, the rising and decay phase of the spike event. For different
harmonic number of gyro-frequency or magnetic field strength, a fitting program
with free plasma parameters is used to minimize the difference between the
observational and theoretical values of the exponential growth and decay rates
for a given spike. The plasma parameters at third harmonic number are more
comparable to their typical values in solar corona. Hence, it is able to
provide a diagnosis for the source parameters (magnetic field, density, and temperature),
the properties of radiations (wave vector and propagation angle), and the
properties of non-thermal electrons (density, pitch angle, and energy). The
results are also comparable with the diagnosis of the gyro-synchrotron
radiation model, the frequency drift rates and a dipole magnetic field model,
as well as the YOHKOH SXT and SOHO MDI data.
l
Huang,
G., H. Nakajima, S. Masuda, K. Kobayashi, and M. Kubo [2006], "Source
Structures of the 1998 November 28 X-Class Flare and Electron
Acceleration," Publ. Astron. Soc. Japan, vol.58, pp.37-45.
Ø
We
studied the 1998 November 28 X-class flare, which showed long-duration,
two-ribbon alpha emission. (1) A soft X-ray loop system developed along the
major magnetic neutral line in the impulsive phase. Hard X-ray and microwave
emissions due to nonthermal electrons were located in some limited regions.
While the compact hard X-ray loop was associated with weak, diffuse soft X-ray
emission, two large microwave loops did not have soft X-ray counterparts. (2)
Time profiles of two large microwave loops were similar to that of hard X-ray
total emission, which emanated mostly from the compact source, even in the fine
time structure in the rising phase. (3) A super-hot thermal hard X-ray source
appeared around the impulsive peak and was located along the major magnetic
neutral line in the declining phase, coinciding with the bright soft X-ray
emission. The thermal component can be explained within the standard
reconnection model to the extent that the super-hot thermal plasma was heated
in the large soft X-ray loop. However, the nonthermal electrons were
accelerated in a localized region where three loops interacted with each other.
The inferred configuration may be a more complicated form of the double-loop
interaction model proposed by Hanaoka (1996) and Nishio et al. (1997).
l
Huang,
J., G. Fazio, J. Younger, D. Wilner, M. Yun, G. Wilson, T. Webb, M. Gurwell, K.
Lai, A. Peck, G. Petitpas, D. Iono, K. Kohno, R. Kawabe, D. Sanders, D. Hughes,
A. Martinez-Sansiger, and S. Kim [2007], "SMA/AzTEC Observations of
Submillimeter Galaxies in the Cosmos Field," American Astronomical Society
Meeting 210, #39.10.
Ø
We
present results of SMA/AzTEC observations of seven bright submillimeter
galaxies (SMGs) in the COSMOS field. All 7 objects were detected by the SMA at
345 GHz with 2 arcsec resolution and position accuracies of 0.2 arcsec. Most of
the SMGs in the sample have no optical, 24 micron, and radio counterparts, but
were detected in the Spitzer/IRAC bands. This suggests that the objects are at
a higher redshift (z > 3.5) when compared to the existing well studied SMG
sample. This is a pioneer study in the exploraton of SMGs in the early universe
with high resolution observations, and an indication of what
l
Iguchi,
S., T. Kurayama,
Ø
The VERA
terminal is a new data-acquisition system developed for the VERA project, which
is a project to construct a new Japanese VLBI array dedicated to make a 3-D map of our
Milky Way Galaxy in terms of
high-precision astrometry. New technology, a gigabit digital filter, was
introduced in the development. The importance and advantages of a digital filter for radio
astronomy have been studied as
follows: (1) the digital filter can realize a variety of observation modes and maintain
compatibility with different
data-acquisition systems (Kiuchi et al. 1997 and Iguchi et al. 2000a),
(2) the folding noise occurring in
the sampling process can be reduced by combination with a higher-order sampling
technique (Iguchi, Kawaguchi 2002),
(3) and an ideal sharp cut-off bandedge and a flat amplitude/phase responses are approached by using a
large number of taps available to
use LSI of a large number of logic cells (Iguchi et al. 2000a). We developed
the custom Finite Impulse Response filter chips and manufactured the Gigabit Digital Filter
Banks (GDFBs) as a digital backend
subsystem in the VERA terminal. In this paper, the design and development of
the GDFB are presented in detail, and the performances and demonstrations of
the developed GDFB are shown.
l
Iguchi,
S. [2005b], "Radio Interferometer Sensitivities for Three Types of
Receiving Systems: DSB, SSB, and 2SB Systems," Publ. Astron. Soc. Japan,
vol.57, pp.643-677.
Ø
The
purpose of this paper is to study the detection sensitivity suitable to the
practical situation for a radio interferometer. For the radio interferometer,
the three types of receiving systems are a double-sideband (DSB), a
single-sideband (SSB), and a two-single-sideband (2SB) systems. The evaluation
of these receiving systems is of significance to explore the best performance
for a radio interferometer. In this paper, the signal-to-noise ratios of these
three-type receiving systems are newly derived to investigate the performance
and key features of each system. We demonstrate the system noise temperatures
of SSB, 2SB, and DSB receiving systems by using the ALMA-specification receiver
noise temperature and the atmosphere condition measured at the
l
Ikeda,
N., K. Sunada, and Y. Kitamura [2007], "A Survey of Dense Cores in the
Orion A Cloud," Astrophys. J., vol.665, pp.1194-1219.
Ø
We have
carried out an H13CO+(J=1-0) core survey in a large area
of 1.5deg x0.5deg, covering the whole region of the Orion
A molecular cloud, using the Nobeyama 45 m radio telescope with the 25 Beam
Array Receiver System (BEARS). This survey is unique in that a large area (~48
pc2) of the cloud was covered with a high spatial resolution of 21" (0.05
pc) and with a deep integration (1 sigma~0.1 K in T*A), resulting in a core
mass detection of 1.6 Msolar. The morphology of the H13CO+(J=1-0)
emission is very similar to that of the 850 mum continuum emission. We identified
236 dense cores from our data with the clumpfind algorithm. The cores are close
to virial equilibrium, independent of whether they are thermal or turbulent. We
predict an initial mass function (IMF) from the core mass function, considering
binary formation and confusion along the line of sight, and find that this IMF
agrees well with the Orion Nebula cluster IMF for a star formation efficiency
of ~40%. Therefore, we suggest that the IMF is determined at the time of the
dense core formation. Furthermore, we discovered three cores with large
velocity widths, significantly wider than those of the other cores, only toward
the M42 H II region, suggesting that the energy input from the H II region
increases the velocity width. Since the three cores can produce the most
massive stars, owing to their large mass accretion rates, massive star
formation in the next generation in the Orion A cloud is likely to be caused by
nearby stellar activity.
l
Imai,
H., J.-I. Nakashima, P. J. Diamond, A. Miyazaki, and S. Deguchi [2005a],
"Biconically Expanding Flow in W43A Traced by SiO Maser Emission,"
Astrophys. J. (Letters), vol.622, pp.L125-L128.
Ø
We
report Very Long Baseline Array and Very Large Array observations of 22 GHz H2O
and 43 GHz SiO (v=1, J=1-0) maser emission as well as 7 mm continuum emission
in W43A, which exhibits a highly collimated jet of molecular gas and a
spherically expanding envelope very similar to that of an OH/IR star. The
spatiokinematical structure of the H2O masers is well fitted to a
precessing jet model with an expansion velocity of 150 km s-1 and a
dynamical age of ~50 yr. The spatiokinematical structure of the SiO masers is
well fitted to a biconically expanding flow model, whose axis is parallel to
the direction of the collimated jet. Astrometry of the H2O and SiO
masers suggests that these maser sources have a common dynamical center,
possibly as part of a binary system, within 70 AU. The SiO masers may be
excited on the surface of the cone that has significant deceleration and
interacts with the jet. A 7 mm continuum emission source is located ~1300 AU
away from these maser sources at a position angle of about -60 from the jet
axis. The physical relation of the continuum to the maser sources is still
unclear.
l
Imai,
H., O. Kameya, M. Miyoshi, T. Sasao, S. Deguchi, S. Horiuchi, and Y. Asaki
[2005b], "Kinematics, Physical Condition, and Magnetic Field of the W3 IRS
5 Region Traced by Water Masers," Proc. of the "Future Directions in
High Resolution Astronomy: A Celebration of the 10th Anniversary of the
VLBA", eds. J. D. Romney, and M. J. Reid, ASP Conf. Ser. vol.340,
pp.358-360.
Ø
Not
Available
l
Imai,
H., K. B. Marvel, K. M. Shibata, T. Sasao, M. Miyoshi, M. Inoue, P. J. Diamond,
V. Migenes, and Y. Murata [2005c], "The 3-D Kinematics of Water Masers
around the Semiregular Variable R Virginis," Proc. of the "Future
Directions in High Resolution Astronomy: A Celebration of the 10th Anniversary
of the VLBA", eds. J. D. Romney, and M. J. Reid, ASP Conf. Ser. vol.340,
pp.407-409.
Ø
Not
Available
l
Imai,
H., T. Omodaka, T. Hirota, T. Umemoto, K. Sorai, and T. Kondo [2006], "A
Collimated Jet and an Infalling-Rotating Disk in G192.16-3.84 Traced by H2O
Maser Emission," Publ. Astron. Soc. Japan, vol.58, pp.883-892.
Ø
We
report on H2O masers associated with the massive-star forming region
G192.16-3.84 observed with the new Japanese VLBI network at three epochs
spanned for two months, which have revealed the three-dimensional kinematical
structure of the H2O maser region in G192.16-3.84, containing two
young stellar objects separated by ~ 1200 AU. The maser spatio-kinematical
structure has well persisted since previous observations, in which the masers
are expected to be associated with a highly collimated bipolar jet and an
infalling-rotating disk in the northern and southern clusters of H2O
maser features, respectively. We estimated a jet expansion speed of ~ 100 km s-1
and re-estimated the dynamical age of the whole jet to be 5.6 x 104
yr. We investigated the spatial distribution of the Doppler velocities during
the previous and present observations and the relative proper motions of H2O
maser features in the southern cluster, as well as the relative bulk motion
between the two maser clusters. They are well explained by a model of an
infalling-rotating disk with a radius of ~ 1000 AU and a central stellar mass
of 5-10 M⦿, rather than by a model of a bipolar
jet perpendicular to the observed CO outflow. Based on the derived H2O
maser spatio-kinematical parameters, we discuss the formation mechanism of the
massive young stellar objects and the outflow development in G192.16-3.84.
l
Imanishi,
M., K. Nakanishi, N. Kuno, and K. Kohno [2004], "Near-Infrared and
Millimeter Constraints on the Nuclear Energy Source of the Infrared-luminous
Galaxy NGC 4418," Astron. J., vol.128, pp.2037-2047.
Ø
We
present near-infrared and millimeter investigations of the nucleus of the
infrared-luminous galaxy NGC 4418, which previous observations suggest
possesses a powerful buried active galactic nucleus (AGN). We find the
following main results: (1) The infrared K-band spectrum shows CO absorption
features at 2.3-2.4 Źm from stars and very strong H2 emission lines.
The luminosity ratios of H2 emission lines are suggestive of a
thermal origin, and the equivalent width of the H2 1-0 S(1) line is
the second largest observed to date in an external galaxy, after the
well-studied strong H2-emitting galaxy NGC 6240. (2) The infrared
L-band spectrum shows a clear polycyclic aromatic hydrocarbon (PAH) emission
feature at 3.3 Źm, which is usually found in star-forming galaxies. The
estimated star formation luminosity from the observed PAH emission can account
for only a small fraction of the infrared luminosity. (3) Millimeter
interferometric observations of the nucleus reveal a high HCN (1-0) to HCO+
(1-0) luminosity ratio of ~1.8, as has been previously found in pure AGNs. (4)
The measurements of HCN (1-0) luminosity using a single-dish millimeter
telescope show that the HCN (1-0) to infrared luminosity ratio is slightly
larger than the average, but within the scattered range, for other
infrared-luminous galaxies. All of these results can be explained by the
scenario in which, in addition to energetically insignificant, weakly obscured
star formation at the surface of the nucleus, a powerful X-ray-emitting AGN
deeply buried in dust and high-density molecular gas is present.
l
Imanishi,
M., K. Nakanishi, and K. Kohno [2006a], "Millimeter Interferometric
Investigations of the Energy Sources of Three Ultraluminous Infrared Galaxies,
UGC 5101, Markarian 273, and IRAS 17208-0014, Based on HCN-to-HCO+
Ratios," Astron. J., vol.131, pp.2888-2899.
Ø
We
present interferometric observations of three ultraluminous infrared galaxies
(ULIRGs; UGC 5101, Mrk 273, and IRAS 17208-0014) in the 3 mm wavelength range,
using the Nobeyama Millimeter Array. Both the HCN (J=1-0) and HCO+
(J-1-0) molecular lines were observed simultaneously. HCN emission was clearly
detected at the nuclear positions of these ULIRGs, and HCO+ emission was
detected at the nuclear positions of UGC 5101 and IRAS 17208-0014. The
HCN-to-HCO+ brightness-temperature rations toward the nuclei of the
three ULIRGs were derived and compared with those of lower luminosity galaxies
known to be dominated by active galactic nuclei (AGNs) or starbursts. In UGC
5101 and Mrk 273, where is evidence for obscured AGNs from previous
observations at other wavelengths, we found high HCN/HCO+ ratios
(> 1.8) that are in the range found for AGN-dominated galaxies. IN IRAS
17208-0014, where the presence of a powerful obscured AGN has been unclear, the
ratio (~1.7) is brightness-temperature ratios in UGC 5101 and Mrk 273 cloud be
the consequence of an HCN abundance enhancement, which is expected from
chemical effects of the central X-ray-emitting AGN on the surrounding dense
molecular gas. Our proposed millimeter interferometric methods base on HCN/HCO+
ratios may be an effective tool for unveiling elusive buried AGNs at the cores
of ULIRs, especially because of the negligible dust extinction at these
wavelengths.
l
Imanishi,
M., and K. Nakanishi [2006b], "Infrared 2-4 Micrometer Spectroscopy and
Millimeter Interferometric HCN and HCO+ Observations of the
Individual Merging Components of Arp 299," Publ. Astron. Soc. Japan,
vol.58, pp.813-828.
Ø
We present
ground-based infrared K - (2-2.5 Źm) and L-band (2.8-4.1 m) spectroscopy, as well as
interferometric observations at É ~ 3mm, for the individual merging components
(A, B and C) of the luminous infrared galaxy Arp 299. The presence and location
of a buried active galactic nucleus (AGN) are investigated. Our
sub-arcsec-resolution infrared spectra clearly reveal the putative buried AGN
resides in the nucleus B1 (a subcomponent of B), based on a very low equivalent
width of 3.3 Źm polycyclic aromatic hydrocarbon emission, a weak 2.3 Źm CO
absorption feature, and a large time variation of the K- and L-band continuum
fluxes. Our interferometric observations simultaneously obtain HCN (J=1-0) and
HCO+ (J=1-0) emission lines with ~ 4" resolution, and we find
the HCN to HCO+ brightness-temperature ratios to be as low as those
found in starburst nuclei in all of the major merging components of Arp 299.
The low ratio even in the AGN-hosting nucleus B may be due to the presence of a
large amount of high-density molecular gas whose chemistry is dominated by
coexisting starbursts and/or shocks, rather than by the central strong
X-ray-emitting AGN.
l
Imanishi,
M. [2007], "Millimeter Interferometric Observations of Nearby Luminous
Infrared Galaxies," Proc. of the "The Central Engine of Active
Galactic Nuclei", eds. Luis C. Ho and Jian-Min Wang, ASP Conf. Ser.,
vol.373, pp.614-615.
Ø
We
present interferometric observations at 3 mm, using the Nobeyama Millimeter
Array, of luminous infrared galaxies (LIRGs) with and without luminous buried
AGN signatures in infrared spectra. Both HCN (J=1-0) and HCO+
(J=1-0) molecular lines are observed simultaneously. The HCN to HCO+
brightness temperature ratios toward the nuclei of these LIRGs are derived and
are compared with those of galaxies known to be dominated by active galactic
nuclei (AGNs) or starbursts. LIRGs with (without) luminous buried AGN
signatures tend to distribute in the range occupied by AGN-dominated
(starburst-dominated) galaxies, suggesting that this millimeter interferometric
method is potentially an effective tool to find elusive buried AGNs, because
dust extinction is negligible in this wavelength range.
l
Inomata,
N., H. Imai, and T. Omodaka [2007], "A Pole-on Bipolar Outflow from the
AGB Star WX Piscium," Publ. Astron. Soc. Japan, vol.59, pp.799-809.
Ø
We
report on H2O masers around the asymptotic giant branch (AGB) star
WX Piscium (WX Psc IRC 10011), observed with the Japanese VLBI Network (JVN) at
three epochs during a span of 2 months. The H2O maser spectrum of WX
Psc consists of double peaks with a separation of 30 km s-1 centered
at the systemic velocity of the star. The maser features are found to split
roughly in two concentrations separated by about 60 mas from north to south.
The northern concentration involves both blueshifted and redshifted components
from both of the double peaks, suggesting that it is near the star driving the
outflow. The maser spatiokinematics is well approximated by a radial expansion
of a thick shell, except for the blueshifted features in the southern
concentration. The spatiokinematics is compared with a fan-shaped morphology
found in near-infrared emission, suggesting the existence of a bipolar outflow.
