A5101646208- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astro and Planetary Science
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Galaxies: Formation, Evolution, Phenomena
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astrophysics and Cosmic Phenomena
- Spectroscopy and Laser Applications
- Calibration and Measurement Techniques
- Atmospheric Ozone and Climate
- Cosmology and Gravitation Theories
- Solar and Space Plasma Dynamics
- Optical Polarization and Ellipsometry
- Spacecraft Design and Technology
- Astronomical Observations and Instrumentation
- Scientific Research and Discoveries
- Semiconductor materials and devices
- Isotope Analysis in Ecology
- Particle Detector Development and Performance
- Advanced optical system design
- Physics of Superconductivity and Magnetism
- Inertial Sensor and Navigation
- Semiconductor Quantum Structures and Devices
Institute of Space and Astronautical Science
2023-2024
The University of Tokyo
2014-2024
Japan Aerospace Exploration Agency
2023-2024
National Astronomical Observatory of Japan
2016-2021
University of Arizona
2021
Planetary Science Institute
2018
Macquarie University
2016
Tokyo Metropolitan University
2007-2013
SRON Netherlands Institute for Space Research
2007
Fourth State (United Kingdom)
1992
We report high-resolution spectroscopic detection of TiO molecular signature in the day-side spectra WASP-33 b, second hottest known hot Jupiter. used High-Dispersion Spectrograph (HDS; R $\sim$ 165,000) wavelength range 0.62 -- 0.88 $\mu$m with Subaru telescope to obtain b. suppress and correct systematic effects instrument, telluric stellar lines by using SYSREM algorithm after selection good orders based on Barnard star other M-type stars. detect a 4.8-$\sigma$ signal at an orbital...
The recently introduced discrete persistent structure extractor (DisPerSE, Sousbie, Paper I) is implemented on realistic 3D cosmological simulations and observed redshift catalogues; it found that DisPerSE traces very well the filaments, walls voids seen both in observations. In either setting, filaments are shown to connect haloes, outskirt walls, which circumvent voids, as topologically required by Morse theory. Indeed this algorithm returns optimal critical set while operating directly...
We undertook a systematic X-ray analysis of six giant radio relics in four clusters galaxies using the Suzaku satellite. The sample included CIZA 2242.8$ +$ 5301, Zwcl 2341.1$-$ 0000, South-East part A 3667 and previously published results North-West 3376. Especially, we first observed narrow (50 kpc) relic 5301 by satellite, which enabled us to reduce projection effect. report on detections shocks at positions SE. At two ZWCL did not detect shocks. From spectroscopic temperature profiles...
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...
Characterizing the surfaces of rocky exoplanets via their scattered light will be an essential challenge in investigating habitability and possible existence life on surfaces. We present a reconstruction method for fractional areas different surface types from colors Earth-like exoplanet. create mock curves Earth without clouds using empirical data. These are fitted to isotropic scattering model consisting four types: ocean, soil, snow, vegetation. In idealized situation where photometric...
The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by Institute Space and Astronautical Science (ISAS). will investigate physics high-energy universe via suite four instruments, covering very wide energy range, from 0.3 keV to 600 keV. These instruments include high-resolution, high-throughput spectrometer sensitive over 0.3-2 with high spectral resolution Delta E < 7 eV, enabled micro-calorimeter array located focal plane thin-foil...
We present the thermal evolution and emergent spectra of solidifying terrestrial planets along with formation steam atmospheres. The lifetime a magma ocean its through atmosphere depends on orbital distance planet from host star. For Type I planet, which is formed beyond certain critical star, emission declines timescale shorter than approximately 106 years. Therefore, young stars should be targets when searching for molten in this region. In contrast, II inside distance, will emit...
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...
ABSTRACT We visually inspected the light curves of 7557 Kepler Objects Interest (KOIs) to search for single transit events (STEs) that were possibly due long-period giant planets. identified 28 STEs in 24 KOIs, among which 14 are newly reported this paper. estimate radius and orbital period objects causing by fitting STE simultaneously with transits other planets system or prior information on host star density. As a result, we found seven those systems consistent Neptune- Jupiter-sized...
We analyse the transmission spectra of KELT-20b/MASCARA-2b to search for possible thermal inversion agents. The data consist three transits obtained using HARPSN and one CARMENES. removed stellar telluric lines before cross-correlating residuals with spectroscopic templates produced a 1D plane-parallel model assuming an isothermal atmosphere chemical equilibrium at solar metallicity. Using likelihood-mapping method, we detect Fe\,{\sc i} $>$ 13-$\sigma$, Ca\,{\sc ii} H$\&$K 6-$\sigma$...
Abstract We analyze the high-resolution emission spectrum of WASP-33b taken using High Dispersion Spectrograph ( R ≈ 165,000) on 8.2 m Subaru telescope. The data cover λ 6170–8817 Å, divided over 30 spectral orders. telluric and stellar lines are removed a de-trending algorithm, S ys em , before cross-correlating with planetary templates. calculate templates assuming 1D plane-parallel hydrostatic atmosphere including continuum opacity bound–free H − Rayleigh scattering by 2 range constant...
