Curriculum Vitaes
Profile Information
- Affiliation
- Institute of Space and Astronautical Science, Japan Aerospace Exploration AgencySchool of Physical Sciences, The Graduate University for Advanced Studies
- Degree
- 理学博士(Mar, 1998)
- J-GLOBAL ID
- 200901028844431929
- researchmap Member ID
- 5000050859
- External link
銀河、銀河団などの宇宙の大規模構造の形成と進化の研究。主にX線による観測を手段とします。
愛知県一宮高校卒業、
名古屋大学 理学部卒業、
東京大学理学系研究科 理学博士取得、
宇宙科学研究所、SRON(NL)にてポスドク。
現在、JAXA/宇宙科学研究所勤務。
愛知県一宮高校卒業、
名古屋大学 理学部卒業、
東京大学理学系研究科 理学博士取得、
宇宙科学研究所、SRON(NL)にてポスドク。
現在、JAXA/宇宙科学研究所勤務。
Major Research Interests
10Research Areas
2Research History
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Nov, 2020 - Present
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Nov, 2020 - Present
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Sep, 2020 - Present
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Apr, 2007 - Present
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Nov, 2020 - Mar, 2021
Awards
3Major Papers
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 71(3), Nov, 2018 Peer-reviewed
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The Astrophysical Journal, 837(1) L15-L15, Jul 25, 2016High-resolution X-ray spectroscopy with Hitomi was expected to resolve the origin of the faint unidentified E=3.5 keV emission line reported in several low-resolution studies of various massive systems, such as galaxies and clusters, including the Perseus cluster. We have analyzed the Hitomi first-light observation of the Perseus cluster. The emission line expected for Perseus based on the XMM-Newton signal from the large cluster sample under the dark matter decay scenario is too faint to be detectable in the Hitomi data. However, the previously reported 3.5 keV flux from Perseus was anomalously high compared to the sample-based prediction. We find no unidentified line at the reported high flux level. Taking into account the XMM measurement uncertainties for this region, the inconsistency with Hitomi is at a 99% significance for a broad dark-matter line and at 99.7% for a narrow line from the gas. We do not find anomalously high fluxes of the nearby faint K line or the Ar satellite line that were proposed as explanations for the earlier 3.5 keV detections. We do find a hint of a broad excess near the energies of high-n transitions of Sxvi (E=3.44 keV rest-frame) -- a possible signature of charge exchange in the molecular nebula and another proposed explanation for the unidentified line. While its energy is consistent with XMM pn detections, it is unlikely to explain the MOS signal. A confirmation of this interesting feature has to wait for a more sensitive observation with a future calorimeter experiment.
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Nature (London), 535(7610), Jul 15, 2016Clusters of galaxies are the most massive gravitationally-bound objects in the Universe and are still forming. They are thus important probes of cosmological parameters and a host of astrophysical processes. Knowledge of the dynamics of the pervasive hot gas, which dominates in mass over stars in a cluster, is a crucial missing ingredient. It can enable new insights into mechanical energy injection by the central supermassive black hole and the use of hydrostatic equilibrium for the determination of cluster masses. X-rays from the core of the Perseus cluster are emitted by the 50 million K diffuse hot plasma filling its gravitational potential well. The Active Galactic Nucleus of the central galaxy NGC1275 is pumping jetted energy into the surrounding intracluster medium, creating buoyant bubbles filled with relativistic plasma. These likely induce motions in the intracluster medium and heat the inner gas preventing runaway radiative cooling; a process known as Active Galactic Nucleus Feedback. Here we report on Hitomi X-ray observations of the Perseus cluster core, which reveal a remarkably quiescent atmosphere where the gas has a line-of-sight velocity dispersion of 164+/-10 km/s in a region 30-60 kpc from the central nucleus. A gradient in the line-of-sight velocity of 150+/-70 km/s is found across the 60 kpc image of the cluster core. Turbulent pressure support in the gas is 4% or less of the thermodynamic pressure, with large scale shear at most doubling that estimate. We infer that total cluster masses determined from hydrostatic equilibrium in the central regions need little correction for turbulent pressure.
Misc.
