Tetsuo Hasegawa
A5013665514- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Spectroscopy and Laser Applications
- Molecular Spectroscopy and Structure
- Astronomy and Astrophysical Research
- Atomic and Molecular Physics
- Astrophysics and Cosmic Phenomena
- Service-Oriented Architecture and Web Services
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Advanced Chemical Physics Studies
- Mobile Agent-Based Network Management
- Radio Astronomy Observations and Technology
- Astronomical Observations and Instrumentation
- Multi-Agent Systems and Negotiation
- Solar and Space Plasma Dynamics
- Web Data Mining and Analysis
- Advanced Combustion Engine Technologies
- Scheduling and Optimization Algorithms
- Atmospheric and Environmental Gas Dynamics
- Superconducting and THz Device Technology
- Semantic Web and Ontologies
National Astronomical Observatory of Japan
2015-2024
National Institutes of Natural Sciences
1990-2024
Yokohama Municipal Citizen's Hospital
2015-2018
Toshiba (South Korea)
2002-2014
Institute of Astronomy and Astrophysics, Academia Sinica
2011-2013
Atacama Large Millimeter Submillimeter Array
2009-2012
Toshiba (Japan)
2000-2011
Waseda University
2009
The University of Tokyo
1995-2007
DoCoMo Communications Laboratories Europe GmbH
2005
Abstract We present a near-infrared ($JHK_{\rm s}$) photometric catalog, including 14811185 point sources for 40 deg$^2$ area of the Large Magellanic Cloud, 2769682 an 11 Small and 434145 4 Bridge. The 10$\sigma$ limiting magnitudes are 18.8, 17.8, 16.6 mag at $J, H$, $K_{\rm s}$, respectively. astrometric accuracies bright 0.03–0.04 0$\rlap {.}{^{\prime\prime}}$1, Based on we also (1) spatial distributions, (2) luminosity functions, (3) color–color diagrams, (4) color–magnitude diagrams...
We present high-resolution CO images of the Galactic center region taken with 2 × focal-plane array receiver mounted on 45 m telescope Nobeyama Radio Observatory. have collected about 44,00012C16O (J = 1-0) spectra and over 13,00013C16O a 34'' (1.4 pc) grid spacing. The 12CO mapping area is roughly -15 ≤ l +34 -06 b +06, which covers almost full extent molecular gas concentration in center. These demonstrate extremely complex distribution kinematics While its large-scale behavior can be...
view Abstract Citations (182) References (43) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Spectroscopic Study of the DR 21 Outflow Source. III. The CO Line Emission Garden, R. P. ; Hayashi, M. Gatley, I. Hasegawa, T. Kaifu, N. High-angular-resolution observations (C-12)O, (C-13)O, (C-18)O J = 1-0 and H53-alpha hydrogen recombination line emission from energetic outflow are presented examined. suggest that this is probably most massive (greater than 3000...
We determine the magnetic field strength in OMC 1 region of Orion A filament via a new implementation Chandrasekhar-Fermi method using observations performed as part James Clerk Maxwell Telescope (JCMT) B-Fields In Star-Forming Region Observations (BISTRO) survey with POL-2 instrument. combine BISTRO data archival SCUBA-2 and HARP to find plane-of-sky $B_{\rm pos}=6.6\pm4.7$ mG, where $\delta B_{\rm pos}=4.7$ mG represents predominantly systematic uncertainty. develop for measuring angular...
We present the first results from B-fields In STar-forming Region Observations (BISTRO) survey, using Sub-millimetre Common-User Bolometer Array 2 (SCUBA-2) camera, with its associated polarimeter (POL-2), on James Clerk Maxwell Telescope (JCMT) in Hawaii. discuss survey's aims and objectives. describe rationale behind questions which survey will aim to answer. The most important of these is role magnetic fields star formation process scale individual filaments cores dense regions. data...
Abstract Magnetic fields of molecular clouds in the central zone (CMZ) have been relatively under-observed at sub-parsec resolution. Here, we report JCMT/POL2 observations polarized dust emission CMZ, which reveal magnetic field structures dense gas ∼0.5 pc The 11 our sample include two western part CMZ (Sgr C and a farside cloud candidate), four around Galactic longitude 0 (the 50 km s −1 cloud, CO 0.02−0.02, Stone , Sticks Straw among Three Little Pigs), five along Dust Ridge...
Abstract We present the magnetic field in dense material of Central Molecular Zone (CMZ) Milky Way, traced 850 μ m polarized dust emission as part James Clerk Maxwell Telescope B -fields STar-forming Region Observations survey. observe a highly ordered across CMZ between Sgr B2 and C that is strongly preferentially aligned with orbital gas flows within clouds CMZ. find observed relative orientations are nonrandom at >99% confidence level consistent models which vectors 30° to 3D. The...
We present first results from a submillimeter continuum survey of the Galactic center "central molecular zone" (CMZ), made with Submillimeter Common-User Bolometer Array (SCUBA) on James Clerk Maxwell Telescope. SCUBA's scan-map mode has allowed us to make extremely wide field maps thermal dust emission unprecedented speed and sensitivity. also discuss some issues related elimination artifacts in data. Our simultaneous 850/450 μm have total size approximately 28 × 05 (400 75 pc) elongated...