To clarify the mechanism of ossification posterior longitudinal ligament, immunohistochemical localization bone morphogenetic protein-2 and transforming growth factor-β was examined using surgical specimens ligament tissues from an affected patient. Two poly-clonal antibone antibodies anti-human antibody were used as primary antibodies. Bone present in ossified matrix chondrocytes adjacent cartilaginous areas ligament. Although immunostaining with also observed mesenchymal cells fibroblastic...
Scattered lights from terrestrial exoplanets provide valuable information about the planetary surface. Applying surface reconstruction method proposed by Fujii et al. (2010) to both diurnal and annual variations of scattered light, we develop a land distribution with longitudinal latitudinal resolutions. We find that one can recover global map an idealized Earth-like planet on following assumptions: 1) cloudless, 2) face-on circular orbit, 3) known types their reflectance spectra 4) no...
We develop an inversion technique of annual scattered light curves to sketch a two-dimensional albedo map exoplanets in face-on orbits. As test-bed for future observations extrasolar terrestrial planets, we apply this mapping simulated mock Earth-twin at distance 10 pc circular orbit. A primary feature recovered maps traces the mean distribution clouds. To extract information other surface types, attempt reduce cloud signal by taking difference two bands. find that reflectivity between...
Aiming at obtaining detailed information of surface environment Earth analogs, Kawahara & Fujii (2011) proposed an inversion technique annual scattered light curves named the spin-orbit tomography (SOT), which enables one to sketch a two-dimensional albedo map from variation disk-integrated light, and demonstrated method with planet in face-on orbit. We extend it be applicable general geometric configurations, including low-obliquity planets like inclined orbits. simulate orbit three...
We present the results of deep 140 ks Suzaku X-ray observations north-east (NE) radio relic merging galaxy cluster Abell 2255. The temperature structure 2255 is measured out to 0.9 times virial radius (1.9 Mpc) in NE direction for first time. map central region suggests a complex distribution, which agrees with previous work. Additionally, on larger-scale, we confirm that drops from 6 keV around center 3 at outskirts, two discontinuities r ~ 5′ (450 kpc) and ~12′ (1100 center. Their...
Motivated by recent detection of transiting high-density super-Earths, we explore the detectability hot rocky super-Earths orbiting very close to their host stars. In environment enough for surfaces be molten, they would have atmosphere composed gas species from magma oceans. this study, investigate radiative properties that is in gas/melt equilibrium with underlying ocean. Our calculations yield Na, K, Fe, Si, SiO, O, and O$_2$ as major atmospheric species. We compile radiative-absorption...
Abstract We report the discovery of fifth self-lensing binary in which a low-mass white dwarf (WD) gravitationally magnifies its 15th magnitude G-star companion, KIC 8145411, during eclipses. The system was identified from pair such events Kepler photometry, and followed up with Tillinghast Reflector Echelle Spectrograph (TRES) on 1.5 m telescope at Fred Lawrence Whipple Observatory High-Dispersion (HDS) Subaru 8.2 telescope. A joint analysis TRES radial velocities, HDS spectrum, photometry...
As a test bed for future investigations of directly imaged terrestrial exoplanets, we present the recovery surface components Earth from multi-band diurnal light curves obtained with EPOXI spacecraft. We find that presence and longitudinal distribution ocean, soil, vegetation are reasonably well reproduced by fitting observed color variations simplified model composed priori known albedo spectra vegetation, snow, clouds. The effect atmosphere, including clouds, on scattered is modeled using...
Detection of a planetary ring exoplanets remains as one the most attractive but challenging goals in field. We present methodology systematic search for exoplanetary rings via transit photometry long-period planets. The relies on precise integration scheme we develop to compute light curve ringed planet. apply 89 planet candidates from Kepler data so estimate, and/or set upper limits on, parameters possible rings. While majority our samples do not have sufficiently good signal-to-noise ratio...
We present an X-ray spectral analysis of the nearby double radio relic merging cluster Abell 3376 ($z$ = 0.046), observed with $Suzaku$ XIS instrument. These deep ($\sim$360 ks) observations cover entire region in outskirts cluster. diffuse structures are amongst largest and arc-shaped relics combination large-scale shocks a confirm presence stronger shock (${\cal M}_{\rm{W}}$ 2.8 $\pm~0.4$) western direction at $r\sim26$', derived from temperature surface brightness discontinuity across...
The Subaru Coronagraphic Extreme Adaptive Optics (SCExAO) instrument is an extremely modular high- contrast installed on the telescope in Hawaii. SCExAO has a dual purpose. Its position northern hemisphere 8-meter makes it prime for detection and characterization of exoplanets stellar environments over large portion sky. In addition, SCExAO's unique design ideal to test innovative technologies algorithms quickly laboratory setup subsequently deploy them on-sky. benefits from first stage...