Curriculum Vitaes
Profile Information
- Affiliation
- Associate Professor, Institute of Space and Astronautical Science, Department of Space Astronomy and Astrophysics, Japan Aerospace Exploration Agency
- Degree
- 博士(理学)(Mar, 2004, 東京大学)
- Researcher number
- 60446599
- ORCID ID
https://orcid.org/0000-0003-0441-7404- J-GLOBAL ID
- 202001021434500706
- researchmap Member ID
- R000012970
Research Interests
6Research Areas
2Research History
2Education
3-
Apr, 1999 - Mar, 2001
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Apr, 1995 - Mar, 1999
Awards
2Papers
249-
Analytical Chemistry, Jun 8, 2026
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NATURE, 650(8101), Feb 12, 2026 Peer-reviewed
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Journal of Astronomical Telescopes, Instruments, and Systems, 12(01), Jan 28, 2026 Peer-reviewed
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NATURE ASTRONOMY, 10(1), Jan, 2026 Peer-reviewed
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Journal of Astronomical Telescopes, Instruments, and Systems, 11(04), Dec 18, 2025 Peer-reviewed
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PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN, 77(6) 1278-1289, Dec, 2025 Peer-reviewed
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ASTROPHYSICAL JOURNAL LETTERS, 994(1), Nov 20, 2025 Peer-reviewed
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ASTROPHYSICAL JOURNAL LETTERS, 993(1), Nov 1, 2025 Peer-reviewed
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NATURE, 646(8083), Oct 2, 2025 Peer-reviewed
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JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS, 11(4), Oct 1, 2025 Peer-reviewed
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JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS, 11(4), Oct 1, 2025 Peer-reviewed
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ASTRONOMY & ASTROPHYSICS, 702, Oct, 2025 Peer-reviewed
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Optics for EUV, X-Ray, and Gamma-Ray Astronomy XII, 32-32, Sep 18, 2025
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UV, X-Ray, and Gamma-Ray Space Instrumentation for Astronomy XXIV, 36-36, Sep 18, 2025
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ASTROPHYSICAL JOURNAL LETTERS, 988(2), Aug 1, 2025 Peer-reviewed
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Applied Radiation and Isotopes, 222 111845-111845, Aug, 2025 Peer-reviewed
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The Astrophysical Journal Letters, 988(1) L28-L28, Jul 17, 2025 Peer-reviewed
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Publications of the Astronomical Society of Japan, 77(Supplement_1) S86-S95, Jun 16, 2025 Peer-reviewed
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Physical Review Letters, 134(24), Jun 16, 2025 Peer-reviewed
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ASTROPHYSICAL JOURNAL LETTERS, 985(1), May 20, 2025 Peer-reviewed
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Nature, 641(8065) 1132-1136, May 14, 2025 Peer-reviewed
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npj Heritage Science, 13(1), May 10, 2025
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Publications of the Astronomical Society of Japan, 77 S1-S9, Apr 11, 2025 Peer-reviewed
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The Astrophysical Journal Letters, 982(1) L5-L5, Mar 12, 2025 Peer-reviewed
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Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1075 170362-170362, Mar, 2025 Peer-reviewed
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Nature, 638(8050) 365-369, Feb 12, 2025 Peer-reviewed
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Publications of the Astronomical Society of Japan, 77(1) L1-L8, Dec 26, 2024 Peer-reviewed
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The Astrophysical Journal Letters, 977(2) L34-L34, Dec 11, 2024 Peer-reviewedAbstract 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, 76(6) 1186-1201, Oct 10, 2024 Peer-reviewedAbstract 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.
