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
79-
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-
Astronomy and Astrophysics, 433(1) 101-111, Dec 9, 2004
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 56(5) L29-L34, Oct, 2004
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Sep 30, 2003We present XMM-Newton Reflection Grating Spectrometer observations of X-ray clusters and groups of galaxies. We demonstrate the failure of the standard cooling-flow model to describe the soft X-ray spectrum of clusters of galaxies. We also emphasize several new developments in the study of the soft X-ray spectrum of cooling flows. Although there is some uncertainty in the expected mass deposition rate for any individual cluster, we show that high resolution RGS spectra robustly demonstrate that the expected line emission from the isobaric cooling-flow model is absent below 1/3 of the background temperature rather than below a fixed temperature in all clusters. Furthermore, we demonstrate that the best-resolved cluster spectra are inconsistent with the predicted shape of the differential luminosity distribution and the measured distribution is tilted to higher temperatures. These observations create several fine-tuning challenges for current theoretical explanations for the soft X-ray cooling-flow problem. Comparisons between these observations and other X-ray measurements are discussed.
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MATTER AND ENERGY IN CLUSTERS OF GALAXIES, PROCEEDINGS, 301 23-36, 2003
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Publications of the Astronomical Society of Japan, 53(3) 401-420, Apr 4, 2001
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Astrophys. J., 535 602-614, Jan 10, 2000X-ray spectral and imaging data from ASCA and ROSAT were used to measure the total mass profile in the central region of Abell 1060, a nearby and relatively poor cluster of galaxies. The ASCA X-ray spectra, after correcting for the spatial response of the X-ray telescope, show an isothermal distribution of the intra-cluster medium (ICM) within at least $\sim$ 12' (or $160h_{70}^{-1}$ kpc; $H_0 = 70 h_{70}$ km s$^{-1}$Mpc$^{-1}$) in radius of the cluster center. The azimuthally averaged surface brightness profile from the ROSAT PSPC exhibits a central excess above an isothermal $\beta$ model. The ring-sorted ASCA GIS spectra and the radial surface brightness distribution from the ROSAT PSPC were simultaneously utilized to constrain the gravitational potential profile. Some analytic models of the total mass density profile were examined. The ICM density profile was also specified by analytic forms. The ICM temperature distribution was constrained to satisfy the hydrostatic equilibrium, and to be consistent with the data. Then, the total mass distribution was found to be described better by the universal dark halo profile proposed by Navarro, Frenk, and White (1996;1997) than by a King-type model with a flat density core. A profile with a central cusp together with a logarithmic radial slope of $\sim 1.5$ was also consistent with the data. Discussions are made concerning the estimated dark matter distribution around the cluster center.
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Meeting abstracts of the Physical Society of Japan, 54(2) 82-82, Sep 13, 1999
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Astrophysical Journal, 525(1) 58-79, May 15, 1999
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Publications of the Astronomical Society of Japan, 50(6) 537-545, Dec 1, 1998
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Meeting abstracts of the Physical Society of Japan, 53(1) 80-80, Mar 10, 1998
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Meeting abstracts of the Physical Society of Japan, 53(1) 83-83, Mar 10, 1998
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Meeting abstracts of the Physical Society of Japan, 53(1) 84-84, Mar 10, 1998
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Meeting abstracts of the Physical Society of Japan, 53(1) 84-84, Mar 10, 1998
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 50(1) 187-193, Feb 11, 1998
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Meeting abstracts of the Physical Society of Japan, 52(2) 81-81, Sep 2, 1997
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Meeting abstracts of the Physical Society of Japan, 52(2) 81-81, Sep 2, 1997
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Meeting abstracts of the Physical Society of Japan, 52(2) 82-82, Sep 2, 1997
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Meeting abstracts of the Physical Society of Japan, 52(1) 83-83, Mar 17, 1997
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Proceedings of SPIE - The International Society for Optical Engineering, 2518 85-95, Dec 1, 1995
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1995(1) 40-40, Sep 12, 1995
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1995(1) 40-40, Sep 12, 1995
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1995(1) 140-140, Sep 12, 1995
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1995(1) 141-141, Sep 12, 1995
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Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 50(1) 33-33, Mar 16, 1995
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1994(1) 167-167, Sep 12, 1994
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1994(1) 172-172, Sep 12, 1994
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Abstracts of the meeting of the Physical Society of Japan. Sectional meeting, 1994(1) 173-173, Sep 12, 1994
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MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, 268(3) L55-L59, Jun, 1994
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Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 49(1) 175-175, Mar 16, 1994
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Abstracts of the meeting of the Physical Society of Japan. Annual meeting, 49(1) 177-177, Mar 16, 1994
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
