Curriculum Vitaes
Profile Information
- Affiliation
- Professor, Institute of Space and Astronautical Science, Japan Aerospace Exploration AgencyGraduate School of Science, Department of Physics, The University of Tokyo(PI), International Center for Quantum-field Measurement Systems for Studies of the Universe and Particles (QUP)Graduate School of Science, Kitasato University
- Degree
- Ph. D.(Mar, 1996, The University of Tokyo)
- ORCID ID
https://orcid.org/0000-0003-4885-5537- J-GLOBAL ID
- 200901003330670433
- Researcher ID
- C-2252-2008
- researchmap Member ID
- 5000019022
- External link
Research Interests
8Research Areas
2Research History
2Education
2-
Apr, 1989 - Mar, 1993
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Apr, 1985 - Mar, 1989
Committee Memberships
2-
Oct, 2017 - Sep, 2023
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Oct, 2014 - Sep, 2017
Papers
261-
IEEE Transactions on Applied Superconductivity, 35(5) 1-4, Aug, 2025 Peer-reviewed
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The Astrophysical Journal Letters, 985(1) L20-L20, May 19, 2025 Peer-reviewedAbstract The XRISM Resolve microcalorimeter array measured the velocities of hot intracluster gas at two positions in the Coma galaxy cluster: squares at the center and at 6 (170 kpc) to the south. We find the line-of-sight velocity dispersions in those regions to be σ z = 208 ± 12 km s−1 and 202 ± 24 km s−1, respectively. The central value corresponds to a 3D Mach number of M = 0.24 ± 0.015 and a ratio of the kinetic pressure of small-scale motions to thermal pressure in the intracluster plasma of only 3.1% ± 0.4%, at the lower end of predictions from cosmological simulations for merging clusters like Coma, and similar to that observed in the cool core of the relaxed cluster A2029. Meanwhile, the gas in both regions exhibits high line-of-sight velocity differences from the mean velocity of the cluster galaxies, Δv z = 450 ± 15 km s−1 and 730 ± 30 km s−1, respectively. A small contribution from an additional gas velocity component, consistent with the cluster optical mean, is detected along a sight line near the cluster center. The combination of the observed velocity dispersions and bulk velocities is not described by a Kolmogorov velocity power spectrum of steady-state turbulence; instead, the data imply a much steeper effective slope (i.e., relatively more power at larger linear scales). This may indicate either a very large dissipation scale, resulting in the suppression of small-scale motions, or a transient dynamic state of the cluster, where large-scale gas flows generated by an ongoing merger have not yet cascaded down to small scales.
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Nature, May 14, 2025 Peer-reviewed
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Publications of the Astronomical Society of Japan, Apr 11, 2025 Peer-reviewedAbstract The X-Ray Imaging and Spectroscopy Mission (XRISM) is a joint mission between the Japan Aerospace Exploration Agency (JAXA) and the National Aeronautics and Space Administration (NASA) in collaboration with the European Space Agency (ESA). In addition to the three space agencies, universities and research institutes from Japan, North America, and Europe have joined to contribute to developing satellite and onboard instruments, data-processing software, and the scientific observation program. XRISM is the successor to the ASTRO-H (Hitomi) mission, which ended prematurely in 2016. Its primary science goal is to examine astrophysical problems with precise, high-resolution X-ray spectroscopy. XRISM promises to discover new horizons in X-ray astronomy. It carries a 6 × 6 pixelized X-ray microcalorimeter on the focal plane of an X-ray mirror assembly (Resolve) and a co-aligned X-ray CCD camera (Xtend) that covers the same energy band over a large field of view. XRISM utilizes the Hitomi heritage, but all designs were reviewed. The attitude and orbit control system was improved in hardware and software. The spacecraft was launched from the JAXA Tanegashima Space Center on 2023 September 6 (UTC). During the in-orbit commissioning phase, the onboard components were activated. Although the gate valve protecting the Resolve sensor with a thin beryllium X-ray entrance window was not yet opened, scientific observation started in 2024 February with the planned performance verification observation program. The nominal observation program commenced with the following guest observation program beginning in 2024 September.
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The Astrophysical Journal Letters, 982(1) L5-L5, Mar 12, 2025 Peer-reviewedAbstract We present XRISM Resolve observations of the core of the hot, relaxed galaxy cluster Abell 2029 (A2029). We find that the line-of-sight bulk velocity of the intracluster medium (ICM) within the central 180 kpc is at rest with respect to the brightest cluster galaxy, with a 3σ upper limit of ∣v bulk∣ < 100 km s−1. We robustly measure the field-integrated ICM velocity dispersion to be σ v = 169 ± 10 km s−1, obtaining similar results for both single-temperature and two-temperature plasma models to account for the cluster cool core. This result, if ascribed to isotropic turbulence, implies a subsonic ICM with Mach number and a nonthermal pressure fraction of 2.6 ± 0.3%. The turbulent velocity is similar to what was measured in the core of the Perseus cluster by Hitomi, but here in a more massive cluster with an ICM temperature of 7 keV, the limit on the nonthermal pressure fraction is even more stringent. Our result is consistent with expectations from simulations of relaxed clusters, but it is on the low end of the predicted distribution, indicating that A2029 is an exceptionally relaxed cluster with no significant impacts from either a recent minor merger or active galactic nucleus activity.