Two different models are proposed for explaining the observed maser proper
motions: one is a biconically expanding flow with a large opening angle (2Ęcone=
70”-120); the other is a collimated outflow with precession. The
complicated spatiokinematics of the H2O maser features indicates
that the star is currently in the process of launching a bipolar outflow in the
final stage of the AGB phase, shaping a planetary nebula in the next stage.
l
Inoue,
M. [2004], "East Asian VLBI Activities," Proc. of the 7th symposium
of the European VLBI Network on New Developments in VLBI Sciences and Technology,
eds. R. Bachiller, F. Colomer, J.-F. Desmurs, and P. de Vicente, pp.279-280.
Ø
The VLBI
activities in the East Asia region are planning to coordinate among VLBI groups
and institutes in
l
Inoue,
M. [2005], East Asia VLBI Consortium and its Committee, J. Korean Astron. Soc.,
vol.38, pp.77-79.
Ø
We had
the first committee meeting of the East Asia VLBI Consortium during the EAMA6
meeting held in Seoul. A VLBI network composed of telescopes in the East Asia
region could provide extreme properties, and the coordination of them has been
expected. The Committee of the East Asia VLBI Consortium is a standing
committee to promote activities of the consortium, in which participating
countries at present are China, Japan, and Korea over eight
institutes/observatories. Here we introduce the Consortium and Committee.
l
Inoue,
M., K. Asada, and H. Nagai [2007a], "Possible Detection of Faraday
Screen," Proc. of the "The Central Engine of Active Galactic
Nuclei", eds. Luis C. Ho and Jian-Min Wang, ASP Conf. Ser., vol.373,
pp.209-210.
Ø
We
pointed out a possible way to investigate a plasma sheath, Faraday screen,
which has been revealed by recent Faraday rotation studies of AGN jets. A
high-angular resolution observation of VSOP reveals a sharp absorption feature
which suggests free-free absorption by the plasma sheath. The spiral jet
configuration could provide, in general, an opportunity to investigate the
sheath surrounding AGN jets.
l
Inoue,
M., Y. Murata, The Next-Generation Space VLBI Working G. [2007b], "The
Next-Generation Space VLBI Project: VSOP-2," Proc. of the "The
Central Engine of Active Galactic Nuclei", eds. Luis C. Ho and Jian-Min
Wang, ASP Conf. Ser., vol.373, pp.715-716.
Ø
The
space VLBI project VSOP-2 offers superior spatial resolution to enable imaging
of the accretion discs, the regions where jets are produced and collimated in
active nuclei, and the magnetosphere around protostars.
l
Iono,
D., M. S. Yun, M. Elvis, A. B. Peck, P. T. P. Ho, D. J. Wilner, T. R. Hunter,
S. Matsushita, and S. Muller [2006a], "A Detection of [CII] Line Emission
in the z = QSO BR 1202-0725," Astrophys. J. (Letters), vol.645,
pp.L97-L100.
Ø
We
present ~3" resolution of the z=4.7 QSO BR 1202-0725 at 900 Źm from the
Submillimeter Array. The two submillimeter continuum components are clearly
resolved from each other, and the positions are consistent with previous lower
frequency images. In addition, we detect [CII] line emission from the northern
component at L[CII]=4.5x109 Lsolar. The ratio of [C ii}
to far-infrared luminosity is 0.04% for the northern component, and an upper
limit of <0.03% is obtained for the southern component. These ratios are
similar to the low values found in local ultraluminous galaxies, indicating
that the excitation conditions are different from those found in local field
galaxies. X-ray emission is detected by Chandra from the southern component at
L0.5-2keV=3x1045 ergs s-1 and, at 99.6%
confidence, from the northern component at L0.5-2keV~3x1044
ergs s-1, supporting the idea that BR 1202-0725 is a pair of
interacting galaxies at z=4.7 and that each harbors an active nucleus.
l
Iono,
D., Y. Tamura, K. Nakanishi, R. Kawabe, K. Kohno, T. Okuda, K. Yamada, B.
Hatsukade, and M. Sameshima [2006b], "CO (3-2) and CO (2-1) Detections in
a z = 1.3 Hyper-Luminous Starburst Galaxy," Publ. Astron. Soc. Japan,
vol.58, pp.957-963.
Ø
We
present an ~ 2" resolution image of the CO (2-1) emission and an ~ 4"
resolution image of the CO (3-2) emission in the z = 1.3 hyper-luminous
starburst galaxy MIPS J142824.0+352619, obtained at the Nobeyama Radio
Observatory. One new CO (3-2) and CO (2-1) emission detections yield L'CO(3-2)
= 1.4 (}0.5) x 1011 and L'CO(2-1) (}0.3) x 1011
K km s-1 pc2, which translate to a molecular gas mass of
~ 1011 M⦿, assuming a CO to H2 conversion factor appropriate
for ULIRGs. The derived high CO luminosities place this source as being one of
the brightest galaxies detected in CO to date. The CO (3-2) and CO (2-1)
derived redshifts are 1.3248}0.0002 and 1.3250}0.0002. If the bulk of the
molecular gas traced in these lines is completely thermalized, as suggested by
L'CO(3-2)/L'CO(2-1) ~ 1, a constraint to the gas density
of n >/~ 103 cm-3 is obtained from our Large Velocity Gradient
(LVG) analysis. If a significant fraction of the bright FIR luminosity of LFIR
= (3.2}07) x 1013 L⦿ arises from starburst activity, then the Star Formation
Efficiency (SFE) is 320 L⦿ M⦿-1. The
size constraint of 1".3 given by the CO (2-1) map provides an upper limit
to the lensing magnification factor of Ź</~8, which further supports the
earlier claim that the magnification of this source is only modest.
l
Iono,
D., C. Wilson, M. Yun, S. Takakuwa, A. Peck, G. Petitpas, P. Ho, Z. Wang, and
Y. Pihlstrom [2007a], "High Resolution CO(3-2) and HCO+(4-3)
Imaging of the Luminous Infrared Galaxy NGC 6240," Proc. of the IAU Symp.
235, "Galaxy evolution across the Hubble Time", eds. F. Combes &
J. Palous, p.309.
Ø
We
present interferometric CO(3-2), HCO+(4-3) and 870 micron continuum
images of the luminous infrared galaxy NGC 6240 obtained at the Submillimeter
Array (SMA). Our spatially resolved CO(3-2) and HCO+(4-3) emission
peaks between the two nuclear components that are known to both harbor AGNs.
The kinematical information provided by the CO(3-2) emission shows a rotating
disk centered around the northern AGN and a possible face-on disk around the
southern AGN, but the kinematics of gas between the two nuclei is extremely
turbulent.
l
Iono,
D., S. Takakuwa, R. Kawabe, B. Vila-Vilaro, M. Saito, and Y. Tamura [2007b],
"ALMA Imaging Simulations of Nearby and Distant Colliding Galaxies,"
Proceedings in "From Z-Machines to ALMA:(Sub)Millimeter Spectroscopy of
Galaxies", eds. Andrew J. Baker, Jason Glenn, Andrew I. Harris, Jeffrey G.
Mangum and Min S. Yun, ASP Conf. Ser. vol.375, pp.242-245.
Ø
We
present preliminary ALMA (12 m array + ACA) imaging simulations of nearby (D =
300 Mpc) and distant (z = 3) colliding galaxy systems. It is found that the
addition of the ACA will significantly improve the image quality for nearby
systems, but the expected improvements in image quality from adding the ACA for
high-z observations are limited for this particular model observed at 345 GHz.
Improvements are, however, seen when the target source is more extended than
the model used here, or when higher frequency bands are used. These imaging
simulations are especially important for investigating the characteristics of
existing imaging techniques, and for optimizing the pipelining of ALMA data.
l
Iono,
D., M. S. Yun, M. Elvis, A. B. Peck, P. T. P. Ho, D. J. Wilner, T. R. Hunter,
S. Matsushita, and S. Muller [2007c], "A Tentative Detection of [C II]
Line Emission in the z=4.7 QSO BR1202-0725," Proceedings in "From
Z-Machines to ALMA:(Sub)Millimeter Spectroscopy of Galaxies", eds. Andrew
J. Baker, Jason Glenn, Andrew I. Harris, Jeffrey G. Mangum and Min S. Yun, ASP
Conf. Ser. vol.375, pp.246-249.
Ø
Our new
SMA ~ 3'' resolution 900 Źm image of the z=4.7 QSO BR1202-0725 shows two submillimeter
continuum components, consistent with previously published mm images. We
further tentatively detect the redshifted [C II] line emission from the
northern component BR1202N. The derived [C II]-to-FIR luminosity ratio (0.03%)
is comparable to the ratios found in local ULIRGs. In addition, by analyzing
archival Chandra data, we detect X-ray emission in both submm components. We
conclude that BR1202-0725 is likely a pair of AGN host galaxies at z = 4.7,
with both galaxies forming stars at exceedingly high rates.
l
Iono,
D., C. Wilson, S. Takakuwa, M. Yun, G. Petitpas, A. Peck, P. T. P. Ho, S.
Matsushita, Y. Pihlstrom, and Z. Wang [2007d], "High Resolution Imaging of
Warm and Dense Molecular Gas in the Nuclear Region of the Luminous Infrared
Galaxy NGC6240," Astrophys. J., vol.659, pp.283-295.
Ø
We
present ~2" resolution CO (3-2), HCO+(4-3), and 880 Źm
continuum images of the luminous infrared galaxy NGC 6240 obtained at the
Submillimeter Array. We find that the spatially resolved CO (3-2), HCO+
(4-3), and the 880 mum emission peaks between the two nuclear components that
are both known to harbor AGNs. Our large velocity gradient (LVG) analysis
performed on each velocity channel suggests that the peak of the molecular gas
emission traced in our observations is warm (T=20-100 K), dense (nH2=105.0-105.4
cm-3), and moderately
optically thin (tau=0.2-2) in the central 1 kpc. We also find large column
densities of ~1023 cm-2. Such extreme conditions are
observed over ~300 km s-1 centered around the CO-derived systemic
velocity. The derived molecular gas mass from the CO (3-2) emission and a
CO-to-H2 conversion factor commonly used for ULIRGs is (6.9}1.7) 109
Msolar, and this is consistent with the mass derived from previous
CO (2-1) observations. The gas is highly turbulent in the central kpc (¢vFWZI~1175
km s-1). Furthermore, possible inflow or outflow activity is
suggested from the CO (3-2) velocity distribution. We tentatively state that
3.5x108 Msolar of isolated CO (3-2) emission seen west of
the northern disk may be associated with outflows from starburst superwinds,
but the gas outflow scenario from one of the central AGN is not completely
ruled out. Piecing all of the information together, the central region of NGC
6240 harbors 2 AGNs, ~1010 Msolar of molecular gas mass,
5x107 Msolar of dust mass, and has possible evidence of
inflow and outflow activity.
l
Ishitsuka,
J., M. Ishitsukam, N. Kaifu, S. Miyama, M. Inoue, M. Tsuboi, M. Ohishi, K.
Fujisawa, T. Kasuga, K. Miyazawa,
and S. Horiuchi [2004], "A 32 m Parabolic Antena in Pery at 3,370 m of
Altitude," Proc. of the 7th Symposium of the European VLBI Network on New
Developments in VLBI Science and Technology, Edited by R. Bachiller, F.
Colomer, J.-F. Desmurs, and P. de Vicente, pp.295-296.
Ø
At the
altitude of 3,370 m on the Peruvian Andes, a 32m antenna owned by the
telecommunications company Telef nica del Per will be transformed to a Radio
Telescope, it would be transferred to the Geophysical Institute of Peru (IGP).
The parabolic antenna was constructed in 1984 by Nippon Electric Co. (NEC) and
worked as an INTELSAT station until 2000. A team of the National Observatory of
Japan (NAOJ) evaluated the antenna in 2003 and reported its availability to be
used as a Radio Telescope. In collaboration of the NAOJ a 6.7 GHz receiver is
under construction and will be installed within this year. Initially the
telescope as a single dish will monitor and survey Methanol Maser of YSO,
higher frequencies equipment and VLBI instruments will be considered. The
antenna will be managed by the IGP and used by universities in Peru, becoming a
VLBI station will be a grate contribution to astronomy and geodetic community.
l
Ishitsuka,
J. K., M. Ishitsuka,M. Inoue, N. Kaifu, S. Miyama, M. Tsuboi, M. Ohishi, K.
Fujisawa, T. Kasuga, T. Kondo, S. Horiuchi, T. Umemoto, M. Miyoshi, K.
Miyazawa, T. Bushimata, and E. D. Vidal [2006], "A New Astronomical
Facility for Peru: Converting a Telecommunication's 32 Meter Parabolic Antenna
into a Radio Telescope," International Astronomical Union XXVIth General
Assembly, Pragua, 14-25 August, 2006, abstract book, p.477 (SPS5-55 Oral
presentation).
Ø
In 1984
Nippon Electric Company constructed an INTELSAT antenna at 3,370 meters the sea
level on the Peruvian Andes. Entel Peru, the Peruvian telecommunications
company, managed the antenna station until 1993. This year the government
transferred the station to a private telecommunications company, Telefonica del
Peru. Since the satellite communications were rapidly replaced by transoceanic
fiber optics, the beautiful 32 meters parabolic antenna has been unused since
2002. In cooperation with the National Astronomical Observatory of Japan we
began to convert the antenna into a radio telescope. Because researches on
interstellar medium around Young Stellar Objects (YSO) will be able to observe
the methanol masers that emit at 6.7 GHz, initially we will monitor the 6.7 GHz
methanol masers and survey the southern sky. An ambient temperature receiver
with Trx=60K was developed at Nobeyama Radio Observatory and is ready to be
installed. The antenna control system is the Field System FS9 software
installed in a Linux PC. An interface between the antenna and the PC was
developed at Kashima Space Center in Japan. In the near future we plan to
install the 2 GHz, 8GHz, 12GHz, and 22GHz receivers. The unique location and
altitude of the Peruvian Radio Observatory will be useful for VLBI observations
in collaboration with global arrays such as the VLBA array for astronomical
observation and geodetic measurements. For Peru where few or almost no
astronomical observational instruments are available for research, the
implementation of the first radio observatory is a big and challenging step,
and foster sciences at graduate and postgraduate levels of universities.
Worldwide telecommunications antenna possibly are unused and with relative few
investment could be transformed into a useful observational instrument.
l
Ishitsuka,
J. K., Ishitsuka, M. Kaifu, N., Inoue, M., Tsuboi, M., Ohishi, M., Kondo, T.,
Koyama, Y., Kasuga, T., Fujisawa, K., Miyazawa, K., Miyoshi, M., Umemoto, T.,
Bushimata, T., Horiuchi, S., and Vidal, E. D.:A New Astronomical Facility for
Peru: Converting a Telecommunication's 32 Meter Parabolic Antenna into a Radio
Telescope,Proc. of the "Astronomy for the Developing World: IAU 26th
General Assembly in Pragua". eds. J. B. Hearnshaw and P. Martinez, 77-82,
2007.
Ø
Not
Available
l
Ita, Y.,
S. Deguchi, N. Matasunaga, and H. Fukushi [2006], "Search for SiO Masers
in Nearby Miras Pulsating in the First Overtone Mode," Proc. of the
conference "Stellar Pulsation and Evolution", eds. A. R. Walker and
G. Bono, Mem. Soc. Astr. It., vol.77, pp.85-88.
Ø
We
studies the period-K magnitude (P-K) relations of nearby Mira and Mira-like
variables with relatively good Hipparcos parallaxes. They form at least two
prominent sequences on the P-K plane, corresponding to the sequences C (Mira
variables pulsating in the fundamental mode) and C' (Mira variables pulsating
in the 1st overone mode), that were found in the LMC. As a part of an ongoing study
to see the differences between the Mira variables pulsating in the fundamental
and the 1st overone mode, we searched for SiO masers in the nearby variables on
the sequences C' and C using the Nobeyama 45m radio telescope. We observed 28
selected nearby Mira and Mira-like variables without previous maser
observations, and found 3 new emitters. The observational result shows that
there is few or no SiO maser emitters pulsating in the 1st overone mode.
l
Iwata,
I., K. Ohta, K. Nakanishi, P. Chamaraux, and A. Roman [2005], "The Growth
of the Local Void and the Origin of the Local Velocity Anomaly," Proc. of
the "Nearby Large-Scale Structures and the Zone of Avoidance", eds.
A. P. Fairall and P. A. Woudt, ASP Conf. Ser. vol.329, pp.59-66.
Ø
The
Local Void is the nearest void from us and is thought to be playing an
important role in the kinematics of the local universe, especially as one of
the suspected source of the motion of the Local Group. The imbalance between
the mass in the Local Void region and that contained in the concentration at
the opposite side might contribute to the velocity of the Local group
perpendicular to the Supergalactic plane, and this would be a prototype of the
evolution of the large-scale structure. The proximity of the Local Void provides
us the exclusive opportunity to investigate the kinematics around a void. Here
we report the results of our observational study of the peculiar velocities of
about 40 galaxies at the far-side of the Local Void, using the near-infrared
Tully-Fisher relation. The galaxies at the boundary of the void shows an excess
of receding motion, suggesting the expansion of the Local Void. We examined the
effect of selection biases on the peculiar velocity distribution, and concluded
that the excess of receding motion could not fully attribute to selection
biases.
l
Kamazaki,
T., H. Ezawa, K. Tatematsu, N. Yamaguchi, N. Kuno, K.-I. Morita, K. Yanagisawa,
O. Horigome, and J. Maekawa [2005], "The Remote Control System for the
ASTE Telescope," Proc. of the "Astronomical data analysis software
and system XIV", eds. P. Shopbell, M. Britton, and R. Ebert, ASP Conf.
