基本情報
- 所属
- 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 宇宙物理学研究系 教授総合研究大学院大学 先端学術院 宇宙科学コース 教授東京科学大学 理学院 物理学系 特定教授北海道大学 大学院理学院 宇宙理学専攻 客員教授
- 学位
- 博士（理学）(東京大学)修士(東京大学)
- 研究者番号
- 20280555
- ORCID ID
https://orcid.org/0000-0002-2374-7073- J-GLOBAL ID
- 200901095989600566
- researchmap会員ID
- 1000363020
X線マイクロカロリメータを用いた極低温精密X線分光装置の開発に取り組み，2023年9月打ち上げのXRISM衛星に搭載されたResolve観測装置として実現しました．
研究指導のテーマとしては，(1) XRISM衛星による精密X線分光観測データを解析し，銀河団ガスの運動を調べて，宇宙の大規模構造形成過程の理解を深める，(2) 宇宙マイクロ波背景放射の偏光観測を目指すLiteBIRD衛星を見据えた実験的研究を行なう等．特定の自然現象について理解を深めると同時に，複雑な自然現象の背景にある物理法則に至る過程を，実験・解析手法とともにしっかりと身につけてもらいたいと考えています．
経歴
5-
2023年6月 - 現在
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2008年4月 - 2023年5月
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2006年12月 - 2008年3月
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2003年10月 - 2006年11月
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1995年4月 - 2003年9月
学歴
2-
1991年4月 - 1995年3月
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1987年4月 - 1991年3月
委員歴
1-
2009年4月 - 2011年3月
受賞
1-
2010年
論文
172-
The Astrophysical Journal Letters 982(1) L5-L5 2025年3月12日Abstract 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.
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Nature 638(8050) 365-369 2025年2月12日
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Publications of the Astronomical Society of Japan 2024年12月26日Abstract Sagittarius A East is a supernova remnant with a unique surrounding environment, as it is located in the immediate vicinity of the supermassive black hole at the Galactic center, Sagittarius A$^{*}$. The X-ray emission of the remnant is suspected to show features of overionized plasma, which would require peculiar evolutionary paths. We report on the first observation of Sagittarius A East with the X-Ray Imaging and Spectroscopy Mission (XRISM). Equipped with a combination of a high-resolution microcalorimeter spectrometer and a large field-of-view CCD imager, we for the first time resolved the Fe xxv K-shell lines into fine structure lines and measured the forbidden-to-resonance intensity ratio to be $1.39 \pm 0.12$, which strongly suggests the presence of overionized plasma. We obtained a reliable constraint on the ionization temperature just before the transition into the overionization state, of $\gt\! 4\:$keV. The recombination timescale was constrained to be $\lt\! 8 \times 10^{11} \:$cm$^{-3}\:$s. The small velocity dispersion of $109 \pm 6\:$km$\:$s$^{-1}$ indicates a low Fe ion temperature $\lt\! 8\:$keV and a small expansion velocity $\lt\! 200\:$km$\:$s$^{-1}$. The high initial ionization temperature and small recombination timescale suggest that either rapid cooling of the plasma via adiabatic expansion from dense circumstellar material or intense photoionization by Sagittarius A$^{*}$ in the past may have triggered the overionization.
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The Astrophysical Journal Letters 977(2) L34-L34 2024年12月11日Abstract The X-ray binary system Cygnus X-3 (4U 2030+40, V1521 Cyg) is luminous but enigmatic owing to the high intervening absorption. High-resolution X-ray spectroscopy uniquely probes the dynamics of the photoionized gas in the system. In this Letter, we report on an observation of Cyg X-3 with the XRISM/Resolve spectrometer, which provides unprecedented spectral resolution and sensitivity in the 2–10 keV band. We detect multiple kinematic and ionization components in absorption and emission whose superposition leads to complex line profiles, including strong P Cygni profiles on resonance lines. The prominent Fe xxv Heα and Fe xxvi Lyα emission complexes are clearly resolved into their characteristic fine-structure transitions. Self-consistent photoionization modeling allows us to disentangle the absorption and emission components and measure the Doppler velocity of these components as a function of binary orbital phase. We find a significantly higher velocity amplitude for the emission lines than for the absorption lines. The absorption lines generally appear blueshifted by ∼−500–600 km s−1. We show that the wind decomposes naturally into a relatively smooth and large-scale component, perhaps associated with the background wind itself, plus a turbulent, denser structure located close to the compact object in its orbit.
