Masahiko Hayashi
A5055184738- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Atmospheric Ozone and Climate
- Molecular Spectroscopy and Structure
- Gamma-ray bursts and supernovae
- Astrophysical Phenomena and Observations
- Spectroscopy and Laser Applications
- Astronomical Observations and Instrumentation
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Astrophysics and Cosmic Phenomena
- Atomic and Molecular Physics
- Forest Insect Ecology and Management
- Coleoptera: Cerambycidae studies
- Solar and Space Plasma Dynamics
- Ionosphere and magnetosphere dynamics
- Coleoptera Taxonomy and Distribution
- Advanced Chemical Physics Studies
- Cold Atom Physics and Bose-Einstein Condensates
- Calibration and Measurement Techniques
- Superconducting and THz Device Technology
- History and Developments in Astronomy
- Radio Astronomy Observations and Technology
National Astronomical Observatory of Japan
2015-2024
University of Bonn
2021-2024
University of Tsukuba
1979-2023
Kagoshima City Hospital
2023
Japan Society for the Promotion of Science
2022
Tokyo Medical University Hospital
2021
National Institutes of Natural Sciences
1995-2020
The Graduate University for Advanced Studies, SOKENDAI
2006-2018
Subaru (Japan)
2002-2017
Ames Research Center
2017
We present high-resolution, H-band, imaging observations, collected with Subaru/HiCIAO, of the scattered light from transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested existence dust-depleted cavity at r~46AU, our observations reveal presence components as close 0.2" (~28AU) star. Moreover, we have discovered two small-scale spiral structures lying within 0.5" (~70AU). models for using density wave theory, and derive a aspect ratio h~0.1, which is...
Several exoplanets have recently been imaged at wide separations of >10 AU from their parent stars. These span a limited range ages (<50 Myr) and atmospheric properties, with temperatures 800--1800 K very red colors (J - H > 0.5 mag), implying thick cloud covers. Furthermore, substantial model uncertainties exist these young due to the unknown initial conditions formation, which can lead an order magnitude uncertainty in modeled planet mass. Here, we report direct imaging discovery Jovian...
We report high-resolution 1.6 $\micron$ polarized intensity ($PI$) images of the circumstellar disk around Herbig Ae star AB Aur at a radial distance 22 AU ($0."15$) up to 554 (3.$"$85), which have been obtained by high-contrast instrument HiCIAO with dual-beam polarimetry. revealed complicated and asymmetrical structures in inner part ($\lesssim$140 AU) disk, while confirming previously reported outer ($r$ $\gtrsim$200 spiral structure. imaged double ring structure $\sim$40 $\sim$100...
We present the first near-IR scattered light detection of transitional disk associated with Herbig Ae star MWC 758 using data obtained as part Strategic Exploration Exoplanets and Disks Subaru, 1.1 micron HST/NICMOS data. While sub-millimeter studies suggested there is a dust-depleted cavity r=0.35, we find close 0.1 (20-28 AU) from star, no visible at H, K', or Ks. two small-scaled spiral structures which asymmetrically shadow outer disk. model one spirals density wave theory, derive aspect...
We report on the direct conversion of laser-cooled $^{41}\mathrm{K}$ and $^{87}\mathrm{Rb}$ atoms into ultracold $^{41}\mathrm{K}^{87}\mathrm{Rb}$ molecules in rovibrational ground state via photoassociation followed by stimulated Raman adiabatic passage. High-resolution spectroscopy based coherent transfer revealed hyperfine structure weakly bound an unexplored region. Our results show that a rovibrationally pure sample ground-state is achieved all-optical association atoms, opening...
We present a near-infrared image of the Herbig Ae star AB Aur obtained with Coronagraphic Imager Adaptive Optics mounted on Subaru Telescope. The shows circumstellar emission extending out to radius r = 580 AU, double spiral structure detected at 200-450 AU. surface brightness decreases as r-3.0±0.1, steeper than radial profile optical possibly affected by scattered light from envelope surrounding Aur. This result, together size infrared similar that 13CO (J 1-0) disk, suggests is indeed...
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 present the direct imaging discovery of an extrasolar planet, or possible low-mass brown dwarf, at a projected separation 55 +/- 2 AU (1.058 0.007 arcsec) from B9-type star Kappa And. The planet was detected with Subaru/HiCIAO during SEEDS survey, and confirmed as bound companion via common proper motion measurements. Observed near-infrared magnitudes J = 16.3 0.3, H 15.2 0.2, Ks 14.6 0.4, L' 13.12 0.09 indicate temperature ~1700 K. galactic kinematics host are consistent membership in...
We present high resolution H-band polarized intensity (PI; FWHM = 0."1: 14 AU) and L'-band imaging data (FWHM 0."11: 15 of the circumstellar disk around weak-lined T Tauri star PDS 70 in Centaurus at a radial distance 28 AU (0."2) up to 210 (1."5). In both images, giant inner gap is clearly resolved for first time, radius ~70 AU. Our show that geometric center shifts by ~6 toward minor axis. confirm brown dwarf companion candidate north background based on its proper motion. As result SED...