The data from the Nobeyama Radio Observatory 45 m telescope Galactic Center CO survey have been analyzed to generate a compilation of molecular clouds with intense emission in this region. Clouds are identified an automated manner through main part for all peaks exceeding 10 K (T). measured parameters and cross-correlated compare those disk. For center (GC), we find scaling laws type σV S0.40 MVT (LCO)0.88, which similar All GC larger velocity widths virial theorem masses each above σV-S...
view Abstract Citations (195) References (65) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Molecular Cloud Cores in the Orion A Cloud. I. Nobeyama CS (1--0) Survey Tatematsu, Ken'ichi ; Umemoto, Tomofumi Kameya, Osamu Hirano, Naomi Hasegawa, Tetsuo Hayashi, Masahiko Iwata, Takahiro Kaifu, Norio Mikami, Hitomi Murata, Yasuhiro Nakano, Makoto Takenori Ohashi, Nagayoshi Sunada, Kazuyoshi Takaba, Hiroshi Yamamoto, Satoshi first high-resolution survey of...
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...
view Abstract Citations (143) References (35) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Large-Scale Cloud Collision in the Galactic Center Molecular Near Sagittarius B2 Hasegawa, Tetsuo ; Sato, Fumio Whiteoak, John B. Miyawaki, Ryosuke We present high-resolution images of (13)CO(J = 1 to 0) emission from molecular cloud near Sgr star-forming complex taken with Nobeyama 45 m telescope. The data, supplemented by larger maps Bell Labs 7 telescope Bally...
Context. Water is the major component of interstellar ice mantle. In ice, chemical reactivity limited by diffusion reacting molecules, which are usually present at abundances a few percent with respect to water.
Abstract The dependence of the polarization fraction p on total intensity I in polarized submillimeter emission measurements is typically parameterized as ∝ − α ( ≤ 1) and used to infer dust grain alignment efficiency star-forming regions, with an index = 1 indicating near-total lack grains magnetic field. In this work, we demonstrate that non-Gaussian noise characteristics may produce apparent ∼ even data significant signal-to-noise Stokes Q , U emission, so robust angle. We present a...
Context. Molecular filaments and hubs have received special attention recently thanks to new studies showing their key role in star formation. While the (column) density velocity structures of both been carefully studied, magnetic field (B-field) properties yet be characterized. Consequently, B-fields formation evolution hub-filament systems is not well constrained. Aims. We aim understand B-field its interplay with turbulence gravity dynamical NGC 6334 filament network that harbours...
view Abstract Citations (131) References (53) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS The Mass of a Star Formed in Cloud Core: Theory and Its Application to the Orion A Nakano, Takenori ; Hasegawa, Tetsuo Norman, Colin We have investigated mechanisms determining stellar mass process star formation. Because core grows by inflow matter from parent cloud core, growing is fixed when supply stopped. falls onto mostly through an accretion disk, significant...
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 report systematic variations in the emission line ratio of CO J = 2–1 and 1–0 transitions (R2–1/1–0) grand-design spiral galaxy M51. The R2–1/1–0 shows clear evidence for evolution molecular gas from upstream interarm regions into arms back downstream regions. In regions, is typically <0.7 (and often 0.4–0.6); this similar to ratios observed Galactic giant clouds (GMCs) with low far-infrared luminosities. However, rises >0.7 (often 0.8–1.0) arms, particularly at leading (downstream) edge...
We present the results of dust emission polarization measurements Ophiuchus-B (Oph-B) carried out using Submillimetre Common-User Bolometer Array 2 (SCUBA-2) camera with its associated polarimeter (POL-2) on James Clerk Maxwell Telescope (JCMT) in Hawaii. This work is part B-fields In Star-forming Region Observations (BISTRO) survey initiated to understand role magnetic fields star formation for nearby star-forming molecular clouds. a first look at geometry and strength Oph-B. The field...
The low dust temperatures (<14 K) of Planck Galactic cold clumps (PGCCs) make them ideal targets to probe the initial conditions and very early phase star formation. "TOP-SCOPE" is a joint survey program targeting ∼2000 PGCCs in J = 1–0 transitions CO isotopologues ∼1000 850 μm continuum emission. objective surveys (SMT 10 m, KVN 21 NRO 45 m) statistically study occurring during formation evolution molecular clouds, across wide range environments. observations, data analysis, example science...
Abstract We present 850 μ m imaging polarimetry data of the ρ Oph-A core taken with Submillimeter Common-User Bolometer Array-2 (SCUBA-2) and its polarimeter (POL-2) as part our ongoing survey project, <?CDATA ${\boldsymbol{B}}$?> -fields In STar forming RegiOns (BISTRO). The polarization vectors are used to identify orientation magnetic field projected on plane sky at a resolution 0.01 pc. 10 subregions distinct fractions angles in 0.2 pc core; some them can be coherent structure Oph...
We present new observations of the active star-formation region NGC 1333 in Perseus molecular cloud complex from James Clerk Maxwell Telescope B-Fields In Star-forming Region Observations (BISTRO) survey with POL-2 instrument. The BISTRO data cover entire (~1.5 pc x 2 pc) at 0.02 resolution and spatially resolve polarized emission individual filamentary structures for first time. inferred magnetic field structure is as a whole, each filament aligned different position angles relative to...
We report 850~$\mu$m dust polarization observations of a low-mass ($\sim$12 $M_{\odot}$) starless core in the $\rho$ Ophiuchus cloud, C, made with POL-2 instrument on James Clerk Maxwell Telescope (JCMT) as part JCMT B-fields In STar-forming Region Observations (BISTRO) survey. detect an ordered magnetic field projected plane sky core. The across $\sim$0.1~pc shows predominant northeast-southwest orientation centering between $\sim$40$^\circ$ to $\sim$100$^\circ$, indicating that is well...