Shogo Nishiyama
A5051843486- Stellar, planetary, and galactic studies
- Astrophysics and Star Formation Studies
- Astrophysical Phenomena and Observations
- Astronomy and Astrophysical Research
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Astro and Planetary Science
- Pulsars and Gravitational Waves Research
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Mechanics and Biomechanics Studies
- Molecular Spectroscopy and Structure
- Solar and Space Plasma Dynamics
- Atmospheric Ozone and Climate
- Calibration and Measurement Techniques
- Relativity and Gravitational Theory
- History and Developments in Astronomy
- SAS software applications and methods
- Radio Astronomy Observations and Technology
- High-pressure geophysics and materials
- CCD and CMOS Imaging Sensors
- Spectroscopy and Laser Applications
- Scientific Measurement and Uncertainty Evaluation
- Neutrino Physics Research
Kyoto University
2008-2024
Miyagi University of Education
2014-2024
Kyoto Katsura Hospital
2024
Miyagi University
2023
University of California, San Diego
2023
The Aerospace Corporation
2022
California Institute of Technology
2022
National Institutes of Natural Sciences
2007-2018
Astrobiology Center
2018
Hiroshima University
2017
We have determined interstellar extinction law toward the Galactic center (GC) at wavelength from 1.2 to 8.0 micron, using point sources detected in IRSF/SIRIUS near-infrared survey and those 2MASS Spitzer/IRAC/GLIMPSE II catalogs. The central region |l| < 3deg |b| 1deg has been surveyed J, H Ks bands with IRSF telescope SIRIUS camera whose filters are similar Mauna Kea Observatories (MKO) photometric system. Combined GLIMPSE source catalog, we made versus (Ks - lambda) color-magnitude...
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 have determined the ratios of total to selective extinction in near-infrared bands (J, H, Ks) toward Galactic center from observations region |l| < 2.0deg and 0.5deg |b| 1.0deg with IRSF telescope SIRIUS camera. Using positions red clump stars color-magnitude diagrams as a tracer reddening, we determine average be A(Ks)/E(H-Ks) = 1.44+-0.01, A(Ks)/E(J-Ks) 0.494+-0.006, A(H)/E(J-H) 1.42+-0.02, which are significantly smaller than those obtained previous studies. From these ratios,...
(abridged) In this paper we aim at determining the shape, size, and luminosity/mass of Milky Way Nuclear Star Cluster (MWNSC). We use Spitzer/IRAC images 3.6 4.5 micrometer, where interstellar extinction is a minimum but overall emission still dominated by stars. correct micrometer image for PAH with help IRAC 8.0 map [3.6-4.5] colour map. present an central ~300x200 pc^2 Way, as well PAH-emission corrected stellar emission, resolution about 0.2 pc. find that MWNSC appears in projection...
Within the central 10pc of our Galaxy lies a dense nuclear star cluster (NSC), and similar NSCs are found in most nearby galaxies. Studying structure kinematics reveals history mass accretion galaxy nuclei. Because Milky Way (MW) NSC is at distance only 8kpc, we can spatially resolve MWNSC on sub-pc scales. This makes reference object for understanding formation all NSCs. We have used NIR long-slit spectrograph ISAAC (VLT) drift-scan to construct an integral-field spectroscopic map 9.5 x 8pc...
Gravitational redshift in the Galactic Center General relativity predicts that light emitted by an object a strong gravitational field—for example, close to black hole—should be shifted longer wavelengths. This does not exist Newtonian theory of gravity. Do et al. monitored position and spectrum star S0-2 as it passed Sagittarius A*, supermassive hole at center Milky Way. Around closest part S0-2's 16-year orbit, they detected effect on its spectrum. These results are more consistent with...
Abstract The Japan Astrometry Satellite Mission for INfrared Exploration (JASMINE) is a planned M-class science space mission by the Institute of Space and Astronautical Science, Aerospace Agency. JASMINE has two main goals. One Galactic archaeology with Center survey, which aims to reveal Milky Way’s central core structure formation history from Gaia-level (∼25 ${\mu} $as) astrometry in near-infrared (NIR) Hw band (1.0–1.6 $m). other an exoplanet discover transiting Earth-like exoplanets...
We have determined the ratios of total to selective extinction directly from observations in optical V band and near-infrared J toward Galactic center. The OGLE (Optical Gravitational Lensing Experiment) bulge fields been observed with SIRIUS camera on IRSF telescope, we obtain A(V)/E(V-J)=1.251+-0.014 A(J)/E(V-J)=0.225+-0.007. From these ratios, derived A(J)/A(V) = 0.188+-0.005; if combine obtained by Nishiyama et al. for more reddened near center, get A(V) : A(J) A(H) A(Ks) 1 0.188 0.108...
We present a catalog of 9017 X-ray sources identified in Chandra observations 2°× 08 field around the Galactic center. This enlarges number known region by factor 2.5. The incorporates all ACIS-I as 2007 August, which total 2.25 Ms exposure. At distance to center (8 kpc), we are sensitive with luminosities 4 × 1032 erg s−1 (0.5–8.0 keV; 90% confidence) over an area 1 deg2, and up order magnitude more deepest exposure (1.0 Ms) Sgr A*. positions 60% our accurate <1 '' (95% confidence), 20%...
We report the results of a near-infrared survey for long-period variables in field view 20 arcmin by 30 towards Galactic Centre (GC). have detected 1364 variables, which 348 are identified with those reported Glass et al. (2001). present catalogue and photometric measurements discuss their nature. also establish method simultaneous estimation distances extinctions using period-luminosity relations JHKs bands. Our is applicable to Miras periods range 100--350 d mean magnitudes available two...
