HISAKI Project Team
基本情報
- 所属
- 埼玉大学 大学院理工学研究科 理工学研究科 教授国立研究開発法人宇宙航空研究開発機構 宇宙科学研究所 特任教授
- 学位
- 博士(2002年3月 東京大学)
- J-GLOBAL ID
- 200901062224980497
- researchmap会員ID
- 1000368169
- 外部リンク
研究キーワード
14経歴
8-
2025年5月 - 現在
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2025年4月 - 現在
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2025年4月 - 現在
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2018年4月 - 2025年3月
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2007年10月 - 2025年3月
学歴
3-
1999年4月 - 2002年
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1997年4月 - 1999年3月
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1993年4月 - 1997年3月
委員歴
2-
2017年6月 - 2019年6月
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2013年4月 - 2019年4月
論文
379-
Journal of Astronomical Telescopes, Instruments, and Systems 2025年10月This paper describes the development, design, ground verification, and in-orbit verification, performance measurement, and calibration of the timing system for the X-Ray Imaging and Spectroscopy Mission (XRISM). The scientific goals of the mission require an absolute timing accuracy of 1.0~ms. All components of the timing system were designed and verified to be within the timing error budgets, which were assigned by component to meet the requirements. After the launch of XRISM, the timing capability of the ground-tuned timing system was verified using the millisecond pulsar PSR~B1937+21 during the commissioning period, and the timing jitter of the bus and the ground component were found to be below $15~\mu$s compared to the NICER (Neutron star Interior Composition ExploreR) profile. During the performance verification and calibration period, simultaneous observations of the Crab pulsar by XRISM, NuSTAR (Nuclear Spectroscopic Telescope Array), and NICER were made to measure the absolute timing offset of the system, showing that the arrival time of the main pulse with XRISM was aligned with that of NICER and NuSTAR to within $200~\mu$s. In conclusion, the absolute timing accuracy of the bus and the ground component of the XRISM timing system meets the timing error budget of $500~\mu$s....
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The Astrophysical Journal Letters 988(1) L28-L28 2025年7月17日Abstract We report on XRISM/Resolve spectroscopy of the recurrent transient and well-known black hole candidate 4U 1630−472 during its 2024 outburst. The source was captured at the end of a disk-dominated high/soft state at an Eddington fraction of λ Edd ∼ 0.05 (10 M ⊙/M BH). A variable absorption spectrum with unprecedented complexity is revealed with the Resolve calorimeter. This marks one of the lowest Eddington fractions at which highly ionized absorption has been detected in an X-ray binary. The strongest lines are fully resolved, with He-like Fe XXV separated into resonance and intercombination components and H-like Fe XXVI seen as a spin–orbit doublet. The depth of some absorption lines varied by almost an order of magnitude, far more than expected based on a 10% variation in apparent X-ray flux and ionization parameter. The velocity of some absorption components also changed significantly. Jointly modeling two flux segments with a consistent model including four photoionization zones, the spectrum can be described in terms of highly ionized but likely failed winds that sometimes show redshifts, variable obscuration that may signal asymmetric structures in the middle and outer accretion disk, and a tentative very fast outflow (v = 0.026–0.033c). We discuss the impact of these findings on our understanding of accretion and winds in stellar-mass black holes and potential consequences for future studies.
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Publications of the Astronomical Society of Japan 2025年5月21日Abstract We report the azimuthal distribution of the X-ray energy spectrum of the non-thermal dominant supernova remnant (SNR) RX J0852.0-4622. The X-rays from the shock region observed by the X-ray astronomy satellite Suzaku/XIS in the energy range of 2–8 keV are well described by the absorbed power-law model and can be parametrized with the flux and photon index. The X-ray flux and photon index are bimodally distributed in relation to the azimuthal angle. To understand the origin of the azimuthal variation, we examined three possible causes: the Galactic magnetic field, cloud density, and shock velocity. From the polarization observations of stars near the SNR, we find that the Galactic magnetic field around the SNR is not aligned. This result leads us to conclude that the azimuthal variation of the X-ray spectrum is most likely not caused by the Galactic magnetic field. The X-ray fluxes are positively correlated with the cloud density with a significance of ${\sim }5\sigma$, and the azimuthal distributions of these physical quantities are particularly pronounced in the northern part of the SNR. In addition, the X-ray fluxes on the southern part of the SNR are positively correlated with the shock velocity. This phenomenon can be qualitatively explained by the increase in roll-off energy due to the amplification of the magnetic field by the interaction between the shock and dense clouds in the north and by the fast shock velocity in the south of the SNR. Because the shock velocity is likely related to the cloud density interacting with the shock, we conclude that the azimuthal variation of cloud density most likely causes the azimuthal variations of the X-ray flux and photon index.
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Publications of the Astronomical Society of Japan 2025年4月11日 査読有りAbstract 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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Nuclear Instruments and Methods in Physics Research A 2025年4月 査読有りThe camera of the Large-Sized Telescopes (LSTs) of the Cherenkov Telescope Array Observatory (CTAO) consists of 1855 pixels that are grouped into 265 high-performance photomultiplier tube (PMT) modules. Each module comprises a seven-light-guide plate, seven PMT units, a slow control board, and a readout board with a trigger board. The requirements for the PMT modules include various aspects, such as photon detection efficiency, dynamic range, buffer depth, and test pulse functionality. We have developed a high-performance PMT module that fulfills all these requirements. Mass-production and quality control (QC) of modules for all four LSTs of the northern CTAO have been completed. Here we report on the technical details of each element of the module and its performance, together with the methods and results of QC measurements....
MISC
276-
2024年2月12日欧州第一回XRISM科学データ解析ワークショップ 開催主催
書籍等出版物
4-
World Scientific Publishing Co. Pte. Ltd., 2019年1月 (ISBN: 9789813270091)
講演・口頭発表等
150所属学協会
6-
2011年2月
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2002年10月
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1998年9月
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1998年9月
共同研究・競争的資金等の研究課題
13-
日本学術振興会 科学研究費助成事業 2021年4月 - 2026年3月
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日本学術振興会 科学研究費助成事業 2021年4月 - 2026年3月
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日本学術振興会 科学研究費助成事業 2020年4月 - 2026年3月
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日本学術振興会 科学研究費助成事業 2018年4月 - 2020年3月
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日本学術振興会 科学研究費助成事業 2015年4月 - 2017年3月