Ser. vol.347, pp.533-537.
Ø
The
Atacama Submillimeter Telescope Experiment (ASTE) is a project to operate a
10-m submillimeter telescope at a high altitude site (4,800 m) in the Atacama
desert in northern Chile. The key to successful telescope operation under the
severe environment of the observing site is to realize a stable remote control
system. The remote control system for ASTE consists of a newly developed
operating software capable of remote observation and a satellite network
facility (56-64 kbps), which connects the telescope site to the outside world
including the operation base in San Pedro de Atacama (altitude 2,400 m) or
institutes in Japan. The control software was developed based on the existing
COSMOS3 system, which has been used for the 45-m telescope and the Millimeter
Array (NMA) of the Nobeyama Radio Observatory (NRO) in Japan. The telescope
operation with N-COSMOS3 in Chile started in April 2002. We have succeeded in
the first remote observation from the base in San Pedro de Atacama in July
2002, followed by the first successful remote observation from Japan in October
2003.
l
Kamegai,
K., M. Hiramatsu, T. Hayakawa, K. Tatematsu, T. Hasegawa, T. Onishi, and A.
Mizuno [2007], "Submillimeter-Wave Observations of Outflow and Envelope
around the Low Mass Protostar IRAS 13036-7644," Proc. of the IAU Symp,
237, "Triggered Star Formation in a Turbulent Interstellar Medium",
eds. B. G. Elmegreen & J. Palous, p.432.
Ø
The
interaction between molecular outflow from a protostar and ambient molecular
cloud would play an important role in dissipating circumstellar envelope,
changing chemical composition, and triggering next generation star formation.
In order to investigate the interaction in submillimeter wavelength, we have
made line observations toward the low mass protostar IRAS 13036-7644 (Class
0/I) in the Cha II dark cloud. Although millimeter observations found CO
outflow and evidence of mass infall toward the protostar (e.g. Lehtinen 1997),
no submillimeter observation has been reported so far.
l
Kameno,
S., M. Inoue, Z.-Q. Shen, S. Sawada-Satoh, and K. Wajima [2004],
"Multi-Frequency VLBI Observations of GHz-Peaked Spectrum Sources,"
Proc. of the 7th symposium of the European VLBI Network on New Developments in
VLBI Sciences and Technology, eds. R. Bachiller, F. Colomer, J.-F. Desmurs, and
P. de Vicente, pp.157-158.
Ø
We
report results of pentachromatic VLBI survey for 18 GHz-peaked spectrum
sources. Spectral fitting at every pixel across five frequencies allows us to
illustrate distribution of optical depth in terms of free-free absorption or
synchrotron self absorption. Quasars and Seyfert 1 sources show one-sided
morphology with a core at the end where the optical depth peaks. Radio galaxies
and Seyfert 2 show symmetric double-sided jets with a optically thick core at
the center.
l
Kameno,
S., N. Nakai, S. Sawada-Satoh, N. Sato, and A. Haba [2005a], "Emergence of
a Narrow H2O Maser Feature in NGC 1052," Astrophys. J.,
vol.620, pp.145-150.
Ø
We
report the emergence of a narrow H2O maser feature with an FWHM of
21 km s-1 in the LINER NGC 1052, which has been known to show only a
broad (FWHM>100 km s-1) maser line profile with relatively bright
continuum radio emission. The new narrow maser feature with a peak flux density
of 47 mJy at VLSR=1787 km s-1 is redshifted by 328 km s-1
with respect to the systemic velocity. Broad features with peak velocities of
1510 and 1704 km s-1, more redward than ever observed before, are
also detected. The profile of the new narrow feature possibly shows brightening
by 16%}9% and narrowing by 30%}12% between 2003 May 30 and June 2. During the
same time, the continuum flux density has increased by 21%. Synchronous
variation of maser and continuum flux densities on a timescale of days
resembles that in Mrk 348, which is also a broad megamaser source with a bright
radio continuum. Continuum and maser brightening and narrowing indicate that an
increase of the background seed photon and an increase of maser gain have
occurred simultaneously. A jet component running behind a mixture of ionized
regions and X-ray dissociation regions at a subrelativistic velocity can
produce such short-time variation. Another explanation is an interaction
between the jet and molecular clouds.
l
Kameno,
S., and VSOP-2 Science Working Group [2005b], "VSOP-2 Science Case,"
Proc. at the XXVIIIth General Assembly of the URSI, October 2005, India.
(CD-ROM : J04-P.5)
Ø
VSOP-2 is
a space VLBI project, following the VSOP (VLBI Space Observatory Programme),
organized by the space VLBI working group consisting of the Japan Aerospace
Exploration Agency (JAXA), the National Astronomical Observatory of Japan
(NAOJ), and the university interest group. We aim synthesis imaging with the
angular resolutions of 38, 75, and 205 microarcsec at 43, 22, and 8 GHz,
respectively, to unveil extremely compact celestial objects. Phase referencing
capability, 1-Gbps wideband downlink, and dual polarization receivers will be
able to provide high sensitivity, with the minimum detectable brightness
temperature of a few 108 K. Dual polarization observations are
supported for 4-Stokes-parameter imaging. The VSOP-2 science working group have
continued discussion on VSOP-2 science case. The main astronomical targets are
active galactic nuclei (AGNs) and young stellar objects (YSOs). VSOP-2 will
image accretion disks, roots of jets, and circumnuclear regions of nearby AGNs
with a resolution of ~ 10 Schwarzschild radii. It also allows us to investigate
magnetospheres, protoplanetary disks, and roots of outflows of YSOs with a
resolution of ~ 1 solar radius in nearby star-forming regions.
l
Kameno,
S., M. Inoue, K. Wajima, Z.-Q. Shen, and S. Sawada-Satoh [2005c], "Free-Free
Absorption towards Active Galactic Nuclei," Proc. of the "Future
Directions in High Resolution Astronomy: A Celebration of the 10th Anniversary
of the VLBA", eds. J. D. Romney, and M. J. Reid, ASP Conf. Ser. vol.340,
pp.145-149.
Ø
We
report results from multifrequency observations for 18 GHz-Peaked Spectrum
(GPS) sources, which show convex radio spectra due to Free-Free Absorption
(FFA). Trichromatic VLBA observations showed that radio galaxies and Seyfert-2
sources tend to show symmetric opacity distributions along double-sided jets
while asymmetric profiles are found in QSO and Seyfert-1. The significant
difference can be related to the orientation of the jets. Pentachromatic VSOP
and VLBA observations for the nearest object, NGC 1052, revealed spatial
distribution of cold dense plasma around the nucleus are obtained via opacities
of FFA. The density distribution indicates a dense disk or torus of ~ 1 pc in
radius.
l
Kameno,
S., Y. Murata, H. Hirabayashi, Y. Hagiwara, and M. Inoue [2006], "The
Space VLBI VSOP-2 to Image 10-Schwartzschild-Radii Vicinity of AGN
Engines," International Astronomical Union XXVIth General Assembly,
Pragua, 14-25 August, 2006, abstract book, p.178 (S238-115 Poster).
Ø
VSOP-2
is a space VLBI mission using the ASTRO-G satellite to be launched in 2012 by
the Japan Aerospace Exploration Agency (JAXA) and collaborated ground radio
telescopes. It will bring synthesis imaging capability with the angular
resolutions of 44, 87, and 240 Źas at 43, 22, and 8 GHz, respectively. Cooled
on-board dual polarization receivers, 1-Gbps wideband downlink, and phase
referencing capability will be able to provide highsensitivity, with the
minimum detectable flux densities of 6, 8, and 11 mJy or brightness
temperatures 7, 13, and 21 x 108 K, when correlated with 25-m ground
telescopes. Dual polarization observations are supported for
4-Stockes-parameter imaging. The primary aim of the VSOP-2 is to image
accretion disks around supermassive black holes in Active Galactic Nuclei
(AGNs). Accretion disks are considered to generation all of AGN power in ~10 -
100 Schwartzschild radii (r[s]). The disk size of nearby AGNs corresponds to
tens of as, comparable to
resolutions of the VSOP-2. The best target object is the radio galaxy M87,
which hosts a massive black hole of 3.2x109 solar masses, where
VSOP-2 resolution corresponds to 10 r[s]. There are at least three objects in
which the VSOP-2 beam is sharper than 20 r[s] and at least 13 objects for 200
r[s] within 20 Mpc. The VSOP-2 is the most promising telescope to image AGN
directly. Relativistic AGN jets are also main targets of the VSOP-2. It will
image fine structures in the jet formation region to clarify the acceleration
mechanism. Polarization imaging capabilities of VSOP-2 is essential to
illustrate magnetic fields which are related to physics of jets. In this
presentation we introduce a sneak preview of the extremely high-resolution
universe brought by the VSOP-2.
l
Kameya,
O., T. Kurayama, H. Suda, and Vera Members [2004], "H2O Maser
Observations of W3OH Using VERA," Proc.of the 7th Symposium of the
European VLBI Network on New Developments in VLBI Science and Technology,
Edited by R. Bachiller, F. Colomer, J.-F. Desmurs, and P. de Vicente,
pp.195-198.
Ø
We have
started multi-epoch differential VLBI observations towards W3(OH) H2O
maser source and a reference source J0244+6228 using VERA (VLBI Exploration of
Radio Astrometry), which has a dual beam VLBI system. Some results of the
observations will be shown. The H2O maser positions are basically
consistent to the former ones indicating that the mapping capability of VERA is
available for conventional mapping observations. The reference source
J0244+6228 was also detected with good S/N ratio and point-like indicating this
source is good for reference of differential VLBI. Our VERA system probably has
a good performance for VLBI imaging.
l
Kamikura,
M., Y. Tomimura, Y. Sekimoto, S. Asayama, W. Shan, N. Satou, Y. Iizuka, T. Ito,
T. Kamba, Y. Serizawa, and T. Noguchi [2006], "A 385-500 GHz
Sideband-Separating (2SB) SiS Mixer Based on a Waveguide Split-Block
Coupler," Int. J. of IR and MM Waves, vol.27, pp.37-53.
Ø
We have
developed a 385 - 500 GHz sideband-separating (2SB) mixer, which is based on a
waveguide split-block coupler at the edge of the H-plane of the 508 Źm x 254 Źm
(WR 2.0) waveguide, for the Atacama Large Millimeter/submillimeter Array
(ALMA). An RF/LO coupler, which contains an RF quadrature hybrid, two LO
couplers, and an in-phase power divider, was designed with the issue of
mechanical tolerance taken into account. The RF/LO coupler was measured
optically with a microscope and electrically with a submillimeter vector
network analyzer. The image rejection ratio (IRR) and the single-sideband (SSB)
noise temperature of the receiver using the RF/LO coupler have also been
measured. The IRR was found to be larger than 8 dB and typically ~ 12 dB in the
385 - 500 GHz band. The SSB noise temperature of this receiver is 80 K at the
band center, which corresponds to 4 times the quantum noise limit (hf/k) in
SSB, and 250 K at the band edges.
l
Kamohara,
R., S. Deguchi, M. Miyoshi, and
Z.-Q. Shen [2005], "Time Variation of SiO Masers in VX Sagittarii over an
Optically Quiescent Phase," Publ. Astron. Soc Japan, vol.57, pp.341-345.
Ø
The time
variation of SiO masers in a semi-regular variable, VX Sgr, was investigated in
the period between 1994 and 2004 when the optical light curve exhibited an
~6-yr quiescent phase intercepting a regularly pulsating era. The quiescent
period occurred with a delay of several years after a decrease in the SiO maser
flux. VLBA observations of SiO masers made during this period showed no drastic
spatial variation except for emission features being shifted from south-west to
north-east. The SiO maser flux decrease, and a succeeding optical quiescent
phase, may indicate that the stellar mass-loss rate diminished over a few years
around 1994. A SiO maser flare occurring in 1999 may be a reminiscence of a
final gas blow, which resulted in the optically quiescent period.
l
Kandori,
R., Y. Nakajima, M. Tamura, K. Tatematsu, Y. Aikawa, T. Naoi, K. Sugitani, H.
Nakaya, T. Nagayama, T. Nagata, M. Kurita, D. Kato, C. Nagashima, and S. Sato
[2005], "Near-Infrared Imaging Survey of Bok Blobules: Density
Structure," Astron. J., vol.130, pp.2166-2184.
Ø
On the
basis of near-infrared imaging observations, we derived the visual extinction
(AV) distribution toward 10 Bok globules through measurement of both the color
excess (EH-K) and the stellar density at J, H, and Ks (star count). Radial
column density profiles for each globule were analyzed with the Bonnor-Ebert
sphere model. Using the data of our 10 globules and four globules in the
literature, we investigated the stability of globules on the basis of Ģmax,
which characterized the Bonnor-Ebert sphere, as well as the stability of the
equilibrium state against gravitational collapse. We found that more than half
the starless globules are located near the critical state (Ģmax = 6.5}2). Thus,
we suggest that a nearly critical Bonnor-Ebert sphere characterizes the typical
density structure of starless globules. The remaining starless globules show
clearly unstable states (Ģmax > 10). Sine unstable equilibrium states are
not long maintained, we expect that these globules are on the way to
gravitational collapse or that they are stabilized by nonthermal support. It
was also found that all the star-forming globules show unstable solution of
Ģmax > 10, which is consistent with the fact that they have started
gravitational collapse. We investigated the evolution of a collapsing gas
sphere whose initial condition is a nearly critical Bonnor-Ebert sphere. We
found that the column density profiles of the collapsing sphere mimic those of
the static Bonnor-Ebert spheres in unstable equilibrium. The collapsing gas
sphere resembles marginally unstable Bonnor-Ebert spheres for a long time. We
found that the frequency distribution of Ģmax for the observed starless
globules is consistent with that from model calculations of the collapsing
sphere. In addition to the near-infrared observations, we out radio molecular
line observations (C18O and H2N+) toward the
same 10 globules. We confirmed that most of the globules are dominated by
thermal support. The line width of each globule was used to estimate the cloud
temperature including the contribution from turbulence, with which we estimated
the distance to the globules from the Bonnor-Ebert model fitting.
l
Kano,
R., H. Hara, M. Shimojo, and S. Tsuneta [2004], "Solar-B X-Ray Telescope
(XRT)," Proc. of the 5th Solar-B Science Meeting, "The Solar-B
Mission and the Forefront of Solar Physics : Dedicated to the Memory of Yutaka
Uchida", ASP Conf. Ser., vol.325, pp.15-25.
Ø
The Soft
X-ray Telescope (XRT) aboard SolarB is a grazing incidence X-ray telescope
equipped with 2kx2k CCD. XRT has 1 arcsec resolution with wide field-of-view of
34x34 arcmin. It is sensitive to <1 MK to 30 MK, allowing us to obtain
TRACE-like low temperature images as well. Co-alignment with SOT and EIS is
realized through the XRT visible light telescope and with temperature overlap
with EIS. Spacecraft mission data processor (MDP) controls XRT through the
sequence tables with versatile autonomous functions such as exposure control,
region-of-interest tracking, flare detection and flare location identification.
Data are compressed either with DPCM or JPEG, depending on the purpose. This
results in higher cadence and/or wider field-of-view for given telemetry
bandwidth. With focus adjust mechanism, higher resolution of Gaussian focus may
be available on-axis.
l
Kasai,
Y., E. Kagi, and K. Kawaguchi [2007], "Analysis of Radio Astronomical Data
of the Negative Ion C6H- in IRC +10 213," Astrophys.
J. (Letters), vol.661, pp.L61-L64.
Ø
Radio
astronomical data of C6H- observed with the Nobeyama 45 m
and IRAM 30 m telescopes have been analyzed by the local thermodynamic
equilibrium approximation to give the column density of (6.1-8.0)x1012
cm-2 and the excitation temperature of 32}3 K, with an assumed
source size of 30''}3''. The abundance of C6H- was
estimated to be 8.6% of C6H. The observed line shapes of C6H-
and C6H indicate that the distribution of C6H-
is more present in the inner region than C6H. The production
mechanism of C6H- is discussed.
l
Kasuga,
T., and M. Tsuboi [2005], "Upgrading at the 40 GHz 6-beam SIS Receiver for
Snuyaev-Zel'dovich Observations," Proc. at the XXVIIIth General Assembly
of the URSI, October 2005, India. (CD-ROM : JB-P.10)
Ø
We
conducted Snuyaev-Zel'dovich observation over 7 years using the Nobeyama 45m
telescope and the 40 GHz 6-beam SIS receiver. In 1998 the receiver dedicated to
the high-sensitivity continuum observation was constructed and boarded on the
45 m telescope. The multi beams and sensitive SIS receiver made it possible for
us to observe distant sources. In 2003 we started to reconstruct and upgrade
the receiver for deeper and more rapid observations and for mapping high-z source. The
points of this up-grade are the use of the cooled HEMT IF amplifier with more
wider bandwidth and stable SIS bias supplies that resist noise environments.
l
Kato,
D., C. Nagashima, T. Nagayama, M. Kurita, J. F. Koerwer, T. Kawai, T. Yamamuro,
T. Zenno, S. Nishiyama, D. Baba, R. Kadowaki, Y. Haba, H. Hatano, H. Shimizu,
M. Nishimura, T. Nagata, S. Sato, Y. Murai, T. Kawazu, Y. Nakajima, H. Nakaya,
R. Kandori, N. Kusakabe, A. Ishihara, N. Kaneyasu, J. Hashimoto, M. Tamura, T.
Tanab*, Y. Ita, N. Matsunaga, Y. Nakada, K. Sugitani, K. Wakamatsu, I. S.