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Publications of the Astronomical Society of Japan 2024年10月10日Abstract We present an initial analysis of the X-Ray Imaging and Spectroscopy Mission (XRISM) first-light observation of the supernova remnant (SNR) N 132D in the Large Magellanic Cloud. The Resolve microcalorimeter has obtained the first high-resolution spectrum in the 1.6–10 keV band, which contains K-shell emission lines of Si, S, Ar, Ca, and Fe. We find that the Si and S lines are relatively narrow, with a broadening represented by a Gaussian-like velocity dispersion of $\sigma _v \sim 450$ km s$^{-1}$. However, the Fe He$\alpha$ lines are substantially broadened with $\sigma _v \sim 1670$ km s$^{-1}$. This broadening can be explained by a combination of the thermal Doppler effect due to the high ion temperature and the kinematic Doppler effect due to the SNR expansion. Assuming that the Fe He$\alpha$ emission originates predominantly from the supernova ejecta, we estimate the reverse shock velocity at the time when the bulk of the Fe ejecta were shock heated to be $-1000 \lesssim V_{\rm rs}$ (km s$^{-1}$) $\lesssim 3300$ (in the observer frame). We also find that Fe Ly$\alpha$ emission is redshifted with a bulk velocity of $\sim 890$ km s$^{-1}$, substantially larger than the radial velocity of the local interstellar medium surrounding N 132D. These results demonstrate that high-resolution X-ray spectroscopy is capable of providing constraints on the evolutionary stage, geometry, and velocity distribution of SNRs.
MISC
131-
PASJ : publications of the Astronomical Society of Japan 59(1 SPEC. ISS.) S77-S112 2007年
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PASJ : publications of the Astronomical Society of Japan 59(1 SPEC. ISS.) S339-S349 2007年
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Progress of Theoretical Physics Supplement (169) 322-325 2007年We present the in-flight performance of the X-ray telescopes (XRTs) onboard Suzaku. The imaging capability is significantly improved over the ASCA XRT, which had half-power diameters of 3'.6, to 1'.8-2'.3 for all four XRT-I modules. Contemporaneous fits of a power law to all the XIS spectra of the Crab Nebula taken at the two standard observing positions (XIS/HXD-default positions) gives a flux consistent with that obtained by Toor & Seward (1974) to within〜2%. The pre-collimator on the top of each XRT module successfully reduces the intensity of the stray light from the 20' and 50'-off directions down to the level of pre-flight expectations. We also present the thermal wobbling of the satellite. The wobbling causes the alignment error between the XRT-XIS system and the attitude and orbit control system. The wobbling of the alignment is as large as〜1arcmin. In the currently processed data, the absolute coordinate also has systematic uncertainty of up to〜1arcmin.
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PASJ : publications of the Astronomical Society of Japan 59(1 SPEC. ISS.) S269-S282 2007年
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スターリングサイクルシンポジウム講演論文集 2006(10) 73-74 2006年10月19日Cryogenic cooling is useful to most detectors in astronomical and atmospheric observation for improving the sensitivity and reducing the background noise. Recently cryocoolers are often adopted as cooling devices. This paper describes a single stage Stirling cryocooler. It is designed, manufactured and tested for space borne mission. The typical cooling power is 2W at 80K with 50W input. The cooler on the X-ray telescope satellite "Suzaku" was launched July 2005. It is operating over 1 year without any trouble. On the other hand, a cooler achieved 50,000 hour operation in the lifetime test on the ground. Same type coolers will be launched on the lunar explorer and the Venus orbiter of Japan
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日本物理学会講演概要集 61(2) 72-72 2006年8月18日
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日本物理学会講演概要集 61(1) 87-87 2006年3月4日
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Space Telescopes and Instrumentation II: Ultraviolet to Gamma Ray, Pts 1 and 2 6266(No.) G2660-G2660 2006年We present our proposal for a small X-ray mission DIOS (Diffuse Intergalactic Oxygen Surveyor), consisting of a 4-stage X-ray telescope and an array of TES microcalorimeters, cooled with mechanical coolers, with a total weight of about 400 kg. The mission will perform survey observations of warm-hot intergalactic medium using OVII and OVIII emission lines, with the energy coverage up to 1.5 keV. The wide field of view of about 50' diameter, superior energy resolution close to 2 eV FWHM, and very low background will together enable us a wide range of science for diffuse X-ray sources. We briefly describe the design of the satellite, performance of the subsystems and the expected results.