We present a new Subaru/HiCIAO high-contrast H-band polarized intensity (PI) image of nearby transitional disk associated with TW Hydrae. The scattered light from the was detected 0.2" to 1.5" (11 - 81 AU) and PI shows clear axisymmetric depression in at ~ 0.4" (~ 20 central star, similar 80 AU gap previously reported HST images. Azimuthal profile also beyond is almost axisymmetric. discuss two possible scenarios explaining origin depression: 1) structure may exist star because shallow slope...
Transitional circumstellar disks around young stellar objects have a distinctive infrared deficit 10 μm in their spectral energy distributions, recently measured by the Spitzer Infrared Spectrograph (IRS), suggesting dust depletion inner regions. These been confirmed to giant central cavities imaging of submillimeter continuum emission using Submillimeter Array (SMA). However, polarized near-infrared scattered light images for most systematic IRS/SMA cross sample, obtained HiCIAO on Subaru...
We present results from the first three years of observations moving group targets in SEEDS high-contrast imaging survey exoplanets and disks using Subaru telescope. achieve typical contrasts ~10^5 at 1" ~10^6 beyond 2" around 63 proposed members nearby kinematic groups. review each associations to which our belong, concluding that five, \beta Pictoris (~20 Myr), AB Doradus (~100 Columba (~30 Tucana-Horogium TW Hydrae (~10 are sufficiently well-defined constrain ages individual targets....
We conduct a statistical analysis of combined sample direct imaging data, totalling nearly 250 stars. The stars cover wide range ages and spectral types, include five detections ($\kappa$ And b, two $\sim$60 M$_{\rm J}$ brown dwarf companions in the Pleiades, PZ Tel B, CD$-$35 2722B). For some analyses we add currently unpublished set SEEDS observations, including GJ 504b 758B. uniform, Bayesian all stellar using both membership kinematic moving group activity/rotation age indicators. then...
Two studies utilizing sparse aperture masking (SAM) interferometry and $H_{\rm \alpha}$ differential imaging have reported multiple jovian companions around the young solar-mass star, LkCa 15 (LkCa bcd): first claimed direct detection of infant, newly-formed planets ("protoplanets"). We present new near-infrared imaging/spectroscopy from SCExAO system coupled with CHARIS integral field spectrograph multi-epoch thermal infrared Keck/NIRC2 at high Strehl ratios. These data provide look same...
Abstract We present the direct-imaging discovery of a substellar companion in orbit around Sun-like star member Hyades open cluster. So far, no other companions have been unambiguously confirmed via direct imaging main-sequence stars Hyades. The HIP 21152 is an accelerating as identified by astrometry from Gaia and Hipparcos satellites. detected companion, B, multiple epochs using high-contrast SCExAO/CHARIS Keck/NIRC2. also obtained stellar radial-velocity data Okayama 188 cm telescope....
Direct imaging of gas giant exoplanets provides information on their atmospheres and the architectures planetary systems. However, few planets have been detected in blind surveys with direct imaging. Using astrometry from Gaia Hipparcos spacecraft, we identified dynamical evidence for a planet around nearby star HIP 99770. We confirmed detection this using Subaru Coronagraphic Extreme Adaptive Optics instrument. The planet, 99770 b, orbits 17 astronomical units its host star, receiving an...
We report new interferometric observations of IRAS 04368+2557 (L1527) in 13CO (J = 1-0), C18O and 2.7 mm continuum emission using the Nobeyama Millimeter Array. The map shows a well-defined peak with slightly extended features. features are consistent an 800 μm map. blueshifted redshifted outflowing shells characterized by bipolar V-shape structure wide opening angle toward east west central source. Near systemic velocity, X-shaped condensation was detected its coincident symmetrical...
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...
We discovered a unique morphology in disk around the Herbig Ae star HD 142527 by near-infrared (H and K bands) adaptive optics imaging observations. The almost face-on consists of two bright arcs facing one another along east-west direction (banana-split structure) spiral arm extending to north from western arc. eastern arc is located at ~100-400 AU radius star, detected ~150-490 AU. stellar position displaced center about 20 north, also inner hole. show an asymmetry their size brightness;...
An overview of the current status 8.2 m Subaru Telescope constructed and operated at Mauna Kea, Hawaii, by National Astronomical Observatory Japan is presented. The basic design concept verified performance telescope system are described. Also given instrument package offered to astronomical community, operation, some future plans. reported in a number SPIE papers as summer 2002 incorporated with updates included 2004 February. However, readers encouraged check most updated through home...
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...
We present a new high-quality observation of HL Tau carried out with Nobeyama Millimeter Array in the 13 CO (J=1-0) emission. have confirmed presence gas disk elongated perpendicular to optical jet. The has mass and radius 0.03 M ○. 1400 AU, respectively, is located outside inner compact observed dust Examination velocity field revealed that accreting motion dominated plane, although there an indication rotation at speed 0.2 km s -1 measured 700 AU radius. radial 1 consistent obtained when...
We present H- and Ks-band imaging data resolving the gap in transitional disk around LkCa 15, revealing surrounding nebulosity. detect sharp elliptical contours delimiting nebulosity on inside as well outside, consistent with shape, size, ellipticity, orientation of starlight reflected from far-side wall, whereas near-side wall is shielded view by disk's optically thick bulk. note that forward scattering surface could provide an alternate interpretation In either case, this discovery...