Glass, M. W. Feast, J. W. Menzies, P. A. Whitelock, P. Fourie, J. Stoffels, G.
P. Evans, and T. Hasegawa [2007], "The IRSF Magellanic Clouds Point Source
Catalog," Publ. Astron. Soc. Japan, vol.59, pp.615-641.
Ø
We
present a near-infrared (JHKs) photometric catalog, including 14811185 point
sources for a 40 deg2 area of the Large Magellanic Cloud, 2769682
sources for an 11 deg2 area of the Small Magellanic Cloud, and
434145 sources for a 4 deg2 area of the Magellanic Bridge. The 10
limiting magnitudes are 18.8, 17.8, and 16.6 mag at J, H, and Ks, respectively.
The photometric and astrometric accuracies for bright sources are 0.03-0.04 mag
and 0".1, respectively. Based on the catalog, we also present (1) spatial
distributions, (2) luminosity functions, (3) color-color diagrams, and (4)
color-magnitude diagrams for point sources toward the Magellanic Clouds.
l
Kawabe,
R. [2005], "Progress Report in the Japanese ALMA Project," Proc. of
the "The Cool Universe: Observing Cosmic Dawn", eds. C. Lidman and D.
Alloin, ASP Conf. Ser. vol.344, pp.237-241.
Ø
We
report here on the progress of the Japanese ALMA project (ALMA-J). The Japanese
ALMA project culminates 20 years of development. There are two main Japanese
contributions to the ALMA project, commonly called "enhancements''. One is
the design and construction of the Atacama Compact Array (ACA). ACA is composed
of a total power array with four 12 m antennas and a 7 m array with twelve 7 m
antennas. The main role of ACA is to guarantee high fidelity imaging by
combining total power data and short baseline data with data that are taken
with the larger 64 antenna array. The other enhancement is the production of 80
receiver cartridges for each of three bands, bands 4, 8, and 10, to be
installed into both the 64 antenna array and the 16 ACA antennas. The
construction budget for these enhancements has been funded since April 2004.
l
Kawaguchi,
K., R. Fujimori, S. Aimi, S. Takano, E. Y. Okabayashi, H. Gupta, S. Brunken, C.
A. Gottlieb, M. C. McCarthy, and P. Thaddeus [2007], "Observation of H8H-
toward IRC+10216," Publ. Astron. Soc. Japan, vol.59, pp.L47-L50.
Ø
Five
rotational lines of the C8H- ion were observed in the
circumstellar envelope of IRC+10216 with the Nobeyama 45m telescope. An
improved value of the column density of the C8H radical yielded a [C8H-]/[C8H]
ratio of 37% - nearly 4 times larger than the [C6H-]/[C6H]
ratio (8.6%) and nearly 1500 times the [C4H-]/[C4H]
ratio (0.024%), which may indicate more efficient formation of longer carbon
chain anions. The excitation temperature of C8H- (16}2K)
derived here is somewhat lower than that of the two smaller anions C6H-
(32K) and C4H- (23K) in IRC+10216.
l
Kawaguchi,
N., Y. Kono, and H. Suda [2005], "Detection of Faint Radio Sources by
Using an Optical Fiber Connected VLBI Array," Proc. at the XXVIIIth
General Assembly of the URSI, October 2005, India. (CD-ROM : J06-P.4)
Ø
Not
Available
l
Kawamura,
A., T. Minamidani, Y. Mizuno, N. Mizuno, T. Onishi, A. Mizuno, Y. Fukui, M.
Filipovic, L. Staveley-Smith, L. E. B. Johansson, S. Nikoloc, R. S. Booth, A.
Heikkila, L.-A. Nyman, M. Lerner, K. Tatematsu, T. Hasegawa, and M. Ikeda [2007a],
"Molecular Clouds and Star Formation in the Large Magellanic Cloud,"
Proceedings in "Protostars and Planets V", LPI contribution no. 1286,
p.8300.
Ø
Not
Available
l
Kawamura,
A., T. Minamidani, Y. Mizuno, T. Onishi, N. Mizuno, A. Mizuno, and Y. Fukui
[2007b], "Giant Molecular Clouds and Star Formation in the Large
Magellanic Cloud," Proc. of the IAU Symp, 237, "Triggered Star
Formation in a Turbulent Interstellar Medium", eds. B. G. Elmegreen &
J. Palous, pp.101-105.
Ø
In order
to elucidate star formation in the Large Magellanic Cloud, a complete survey of
the molecular clouds was carried out by NANTEN. In this work, we compare 230
giant molecular clouds (GMCs), whose physical quantities are well determined,
with young clusters and HII regions. We find that about 76% of the GMCs are
actively forming stars or clusters, while 24% show no signs of massive star or
cluster formation. Effects of supergiant shells (SGSs) on the formation of GMCs
and stars are also studied. The number and surface mass densities of the GMCs
are higher by a factor of 1.5-2 at the edge of the SGSs than elsewhere. It is
also found that young stellar clusters are more actively formed in the GMCs
facing to the center of the SGSs. These results are consistent with the
previous studies by Yamaguchi et al. and suggest the formation of GMCs and the
cluster is triggered by dynamical effects of the SGSs
l
Kikuchi,
F., J. Ping, X. Hong, Y. Aili, Q. Liu, K. Matsumoto, K. Asari, S. Tsuruta, Y.
Kono, H. Hanada, and N. Kawano [2005], "VLBI Observations of Narrow
Bandwidth Signals from the Spacecraft," 36th Ann. Lunar & Planetary
Sci. Conf., abstract no. 1551.
Ø
We
carried out a VLBI observation of GEOTAIL by using a narrow bandwidth system. A
few carrier waves with frequency interval of 1.5 MHz were correlated by
software. As a result, the group delay was estimated within an error of less
than 1 ns.
l
Kinoshita,
D., K. Ohtsuka, T. Sekiguchi, J. Watanabe, T. Ito, H. Arakida, T. Kasuga, S.
Miyasaka, R. Nakamura, and H.-C. Lin [2007], "Surface Heterogeneity of 2005
UD from Photometric Observations," Astron. Astrophys., vol.466,
pp.1153-1158.
Ø
Context.
The recently discovered Apollo-type near-Earth asteroid 2005 UD has been
suggested to be a fragment of (3200) Phaethon. Aims. To test this hypothesis,
we carried out photometric observations of 2005 UD using the 1-m telescope at
Lulin Observatory. Methods. Multi-color photometry was used to compare the
surface properties of (3200) Phaethon and 2005 UD. Surface-color variation due
to the rotation was also examined. Results. The time-resolved differential
photometry showed clear brightness variation, and the lightcurve was fitted
with a rotation period of 5.23 h and an amplitude of 0.44 mag. Using this
rotational lightcurve, we derived the surface colors of 2005 UD. The surface of
2005 UD exhibits colors similar to those of F- and B-type asteroids, which is
consistent with (3200) Phaethon. Furthermore, the (R-I) color of 2005 UD shows
variation during the rotation of the body. Conclusions. The similarity of
surface colors between (3200) Phaethon and 2005 UD observationally supports the
hypothesis that 2005 UD is likely to be a fragment of (3200) Phaethon. A simple
explanation for the inhomogeneity of the surface is that we see the surface and
subsurface of the precursor object. Another explanation is the topographical
structure that such as a large crater causes on this heterogeneous surface.
l
Kiuchi,
H. [2005], "Parallel Bit Stream Correlation System for Very Long Baseline
Interferometry," Radio Science, vol.40, p.RS5013.
Ø
Improvements
in sampling and recording technology have made it possible to acquire data at
rates of higher than 1 Gbit/s. In very long baseline interferometry, the use of
wide-bandwidth data produces a high SNR, which is proportional to $\sqrt{2BT (B
is bandwidth and T is integration time). In astronomical applications,
wide-bandwidth data acquisition can be used to detect very small flux densities
of cosmic radio sources. It is also useful in geodetic applications. The signal
processing of the current correlation processing algorithm is bit serial. The
data-processing speed, however, is restricted by the correlation device clock
in serial data processing, and as a result, the device speed prevents the whole
(channel) bandwidth from being used for observations. To overcome this problem,
a new correlation processing algorithm for parallel bit stream set processing
has been developed. This article focuses on how to derive serial data
processing algorithms for parallel bit stream.
l
Kiuchi,
H., T. Kawanishi, M. Yamada, T. Sakamoto, M. Tsuchiya, J. Amagai, and M. Izutsu
[2007a], "High Extinction Ratio Mach-Zehnder modulator Applied to a Highly
Stable Optical Generator," IEEE Trans. on Microwave Theory and Techniques,
vol.55, pp.1964-1972.
Ø
Research
into optical modulators has made remarkable progress in recent years. This
paper discusses the possibility of applying the high extinction ratio optical
modulator to a high-stability and high-frequency (over 100 GHz) optical
reference signal generator. High-frequency reference signals are generated by a
highly stable optical two-tone generator, which is used for high-rate
communication and astronomical application. One method to generate two optical
signals is producing them from a pair of laser sources using an optical phase-locked
loop for feed back control; however, the optical phase-locked loop has a
stability problem in its operation. A good alternative method to the optical
phase-locked scheme is the LiNbO3 Mach-Zehnder (MZ) optical
intensity modulator, which is capable of generating two highly stable optical
signals (upper sideband and lower sideband components) by applying a sinusoidal
microwave signal to an input laser signal. The two optical signals require
phase stability better than 10-13 in the Allan standard deviation,
vibration robustness, and polarization maintaining capability. The signal
coherence loss estimated from the phase stability of the two optical signals
generated by the MZ modulator shows that the optical MZ modulator has the
ability to generate highly stable optical signals.
l
Kiuchi,
H., S. Okumura, J. Amagai, S. Iguchi, and T. Kondo [2007b], "Directory
Controlled Reference Frequency Wavefront Clock Method Applied to 100-GHz Radio
Interferometry and Fringe Simulator," Radio Science, vol.42, p.RS3012 (1 of
11).
Ø
Currently,
there are tow types of interferometers in the world: One is the conventional
interferometer using the fixed local signal as a reference signal, and the
other interferometer using the wavefront clock. In this paper, we propose a new
method of the wavefront clock system under development. The new wavefront clock
system has a great advantage for the Doppler compensation. The Doppler
shift,which is caused by the Earth's rotation, is compensated for during the
correlation processing or when signals are received in order to detect fringes
(interferometer patterns). Also, the proposed interferometry. The main feature
of this method is that the reference signals for the front end and back end of
the interferometer system are directly controlled from the observing site
according to a calculated a priori delay rate. In this method, fringe stopping
and delay tracking can be simultaneously performed on all received frequencies
as well as on frequency-converted signals in both the upper sideband (USB) and
lower sideband (LSB). Furthermore, this method can be introduced with just a
slight modification to the current interferometer systems (including very long
baseline interferometry) and can also be applied to a pseudofringe (Doppler
shift and delay) simulator to check the correlation processor.
l
Knapen,
J. H., R. J. Allen, H. I. Heaton, N. Kuno, and N. Nakai [2006], "CO
Emission from Candidate Photo-Dissociation Regions in M 81," Astron.
Astrophys., vol.455, pp.897-902.
Ø
Context:
At least a fraction of the atomic hydrogen inspiral galaxies is suspected to be
the result of molecular hydrogen which has been dissociated by radiation from
massive stars.
Aims: In this paper, we extended our earlier set of data from a small region of
the Western spiral arm of M 81 with CO observations on order to study the
interplay between the radiation filed and the molecular and atomic hydrogen.
Methods: We report CO(1-0) observations with the Nobeyama 45 m dish and the
Owens Valley interferometer array of selected regions in the Western spiral arm
of M 81.
Results: From our Nobeyama data, we detect CO(1-0) emission at several
locations, coinciding spatially with HI features near a far-UV source. The
levels and widths of the detected CO profiles are consistent with the CO(1-0)
emission that can be expected from several large photo-dissociation regions
with typical sizes of some 50 x 150 pc located within our telescope beam. We do
not detect emission at other pointings, even though several of those are near
far-UV sources and accompanied by bright HI. This non-detection is likely a
consequence of the marginal area filling factor of photo-dissociation regions
in our observations. We detect no emission in our Owens Valley data, consistent
with the low intensity of the CO emission detected in that field by the
Nobeyama Dish.
Conclusions: We explain the lack of CO(1-0) emission at positions farther from
far-UV sources as a consequence of insufficient heating and excitation of the
molecular gas at these positions, rather than as an absence of molecular
hydrogen.
l
Kobayashi,
H., N. Kawaguchi, S. Manabe, T. Omodaka, O. Kameya, K. M. Shibata, T. Miyaji,
M. Honma, Y. Tamura, T. Hirota, H. Imai, S. Kuji, K. Horiai, K. Sakai, K. Sato,
K. Iwadate, Y. Kan-ya, T. Jike, T. Fujii, and T. Kasuga [2004], "VERA
System," Proc. of the 7th Symposium of the European VLBI Network on New
Developments in VLBI Science and Technology, eds. R. Bachiller, F. Colomer,
J.-F. Desmurs, and P. de Vicente, pp.275-278.
Ø
VERA is
the first VLBI array to be designed to be free from the atmosphere phase
fluctuations. It has four VLBI station with 2,300 km maximum baseline length
within Japan islands. To compensate phase fluctuations of interferometer
visibilities, which are mainly caused by the atmosphere and local oscillators,
VERA antenna has two receivers and observes two objects simultaneously. By the
comparison the visibility phase between these two objects, simultaneous phase
referencing VLBI will be achieved. The goal accuracy of astrometry observations
is 10 micro arcseconds. . Currently the construction of four stations was
complete. And test observations are undergoing and phase fluctuations are
ideally compensated between two objects. We show the scientific goal,
instrumental accuracy and some results of VERA.
l
Kobayashi,
H., N. Kawaguchi, S. Manabe, T. Omodaka, K. M. Shibata, M. Honma, Y. Tamura, O.
Kameya, T. Hirota, and H. Imai [2005a], "The VERA Project (VLBI
Exploration of Radio Astrometry)," Proc. of the IAU Colloq. 196,
"Transits of Venus: New Views of the Solar System and Galaxy", ed. D.
W. Kurtz, p.496.
Ø
VLBI -
Very Long Baseline Interferometry - is a radio interferometry technique which
provides the highest spatial resolution observations to human kind. But at the
present, the accuracy of the astrometry observations is limited by the
atmospheric light path variations and instrumental phase errors, and only group
delay measurements are used. To overcome these error factors, we have developed
the VERA system, which has the first dual beam system. VERA is the first VLBI
array to be free from the atmospheric phase fluctuations. It has four VLBI
stations with 2300-km maximum baseline length in Japan. To compensate phase
fluctuations of interferometer visibilities, which are mainly caused by the
atmosphere, the VERA antenna observes two objects simultaneously. In order to
do observations, VERA has a two-receiver system, which tracks a focal plane
according to a separation angle between observing objects. By comparing the
visibility phase between two beams, simultaneous phase referencing VLBI will be
achieved. The goal accuracy astrometry observations is 10 micro-arcseconds,
which makes parallax and proper motion measurements of galactic maser possible.
10 micro-arcsecond accuracy is equivalent to 10% distance accuracy for the
galactic centre. This becomes 20% accuracy at the opposite side of the galaxy.
The main scientific targets of VERA are to make a 3-dimensional maser object
map of the galaxy and reveal the velocity field of the galaxy. This will show
the mass distribution of the galaxy. Currently, construction of four stations
is complete, and test observations are underway. We show the scientific goal,
current results and instrumental accuracy of VERA.
l
Kobayashi,
H., N. Kawaguchi, S. Manabe, T. Omodaka, K. M. Shibata, T. Miyaji, M. Honma, O.
Kameya, Y. Tamura, T. Hirota, H. Imai, S. Kuji, K. Horiai, S. Sasaki, K.
Iwadate, Y. Kan-ya, T. Jike, T. Fujii, T. Oyama, and T. Kurayama [2005b],
"Progress of VERA Project," Proc. at the XXVIIIth General Assembly of
the URSI, October 2005, India. (CD-ROM : J01.3)
Ø
VERA is
the first VLBI array, which is designed to be free from the atmosphere phase
fluctuations. It has four VLBI station with 2,300 km maximum baseline length
within Japan islands. And observing frequency bands are 2. 8. 22. and 43 GHz.
22 and 43 GHz bands are mainly used for H2O and SiO maser objects observations,
respectively. And 2 and 8 GHz bands are mainly used for geometric observations
to determine the station positions. And VERA uses a 1Gbps recording system with
cassette magnetic tapes. They are correlated by the VSOP correlator at Mitaka.
l
Kobayashi,
H., Z.-Q. Shen, and H. Minh [2005c], "Activities of East Asia VLBI
Network," Proc. at the XXVIIIth General Assembly of the URSI, October
2005, India. (CD-ROM : J01.4)
Ø
The
consortium of East Asia VLBI network was established on November of 2004. And
the committee members are elected from China, Japan and Korea. At the meeting
of the millimeter VLBI in 2003, which was held on Shanghai, a preparation
committee was established to organize the consortium committee.
l
Kobayashi,
K., K. Ogata, S. Tsunekawa, and S. Takano [2007], "Torsionally Excited
Methyl Formate in Orion KL," Astrophys. J., vol.657, pp.L17-L19.
