A5082231675- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astrophysics and Cosmic Phenomena
- Spectroscopy and Laser Applications
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Molecular Spectroscopy and Structure
- Galaxies: Formation, Evolution, Phenomena
- Superconducting and THz Device Technology
- Astro and Planetary Science
- Radio Astronomy Observations and Technology
- Atmospheric Ozone and Climate
- Advanced Combustion Engine Technologies
- Astronomical Observations and Instrumentation
- Astronomy and Astrophysical Research
- Calibration and Measurement Techniques
- Advanced Chemical Physics Studies
- Gear and Bearing Dynamics Analysis
- Surface and Thin Film Phenomena
- Laser Design and Applications
- Tribology and Lubrication Engineering
- Adaptive optics and wavefront sensing
- Hydraulic and Pneumatic Systems
- Semiconductor Quantum Structures and Devices
- Magnetic Bearings and Levitation Dynamics
National Astronomical Observatory of Japan
2015-2025
National Institutes of Natural Sciences
2021-2025
Universidad de Guadalajara
2023
The University of Tokyo
2021-2022
Osaka Prefecture University
2012-2021
Tokyo University of Science
2021
Nagoya University
2016-2020
University of Tsukuba
2018
Shimane University
2013-2015
Aino University
2015
We present fully sampled ∼3' resolution images of 12CO(J = 2–1), 13CO(J and C18O(J 2–1) emission taken with the newly developed 1.85 m millimeter–submillimeter telescope over entire area Orion A B giant molecular clouds. The data were compared J 1–0 12CO, 13CO, C18O Nagoya 4 NANTEN at same angular to derive spatial distributions physical properties gas. explore large velocity gradient formalism determine gas density temperature using line combinations 1–0) assuming a uniform abundance ratio...
We report the development of new 4-beam, 2-polarization, 2-sideband, 100 GHz band SIS receiver "FOREST" (FOur beam REceiver System on 45-m Telescope) and results from commissioning observations Nobeyama Telescope operated by Radio Observatory, a branch National Astronomical Observatory Japan. FOREST aims to add capabilities large-area mapping simultaneous multi-line observation at 80 { 116 Telescope, which is one largest millimeter radio telescopes in world. The configuration four beams...
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...
Abstract The Orion Nebula Cluster toward the H ii region M42 is most outstanding young cluster at smallest distance (410 pc) among rich high-mass stellar clusters. By newly analyzing archival molecular data of 12 CO( J = 1–0) emission 21″ resolution, we identified least three pairs complementary distributions between two velocity components 8 and 13 km s −1 . We present a hypothesis that clouds collided with each other triggered formation stars, mainly regions including nearly 10 O stars in...
Abstract We have conducted ALMA CO isotopes and 1.3 mm continuum observations toward filamentary molecular clouds of the N159W-South region in Large Magellanic Cloud with an angular resolution ∼0.″25 (∼0.07 pc). Although previous lower-resolution (∼1″) revealed that there is a high-mass protostellar object at intersection two line-shaped filaments 13 length scale ∼10 pc, spatially resolved observations, particular, highest column density part traced by emission, clump, show complicated...
Abstract We present ALMA observations of CO isotopes and 1.3 mm continuum emission toward the N159E-Papillon Nebula in Large Magellanic Cloud (LMC). The spatial resolution is 0.″25–0.″28 (0.06–0.07 pc), which a factor 3 higher than previous this region. high allowed us to resolve highly filamentary distributions with typical widths ∼0.1 pc (full width half maximum) line masses few 100 M ⊙ −1 . filaments (more ten number) show an outstanding hub-filament structure emanating from nebular...
We present an analysis of the interstellar medium (ISM) toward γ-ray supernova remnant (SNR) W44. used NANTEN2 12CO(J = 2–1) and 1–0) data Arecibo H i in order to identify molecular atomic gas SNR. confirmed that is located SNR shell with a primary peak eastern edge shell. newly identified high-excitation along addition broad previously observed inside shell; line intensity ratio between transitions these regions greater than ∼1.0, suggesting kinetic temperature 30 K or higher, which most...
We carried out new CO ($J=$1-0, 2-1 and 3-2) observations with NANTEN2 ASTE in the region of twin Galactic mini-starbursts NGC 6334 6357. detected two velocity molecular components 12 km s$^{-1}$ separation, which is continuous over 3 degrees along plane. In show similar two-peaked intensity distributions toward young HII regions are linked by a bridge feature. 6357 we found spatially complementary distribution between as well feature velocity. Based on these results hypothesize that clouds...
Abstract The Hitachi and Takahagi 32 m radio telescopes (former satellite communication antennas) were so upgraded as to work at 6, 8, 22 GHz. We developed the receiver systems, IF back-end systems (including samplers recorders), reference systems. measured performance of antennas. system temperature including atmosphere toward zenith, $T_{\rm sys}^{\ast }$, is be ∼30–40 K for 6 GHz ∼25–35 8 }$ ∼40–100 in winter ∼150–500 summer seasons, respectively. aperture efficiency 55%–75% GHz, 55%–65%...
We performed new comprehensive $^{13}$CO($J$=2--1) observations toward NGC 2024, the most active star forming region in Orion B, with an angular resolution of $\sim$100'' obtained NANTEN2. found that associated cloud consists two independent velocity components. The components are physically connected to H{\sc ii} as evidenced by their close correlation dark lanes and emission nebulosity. show complementary distribution a displacement $\sim$0.6 pc. Such is typical colliding clouds discovered...