Misc.
190-
Space Telescopes and Instrumentation 2020: Optical, Infrared, and Millimeter Wave, Dec 21, 2020
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Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X, Dec 16, 2020
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Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy X, Dec 16, 2020
Teaching Experience
1-
Mar, 2003 - PresentAstrophysics I (Dept. of Physics, University. of Tokyo)
Professional Memberships
3-
2010 - Present
Research Projects
22-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Nov, 2020 - Mar, 2025
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Nov, 2020 - Mar, 2025
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科学研究費助成事業 基盤研究(A), 日本学術振興会, Apr, 2019 - Mar, 2022
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Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2018 - Mar, 2022
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Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research (B), Japan Society for the Promotion of Science, Apr, 2018 - Mar, 2021
教育内容やその他の工夫
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SubjcetGraduate School in ISASSummaryWe accept graduate students from University of Tokyo and Kitasato University. Our main scope is observational research of the large scale structure in the Universe utilizing X-ray spectroscopy.
During the graduate school, professional education for development of new detectors and their applications, and observational astrophysics are accessed.
● 指導学生等の数
10-
Fiscal Year2018年度(FY2018)Doctoral program1Master’s program1
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Fiscal Year2019年度(FY2019)Doctoral program1Master’s program3
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Fiscal Year2020年度(FY2020)Doctoral program1Master’s program3
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Fiscal Year2018年度(FY2018)Doctoral program1Master’s program1
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Fiscal Year2019年度(FY2019)Doctoral program1Master’s program3
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Fiscal Year2020年度(FY2020)Doctoral program1Master’s program3
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Fiscal Year2022年度(FY2022)Doctoral program3Master’s program2
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Fiscal Year2023年度(FY2023)Doctoral program2Master’s program1
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Fiscal Year2024年度(FY2024)Doctoral program2Master’s program2
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Fiscal Year2025年度(FY2025)Doctoral program2Master’s program5
● 指導学生の顕著な論文
6-
Student nameRyota TakakuStudent affiliation東京大学Author(s), journal, volume number, pagination (year of publication)Takaku et al. , Journal of Applied Physics, 128(22), id.225302, (2020)TitleBroadband, millimeter-wave anti-reflective structures on sapphire ablatedwith femto-second laserDOIhttp://doi.org/10.1063/5.0022765
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Student nameYuki NakashimaStudent affiliationUniv. of TokyoAuthor(s), journal, volume number, pagination (year of publication)Nakashima et al. Applied Physics Letters, 117 122601 (2020)TitleLow-noise microwave SQUID multiplexed readout of 38 x-ray transition-edge sensor microcalorimetersDOIhttp://doi.org/10.1063/5.0016333
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Student nameRyohei KonnoStudent affiliationKitasato Univ.Author(s), journal, volume number, pagination (year of publication)Konno et al. Journal of Low Temperature Physics 199, 654 (2019)TitleDevelopment of TES micsrocalorimters with solar-axion converterDOIhttp://doi.org/10.1007/s10909-019-02257-9
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Student nameRyo YamamotoStudent affiliationUniv. of TokyoAuthor(s), journal, volume number, pagination (year of publication)Yamamoto et al. , Journal of Cosmokogy and Astrophysics, 02 (2020) 011TitleA Search for a Contribution from Axion-Like Particles to the X-Ray Diffuse Background Utilizing the Earth's Magnetic FieldDOIhttp://doi.org/10.1088/1475-7516/2020/02/011
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Student nameNorio SekiyaStudent affiliationUniversity. of TokyoAuthor(s), journal, volume number, pagination (year of publication)Sekiya, Yamasaki, and Mitsuda, Publications of Astronomical Society in Japan, 68(SP1), S31 (2016)TitleSearch for a keV Signature of Radiatively Decaying Dark Matter with Suzaku XIS Observations of the X-ray Diffuse BackgroundDOIhttp://doi.org/10.1093/pasj/psv081
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Student nameIkuyuki MitsuishiStudent affiliationUniv. of TokyoAuthor(s), journal, volume number, pagination (year of publication)Mitsuishi, Yamasaki, and Takei, Publications of Astronomical Society in Japan, 65, 44 (2013)TitleAn X-Ray Study of the Galactic-Scale Starburst-Driven Outflow in NGC 253DOIhttp://doi.org/10.1093/pasj/65.2.44
● 専任大学名
1-
Affiliation (university)東京大学(University of Tokyo)
● 所属する所内委員会
1-
ISAS CommitteeSteering committee for ISAS nono-electronics clean room