296 citations · 1.4k across the 26 of their papers we have counts for
26 papers
JASMINE: Near-Infrared Astrometry and Time Series Photometry Science
Daisuke Kawata, Hajime Kawahara, Naoteru Gouda +86
Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, the Japan Aero…
Nobeyama 45-m mapping observations toward nearby molecular clouds, Orion A, Aquila Rift, and M17: Project overview
Fumitaka Nakamura, Shun Ishii, Kazuhito Dobashi +16
We carried out mapping observations toward three nearby molecular clouds, Orion A, Aquila Rift, and M17, using a new 100 GHz receiver, FOREST, on the Nobeyama 45-m telescope. In th…
Nobeyama 45-m Mapping Observations toward Orion A. III. Multi-Line Observations toward an Outflow-shocked Region, OMC-2 FIR
Fumitaka Nakamura, Shuri Oyamada, Sachiko Okumura +13
We present the results of mapping observations toward an outflow-shocked region, OMC-2 FIR 4 using the Nobeyama 45-m telescope. We observed the area in CO (), C$^{18}…
Evidence For Cloud-Cloud Collision and Parsec-Scale Stellar Feedback Within the L1641-N Region
Fumitaka Nakamura, Tomoya Miura, Yoshimi Kitamura +7
We present high spatial resolution CO () images taken by the Nobeyama 45m telescope toward a area including the L1641-N cluster. The effective spatia…
The Molecular Outflows in the rho Ophiuchi Main Cloud: Implications For Turbulence Generation
Fumitaka Nakamura, Yuhei Kamada, Takeshi Kamazaki +13
We present the results of CO (J=3-2) and CO (J=1-0) mapping observations toward the active cluster forming clump, L1688, in the rho Ophiuchi molecular cloud. From the CO (J=3-2) an…
Physical Properties of Dense Cores in the Rho Ophiuchi Main Cloud and A Significant Role of External Pressures in Clustered Star Formation
Hajime Maruta, Fumitaka Nakamura, Ryoichi Nishi +2
Using the archive data of the H13CO+ (J=1-0) line emission taken with the Nobeyama 45 m radio telescope with a spatial resolution of about 0.01pc, we have identified 68 dense cores…
Primordial Molecular Emission in Population III Galaxies
Hiromi Mizusawa, Kazuyuki Omukai, Ryoichi Nishi
We study formation of molecules in primordial prestellar clumps and evaluate the line luminosities to assess detectability by next-generation facilities. If the initial H_2 fractio…
H_2 Line Emission Associated with the Formation of the First Stars
Hiromi Mizusawa, Ryoichi Nishi, Kazuyuki Omukai
Molecular hydrogen line radiation emitted in formation events of first-generation stars are evaluated in a discussion of its detectability by future observational facilities. H_2 l…
Microlensing optical depth towards the Galactic bulge from MOA observations during 2000 with Difference Image Analysis
T. Sumi, F. Abe, I. A. Bond +27
We analyze the data of the gravitational microlensing survey carried out by by the MOA group during 2000 towards the Galactic Bulge (GB). Our observations are designed to detect ef…
Mechanism of Magnetic Flux Loss in Molecular Clouds
Takenori Nakano, Ryoichi Nishi, Toyoharu Umebayashi
We investigate the detailed processes working in the drift of magnetic fields in molecular clouds. To the frictional force, whereby the magnetic force is transmitted to neutral mol…
Self-Regulation of Star Formation in Low Metallicity Clouds
Ryoichi Nishi, Motomichi Tashiro
We investigate the process of self-regulated star formation via photodissociation of hydrogen molecules in low metallicity clouds. We evaluate the influence region's scale of a mas…
On the Thermal Instability in a Contracting Gas Cloud and Formation of a Bound Cluster
Motomichi Tashiro, Ryoichi Nishi
We perform linear analysis of thermal instability in a contracting large cloud filled with warm HI gas and investigate the effect of metallicity and radiation flux. When the cloud…
On the Decelerating Shock Instability of Plane-Parallel Slab with Finite Thickness
Ryoichi Nishi, Hideyuki Kamaya
Dynamical stability of the shock compressed layer with finite thickness is investigated. It is characterized by self-gravity, structure, and shock condition at the surfaces of the…
Kepler Rotation Effects on the Binary-Lens Microlensing Events
K. Ioka, R. Nishi, Y. Kan-ya
We investigate the effects of the Kepler rotation of lens binaries on the binary-microlensing events towards the Large Magellanic Cloud (LMC) and the Small Magellanic Cloud (SMC).…
Formation and Disruption of Cosmological Low Mass Objects
Ryoichi Nishi, Hajime Susa
We investigate the evolution of cosmological low mass (low virial temperature) objects and the formation of the first luminous objects. First, the `cooling diagram' for low mass ob…
Photodissociative Regulation of Star Formation in Metal-Free Pregalactic Clouds
Kazuyuki Omukai, Ryoichi Nishi
We study the H2 photodissociation regions around OB stars in primordial gas clouds whose virial temperatures are between a few hundred and a few thousand Kelvin. In such small obje…
Thermal and Dynamical Evolution of Primordial Gas Clouds - On the Formation of First Luminous Objects -
Ryoichi Nishi, Hajime Susa, Hideya Uehara +2
We investigate the thermal and dynamical evolution of primordial gas clouds in the universe after decoupling. Comparing the time-scale of dynamical evolution with that of fragmenta…
Formation of Primordial Protostars
Kazuyuki Omukai, Ryoichi Nishi
The evolution of collapsing metal free protostellar clouds is investigated for various masses and initial conditions. We perform hydrodynamical calculations for spherically symmetr…
Back Reaction to the Spectrum of Magnetic Field in the Kinetic Dynamo Theory --- Modified Kulsrud and Anderson Equation ---
Tetsuya Shiromizu, Ryoichi Nishi
We take account of the lowest order back reaction on the fluid and modify the Kulsrud and Anderson equation obtained in the kinetic dynamo the…
Evolution of Primordial Protostellar Clouds --- Quasi-Static Analysis ---
Kazuyuki Omukai, Ryoichi Nishi, Hideya Uehara +1
The contraction processes of metal-free molecular clouds of starlike mass (or cloud cores) are investigated. We calculate radiative transfer of the H_2 lines and examine quasi-stat…
The Thermal Evolution of the Postshock Layer in Pregalactic Clouds
Hajime Susa, Ryoichi Nishi, Hideya Uehara +1
We re-examine the thermal evolution of the postshock layer in primordial gas clouds. Comparing the time scales, we find that the evolutionary paths of postshock regions in primordi…
Expected EAGLE event rate towards the Magellanic Clouds
Takashi Nakamura, Ryoichi Nishi
We propose to search for MACHOs by observing EAGLE (Extremely Amplified Gravitational LEnsing) events of a majority of dim stars. This search is independent of the usual one. For t…
The Minimum Total Mass of MACHOs and Halo Models of the Galaxy
T. Nakamura, Y. Kan-ya, R. Nishi
If the density distribution ρ(r) of MACHOs is spherically symmetric with respect to the Galactic center, it is shown that the minimal total mass M_{min}^{ MACHO} of the MACHOs is 1…
Fragmentation of the Primordial Gas Clouds and the Lower Limit on the Mass of the First Stars
Hideya Uehara, Hajime Susa, Ryoichi Nishi +2
We discuss the fragmentation of primordial gas clouds in the universe after decoupling. Comparing the time scale of collapse with that of fragmentation, we obtain the typical mass…