Ø
We
report the first detection of rotational transitions of methyl formate (HCOOCH3)
in the first torsionally excited state (vt =1). Recent progress on
the assignment of laboratory spectra of methyl formate made it possible for us
to assign about 20 unidentified lines in Orion KL from previous line surveys
below 200 GHz to the first torsionally excited methyl formate. The rotational
temperature and column density obtained in the first torsionally excited state
were 44}10 K and( 8.6}3.2) x 1014 cm-2, respectively.
They were compared with those in the ground state.
l
Kobayashi,
N., C. Yasui, A. T. Tokunaga, and M. Saito [2007], "Embedded Stellar
Clusters in the Most Distant Molecular Cloud in Far Outer Galaxy: a Laboratory
for Supernova Triggered Star Formation," Proceedings in "Protostars
and Planets V", LPI contribution no. 1286, p.8639.
Ø
Not
Available
l
Koda,
J., T. Okuda, K. Nakanishi, N. Kuno, S. K. Okumura, K. Kohno, and S. Ishizuki
[2004a], "Interferometer SO Survey of Early-Type Spiral Galaxies,"
Proc. of "The Neutral ISM in Starbust Galaxies", eds. S. Aalto, S.
Huttemeiister, and A. Pedlar, ASP Conf. Ser. vol.320, pp.42-43.
Ø
We
report an on-going interferometer CO survey of early-type spiral galaxy
(S0-Sab). We have observed 5 targets with HII region-like nuclei. Distinct
nature of nuclear star formation from global ones in disk galaxies has been
reported in many studies (Kennicutt 1998 for review). In contrast to low global
star formation in early-type disks, vigorous circumnuclear star formation is
sometimes found in early-type galaxies. Ho, Filippenko, & Sargent (1997a)
reported (1) that the occurrence for hosting HII-nuclei (HII regions-like
spectra) is less frequent in early-type spirals than in late-type spirals, (2)
however that among the galaxies with HII-nuclei, the average H -luminosity in
early-type spirals is higher than that in late-types. Therefore, assuming a
constant star formation efficiency, it is expected that early-type spirals
would have larger gas mass in circumnuclear regions than late-types. However,
our survey so far indicates the opposite trend: our early-type samples have
smaller gas masses than the late-type (collected from the literature), although
both samples shows similar dynamical masses and star formations rates.
l
Koda,
J., and T. Sawada [2004b], "Preferential Direction of Supersonic Motion in
Molecular Clouds," American Astronomical Society Meeting 205, #59.08.
Ø
CO data
are analyzed to understand the shape and internal motion of molecular clouds in
the Milky Way. For a sample of more than five hundreds molecular clouds, we
find on a statistical basis that they are preferentially elongated toward the
Galactic plane. The elongations are not supported by internal spins but by
internal supersonic motions. It has been known that an external driving
mechanism for the supersonic velocity dispersion is necessary to prevent their
rapid decay. The mechanism must also account for the preferential direction of
molecular clouds. This constraint excludes some suggested mechanisms, such as
supernovae and stellar winds, because they do not produce the preferential direction
along the Galactic plane.
l
Koda,
J., T. Okuda, K. Nakanishi, K. Kohno, S. Ishizuki, N. Kuno, and S. K. Okumura
[2005a], "Starbursting Nuclear CO Disks of Early-Type Spiral
Galaxies," Astron. Astrophys., vol.431, pp.887-891.
Ø
We have
initiated the first CO interferometer survey of early-type spiral galaxies
(S0-Sab). We observed five early-type spiral galaxies with HII nuclei
(indicating circumnuclear starburst activities). These observations indicate
gas masses for the central kiloparsec of ~1~5% of the dynamical masses. Such
low gas mass fractions suggest that large-scale gravitational instability in
the gas is unlikely to be the driving cause for the starburst activities. We
estimated Toomre Q values and found that these galaxies have Q>1 (mostly
>3) within the central kiloparsec, indicating that the gas disks are
globally gravitationally stable. From the brightness temperatures of the CO
emission we estimated the area filling factor of the gas disks within the
central kiloparsec to be about 0.05. This small value indicates the existence
of lumpy structure, i.e. molecular clouds, in the globally-gravitationally
stable disks. The typical surface density of the molecular clouds is as high as
~3000 M⦿ pc-2. In the light of these new observations, we
reconsider the nature of the Toomre Q criterion, and conclude that the Toomre Q
parameter from CO observations indicates neither star formation nor molecular
cloud formation. This argument should be valid not only for the circumnuclear
disks but also for any region in galactic disks. We tentatively explore an
alternative model as an initiating mechanism of star formation. Cloud-cloud
collisions might account for the active star formation.
l
Koda,
J., and T. Sawada [2005b], "Results from the Nobeyama/CSO/ASTE Galactic
Plane CO Survey," American Astronomical Society Meeting 207, #81.24.
Ø
We
present the first results from our Galactic CO survey. We observed a test
region in the Galactic plane (0.35deg x 0.5deg) in 12 & 13 CO J=1-0, 2-1,
3-2 lines. We used the Nobeyama 45m telescope, Caltech Sumbillimeter
Observatory (CSO), and Atacama Submillimeter Telescope Experiment (ASTE). We
found that the molecular gas in interarm regions don't have clumpy structure
and is largely extended, although the gas in arms is clumpy. The ratio analyses
among the transitions indicate that the interarm gas is cooler than the arm
gas.
l
Koda,
J., T. Sawada, T. Hasegawa, and N. Scoville [2006a], "The Elongations and
Supersonic Motions of Molecular Clouds," Astrophys. J., vol.638,
pp.191-195.
Ø
New 13CO
data from the BU-FCRAO Milky Way Galactic Ring Survey (GRS) are analyzed to
elucidate the shape and internal motions of molecular clouds. For a sample of
more than 500 molecular clouds, we find that they are preferentially elongated
along the Galactic plane. On the other hand, their spin axes are randomly
oriented. We therefore conclude that the elongation is not supported by
internal spin but by internal velocity anisotropy. It has been known that some
driving mechanisms are necessary to sustain the supersonic velocity dispersion
within molecular clouds. The mechanism for generating the velocity dispersion
must also account for the preferred elongation. This excludes some driving
mechanisms, such as stellar winds and supernovae, because they do not produce
the systemic elongation along the Galactic plane. Driving energy is more likely
to come from large-scale motions, such as Galactic rotation.
l
Koda,
J., and Y. Sofue [2006b], "The Virgo High-Resolution CO Survey: VI. Gas Dynamics
and Star Formation along the Bar in NGC 4303," Publ. Astron. Soc. Japan,
vol.58, pp.299-312.
Ø
We
present CO interferometer observations of the barred galaxy NGC 4303 (M 61).
This galaxy has a strong gas concentration at the central region and prominent
offset ridges at the leading sides of the bar. Sharp velocity gradients are
apparent across the ridges. The brightness temperature in the ridges is low,
indicating the existence of unresolved molecular clouds. Additionally, an
analysis of the newborn stellar clusters revealed in HST images suggests that
the parent molecular clouds had masses of 104-6M⦿. The observed shear
velocity gradient across the ridges is too small to break up giant molecular
clouds. Therefore, the clouds are likely to survive passage through the ridges.
We discuss a cloud orbit model in a bar potential for understanding the gas
distribution, dynamics, and star formation in NGC 4303. The model reproduces
the narrow offset ridges and sharp velocity gradients across the ridges, although
no shock is associated with the ridges. We discuss cloud-cloud collisions (and
close interactions) as a possible triggering mechanism for star formation. The
newborn stellar clusters in NGC 4303 are located predominantly at the leading
sides of the offset ridges. Cloud orbits are densely populated in the region
where the clusters are found, suggesting a high collisional frequency and
possibly a high rate of triggered star formation. Cloud-based dynamics is less
dissipative than smooth hydrodynamic models, possibly extending the timescales
of gas dynamical evolution and gas fueling to central regions in barred
galaxies.
l
Kohno,
K., T. Tosaki, T. Okuda, K. Nakanishi, T. Kamazaki, K. Muraoka, S. Onodera, Y.
Sofue, S. K. Okumura, N. Kuno, N. Nakai, K. Ohta, S. Ishizuki, R. Kawabe, and
N. Kawai [2005a], "Nobeyama Millimeter Array Observations of GRB 030329: a
Decay of Afterglow with Bumps and Molecular Gas in the Host Galaxy," Publ.
Astron. Soc. Japan, vol.57, pp.147-153.
Ø
Nobeyama
Millimeter Array was used to observe millimeter-wave afterglow of GRB 030329 at
93GHz and 141GHz from 2003 April 6 (8.23 days after the burst) to 2003 May 30
(61.97 days). A sensitive search for CO (J=1-0) emission/absorption from the
host galaxy of GRB 030329 was also carried out. Unresolved millimeter continuum
emission at the position of GRB 030329 was detected until 2003 April 21. We
found a steep decline of continuum flux (åt-2.0) during this period,
in accord with a previous report. Moreover, our data implies that the decay was
accompanied by possible plateaus phases, or bumps, on a time scale of several
days. From an integrated spectrum, produced by summing up the data from 2003
April 10 to 2003 May 30, we found a possible emission feature, which could be a
redshifted CO (J=1-0) line. Its position and redshift coincide well with those
of GRB 030329, though further observations are required to confirm the
detection. If the emission feature is real, the observed CO flux is
1.4}0.52Jykm s-1, corresponding to a large molecular gas mass of M(H2)
>109 Msolar. This implies that the host galaxy, which
is optically faint, is highly obscured due to a rich interstellar medium.
l
Kohno,
K. [2005b], "The Atacama Submillimeter Telescope Experiment," Proc.
of the "The Cool Universe: Observing Cosmic Dawn", eds. C. Lidman and
D. Alloin, ASP Conf. Ser. vol.344, pp.242-247.
Ø
The
Atacama Submillimeter Telescope Experiment (ASTE) is a joint project between
Japan and Chile to install and operate a high-precision, 10 m telescope in the
Atacama desert for exploration of the southern sky in the sub-millimeter.
Currently, we have achieved a main reflector surface accuracy of 19 mum (RMS)
and a pointing accuracy of 1.2 arcsec (RMS). A new 350 GHz cartridge-type
receiver, installed in September 2004, shows good performance, with a typical
system noise temperature of 200 K (DSB (Double Sideband)) and a main beam
efficiency of up to 0.8 during winter nights. Four banks of 512 MHz (or 128
MHz) width digital spectrometers with 1024 channels are available. Extensive sub-millimeter
observations of various objects such as massive star forming regions in our
Galaxy have been started with ASTE.
l
Kohno,
K., K. Muraoka, K. Nakanishi, T. Tosaki, N. Kuno, R. Miura, T. Sawada, K.
Sorai, T. Okuda, K. Kamegai, K. Tanaka, A. Endo, B. Hatsukade, H. Ezawa, S.
Sakamoto, J. Cortes, N. Yamaguchi, H. Matsuo, and R. Kawabe [2007a], "ASTE
Observations of Dense Molecular Gas in Galaxies," Proc. of the IAU Symp,
237, "Triggered Star Formation in a Turbulent Interstellar Medium",
eds. B. G. Elmegreen & J. Palous, p.436.
Ø
Atacama
Submillimeter Experiment (ASTE) is a joint project between Japan and Chile for
installing and operating a 10 m high precision telescope in the Atacama Desert
in order to explore the southern sky through the submillimeter wavelength. We
have achieved an accuracy of 90 micron m (rms) for the main reflector surface
and a stable radio pointing accuracy of about 2 arcsec (rms). A 350 GHz
cartridge type SIS mixer receiver achieves good performance with a typical
system noise temperature of 150 - 250 K in DSB and a main beam efficiency of
0.6 - 0.7 during winter nights. Four banks of a 512 MHz (or 128 MHz) digital
spectrometer with 1024 channels have been installed. Recent scientific results
obtained with ASTE, such as a wide area CO(3-2) mapping of nearby spiral
galaxies (M 83, M 33, NGC 1672 etc.) and a possible detection of CO(3-2)
emission toward the host galaxy of GRB 98042, are reported.
l
Kohno,
K., K. Nakanishi, and M. Imanishi [2007b], "Compact Starburst in the
Central Regions of Seyfert Galaxies," Proc. of the "The Central
Engine of Active Galactic Nuclei", eds. Luis C. Ho and Jian-Min Wang, ASP
Conf. Ser., vol.373, pp.647-650.
Ø
We have
conducted a high-resolution "3D" imaging survey of the CO(1-0),
HCN(1-0), and HCO+(1-0) lines toward the central a few kpc regions
of the Seyfert and starburst galaxies in the local universe using the Nobeyama
Millimeter Array. We detected luminous HCN(1-0) emissions toward a considerable
fraction of these Seyfert galaxies (10 of 12 in our sub-sample), which
indicated that some of these Seyfert galaxies, such as NGC 3079, NGC 3227, NGC
4051, NGC 6764, and NGC 7479, are indeed accompanied with compact nuclear
starburst, given the tight correlation between the HCN(1-0) luminosity and the
star formation rate among star-forming galaxies. However, we suggest that the
elevated HCN(1-0) emission from some of these Seyfert galaxies, including NGC
1068, NGC 1097, NGC 5033, and NGC 5194, does not signify the presence of
massive starbursts there. This is because these Seyfert nuclei show abnormally
high HCN(1-0)/HCO+(1-0) ratios (2-3), which were never observed in
the starburst nuclei in our sample. This could be attributed to the
overabundance of HCN molecules in the X-ray dominated regions (XDRs) at the centers
of these Seyfert galaxies.
l
Komugi,
S., Y. Sofue, H. Nakanishi, S. Onodera, and F. Egusa [2005], "The Schmidt
Low at High Molecular Densities," Publ. Astron. Soc. Japan, vol.57,
pp.733-741.
Ø
We
combined Hæ and recent high-resolution 12CO(J=1-0) data to consider
the quantitative relation between the gas mass and the star-formation rate, or
the so-called Schmidt law in nearby spiral galaxies at regions of high
molecular density. The relation between the gas quantity and the star-formation
rate has not been previously studied for high-density regions, but using
high-resolution CO data obtained at the Nobeyama Millimeter Array, we found
that the Schmidt law is valid at densities as high as 103 Modot
pc-2 for sample spiral galaxies, which is an order of magnitude
denser than what has been known to be the maximum density at which the
empirical law holds for non-starburst galaxies. Furthermore, we obtained a
Schmidt law index of N = 1.33 } 0.09 and a roughly constant star-formation
efficiency over the entire disk, even within several hundred parsecs of the
nucleus. These results imply that the physics of star formation does not change
in the central regions of spiral galaxies. Comparisons with starburst galaxies
are also given. We find a possible discontinuity in the Schmidt law between
normal and starburst galaxies.
l
Komugi,
S., Y. Sofue, K. Kohno, H. Nakanishi, S. Onodera, F. Egusa, T. Tosaki, K.
Muraoka, and J. Young [2006], "CO(J=1-0) and CO(J=3-2) Survey of Nearby
Galactic Centers: The Schmidt Law as a Function of Galactic Properties,"
International Astronomical Union XXVIth General Assembly, Pragua, 14-25 August,
2006, abstract book, pp.133-134 (S237-149 Poster).
Ø
The
relation between molecular gas quantity and star formation rate (SFR), known as
the Schmidt law, has been a long debated but poorly understood subject
regarding its properties and implications. Although previous studies have
assumed that galaxies of a wide range of morphology and activity follows a
common law, sample size and angular resolution has limited a comprehensive
study of the physical parameters that are indicative of the underlying physics
of the Schmidt law. We have conducted a large scale survey of the CO(J=1-0)
emission in nearby galaxies, with emphasis on the form of the Schmidt law at high
molecular densities. High resolution (16 arcsec.) single dish observations of
69 galaxies (mainly spirals) were done at the NRO 45m telescope, and compiled
with previous surveys with similar resolution. The final dataset is comprised
of 176 galaxies observed at the central positions. Which is the largest size to
date with such resolution. These data were compared to SFR derived using
internal extinction corrected H alpha. The Schmidt law index N, given SFR°N,
is found to vary considerably with inclination and distance between 0.7 to 1.4.
After accounting for these "unphysical" parameters, the Schmidt law
is categorized according to type (early/late) and the presence of bars.
Consequently, we find that barred galaxies occupy the denser regime of the Schimdt
law, but with no apparent difference in the star formation efficiency (SFE),
indicating that bars stimulate central inflow of gas, but that star formation
still occurs along a common star formation law as with non-barred galaxies. A
possible categorization of the Schmidt law with galaxy type. is also suggested.
We have also conducted a survey in CO(J=3-2) emission for some of the galaxies
above using ASTE. A striking correlation between CO(J=3-2) intensity and H
alpha derived SFR is found for the first time, with N=1.0. This indicates that
even in dusty environments, H alpha emission can be a reliable tracer of
massive SF if the internal extinction is accounted for.
l
Komugi,
S., K. Kohno, T. Tosaki, H. Nakanishi, S. Onodera, F. Egusa, and Y. Sofue
[2007], "ASTE Observations of Nearby Galaxies: A Tight Correlation between
CO (J = 3-2) Emission and Hæ," Publ. Astron. Soc. Japan, vol.59, pp.55-60.
