A5002576121- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Cosmic Phenomena
- Spectroscopy and Laser Applications
- Galaxies: Formation, Evolution, Phenomena
- Atmospheric Ozone and Climate
- Astronomical Observations and Instrumentation
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Radio Astronomy Observations and Technology
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Molecular Spectroscopy and Structure
- Geophysics and Gravity Measurements
- Atomic and Molecular Physics
- Higher Education Learning Practices
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Particle Accelerators and Free-Electron Lasers
- History and Developments in Astronomy
- Scientific Measurement and Uncertainty Evaluation
- Phase Equilibria and Thermodynamics
- Pulsars and Gravitational Waves Research
- GNSS positioning and interference
Kagoshima University
2015-2024
The University of Tokyo
2004-2015
Institute of Astronomy
1994-2012
National Astronomical Observatory of Japan
1987-2010
Canon (Japan)
2009
Tokyo University of Science
1970-1998
Misato Observatory
1986-1989
Astronomical Observatory
1985
We have observed a 160' × 40' (l b) region around the Galactic center in CS J=1-0 line with high spatial resolution and sensitivity using 45 m telescope at Nobeyama Radio Observatory. The area includes Sgr A radio arc complex, B, C, D. About 24,000 spectra of J = 1-0 emission, which is good tracer high-density (n ≅ 104 cm-3) molecular clouds, were obtained. data are presented l-b, l-v, b-v maps. total flux this ∫ S dv 1.1 106 Jy km s-1. Typical optical thickness C32S emission equal to or...
We present analyses to determine the fundamental parameters of Galaxy based on VLBI astrometry 52 Galactic maser sources obtained with VERA, VLBA and EVN. model Galaxy's structure a set including center distance R_0, angular rotation velocity at LSR Omega_0, mean peculiar motion respect (U_src, V_src, W_src), rotation-curve shape index, V component Solar motions V_sun. Based Markov chain Monte Carlo method, we find that is constrained 5% level be R_0 = 8.05 +/- 0.45 kpc, where error bar...
Rotational transition lines of CO play a major role in molecular radio astronomy and particular the study star formation Galactic structure. Although wealth data exists plane some well-known clouds, there is no available high sensitivity all-sky survey to date. Such surveys can be constructed using \Planck\ HFI because three lowest rotational at 115, 230 345 GHz significantly contribute signal 100, 217 353 channels respectively. Two different component separation methods are used extract...
We present the first astrometry catalog from Japanese VLBI (very long baseline interferometer) project VERA (VLBI Exploration of Radio Astrometry). have compiled all results VERA, providing accurate trigonometric annual parallax and proper motion measurements. In total, 99 maser sources are listed in catalog. Among them, 21 newly reported while rest 78 referred to previously published or those preparation for forthcoming papers. The accuracy revisited compared with other projects such as...
A large-scale 12C16O (J = 2-1) survey of the inner few hundred parsecs Galaxy has been conducted using University Tokyo-Nobeyama Radio Observatory 60 cm telescope. We have taken about 70012C16O spectra in region -25 ≤ l 25 and |b| 1° with 0125 grid spacing, covering entire huge molecular cloud complex Galactic center. refer to CO 1-0) data Columbia 1.2 m telescope calculate J 2-1 1-0 intensity ratio. Velocity channel maps longitude-velocity line are presented, corresponding 2-1/J
We present results of CO J = 2-1 line mapping molecular clouds in the vicinity supernova remnants (SNRs) W44 and IC 443. Large areas spanning ~15 × 2° were observed with 9' beam University Tokyo-Nobeyama Radio Observatory 60 cm Survey Telescope. identified six giant (GMCs) masses (0.3-3) 105 M☉ around W44. Three show evidence interaction SNR. In particular, one exhibits a wing emission an abrupt velocity shift at position which cloud overlaps The 2-1/J 1-0 intensity ratio significantly...
The authors have observed the distribution of linear polarization over central 2°.5×3°.0 region galaxy at 9.05, 9.55, 10.05, and 10.55 GHz. They found that prominent polarized plumes extend 1°.6 perpendicular to galactic plane. Except for these plumes, detected no remarkable feature within 200 pc center. western side (in coordinates) Galactic center lobe (GCL), which was noticed by Sofue Handa, is thus not polarized, while eastern it agrees with northern plume highly up 40%. This imples...
The FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45-m telescope (FUGIN) project is one of legacy projects using new multi-beam receiver installed on telescope. This aims to investigate distribution, kinematics, and physical properties both diffuse dense molecular gas in Galaxy at once by observing 12CO, 13CO, C18O J=1-0 lines simultaneously. mapping regions are a part 1st quadrant (10d < l 50d, |b| 1d) 3rd (198d <236d, Galaxy, where spiral arms, bar structure, ring...
We report the results of VERA (VLBI Exploration Radio Astrometry) multi-epoch VLBI (very long baseline interferometry) 22 GHz water maser observations S255IR-SMA1, a massive young stellar object located in S255 star-forming region. By annual parallax source distance was measured as D|$= 1.78^{+0.12}_{-0.11}$| kpc and systemic motion (μαcos δ, μδ) = (−0.13 ± 0.20, −0.06 0.27) mas yr−1. Masers appear to trace U-shaped bow shock whose morphology proper motions are well reproduced by jet-driven...
We present a method to derive positions of molecular clouds along the lines sight from quantitative comparison between 2.6 mm CO emission and 18 cm OH absorption lines, apply it central kiloparsecs Milky Way.With some simple but justifiable assumptions, we face-on distribution brightness corresponding radial velocity in Galactic centre without any help kinematical models.The derived gas is elongated inclined so that Galactic-eastern (positive longitude) side closer us.The dominated by...
view Abstract Citations (110) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Large Area CO(J = 2--1) Mapping of the Giant Molecular Clouds in Orion Sakamoto, Seiichi ; Hayashi, Masahiko Hasegawa, Tetsuo Handa, Toshihiro Oka, Tomoharu We made a large area mapping CO (J 2 goes to 1) emission toward entire extent and B giant molecular clouds using Tokyo-NRO 60 cm survey telescope, covering approximately 35 square degrees with an angular...
We measured the trigonometric parallax of an H2O maser source associated with massive star-forming region NGC 6334I(North), hereafter as 6334I(N), VLBI Exploration Radio Astrometry. The derived annual is 0.789 ± 0.161 mas, corresponding to a distance 1.26 kpc. Using new distance, we recalculated physical parameters (masses and luminosities) dust continuum cores in region, revised are only ∼50% their originally reported values. also traced 23 relative proper motions masers SMA1 (central...
As a part of the Tokyo-Onsala-ESO-Calán Galactic CO survey, we have made large-scale mapping observations center in J = 2-1 line using 60 cm survey telescope Chile. The data were taken with same beam size (9') and sampling grid (75) as 1-0 Columbia so that two sets can be compared directly. Velocity channel maps longitude-velocity diagrams 12CO line, covering -6° ≤ l 6°, -2° b 2°, -300 vLSR 300 km s-1, are presented, along corresponding 2-1/J intensity ratio [R2-1/1-0(12CO)]. A diagram 13CO...
Physical conditions of molecular gas in the first quadrant Galaxy are examined through comparison CO J = 2-1 data Tokyo-Nobeyama Radio Observatory survey with 1-0 Columbia survey. A gradient 2-1/J intensity ratio (≡ R2-1/1-0) Galactocentric distance is reported. The varies from ≃0.75 at 4 kpc to ≃0.6 8 distance. This confirms early in-plane results reported by Handa et al.
We found, from the data of our CS (J = 1-0/2-1) survey with Nobeyama 45 m telescope, that a molecular cloud associated "vertical filaments" Galactic center arc has shell-like structure and is expanding velocity 20 km s-1. The limb shell high density, n(H2) 6 × 104 cm-3. may have originated 10-100 supernovae within last 105 yr. At point contact filaments, deformed filaments are bent in opposite direction. These compensative deformations suggest dynamically interacting filaments. interaction...
The University of Tokyo Atacama Observatory (TAO) is a project to construct 6.5m infrared-optimized telescope at the summit Co. Chajnantor, 5,640 m altitude, in northern Chile, promoted by Institute Astronomy, Tokyo. Thanks high altitude and low water vapor, continuous window from 0.9 2.5μm as well new windows wavelength longer than 25μm appears. site shows extremely precipitable vapor 0.5mm (25 percentile), fraction usable night more 80%. Measured median seeing 0".69, which comparable or...