87-
Publications of the Astronomical Society of Japan, 67(2) 231-2316, Dec 5, 2014
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Suzaku-MAXI 2014: Expanding the Frontiers of the X-ray Universe, 406-407, 2014
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Suzaku-MAXI 2014: Expanding the Frontiers of the X-ray Universe, 414-415, 2014
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ADVANCES IN SPACE RESEARCH, 47(9) 1455-1462, May, 2011
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Apr 14, 2011The results from Suzaku observations of the galaxy cluster Abell2256 are presented. This cluster is a prototypical and well-studied merging system, exhibiting substructures both in the X-ray surface brightness and in the radial velocity distribution of member galaxies. There are main and sub components separating by 3'.5 in the sky and by about 2000 km s$^{-1}$ in radial velocity peaks of member galaxies. In order to measure Doppler shifts of iron K-shell lines from the two gas components by the Suzaku XIS, the energy scale of the instrument was evaluated carefully and found to be calibrated well. A significant shift of the radial velocity of the sub component gas with respect to that of the main cluster was detected. All three XIS sensors show the shift independently and consistently among the three. The difference is found to be 1500 $\pm 300$ (statistical) $\pm 300$ (systematic) km s$^{-1}$. The X-ray determined absolute redshifts of and hence the difference between the main and sub components are consistent with those of member galaxies in optical. The observation indicates robustly that the X-ray emitting gas is moving together with galaxies as a substructure within the cluster. These results along with other X-ray observations of gas bulk motions in merging clusters are discussed.
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Publications of the Astronomical Society of Japan, Vol.62, No.6(2010), pp.1423--1433, Sep 16, 2010We studied the high temperature plasma in the direction of the Sculptor<br /> supercluster at z=0.108 with Suzaku. Suzaku carried out four observations in<br /> the supercluster: namely, A2811, A2811 offset, A2804, A2801 regions in 2005<br /> Nov.--Dec., including the regions beyond the virial radii of these clusters.<br /> The study needed precise background estimation because the measured intensity<br /> of the redshifted lines, especially those from oxygen, were strongly affected<br /> by the the Galactic emission. The spectra taken in the regions outside of the<br /> virial radii of the member clusters were used as the backgrou...
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 62(3) 743-754, Jun 22, 2010
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ASTROPHYSICAL JOURNAL LETTERS, 705(1) L62-L66, Sep 28, 2009
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Publications of the Astronomical Society of Japan, 60(4) 695-705, Apr 1, 2008
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Astrophysical Journal, 680(2) 1049-1052, Mar 19, 2008
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 60 S317-S331, Nov 9, 2007
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Meeting abstracts of the Physical Society of Japan, 62(1) 102-102, Feb 28, 2007
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Publications of the Astronomical Society of Japan, 59(2) 299-317, Jan 11, 2007
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PROGRESS OF THEORETICAL PHYSICS SUPPLEMENT, (169) 20-24, 2007
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Astrophysical Journal, 655(2 I) 831-842, Oct 13, 2006
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 59 S351-S359, Sep 20, 2006
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 59 S327-S338, Sep 4, 2006
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Meeting abstracts of the Physical Society of Japan, 61(2) 78-78, Aug 18, 2006
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Publ.Astron.Soc.Jap.59:339-349,2007, Aug 3, 2006We searched for redshifted O emission lines from the possible warm-hot intergalactic medium (WHIM) surrounding the cluster of galaxies A2218 at z=0.1756 using the XIS instrument on Suzaku. This cluster is thought to have an elongated structure along the line of sight based on previous studies. We studied systematic uncertainties in the spectrum of the Galactic emission and in the soft X-ray response of the detectors due to the contamination building up on the XIS filters. We detected no significant redshifted O lines, and set a tight constraint on the intensity with upper limits for the surface brightness of OVII and OVIII lines of 1.1 x 10^-7 and 3.0 x 10^-7 photons cm^-2 s^-1 arcmin^-2, respectively. These upper limits are significantly lower than the previously reported fluxes from the WHIM around other clusters of galaxies. We also discuss the prospect for the detection of the WHIM lines with Suzaku XIS in the future.
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Meeting abstracts of the Physical Society of Japan, 61(1) 87-87, Mar 4, 2006
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Meeting abstracts of the Physical Society of Japan, 60(1) 197-197, Mar 4, 2005
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Meeting abstracts of the Physical Society of Japan, 60(1) 209-209, Mar 4, 2005
Books and Other Publications
1Presentations
4Teaching Experience
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May, 2022 - May, 2022Space and Earth Physics Introduction (Rikkyo University)
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Apr, 2020 - Mar, 2021Basic Physics (Salesian Polytechnic)
Professional Memberships
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Apr, 2022 - Present
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Jul, 2021 - Present
Research Projects
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Grants-in-Aid for Scientific Research Grant-in-Aid for Transformative Research Areas (A), Japan Society for the Promotion of Science, Nov, 2020 - Mar, 2025
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2014 - Mar, 2018
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (C), Japan Society for the Promotion of Science, Apr, 2012 - Mar, 2015
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, 2007 - 2009
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科学研究費補助金(若手研究(B)), 文部科学省, 2004 - 2006