Ø
Star
formation rates (SFRs) obtained via extinction corrected Hæ are compared to
dense gas, as traced by 12CO(J=3-2) emission at the centers of
nearby galaxies, observed with the ASTE telescope. It is found that, although
many of the observed positions are dusty and therefore heavily absorbed at Hæ,
the SFR shows a striking correlation with dense gas in the form of the Schmidt
law with an index 1.0. The correlation is also compared between gas traced by 12CO(J=1-0)
and application of H alpha extinction correction. We find that dense gas
produces a far better correlation with SFR in view of surface density values.
l
Kono,
Y., Y. Murata, H. Hirabayashi, K. Wajima, N. Mochiduki, T. Toda, and N.
Kawaguchi [2005], "Broadband VLBI Data Downlink of VSOP-2," Proc. at
the XXVIIIth General Assembly of the URSI, October 2005, India. (CD-ROM :
CP5.10)
Ø
Following
the success of the VLBI Space Observatory Programme (VSOP), a next generation
space VLBI mission, currently called VSOP-2, is being planned. The mission will
provide a downlink data rate of 1 Gbps to improve sensitivity in observing
continuum emission. A possible band based on frequency allocation regulations
is 37-38 GHz for this data transfer. The uplink frequency for frequency and
phase transfer. on the other hand, will be 40 GHz. We adopt an OFDM (Orthogonal
Frequency Division Multiplex) method for the data transfer to reduce the
outband emission. The link budget is more severe than that of VSOP, but the
reasonable design is possible.
l
Kosugi,
T., K. Matsuzaki, T. Sakao, T. Shimizu, Y. Sone, S. Tachikawa, T. Hashimoto, K.
Minesugi, A. Ohnishi, T. Yamada, S. Tsuneta, H. Hara, K. Ichimoto, Y. Suematsu,
M. Shimojo, T. Watanabe, S. Shimada, J. M. Davis, L. D. Hill, J. K. Owens, A.
M. Title, J. L. Culhane, L. K. Harra, G. A. Doschek, and L. Golub [2007],
"The Hinode (Solar-B) Mission: An Overview," Solar Phys., vol.243,
pp.3-17.
Ø
The
Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency's
Institute of Space and Astronautical Science (ISAS/JAXA) was successfully
launched in September 2006. As the successor to the Yohkoh mission, it aims to
understand how magnetic energy gets transferred from the photosphere to the
upper atmosphere and results in explosive energy releases. Hinode is an
observatory style mission, with all the instruments being designed and built to
work together to address the science aims. There are three instruments onboard:
the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the
X-Ray Telescope (XRT). This paper provides an overview of the mission,
detailing the satellite, the scientific payload, and operations. It will conclude
with discussions on how the international science community can participate in
the analysis of the mission data.
l
Krips,
M., R. Neri, A. Eckart, R. Barvainis, A. Peck, D. Downes, P. Planesas, J.
Martin-Pintado, D. Iono, and G. Petitpas [2007], "Differential Lensing
Effects in High-z Sources: Constraining the Size and Shape of the Emitting
Regions," Proceedings in "From Z-Machines to ALMA:(Sub)Millimeter
Spectroscopy of Galaxies", eds. Andrew J. Baker, Jason Glenn, Andrew I.
Harris, Jeffrey G. Mangum and Min S. Yun, ASP Conf. Ser. vol.375, pp.250-253.
Ø
One of
the greatest obstacles in determining the physical parameters of galaxies in
the early universe is our inability to accurately constrain the sizes of the
sources detected. Current cutting-edge mm/submm interferometers such as the
Submillimeter Array (SMA) and the Plateau de Bure Interferometer IRAM (PdBI)
yield angular resolutions of about 1'', which is in most cases not sufficient
to resolve the observed emission at high z. However, if the high-redshift
source is gravitationally lensed by an intervening galaxy, the angular
resolution can be improved by up to two orders of magnitude, as demonstrated in
the case of the Cloverleaf galaxy. Light from extended regions is deflected in
a different way than light from compact structures, so that the lensed images
set tight constraints on their true sizes and shapes. We will discuss the use
of such differential lensing effects for three gravitationally lensed
high-redshift quasars: Q0957+561 (z=1.41), SBS1520+530 (z=1.86), and
APM08279+5255 (z=3.9). We have recently detected molecular gas emission traced
by CO in the first two sources, doubling the number of CO detections in this
mostly unexplored redshift range of z=1-2. We will be able to use this technique
as well to place even tighter constraints on the size of the dust emission in
APM08279+5255, using the new very extended configurations of the SMA and PdBI
with their angular resolutions of 0.3''-0.4''.
l
Kundu, M.
R., E. J. Schmahl, P. C. Grigis, V. i. Garaimov, and K. Shibasaki [2006],
"Nobeyama Radio Heliograph Observations of RHESSI Microflares,"
Astron. Astrophys., vol.451, pp.691-707.
Ø
Aims.We
present a summary of the analysis of thirty microflares, observed simultaneously
by the Ramaty High Energy Solar Spectroscopic Imager (RHESSI) in hard X-rays
and by Nobeyama RadioHeliograph (NoRH) in microwaves (17 GHz).
Methods. We used microflares observed by RHESSI in the energy range 3-25 keV,
and for larger events, up to 35 keV. The observations were made 2002, May 2-6.
Results. We describe the imaging
characteristics of these microflares including their locations in hard X-rays
and microwaves and the relative positions of the micro-flaring sources. We
discuss the brightness temperatures, emission measures and their hard X-ray
spectral properties. We see small (mini) flaring loops clearly in NoRH and
RHESSI images. The microwave emission often seems to come from the RHESSI foot
points (for higher energies), and from the entire small (mini) flaring loop
(for lower energies). Sometimes the two (microwave and hard X-ray) sources
coincide, at other times they are at opposite ends of a mini flaring loop.
Typically, the hard X-ray spectrum of the microwave associated RHESSI
microflares can be fit by an isothermal component at low energies (below 10 or
12 keV) and a nonthermal component at higher energies (above 12 keV).
Conclusions: .Microflares in hard
X-rays and in microwaves behave like normal flares in many respects. They can
have both thermal and nonthermal components appearing in bremsstrahlung and
gyrosynchrotron radiation.
l
Kuno,
N., H. Mikoshiba, A. Hirota, K. Maruyama, T. Kasuga, K. Sunada, and A. Mori
[2005a], "Wind Effects on the Nobeyama 45-m Telescope," Proc. at the
XXVIIIth General Assembly of the URSI, October 2005, India. (CD-ROM : JB-P.1)
Ø
We
investigated the wind effects on the Nobeyama 45-m telescope. We measured the
movement of the sub-reflector and the deformation of the main reflector by
wind. We found a tight correlation between the pointing offset and the
deformation of the main reflector. It is confirmed that the change of the beam
shape is more significant at higher frequency when the wind is so strong.
l
Kuno,
N., N. Sato, H. Nakanishi, A. Hirota, T. Tosaki, Y. Shioya, N. Nakai, K. Sorai,
K. Nishiyama, Y. Ishihara, and B. Vila-Vilaro [2005b], "Nobeyama CO Atlas
of Nearby Spiral Galaxies," Proc. at the XXVIIIth General Assembly of the
URSI, October 2005, India. (CD-ROM : JB-P.7)
Ø
We
present the preliminary results of CO mapping survey of nearby spiral galaxies.
The survey was performed by using the multi-beam receivers mounted on the
Nobeyama 45-m telescope. The data are used to investigate distribution and
kinematics of molecular gas in spiral galaxies.
l
Kuno,
N., N. Sato, K. Nakanishi, A. Hirota, T. Tosaki, Y. Shioya, K. Sorai, N. Nakai,
K. Nishiyama, and B. Vila-Vilaro [2007a], "Nobeyama CO Atlas of Nearby
Spiral Galaxies: Distribution of Molecular Gas in Barred and Non-Barred Spiral
Galaxies," Publ. Astron. Soc. Japan, vol.59, pp.117-166.
Ø
The data
from a CO (J=1-0) mapping survey of 40 nearby spiral galaxies, performed with
the Nobeyama 45 m telescope, are presented. The criteria of the sample
selection were: (1) RC3 morphological type ranging from Sa to Scd, (2) distance
of less than 25 Mpc, (3) inclination angle less than 79 (RC3), (4) flux at 100
Źm higher than ~ 10 Jy, and (5) spiral structure not destroyed by any
interaction. The maps of CO cover most of the optical disk of the galaxies. We
investigated the influence of bars on the distribution of molecular gas in
spiral galaxies using these data. We confirmed that the degree of the central
concentration is higher in barred spiral than in nonbarred spirals, as shown by
previous studies. Furthermore, we present observational evidence that bars are
efficient in driving molecular gas that lies within the bar length toward the
center, while the role in bringing gas in from the outer parts of the disks is
small. The transported gas accounts for about half of the molecular gas within
the central region in barred spiral galaxies. We found a correlation between
the degree of central concentration and the bar strength. Galaxies with
stronger bars tend to have a higher central concentration. The correlation implies
that stronger bars accumulate molecular gas toward the center more efficiently.
These results are consistent with long-lived bars.
l
Kuno,
N., K. Nakanishi, K. Sorai, and T. Shibatsuka [2007b], "Central Structure
of Molecular Gas in Maffei 2," Astrophysics and Space Science Proceedings,
"Island Universes", ed. R. S. de Jong, pp.379-382.
Ø
We
present results of CO observations of the barred spiral galaxy Maffei 2 with
Nobeyama Millimeter Array (NMA). The distribution of the molecular gas in the
central regionshows elongated structure with two peaks as shown in the previous
data. We found that theelongated structure resolved into spiral arms that
continue from the offset ridges along the bar to a radius of less than 50 pc.
l
Kuno,
N., N. Sato, H. Nakanishi, A. Hirota, T. Tosaki, Y. Shioya, K. Sorai, N. Nakai,
K. Nishiyama, and B. Vila-Vilaro [2007c], "Distribution of Molecular Gas
in Barred Spiral Galaxies," Proc. of the IAU Symp. 235, "Galaxy
evolution across the Hubble Time", eds. F. Combes & J. Palous, p.116.
Ø
We made
a CO(1 - 0) mapping survey of 40 nearby spiral galaxies with the Nobeyama 45-m
telescope to provide useful data for detailed and systematic studies of
molecular gas in the galaxies (Kuno et al. 2006). Using these data we have
compared the distribution of molecular gas in barred and non-barred spirals and
investigated the influence of the bar. We confirmed that the degree of the
central concentration of molecular gas within the radial distances of the order
of a bar length in barred spirals is significantly higher than that in
non-barred spirals as shown by Sakamoto et al. (1999) and Sheth et al. (2005).
This is contrast with the degree of the concentration of the total molecular
gas mass within the radial distances of the order of the bar, which is similar
for both barred and non-barred spirals. This implies that the bars appear to be
efficient in driving gas that lies within their radial scales toward the center
of the host galaxies, but that they play quite a smaller role at larger spatial
scales on the disks. Thus the characteristic feature of the radial distribution
of molecular gas seen in barred spirals, i.e. the strong intensity peaks at
their centers, the shallow gradients within the bar regions or/and the
secondary peaks at the radius of the bar-ends, can be explained by the
accumulation of molecular gas within the bar regions. The accumulated gas by
bars accounts for about half of molecular gas mass within the central region.
We also found a correlation between the degree of central concentration of
molecular gas and the bar strength. Galaxies with stronger bars tend to have
higher central concentrations. The result indicates that stronger bar
accumulate molecular gas toward the center more efficiently. The correlation
between the degree of central concentration of molecular gas and the strength
seems to be consistent with long-lived bars rather than short-lived ones which
are destroyed by the gas accumulation toward the center many times in the
Hubble time.
l
Kurayama,
T., T. Sasao, and H. Kobayashi [2005a], "Parallax Measurements of the
Mira-Type Star UX Cygni with Phase-Referencing VLBI," Astrophys. J.
(Letters), vol.627, pp.L49-L52.
Ø
We have
measured the annual parallax of the Mira-type variable star UX Cyg at ϖ=0.54}0.06 mas from phase-referencing VLBI observations of its
circumstellar water masers with the VLBA. The corresponding distance is 1.85+0.25-0.19
kpc. This is the first measurement of an annual parallax based on observations
of water masers. It is important to calibrate the period-luminosity relation of
Mira variables because it is an important distance indicator in astronomy. We
discuss the distance to the Large Magellanic Cloud by comparing our results
with the period-luminosity relation in the Large Magellanic Cloud. We obtained
the three-dimensional position and velocity of UX Cyg in our Galaxy:
(R,Ę,z)=(8.20}0.01 kpc, 12.4+1.7-1.3, -0.30+0.03-0.04
kpc), (VR,VĘ,Vz)=(-81.6+14.0-15.3,
204.0+3.6-3.4, -12.1+10.2-10.3) km
s-1. We also discuss the origin of UX Cyg.
l
Kurayama,
T., H. Kobayashi, and T. Sasao [2005b], "Annual Parallax Measurements of
Mira-Type Variable with Ohase-Referencing VLBA Observation," Proc. of the
"Future Directions in High Resolution Astronomy: A Celebration of the 10th
Anniversary of the VLBA", eds. J. D. Romney, and M. J. Reid, ASP Conf.
Ser. vol.340, pp.471-476.
Ø
We have
measured an annual parallax of water masers around a Mira-type variable, UX
Cyg, 0.8 } 0.1 mas with phase-referencing VLBI observations. This parallax
needs for the establishment of period-luminosity relation of Miras, which is a
cosmic distance scale.
l
Kurono,
Y., R. Kawabe, M. Saito, Y. Kitamura, S. Yokogawa, T. Tsukagoshi, and N. Ikeda
[2007], "Observations of CB244 - Binary System of Protostellar and
Prestellar Cores?," Proceedings in "Protostars and Planets V",
LPI contribution no. 1286, p.8427.
Ø
Not
Available
l
Lee,
J.-J., B.-C. Koo, and K. Tatematsu [2004a], "The Environment of Tycho:
Possible Interaction with Molecular Clouds," Proc. of the IAU Symp. 218,
"Young Neutron Stars and Their Environments", edited by Fernando
Camilo and Bryan M. Gaensler, pp.71-72.
Ø
We have
conducted 12CO observations with the Nobeyama 45-m telescope in the
area of Tycho's supernova remnant. These high-resolution (16") data show
that the molecular cloud surrounds the SNR along the northeastern boundary. We
suggest that Tycho's SNR and the molecular cloud are located at comparable
distances within the Perseus arm and that they are physically interacting. We
also discuss the possible connection between the molecular cloud and the
Balmer-dominated optical filaments and propose that the preshock gas may be
accelerated within the cosmic-ray and/or fast neutral precursor.
l
Lee,
J.-J., B.-C. Koo, and K. Tatematsu [2004b], "The Environment of Tycho:
Possible interaction with a Molecular Clouds," J. Korean Astron. Soc.,
vol.37, pp.223-224.
Ø
The
Tycho supernova remnant (SNR), as one of the few historical SNRs, has been
widely studied in various wavebands and previous observations have shown
evidence that Tycho is interacting with a dense ambient medium toward the
northeast direction, In this paper, we report our high-resolution (16 arcsec) 12CO
observation of the remnant using the Nobeyama 45m radio telescope. The Nobeyama
data shows that a large molecular cloud surrounds the SNR along the
northeastern boundary. We suggest that the Tycho SNR and the molecular cloud
are both located in the Perseus arm and that the dense medium interacting with
the SNR is possibly the molecular cloud. We also discuss the possible
connection between the molecular cloud and the Balmer-dominated optical
filaments, and suggest that the preshock gas may be accelerated within the
cosmic ray and/or fast neutral precursor.
l
Lim, J.,
and S. Takakuwa [2005], "Circumstellar/Protoplanetary Disks and Bipolar
Jets at 5AU Resolution," Proc. of the "The Cool Universe: Observing
Cosmic Dawn", eds. C. Lidman and D. Alloin, ASP Conf. Ser. vol.344,
pp.200-211.
Ø
We
present images of LDN 1551 IRS 5 at angular resolutions as high as ~30 mas,
corresponding to a spatial resolution of ~5 AU, made at 7 mm with the VLA.
Previously known to be a binary protostellar system, we show that LDN 1551 IRS
5 is probably a triple protostellar system. The primary and secondary
components have a projected separation of ~46 AU, whereas the tertiary
component has a projected separation of ~11 AU from the primary component. The
circumstellar dust disks of all three components have dimensions of ~10-15 AU.
Their major axes are closely, but not perfectly, aligned with each other and
with the major axis of the surrounding flattened, rotating, and contracting
molecular condensation (pseudodisk). Furthermore, the orbital motions of the
primary and secondary components are in the same direction as the rotational
motion of this pseudodisk. We suggest that all three protostellar components
formed as a result of the fragmentation of the central region of the molecular
pseudodisk. Both the primary and secondary components, but apparently not the
tertiary component, exhibit a bipolar ionized jet that is centered on and
emerges perpendicular to its associated dust disk. Neither jets are resolved
along their base, implying that they are driven within a radial distance of
~2.5 AU from their central protostars. Our images provide an exciting preview
of what ALMA is likely to obtain for many more protostellar systems.
l
Lim, J.,
and S. Takakuwa [2006], "Properties and Formation of the Multiple
Protostellar System L1551 IRS 5," Astrophys. J., vol.653, pp.425-436.