We have performed the astrometry of H2O masers in Galactic star-forming region Onsala 2 North (ON2N) with VLBI Exploration Radio Astrometry.We obtained trigonometric parallax 0.261+/-0.009 mas, corresponding to heliocentric distance 3.83+/-0.13 kpc. ON2N is expected be on solar circle, because its radial velocity respect Local Standard Rest (LSR) nearly zero. Using present and proper motions masers, Galactocentric Sun rotation at are found R_0 = 7.80+/-0.26 kpc Theta_0 213+/-5 km/s,...
Abstract We present results of a high-resolution wide-field mapping observation the Sagittarius A (Sgr A) molecular cloud complex in H$^{13}$CO$^+$ $J$ $=$ 1–0 and thermal SiO 2–1 emission lines with 25-beam receiver 100 GHz band operating on Nobeyama Radio Observatory 45-m telescope. The area covers 0$^\circ\!\!\!.$5 $\times$ involving several named clouds, for example GCM$-$0.02$-$0.07, GCM$-$0.13$-$0.08, GCM 0.11$-$0.11, Sickle cloud, Arched filaments so on. data have an effective angular...
We report on annual parallax and proper motion observations of H2O masers in S235AB-MIR, which is a massive young stellar object the Perseus Arm. Using multi-epoch VLBI (very long baseline interferometry) astrometry we measured π = 0.63 ± 0.03 mas, corresponding to trigonometric distance |$D= 1.56^{+0.09}_{-0.08}$| kpc, source (μαcos δ, μδ) (0.79 0.12, −2.41 0.14) mas yr−1. Water trace jet diameter 15 au exhibits definite radial velocity gradient perpendicular its axis. 3D maser kinematics...
view Abstract Citations (55) References (28) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS An Out-of-Plane CO (J = 2--1) Survey of the Milky Way. I. The Data Sakamoto, Seiichi ; Hasegawa, Tetsuo Hayashi, Masahiko Handa, Toshihiro Oka, Tomoharu We present extensive 2-1) survey data first quadrant Galaxy taken with same angular resolution as Columbia 1-0) survey. were compared Cohen, Dame, & Thaddeus. distribution emission mimics that 2-1)/CO intensity ratio...
We performed the astrometry of H2O masers in Galactic star-forming region G48.61+0.02 with VLBI Exploration Radio Astrometry (VERA). derived a trigonometric parallax 199+/-7 micro as, which corresponds to distance 5.03+/-0.19 kpc. The is about half its far kinematic distance, was often assumed previously. This places Sagittarius-Carina arm and near active star forming supernova remnant W51. also obtained three dimensional motion G48.61+0.02, found that it has large peculiar 40+/-5 km/s....
We conducted the astrometry of H2O masers in Galactic star-forming region Onsala 1 (ON1) with VLBI Exploration Radio Astrometry (VERA). measured a trigonometric parallax 0.404+/-0.017 mas, corresponding to distance 2.47+/-0.11 kpc. ON1 is appeared be located near tangent point at longitude 69.54 deg. estimate angular velocity rotation Sun, ratio from Sun center and 28.7+/-1.3 km/s/kpc using proper motion ON1. This value larger than IAU recommended 25.9 km/s/kpc, but consistent other results...
In our multi-epoch observation of the star-forming region NGC 2264 with VLBI Exploration Radio Astrometry, we detected two water maser features. We have measured annual parallax sources for first time in and derived 1.356 ± 0.098 mas, corresponding to distance pc, which is consistent its previously reported photometric observations. One features located near a dust continuum core, CMM4S, positionally X-ray source FMS2-1269 listed Flaccomio et al. Re-analyzing Chandra data, found that still...
Abstract We have developed a new mm-submm telescope with diameter of 1.85-m installed at the Nobeyama Radio Observatory. The scientific goal is to precisely reveal physical properties molecular clouds in Milky Way Galaxy by obtaining large-scale distribution gas, which can also be compared observations various wavelengths. target frequency $\sim$230 GHz; simultaneous rotational lines $J =$2–1 three carbon monoxide isotopes ($^{12}$CO, $^{13}$CO, C$^{18}$O) are achieved beam size (HPBW)...