The Serpens South embedded cluster, which is located in the constricted part of a long, filamentary, infrared dark cloud, believed to be very early stage cluster formation. We present results near-infrared (JHKs) polarization observations filamentary cloud. Our measurements point sources indicate well-ordered global magnetic field that perpendicular main filament, implying likely have controlled formation filament. On other hand, sub-filaments, converge on central tend run along field....
IRD is the near-infrared high-precision radial velocity instrument for Subaru 8.2-m telescope. It a relatively compact (~1m size) spectrometer with new echelle-grating and Volume-Phase Holographic gratings covering 1-2 micron wavelengths combined an original frequency comb using optical pulse synthesizer. The will employ 4096x4096-pixel HgCdTe array under testing at IfA, University of Hawaii. Both telescope/Adaptive Optics beams are fed to via fibers, while placed Nasmyth platform Expected...
The Infrared Doppler (IRD) instrument is a fiber-fed high-resolution NIR spectrometer for the Subaru telescope covering Y,J,H-bands simultaneously with maximum spectral resolution of 70,000. main purpose IRD search Earth-mass planets around nearby M-dwarfs by precise radial velocity measurements, as well spectroscopic characterization exoplanet atmospheres. We report current status instrument, which undergoing commissioning at Telescope, and first light observation successfully done in...
The Galactic Centre is of fundamental astrophysical interest, but existing near-infrared surveys fall short to cover it adequately. We introduce the GALACTICNUCLEUS survey, a $JHK_s$ imaging survey centre Milky Way with $0.2"$ angular resolution. present observations Field 1 our centred approximately on SgrA* an approximate size $7.95'\times3.43'$. describe observational set-up and data reduction pipeline discuss quality data. Finally, we some preliminary analysis were acquired camera HAWK-I...
We present the result of a near-infrared (JHKs) survey along Galactic plane, -105 ≤ l 105 and b = +1°, with IRSF 1.4 m telescope SIRIUS camera. Ks versus H - color-magnitude diagrams reveal well-defined population red clump stars whose apparent magnitude peak changes continuously from 13.4 at -10° to 12.2 10° after dereddening. This variation can be explained by barlike structure found in previous studies, but we find an additional inner ∣ ≲ 4°, where longitude-apparent relation is distinct...
Studies of the structure and evolution protoplanetary disks are important for understanding star planet formation. Here, we present direct image an interacting binary system. Both circumprimary circumsecondary resolved in near-infrared. There is a bridge infrared emission connecting two long spiral arm extending from disk. Numerical simulations show that corresponds to gas flow shock wave caused by collision rotating around primary secondary stars. Fresh material streams along arm,...
Microlensing detections of cool planets are important for the construction an unbiased sample to estimate frequency beyond snow line, which is where giant thought form according core accretion theory planet formation. In this paper, we report discovery a detected from analysis light curve high-magnification microlensing event MOA 2010-BLG-477. The measured planet–star mass ratio q = (2.181 ± 0.004) × 10−3 and projected separation s 1.1228 0.0006 in units Einstein radius. angular radius...
The high extinction and extreme source crowding of the central regions Milky Way are serious obstacles to study structure stellar population Galactic centre (GC). Existing surveys that cover GC region (2MASS, UKIDSS, VVV, SIRIUS) do not have necessary angular resolution. Therefore, a high-angular-resolution survey in near infrared is crucial improve state art. Here, we present GALACTICNUCLEUS catalogue, $JHK_s$ ($0.2''$) nuclear bulge Way. We explain detail data reduction, analysis,...
Searching for space-time variations of the constants Nature is a promising way to search new physics beyond general relativity and standard model motivated by unification theories models dark matter energy. We propose variation fine-structure constant using measurements late-type evolved giant stars from S star cluster orbiting supermassive black hole in our Galactic Center. A measurement difference between distinct absorption lines (with different sensitivity fine structure constant) leads...
On the basis of near infrared observations bulge red clump stars Galactic center, we have determined galactocentric distance to be R_0 = 7.52 +- 0.10 (stat) 0.35 (sys) kpc. We observed at |l| < 1.0 deg and 0.7 |b| with IRSF 1.4 m telescope SIRIUS camera in H Ks bands. After extinction population corrections, obtained (m - M)_0 14.38 0.03 (sys). The statistical error is dominated by uncertainty intrinsic local stars' luminosity. systematic estimated including uncertainties correction,...
Context.In spring 2005 the blazar 3C 454.3 was observed in an unprecedented bright state from near-IR to hard X-ray frequencies. A mm outburst peaked June–July 2005, and it followed by a flux increase at high radio
The quasar 3C 279 was the target of an extensive multiwavelength monitoring campaign from 2006 January through April. An optical-IR-radio by Whole Earth Blazar Telescope (WEBT) collaboration organized around target-of-opportunity X-ray and soft γ-ray observations with Chandra INTEGRAL in mid-January, additional coverage RXTE Swift XRT. In this paper we focus on results WEBT campaign. source exhibited substantial variability optical flux spectral shape, a characteristic timescale few days....
We present the results of CO ($J=3-2$) and HCO$^+$ ($J=4-3$) mapping observations toward a nearby embedded cluster, Serpens South, using ASTE 10 m telescope. Our map reveals that many outflows are crowded in dense cluster-forming clump can be recognized as with size $\sim$ 0.2 pc mass 80 M$_\odot$. The contains several subfragments sizes 0.05 pc. By comparing 1.1 mm dust continuum image taken by AzTEC on ASTE, we find spatial extents outflow lobes sometimes anti-correlated distribution gas...