Ø
We present
an observation of L1551 IRS 5 at 7 mm with an angular resolution as high as
~0".04 (5 AU). Apart from the two main components oriented north-south
with a projected separation of 47 AU, we discover a third component lying 13 AU
to the southeast of the northern component, thereby making L1551 IRS 5 a triple
protostellar system. The two main components comprise circumstellar dust disks
with dimensions of ~ 17 AU, together with bipolar ionized jets collimated
within a radial distance of <~3 AU from their central protostars. The third
component likely has an even smaller circumstellar dust disk with a dimension
of ~9 AU. The relative proper motion of the two main components is consistent
with a circular coplanar orbit with an orbital separation of ~50 AU, orbital
period of ~380 yr, and total mass of ~90 Msolar. Their measured disk sizes are
smaller than the predicted gravitationally truncated sizes of ~26 AU. Together
with the predicted minimum size for a circumbinary gap, noncircular coplanar
orbits are constrained to an eccentricity <~0.3. The disks of the two main
components are accurately aligned with each other, as well as with a
surrounding molecular pseudodisk. Furthermore, the clockwise orbital motion of
these components coincides with the clockwise rotational motion of the
pseudodisk. These attributes constitute a smoking gun for the formation of the
two main components as a result of fragmentation within the inner regions of
their parent pseudodisk. By contrast, the disk of the third component is significantly
misaligned; measurements of its relative proper motion are required in order to
help deduce its origin.
l
Lim, J.,
N. Hirano, N. Ohashi, and S. Takakuwa [2007], "Observational Tests of
Binary/Multiple Protostellar Formation," Proceedings in "Protostars
and Planets V", LPI contribution no. 1286, p.8380.
Ø
Not
Available
l
Liu, Q.,
M. Nishio, K. Yamamura, T. Miyazaki, M. Hirata, T. Suzuyama, S. Kuji, K.
Iwadate, O. Kameya, and N. Kawano [2005], "Statistical Characteristics of
Atmospheric Phase Fluctuations Observed by a VLBI System Using a Beacon Wave
from a Geostationary Satellite," IEEE Tran. on Antennas & Propagation,
vol.53, pp.1519-1527.
Ø
This
paper reports the statistical characteristics of phase fluctuations obtained by
a very long baseline interferometry, which received beacon waves from a
geostationary satellite. Observations wave made in different weather conditions
by the 6-m Kagoshima and the 10-m Mizusawa radio telescopes, which were 1284 km
apart from one another. Atmospheric phase fluctuations ranging from 0.2 to
about 1000 s were detected. To study a variety of statistical characteristics
of these phase fluctuations, the Allan standard deviation, Šy(Ń), the temporal
structure function, D (Ń), and the square root of power spectrum, G (f), were calculated
from the observation results. These qualities were found to depend on the time
interval or the frequency f (f = 1/2Ń) as follows:Š(Ń) å Ń-0.6, Ń-0.3, D (Ń) å
Ń0.9, Ń1.3 for 0.2 s <Ń< 1.5 s and 1.5 s <Ń< 400 s. G (f) å f-0.8
for 2.5 Hz > f > 0.33 Hz and G ( f ) å f-1.3 for 0.33 Hz > f >
0.00125 Hz. The curves of Šy(Ń) and D (Ń) exhibited shifts whose
magnitudes followed the weather
order clear, cloudy, and rainy. For Ń > 1.5 s (or f < 0.33 Hz), the
experimental results were consistent with the theoretical values predicted by
Kolmogorov!s turbulence theory and a frozen-screen model. But for Ń< 1.5 s
(or f > 0.33Hz), the model has to be modified to explain the experimental
results.
l
Liu, Q.,
F. Kikuchi, S. Tsuruta, K. Matsumoto, H. Hanada, O. Kameya, Y. Tamura, K.
Asari, and N. Kawano [2007a], "Effects of Phase Characteristics of
Telescopes on Same-Beam Differential VLBI," IEEE Trans. Antenna &
Propagation, vol.55, pp.1466-1470.
Ø
Phase
characteristics, which are systematic phase offsets across the main beam of an
actual telescope, may be a problem for achieving the same-beam differential
very long baseline interferometer (VLBI) technique. This technique is essential
for differential phase delay measurements such as those used in the Japanese
Selenological and Engineering Explorer (SELENE) project, where the phase has to
be determined to an accuracy of 0.075 radians arms. Accurate measurement and
correction of phase characteristics are very important. The phase
characteristics at 2.2375 and 2.2807 GHz of the 20-m and 10-m telescopes at
Mizusawa were measured to an error of approximately 0.04 radians rms. The phase
characteristics were 0.06 radians rms for the 20-m and 0.055 radians rms for
the 10-m telescopes in the main beams, and the post-fit residuals decreased to
0.03 and 0.04 radians rms, respectively, after correcting by using quadratic
formulas. These results confirmed the effectiveness of the same-beam
differential VLBI technique for VLBI observations of SELENE.
l
Liu, Q.,
F. Kikuchi, K. Matsumoto, K. Asari, S. Tsuruta, J. Ping, H. Hanada, and N.
Kawano [2007b], "Erro Analysis of Sama-Beam Differential VLBI Techinique
using Two SELENE Satellite, Adv, Space Res., vol.40, pp.43-50.
Ø
The
Japanese SELENE project consists of a main satellite, a relay sub-satellite
(Rstar), and a VLBI sub-satellite (Vstar). Rstar will relay the Doppler ranging
signal between the main satellite and the ground station for the world's first
direct measurement of the gravity field on the far side of the Moon. The
differential VLBI radio sources onboard Rstar and Vstar will be used to
determine the gravity field of the Moon precisely, especially near the rim.
Rstar and Vstar only transmit three pairs of carriers in the S-band and one
pair of carriers in the X-band, and the difference in phase delays of Rstar and
Vstar will be obtained from the relation between correlation phase and
frequency of four pairs of carriers. In particular, the difference in
correlation phase at each frequency has to be estimated without the 2pi
ambiguity, and this imposes strict conditions; e.g., the correlation phase
error must be lower than 4.3 and the error of differences in total electron
content in the ionosphere must be less than 0.23 TECU. To resolve the 2pi
ambiguity problem, we use the same-beam differential VLBI technique, in which
Rstar and Vstar are simultaneously observed by using the same beam of the
receiving antenna. In this case, the influences of the atmosphere, ionosphere,
and receivers can nearly be canceled in the difference in correlation phases,
the difference in delay can be obtained with an accuracy of several picoseconds
from the correlation phases, and the relative positions of Rstar and Vstar can
be determined with a very high sensitivity (tens of cm). In this paper, we
estimate the chance for same-beam differential VLBI observations in SELENE. We
give a procedure and conditions for the obtaining differential phase delay, and
predict the measurement errors in same-beam differential VLBI by using GPS
techniques and by observing three satellites, Shuangxing, Geotail, and a
geostationary satellite.
l
Lu,
R.-S., Z.-Q. Shen, T. P. Krichbaum, W. Alef, S. Iguchi, S. Kameno, S., and M.
Titus [2007], "Millimeter VLBI Observations of PKS 1749+096," Proc.
of the "The Central Engine of Active Galactic Nuclei", eds. Luis C.
Ho and Jian-Min Wang, ASP Conf. Ser., vol.373, pp.237-238.
Ø
We
present preliminary results of the two 3mm and one 7mm high-resolution
millimeter VLBI observations of PKS 1749+096. These observations reveal a
consistent core-dominated morphology with a bending jet to the north-east of
the core. We also show an approximate fit to the overall bending structure
using a helical jet model.
l
Lubowich,
D. A., N. Kuno, H. Roberts, T. J. Millar, C. Henkel, J. M. Pasachoff, and R.
Mauersberger [2004], "Deuterium Nucleosynthesis in AGN: Is D
Cosmological?," American Astronomical Society Meeting 205, #118.07.
Ø
Although
deuterium is predicted to be primarily cosmological, D can also be produced by
cosmic-ray or gamma -ray spallation reactions - possibly between high energy
jets and the surrounding gas in AGN. We used the Nobeyama mm array with a
3" resolution (220 pc) in April 2003 to search for any enhanced D from the
DCN J = 2-1 line in the Seyfert galaxy NGC 1068. NGC 1068 is an optimal target
because it has jets, starburst activity, a circumuclear molecular ring and
disk, dense optically thick concentrations of HCN, and a low-energy X-ray flux
of 1042 erg/s (the highest X-ray flux of any galaxy in which HCN has been
detected and the flux required to produce high D abundances). We did not detect
DCN (which is detected in all other molecular clouds with optically thick HCN
in the Galaxy or LMC) and we obtained an upper limit of S<=15 mJy/beam =
48.5 mK in the circumnuclear region and a DCN/HCN ratio of 0.0046. Using our
5300 reaction chemical network we estimate D/H leq1.5x10-5 as
compared to the local Galactic ISM D/H = 1.4x10-5. Thus there is no
significant D production in the nuclear region of NGC 1068 and NGC 1068 has
probably not had a recent period of activity with a gamma -ray or cosmic-ray
luminosity > 1042 erg/s. If jet-cloud nucleosynthesis produces
significant amounts of D, then the D is produced outside of the nuclear region
where the subsequent infall may be one way to continuously supply galactic
nuclei with D. However, any enhanced D produced via spallation reactions would
have been destroyed via astration due to the faster star formation rate. Our
results are additional evidence that D is primarily cosmological and that AGN
do not produce D.
l
Maezawa,
H., T. Sato, and T. Noguchi [2005], "Process Simulation of Reactive DC
Magnetron Sputtering for Thin Film Deposition of Niobium-Titanium
Nitride," IEEE Trans, Appl. Superconductivity, vol.15, pp.3520-3523.
Ø
A
process simulation for depositions of Niobium-Titanium Nitride (NbTiN) films
with a reactive magnetron sputtering system was demonstrated. In the modeling,
VAr-dependent sputtering yields with quasi target erosion profile were newly
incorporated for the precise optimization of the sputtering conditions. The
numerical results were found to agree well with the experimental data. We
present the dependence of the film resistivity and Tc on the chemical
composition. It was also confirmed by the simulation that ¢V can be a good indicator to control
the chemical compositions for the fabrications of high Tc films. In addition,
the resistivity and stars were found to deeply relate to the total process
pressure and residual N2 gas in the plasmas as suggested in the atomic peeing
model. Preliminary results suggest that the process simulation has a potential
of the useful tool to control the properties of superconducting films.
l
Maksimov,
V. P., D. V. Prosovetsky, V. V. Grechnev, B. B. Krissinel, and K. Shibasaki
[2006], "On the Relation of Brightness Temperatures in Coronal Hoes at 5.7
and 17 GHz," Publ. Astron. Soc. Japan, vol.58, pp.1-10.
Ø
From the
analysis of simultaneous observations with the Siberian Solar Radio Telescope
and Nobeyama Radioheliograph we show that coronal holes are not uniform. In particular,
in coronal holes small-scale features exist with anticorrelating brightness
temperatures at 5.7 and 17GHz. The features are disposed radially, which
suggests radial heat transfer in them. We propose that the favorable heating
mechanism within those features is dissipation of Alfvén waves.
l
Matsuda,
Y., D. Iono, K. Ohta, T. Yamada, R. Kawabe, T. Hayashino, A. B. Peck, and G. R.
Pettipas [2007], "High-Resolution Submillimeter Imaging of the Lyalpha
Blob 1 in SSA 22," Astrophys. J., vol.667, pp.667-672.
Ø
We
present ~2" resolution submillimeter observations of the submillimeter
luminous giant Lyalpha blob (LAB1) in the SSA 22 protocluster at redshift z=3.1
with the Submillimeter Array (SMA). Although the expected submillimeter flux
density is 16 mJy at 880 mum, no emission is detected with the 2.4''Å-1.9''
(18Å-14 kpc) beam at the 3 sigma level of 4.2 mJy beam-1 in the SMA field of
view of 35". This is in contrast to the previous lower angular resolution
(15") observations where a bright (17 mJy) unresolved submillimeter source
was detected at 850 mum toward the LAB1 using the Submillimeter Common-User
Bolometer Array on the James Clerk Maxwell Telescope. The SMA nondetection
suggests that the spatial extent of the submillimeter emission of LAB1 should be
larger than 4" (>30 kpc). The most likely interpretation of the
spatially extended submillimeter emission is that starbursts occur throughout
the large area in LAB1. Some part of the submillimeter emission may come from
spatially extended dust expelled from starburst regions by galactic superwind.
The spatial extent of the submillimeter emission of LAB1 is similar to those of
high-redshift radio galaxies rather than submillimeter galaxies.
l
Matsumoto,
K., T. Sato, H. Fujimoto, Y. Tamura,
M. Nishio, R. Hino, T. Higashi, and T. Kanazawa [2006], "Ocean Bottom
Pressure Observation off Sanriku and Comparison with Ocean Tide Models,
Altimetry, and Barotropic Signals from Ocean Models," Geophys. Res.
Letters, vol.33, p.L16602.
Ø
We
discuss tidal and non-tidal signals which are obtained from ocean bottom
pressure (OBP) measurements at two sites off Sanriku, Japan. Comparison between
the observed tidal component and five ocean tide models shows that recent
models have accuracy better than 1.3 cm in terms of root sum square of vector
differences for eight principal constituents. The empirical estimates of
non-tidal signal from TOPEX/POSEIDON (T/P) and JASON-1 deviate from barotropic
signals observed by OBP recorders, which can be attributed to baroclini
component in the altimeter data. We also compared the non-tidal barotropic
signal derived from the observation with those from ECCO model (wind-driven)
and Kyusu University model (pressure-driven). The comparison indicates that the
pressure-driven model increases explained variance and it is suggested to
combine the wind-drive model and the pressure-driven model in order to describe
non-tidal ocean mass variability in particular at period shorter than 30 days.
l
Matsumoto,
T., T. Nakazato, and K. Tomisaka [2006], "Alignment of Outflows with
Magnetic Fields in Cloud Cores," Astrophys. J. (Letters), vol.637,
pp.L105-L108.
Ø
We
estimate the polarized thermal dust emission from MHD simulations of
protostellar collapse and outflow formation in order to investigate the
alignment of outflows with magnetic fields. The polarization maps indicate that
the alignment of an outflow with the magnetic field depends on the field
strength inside the cloud core; the direction of the outflow, projected on the
plane of the sky, is aligned preferentially with the mean polarization vector
for a cloud core with a magnetic field strength of 80 muG, while it does not
tend to be aligned for 50 muG as long as the 1000 AU scale is considered. The
direction of the magnetic field at the cloud center is probed by the direction
of the outflow. In addition, the magnetic field at the cloud center can be
revealed by the Atacama Large Millimeter Array (ALMA) even when the source is
embedded deeply in the envelope. The Chandrasekhar-Fermi formula is examined
using the polarization maps, indicating that the field strength predicted by
the formula should be corrected by a factor of 0.24-0.44. The correction factor
has a tendency to be lower for a cloud core with a weaker magnetic field.
l
Matsunaga,
N., S. Deguchi, Y. Ita, T. Tenabe, and Y. Nakada [2005[, "SiO Maser
Sources toward Globular Clusters," Publ. Astron. Soc. Japan, vol.57,
pp.L1-L6.
Ø
We
report on the detection of SiO masers in Asymptotic Giant Branch variables
toward bulge/disk globular clusters. In five out of six cases, the radial
velocities are compatible with the optically measured radial velocities of
globular clusters in the assessed uncertainty. Two sources, toward Terzan 5 and
Terzan 12, lie very close to the cluster centers. The objects toward Pal 6 and
Terzan 12 have luminosities appropriate to the AGB tip in globular clusters,
while those toward NGC 6171, Pal 10, and Terzan 5 are brighter than expected.
It is suggested that the latter three may have evolved from merged binaries, offering
a test for binary-evolution
scenarios in globular clusters, if the membership is approved.
l
Matsushita,
S., R. Kawabe, K. Kohno, N. Matsumoto, T. G. Tsuru, and B. Vila-Vilaro [2004],
"Starburst at the Molecular Superbubble in M82," Proc. of "The Neutral
ISM in Starbust Galaxies", eds. S. Aalto, S. Huttemeiister, and A. Pedlar,
ASP Conf. Ser. vol.320, pp.138-141.
Ø
We
present high spatial resolution 100 GHz continuum emission observations with
the Nobeyama Millimeter Array (NMA) toward an expanding molecular superbubble
in the central region of M 82. The 100 GHz continuum image, which is dominated
by free-free emission, revealed that the strongest peaks are concentrated at
the inner edge of the superbubble. Star formation at these peaks is an order of
magnitude more active in terms of ionizing flux than from the most massive star
forming regions in our Galaxy. At this region, high velocity ionized gas,
masers, and diffuse hard X-ray emission are also concentrated. These
observations suggest that a strong starburst produced plasma and the
superbubble expansion, and induced the present starburst regions. These results
provide the first clear evidence of a self-propagating starburst in external
galaxies.
l
Matsushita,
S., R. Kawabe, K. Kohno, H. Matsumoto, T. G. Tsuru, and B. Vila-Vilaro [2005a],
"Starburst at the Expanding Molecular Superbubble in M82: Self-induced
Starburst at the Inner Edge of the Superbubble," Astrophys. J., vol.618,
pp.712-722.