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The Astrophysical Journal Letters, 973(1) L25-L25, Sep, 2024 Peer-reviewed
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Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 85-85, Aug 21, 2024
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Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 224-224, Aug 21, 2024
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Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 11(4) 235-235, Aug 21, 2024
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Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 92-92, Aug 21, 2024
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Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray, 52-52, Aug 21, 2024
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Scientific Reports, 14(1), Feb 9, 2024 Peer-reviewedAbstract To detect and track structural changes in atomic nuclei, the systematic study of nuclear levels with firm spin-parity assignments is important. While linear polarization measurements have been applied to determine the electromagnetic character of gamma-ray transitions, the applicable range is strongly limited due to the low efficiency of the detection system. The multi-layer Cadmium-Telluride (CdTe) Compton camera can be a state-of-the-art gamma-ray polarimeter for nuclear spectroscopy with the high position sensitivity and the detection efficiency. We demonstrated the capability to operate this detector as a reliable gamma-ray polarimeter by using polarized 847-keV gamma rays produced by the $$^{56}\textrm{Fe}$$($${ p},{ p'}\gamma $$) reaction. By combining the experimental data and simulated calculations, the modulation curve for the gamma ray was successfully obtained. A remarkably high polarization sensitivity was achieved, compatible with a reasonable detection efficiency. Based on the obtained results, a possible future gamma-ray polarimetery is discussed.
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Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1059 169024-169024, Feb, 2024 Peer-reviewed
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SPACE TELESCOPES AND INSTRUMENTATION 2024: ULTRAVIOLET TO GAMMA RAY, PT 1, 13093, 2024
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Meeting Abstracts of the Physical Society of Japan, 79.1 533-533, 2024
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Meteoritics and Planetary Science, 2024 Peer-reviewed
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IEEE Transactions on Radiation and Plasma Medical Sciences, 7(8) 860-870, Nov, 2023 Peer-reviewed
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Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, 1050 168175-168175, May, 2023 Peer-reviewed
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Physical Review Letters, 130(17), Apr 27, 2023 Peer-reviewed
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Physical Review Letters, 130(11), Mar 15, 2023 Peer-reviewed
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ACS Earth and Space Chemistry, 7(4) 699-711, Mar 9, 2023 Peer-reviewed
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Journal of Instrumentation, 18(01) P01030-P01030, Jan 1, 2023 Peer-reviewedAbstract We have developed a γ-ray computed tomography system using a CdTe double-sided strip detector. Owing to a 250 μm fine strip pitch and high energy resolution with photon-counting capability, the system provides highly accurate images, with which the materials and their distributions inside the target can be determined according to the photon transmittances. We evaluated the key performance of the system, conducting transmission measurements for Al, Cu, and Pb plates and also for Al, Fe, Cu, and Pb rod-phantoms, both using X-rays (∼30 keV) and γ-rays (∼80 keV) from a 133Ba source. The measured transmittances agreed well with the calculated values from simulations. We successfully reconstructed the three-dimensional structure of the rod-phantom and distinguished the elements inside the phantom. Compared with the simulated photon transmittances, we found that material identification based on tomographic images obtained with the system is efficient as long as the target object does not contain thick high-Z elements.
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Science, 379(6634), Sep 22, 2022 Peer-reviewedSamples of the carbonaceous asteroid Ryugu were brought to Earth by the Hayabusa2 spacecraft. We analyzed seventeen Ryugu samples measuring 1-8 mm. CO 2 -bearing water inclusions are present within a pyrrhotite crystal, indicating that Ryugu’s parent asteroid formed in the outer Solar System. The samples contain low abundances of materials that formed at high temperatures, such as chondrules and Ca, Al-rich inclusions. The samples are rich in phyllosilicates and carbonates, which formed by aqueous alteration reactions at low temperature, high pH, and water/rock ratios < 1 (by mass). Less altered fragments contain olivine, pyroxene, amorphous silicates, calcite, and phosphide. Numerical simulations, based on the mineralogical and physical properties of the samples, indicate Ryugu’s parent body formed ~ 2 million years after the beginning of Solar System formation.
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RADIOISOTOPES, 71(2) 141-151, Jul 15, 2022 Peer-reviewed
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IEEE Transactions on Radiation and Plasma Medical Sciences, 6(5) 592-600, May, 2022 Peer-reviewed
Misc.
288-
日本天文学会年会講演予稿集, 2025, 2025
Presentations
141-
日本天文学会2026年春季年会, Mar 5, 2026
Research Projects
18-
科学研究費助成事業, 日本学術振興会, Apr, 2025 - Mar, 2029
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科学研究費助成事業, 日本学術振興会, Apr, 2024 - Mar, 2029
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科学研究費助成事業, 日本学術振興会, Apr, 2025 - Mar, 2028
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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, 2021 - 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, 2020 - Mar, 2024