To reveal the origin of mini-starbursts in Milky Way, we carried out large-scale CO observations toward RCW 106 giant molecular cloud (GMC) complex using NANTEN2 4-m radio telescope operated by Nagoya University. We also analyzed Mopra Southern Galactic plane survey and Herschel infrared continuum archival data. The GMC contains radial velocity components $-68$ km s$^{-1}$ $-50$ reported Nguyen et al. (2015). Focusing on East West region with massive star formation having bright dust...
Abstract To reveal the origin of mini-starbursts in Milky Way, we carried out large-scale CO observations toward RCW 106 giant molecular cloud (GMC) complex using NANTEN2 4 m radio telescope operated by Nagoya University. We also analyzed Mopra Southern Galactic Plane survey and Herschel infrared continuum archival data. The GMC contains radial velocity components −68 km s −1 −50 reported H. Nguyen et al. (2015). Focusing on East West region with massive star formation having bright dust...
Abstract We propose a deep-learning model that can detect Spitzer bubbles accurately using two-wavelength near-infrared data acquired by the Space Telescope and JWST. The is based on single-shot multibox detector as an object detection model, trained validated identified Milky Way Project (MWP bubbles). found only MWP with clear structures, along normalization augmentation, significantly improved performance. To reduce dataset bias, we also use without in selected combining two techniques:...
We have developed a two-beam waveguide-type dual-polarization sideband-separating SIS receiver system in the 100-GHz band for z-machine on 45-m radio telescope at Nobeyama Radio Observatory. The is intended astronomical use searching highly redshifted spectral lines from galaxies of unknown redshift. This has two beams, which 45'' beam separation and allow observation with switch on-on position. each composed an ortho-mode transducer mixers, are both based waveguide technique, four...
We present $^{12}$CO $J=$1--0, $^{13}$CO $J=$1--0 and C$^{18}$O images of the M17 giant molecular clouds obtained as part FUGIN (FOREST Ultra-wide Galactic Plane Survey InNobeyama) project. The observations cover entire area SW N at highest angular resolution ($\sim$19$"$) to date which corresponds $\sim$ 0.15 pc distance 2.0 kpc. find that region consists four different velocity components: very low (VLV) clump, component (LVC), main (MVC), high (HVC). LVC HVC have cavities. UV photons...
A collision between two molecular clouds is one possible candidate for high-mass star formation. The HII region RCW 36, located in the Vela ridge, contains a young cluster with O-type stars. We present new CO observations of 36 NANTEN2, Mopra, and ASTE using $^{12}$CO($J$ = 1-0, 2-1, 3-2) $^{13}$CO($J$ 2-1) line emissions. have discovered lying at velocities $V_\mathrm{LSR} \sim$5.5 9 km s$^{-1}$. Both are likely to be physically associated cluster, as verified by good spatial correspondence...
Abstract PeVatrons are the most powerful naturally occurring particle accelerators in Universe. The identification of counterparts associated to astrophysical objects such as dying massive stars, molecular gas, star-forming regions, and star clusters is essential clarify underlying nature PeV emission, i.e., hadronic or leptonic. We present 12,13CO (J = 2→1) observations made with 1.85 m radio-telescope Osaka Prefecture University toward Cygnus OB7 cloud, which contains PeVatron candidate...
We present results of the observations carried out toward S247, S252, and BFS52 H ii regions with various molecular lines using 1.85 m radio telescope 45 at Nobeyama Radio Observatory. There are least 11 young infrared clusters (IR clusters) within observed region. found that there two velocity components in 12CO (J = 2–1), also their spatial distributions show an anti-correlation. The IR located interfaces, suggesting distinct clouds different velocities colliding each other, which may have...
Abstract W$\, 51\,$A is one of the most active star-forming regions in Milky Way, and includes copious amounts molecular gas with a total mass ${\sim }6\times 10^{5}\, M_{\odot }$. The has multiple velocity components over ∼20 km s−1, interactions between these have been discussed as mechanism that triggered massive star formation 51\,$A. In this paper, we report on an observational study using new 12CO, 13CO, C18O (J = 1–0) data covering 1${^{\circ}_{.}}$4 × 1${^{\circ}_{.}}$0 area obtained...
We performed new large-scale $^{12}$CO, $^{13}$CO, and C$^{18}$O $J=$1--0 observations of the W43 giant molecular cloud complex in tangential direction Scutum arm ($l\sim {30^\circ}$) as a part FUGIN project. The low-density gas traced by $^{12}$CO is distributed over 150 pc $\times$ 100 ($l \times b$), has large velocity dispersion (20-30 km s$^{-1}$). However, dense localized Main, G30.5, South (G29.96-0.02) high-mass star-forming regions GMC complex, which have clumpy structures. found at...
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)...
High-mass star formation is an important step which controls galactic evolution. GM 24 a heavily obscured cluster including single O9 with more than $\sim$100 lower mass stars within 0.3 pc radius toward $(l,b)\sim$ (350.$^{\circ}$5, 0.$^{\circ}$96), close to the Galactic min-starburst NGC 6334. We found two velocity components associated by new observations of $^{12}$CO $J=$ 2-1 emission, whereas cloud was previously considered be single. distribution $5$ km s$^{-1}$ separation shows...