宇宙物理学研究系
Profile Information
- Affiliation
- Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency
- ORCID ID
https://orcid.org/0000-0002-7962-4136- J-GLOBAL ID
- 202501003078234700
- researchmap Member ID
- R000092664
Research History
5-
Aug, 2025 - Present
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Feb, 2020 - Mar, 2022
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Apr, 2019 - Jan, 2020
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Apr, 2017 - Mar, 2019
Papers
84-
The Astrophysical Journal, 1002(2) 222-222, May 8, 2026Abstract We present updated hard X-ray polarization measurements of the Crab pulsar and nebula obtained with the balloon-borne polarimeter XL-Calibur in the ∼19–64 keV energy range. During the flight, intermittent failure of the Global Positioning System (GPS) receiver resulted in poorly constrained timing for ∼38% of the Crab dataset. By implementing a new phase recovery method that reconstructs timing during extended GPS-off intervals, phase tag data are recovered for ∼95% of the GPS-off dataset, increasing the precision of the phase-resolved analysis. Phase information for the data is recovered by using the Crab pulsar, with its 33 ms period, as an external timing source. Using a Markov Chain Monte Carlo framework to jointly fit phase offsets and frequency derivatives, sufficient phase accuracy is achieved across multiple periods without GPS for a phase-resolved analysis. This enables inclusion of nearly the full dataset in the polarization study. The polarization degree of the nebular emission is found to be (27.7 ± 4.9)% at a polarization angle of 127 2 ± 5 1, confirming previous XL-Calibur results and remaining aligned with the Crab’s spin axis, consistent with synchrotron emission from the inner nebula. Phase-resolved measurements show that the off-pulse and bridge intervals exhibit a strong polarization, while the pulsar peaks, although weakly constrained, remain in agreement with the softer-energy trends of IXPE. These findings reinforce a scenario in which hard X-ray emission arises primarily in the nebular torus and wind regions. The successful recovery of precise phase tagging from GPS-off data demonstrates the capacity to use the pulsar as an external clock even in the case of sparsely populated data.
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Publications of the Astronomical Society of Japan, Apr 28, 2026
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The Astrophysical Journal Letters, Apr 20, 2026
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Nature Astronomy, Mar 31, 2026
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Nature, 651(8107) 909-913, Mar 25, 2026
Misc.
35-
Meeting Abstracts of the Physical Society of Japan, 79.2 711-711, 2024
Presentations
104Professional Memberships
3-
Dec, 2013 - Present
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- Present
Research Projects
3-
Grants-in-Aid for Scientific Research, Japan Society for the Promotion of Science, Apr, 2021 - Mar, 2024
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科学研究費助成事業, 日本学術振興会, Apr, 2019 - Mar, 2022
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科学研究費助成事業, 日本学術振興会, Apr, 2017 - Mar, 2019