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AIP Conference Proceedings 774 379-382 2005年6月13日The XRS microcalorimeter will be launched in 2005 as part of the Astro-E2 mission. It will cover the energy band from 0.3 to 10 keV with a nearly constant energy resolution of 6.0 eV and a peak effective area of 200 cm 2 at 1.5 keV. The XRS will provide unprecedented throughput and resolving power, particularly at high energies. Detailed spectral features in the Fe K region will be resolved for the first time, providing access to spectroscopic diagnostics for a wide range of astrophysical objects. In this presentation we will describe the XRS instrument, details of its spectral performance, and how it compares to the current high-resolution instruments on the Chandra and XMM-Newton observatories. © 2005 American Institute of Physics.
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日本物理学会講演概要集 60(1) 209-209 2005年3月4日
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Journal of the Korean Physical Society 45(SUPPL.) 2004年Approximately 30 to 50 percent of the total baryons in the present universe is supposed to take the form of wa arm/hot intergalactic medium (WHIM) whose X-ray continuum emission is very weak. In order to carry out a direct and homogeneous survey of elusive cosmic missing baryons, we propose a dedicated soft-X-ray mission, DIOS (Diffuse Intergalactic Oxygen Surveyor). The unprecedented energy resolution (∼ 2eV) of the XSA (X-ray Spectrometer Array) on-board DIOS enables us to identify WHIM with gas temperatures T = 106-7K and overdensity δ= 10-100 located at z < 0.3 through emission lines of OVII and OVIII. DIOS, which will hopefully be launched in several years time, promises to open a new window of detection and characterization of cosmic missing baryons and to provide yet another important and complementary tool to trace the large-scale structure of the universe.
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PASJ : publications of the Astronomical Society of Japan 56(5) L29-L34-L34 2004年
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NANOTECH 2003, VOL 1 1 436-439 2003年An x-ray microcalorimeter is a promising x-ray spectrometer for its extremely good energy resolution and its good detecting efficiency. We are developing an x-ray microcalorimeter for high energy resolution x-ray imaging application. The energy resolution of 43eV(FWHM) at 5.9keV is obtained with our x-ray microcalorimeter. The intrinsic performance of our x-ray microcalorimeter was estimated to be 10.4eV(FWHM) at 5.9keV. This value is more than 10 times better than that of the 2 WORKING PRINCIPLES conventional x-ray CCD.
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BOSTON TRANSDUCERS'03: DIGEST OF TECHNICAL PAPERS, VOLS 1 AND 2 1108-1111 2003年An x-ray microcalorimeter is a noble x-ray spectrometer that can be used for photon counting with a high energy resolution comparable to the gratings. A 2x2 x-ray microcalorimeter array was fabricated and tested. Due to the purpose of imaging application, we have applied so-called 'mushroom-shaped' x-ray microabsorber fabricated using two-step exposure and electrodeposition process. The energy resolution of 180eV(FWHM) at 5.9keV was obtained with the first prototype of the x-ray microcalorimeter array using Sri microabsorber. By using Bi absorber, it is,estimated that the energy resolution can be improved up to 4.5eV.
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低温工学・超電導学会講演概要集 = Meetings of Cryogenics and Superconductivity 67 185-185 2002年10月30日
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低温工学・超電導学会講演概要集 = Meetings of Cryogenics and Superconductivity 67 184-184 2002年10月30日
共同研究・競争的資金等の研究課題
20-
日本学術振興会 科学研究費助成事業 基盤研究(C) 2023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 新学術領域研究(研究領域提案型) 2019年4月 - 2021年3月
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日本学術振興会 科学研究費助成事業 基盤研究(A) 2013年4月 - 2017年3月
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日本学術振興会 科学研究費助成事業 基盤研究(B) 2011年4月 - 2014年3月
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科研費 挑戦的萌芽研究 2008年4月 - 2011年3月