Ø
We
present high spatial resolution (2.3"x1.9" or 43pcx36pc at D=3.9 Mpc)
100 GHz millimeter-wave continuum emission observations with the Nobeyama
Millimeter Array toward an expanding molecular superbubble in the central
region of M82. The 100 GHz continuum image, which is dominated by free-free
emission, revealed that the four strongest peaks are concentrated at the inner
edge of the superbubble along the galactic disk. The production rates of Lyman
continuum photons calculated from 100 GHz continuum flux at these peaks are an
order of magnitude higher than those from the most massive star-forming regions
in our Galaxy. At these regions, high-velocity ionized gas (traced by H41æ and
[Ne II]) can be seen, and H2O and OH masers are also concentrated.
The center of the superbubble, on the other hand, is weak in molecular and
free-free emissions and strong in diffuse hard X-ray emission. These
observations suggest that a strong starburst produced energetic explosions and
the resulting plasma and superbubble expansions and induced the present
starburst regions traced by our 100 GHz continuum observations at the inner
edge of the molecular superbubble. These results, therefore, provide the first
clear evidence of self-induced starburst in external galaxies. The starburst at
the center of the superbubble, on the other hand, is beginning to cease because
of a lack of molecular gas. This kind of intense starburst seems to have
occurred several times within 106-107 yr in the central
region of M82.
l
Matsushita,
S., and J. Lim [2005b], "SMA CO(3-2) Observation of the Seyfert 2 Galaxy
M51," Proc. of the "The Cool Universe: Observing Cosmic Dawn",
eds. C. Lidman and D. Alloin, ASP Conf. Ser. vol.344, pp.90-95.
Ø
We have
obtained the first interferometric CO(3-2) image (3.9 arcsec 1.6 arcsec or 160
pcx65 pc) of the central ~36'' region of the Seyfert 2 galaxy M51 with the
Submillimeter Array (SMA). The CO(3-2) emission is strongly peaked at the
nucleus and is weakly distributed along the spiral arm to the northwest. The
CO(3-2) integrated intensity of the central peak is almost twice as high as
that in CO(1-0), indicating that the circumnuclear molecular gas is warm and
dense. Similar intensity ratios are seen in shocked regions in our Galaxy,
suggesting that the properties of the gas in M51 may be related to AGN or
starburst activity. The circumnuclear molecular gas shows a linear velocity
gradient along the radio continuum jet, in addition to the gradient
perpendicular to it. The velocity gradient along the jet can also be explained
by AGN or starburst activity, which is consistent with the high intensity
ratio.
l
Matsushita,
S., M. Saito, K. Sakamoto, T. R. Hunter, N. A. Patel, T. K. Sridharan, and R.
W. Wilson [2006], "Elevation Angle Dependence of the SMA Antenna Focus
Position," Proc. of the SPIE, vol.6275, p.62751W.
Ø
We
report the measurement results and compensation of the antenna elevation angle
dependences of the Submillimeter Array (SMA) antenna characteristics. Without
optimizing the subreflector (focus) positions as a function of the antenna
elevation angle, antenna beam patterns show lopsided sidelobes, and antenna
efficiencies show degradations. The sidelobe level increases and the antenna
efficiencies decrease about 1% and a few %, respectively, for every 10 change
in the elevation angle at the measured frequency of 237 GHz. We therefore
obtained the optimized subreflector positions for X (azimuth), Y (elevation),
and Z (radio optics) focus axes at various elevation angles for all the eight
SMA antennas. The X axis position does not depend on the elevation angle. The Y
and Z axes positions depend on the elevation angles, and are well fitted with a
simple function for each axis with including a gravity term (cosine and sine of
elevation, respectively). In the optimized subreflector positions, the antenna
beam patterns show low level symmetric sidelobe of at most a few %, and the
antenna efficiencies stay constant at any antenna elevation angles. Using one
set of fitted functions for all antennas, the SMA is now operating with
real-time focusing, and showing constant antenna characteristics at any given
elevation angle.
l
Matsuzaki,
K., M. Shimojo, T. D. Tarbell, L. K. Harra, and E. E. Delica [2007], "Data
Archive of the Hinode Mission, Solar Phys., vol.243, pp.87-95.
Ø
All of
the Hinode telemetry data are to be reformatted and archived in the DARTS
system at ISAS and mirrored to data centers around the word. The archived data
are distributed to users through the Internet. This paper gives an overview of
the files in the archive, including the file formats. All formats are portable
and have heritage from the previous missions. From the reformatted files, index
information is created for faster data search. Users can perform queries based
on information contained in the index. This allows for searches to return
observations that conform to particular observing conditions.
l
Meech,
K. J., N. Ageorges, M. F. A'Hearn, C. Arpigny, A. Ates, J. Ayccock, S. Bagnulo,
J. Bailey, R. Barber, L. Barrera, R. Barrena, J. M. Bauer, M. J. S. Belton, F.
Bensch, B. Bhattacharya, N. Biver, G. Blake, D. Bockelee-Morvan, H. Boehnhardt,
B. P. Bonev, T. Bonev, M. W. Buie, M. G. Burton, H. M. Butner, R. Cabanac, R.
Campbell, H. Campins, M. T. Capria, T. Carroll, F. Chaffee, S. B. Charnley, R.
Cleis, A. Coates, A. Cochran, P. Colom, A. Conrad, I. M. Coulson, J. Crovisier,
J. deBuizer, R. Dekany, J. de Leon, N. Dello Russo, M. Delsanti, J. Drummond,
L. Dundon, P. B. Etzel, T. L. Farnham, P. Feldman, Y. R. Fernandez, M. D.
Filipovic, S. Fisher, A. Titzsimmons, D. Fong, R. Fugate, H. Fujiwra, T.
Fujiyoshi, R. Furusho, T. Fuse, E. Gibb, O. Groussin, S. Gulkis, M. Gurwell, M.
Hadamick, O. Hainaut, D. Harker, D. Harrington, M. Harwit, S. Hasegawa, C. W.
Hergenrother, P. Hirst, K. Hodapp, M. Honda, E. S. Howell, D. Hutsemekers, D.
Iono, W.-H. Ip, W. Jackson, E. Jehin, Z. J. Jiang, G. H. Jones, P. A. Jones, T.
Kadono, U. W. Kamath, H. U. Kaufl, T. Kasuga, H. Kawakita, M. S. Kelley, F.
Kerber, M. Kidger, D. Kinoshita, M. Knight, L. Lara, S. M. Larson, S. Lederer,
C.-F. Lee, A. C. Levasseur-Regourd, J. Y. Li, Q.-S. Li, J. Licandro, Z.-Y. Lin,
C. M. Lisse, G. LoCurto, A. J. Lovell, S. C. Lowry, J. Lyke, D. Lynch, J. Ma,
K. Magee-Sauer, G. Maheswar, J. Manfroid, O. Marco, P. Martin, G. Melnick, S.
Miller, T. Miyata, G. H. Moriarty-Schieven, N. Moskovitz, B. E. A. Mueller, M.
J. Numma, S. Nuneer, D. A. Neufeld, T. Ootsubo, D. Osip, S. K. Pandea, E.
Pantin, R. Paterno-Mahler, B. Patten, B. E. Penprase, A. Peck, G. Petitas, N.
Pinippa-Alonso, J. Pittichova, E. Pompei, T. P. Prabhu, C. Qi, R. Rao, H.
Rauer, H. Reitsema, S. D. Rodgers, P. Rodriguez, R. Ruane, G. Ruch, W.
Rujopakarn, D. K. Sahu, S. Sako, I. Sakon, N. Samarashinha, J. M. Sarkissian,
L. Saviane, M. Schirmer, P. Schultz, R. Schulz, P. Seitzer, T. Sekiguchi, N.
Selman, M. Serra-Ricart, R. Sharp, R. L. Snell, C. Snodgrass, T. Stallard, G.
Stecklein, C. Sterken, J. A. Stuwe, S. Sugita, M. Sumner, N. Suntzeff, R.
Swaters, S. Takakuwa, N. Takato, J. Thomas-Osip, E. Thompson, A. T. Tokunaga,
G. P. Tozzi, H. Tran, M. Troy, C. Trujillo, J. van Cleve, R. Vasundhara, R.
Vazquez, F. Vilas, G. Villanueva, K. von Braun, P. Vora, R. J. Wainscoat, K.
Walsh, J. Watanabe, H. A. Weaver, W. Weaver, M. Weiler, P. R. Weissman, W. F.
Welsh, D. Wilner, S. Wolk, M. Womack, D. Wooden, L. M. Woodney, Z.-Y. Wu, J.-H.
Wu, T. Yamashita, B. Yang, Y.-B. Yang, S. Yokogawa, A. C. Zook, A. Zauderer, X.
Zhao, X. Zhou, and J.-M. Zucconi [2005], "Deep Impact: Observations from a
Worldwide Earth-Based Campaign," Science, vol.310, pp.265-269.
Ø
On 4
July 2005, many observatories around the world and in space observed the collision
of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an
unprecedented coordinated observational campaign. These data show that (i)
there was new material after impact that was compositionally different from
that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta
was much larger than before impact; (iii) the new activity did not last more
than a few days, and by 9 July the comet's behavior was indistinguishable from
its pre-impact behavior; and (iv) there were interesting transient phenomena
that may be correlated with cratering physics.
l
Melnikov,
V. F., V. E. Reznikova, K. Shibasaki, and V. M. Nakariakov [2004],
"Observations of Sausage Mode Oscillations in a Flaring Loop," Proc.
of the IAU Symp. 223, "Multi-Wavelength Investigations of Solar
Activity", ed. A. V. Stepanov, E. E. Benevolenskaya, and A. G. Kosovivhev, pp.647-648.
Ø
We
provide an observational proof of the existence of the global sausage mode
oscillations in a flaring loop studying a microwave burst with quasi-periodical
pulsations observed with the Nobeyama Radioheliograph (NoRH).
l
Melnikov,
V. F., V. E. Rexnikova, K. Shibasaki, and V. M. Nakariakov [2005a],
"Spatially Resolved Microwave PUlsations of a Flare Loop," Astron.
Astrophys., vol.439, pp.727-736.
Ø
A
microwave burst with quasi-periodic pulsations was high spatial resolution
using observations with the Nobeyama Radioheliograph (NoRH). We found that the
time profiles of the microwave emission at 17 and 34 GHz exhibit quasi-periodic
(with two well defined periods P1 = 14-17 s and P2 = 8-11
s) variations of the intensity at different parts of an observed flaring loop.
Detailed Fourier analysis shows the P1 spectral component to be
dominant at the top, while the P2 one near the feet of the loop. The
14-17 s pulsations are synchronous at the top and in both legs of the loop. The
8-11 s pulsations at the legs are well correlated with each other but the
correlation is not so obvious with the pulsations at the loop top. For this P2
spectral component, a definite phase shift, P2/4≈ 2.2 s, between
pulsations in the northern leg and loop top parts of the loop have been found.
The length of the flaring loop is estimated as L = 25 Mm (≈34") and its
average width at half intensity at 34 GHz as about 6 Mm (≈8"). Microwave
diagnostics shows the loop to be filled with a dense plasma with the number
density n0≈1011 cm-3, penetrated by the
magnetic filed changing from B0≈100G near the loop top up to B0≈200
G near the north footpoint. A comparative analysis of different MHD modes of
the loop demonstrates the possibility of the simultaneous existence of two
modes of oscillations in the loop: the global sausage mode, with the period P1
= 14-17 s and the modes at the footpoint, and a higher harmonics mode (possibly
with the radial wave number l > 1), with P2 = 8-11 s.
l
Melnikov,
V. F., S. P. Gorbikov, V. E. Reznikova, and K. Shibasaki [2005b],
"Dynamics of Electron Spatial Distribution in Microwave Flaring
Loops," Proc. of the 11th European Solar Physics meeting "The dynamic
sun: challenges for theory and observations", eds. D. Danesy, S. Poedts,
A. De Groof, and J. Andries, ESA SP-600, 132.1. (CD-ROM)
Ø
The
microwave brightness distribution and its observed temporal evolution along
several well resolved flaring loops are analyzed. Spatial attention is paid to
the redistribution of microwave brightness and formation of the brightness peak
near the loop top on the late phase of a burst. To understand the origin of
this redistribution we do modeling of the evolution of electron spatial
distribution along a magnetic loop by solving the non-stationary Foller-Plank
equation for different positions of the injection site (loop top and foot).
l
Melnikov,
V. F., V. E. Reznikova, S. P. Gorbikov, and K. Shibasaki [2006], "Electron
Spatial Distribution in Microwave Flaring Loops," Recent Advances in
Astronomy and Astrophysics: 7th International Conference of the Hellenic
Astronomical Society, AIP Conf. Proc., vol.848, pp.123-132.
Ø
In this
paper we review recent studies of Nobeyama Radioheliograph observations
concerning 1) spatial distribution of microwave brightness along flaring loops;
2) peculiarities ofits temporal dynamics in different parts of a loop; 3)
consequences of the obtained findings on spatial and pitchangle distributions
of high energy electrons.
l
Migenes,
V., L. Cruz-Vazquez, V. I. Slysh, I. E. Val'Tts, S. Horiuchi, and M. Inoue
[2005], "The VLBA Survey of OH Masers towards SFR: Preliminary
Results," Proc. of the "Future Directions in High Resolution
Astronomy: A Celebration of the 10th Anniversary of the VLBA", eds. J. D.
Romney, and M. J. Reid, ASP Conf. Ser. vol.340, pp.361-363.
Ø
In 2001
the VLBA was used as part of a continuing program to observe OH MASERs towards
Star Forming Regions, to study their structure with the highest angular
resolution possible. One goal is to classify the sources by their structure and
prepare a database composed of those that show highly compact structure and
promise interesting and exciting results when observed with higher resolution
arrays (i.e. Space-VLBI). We present preliminary results from the first 45
sources observed. These are the first high resolution observations for over 50%
of the sources. Approximately 20% exhibit highly compact structure and
moderately strong emission.
l
Miyazaki,
A., T. Tsutsumi, M. Miyoshi, M. Tsuboi, and Z.-Q. Shen [2005], "Flares of
Sagittarius A* at Millimeter Wavelengths," Proc. at the XXVIIIth General
Assembly of the URSI, October 2005, India. (CD-ROM : JB-P.11)
Ø
We have
performed monitoring observations of the flux density toward the Galactic
center compact radio sources, Sagittarius A* (Sgr A*), which is a supermassive
black hole, from 1996 to 2005 using the Nobeyama Millimeter Array of the
Nobeyama Radio Observatory, Japan. The monitoring observations of Sgr A* were
carried out in the 3- and 2-mm (100 and 140 GHz) bands, and we have detected
several flares of Sgr A*. We found intraday variation of Sgr A* in the 2000
March flare. The twofold increase timescale is estimated to be about 1.5 hr at
140 GHz. This intraday variability suggests that the physical size of the
flare-emitting region is compact on a scale at or below about 12 AU (Å150 Rs; Schwarzschild radius). On the other hand, clear
evidence of long-term periodic variability was not found from a periodicity analysis
of our current millimeter data set.
l
Miyazaki,
A., Z.-Q. Shen, M. Miyoshi, M. Tsuboi, and T. Tsutsumi [2006], "Flux
Monitoring of Sagittarius A* at MM-Wavelengths," J. Physics: Conference
Series, vol.54, pp.363-369.
Ø
We
performed the monitoring observations of the fbx density toward the Galactic
center compact radio source, Sagittarius A* (Sgr A*), which is associated with
a supermassive black hole, since 1996 using the Nobeyama Millimeter Array
(NMA). The monitoring observations of Sgr A* were carried out in the 3- and
2-mm (100 and 140 GHz) bands over one to several months on each NMA observable
season. We have detected several fares of Sgr A* with duration of, roughly, one
month. The fbx density at the fare peak increases 100%-200% at 100 GHz band and
200%-400% at 140 GHz band, respectively, while the averaged quiescent fbx
density was about 1 Jy. We also found some intraday variations (IDVs) of Sgr A*
at both 2- and 3-mm bands. The shortest twofold increase timescale of the IDV
is estimated to be about 1.5 hr at 140 GHz. This short timescale variability
suggests that the physical size of emitting region is compact on a scale at or
below about 12 AU (~150 RS). The IDV at mm-wavelengths has a similar increase
timescale as those in the X-ray and infrared fares but has a smaller amplitude.
l
Miyoshi,
M., J. K. Ishitsuka, S. Kameno, Z.-Q. Shen, and S. Horiuchi [2004a],
"Direct Imaging of the Massive Black Hole, Sgr A*," Proc. of the
"Stellar-Mass, Intermediate-Mass, and Supermassive Black Holes", eds.
S. Mineshige and K. Makishima, Porg. Theore. Phys. Supple., No.155, pp.186-189.
Ø
Imaging
the vicinity of black hole is one of the ultimate goals of VLBI astronomy. The
closest massive black hole, SgrA*, located at Galactic center is the leading
candidate for such observations. Combined with recent VLBI recording technique
and sub-mm radio engineering, we now have the sufficient sensitivity for the
observations. We here show performance simulations of sub-mm VLBI arrays for
imaging SgrA*. An excellent image is obtained from a sub-mm VLBI array in
southern hemisphere like the configuration of VLBA. We also note that even with
a small array, we can estimate the shadow size and then the mass of black hole
from visibility analysis. Now, if only constructing a sub-mm VLBI array in
southern hemisphere, we can unveil the black hole environments of SgrA*.