Updated on 2026/03/13

写真a

 
SATO TOSHIKI
 
Organization
Undergraduate School School of Science and Technology Associate Professor
Title
Associate Professor
Homepage
https://toshikisato.wixsite.com/mysite
External link

Degree

  • 博士(理学) ( 2018.3   首都大学東京 )

Research Interests

  • Supernovae

  • Supernova Remnants

  • X-ray Telescope

  • 高エネルギー宇宙物理学

  • 宇宙線

  • Astrophysics

  • X-ray Astronomy

Research Areas

  • Natural sciences / Theoretical studies related to particle-, nuclear-, cosmic ray and astro-physics

  • Natural sciences / Astronomy

Education

  • Tokyo Metropolitan University

    2015.4 - 2018.3

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  • Tokyo Metropolitan University

    2013.4 - 2015.3

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  • Tokyo Metropolitan University

    2009.4 - 2013.3

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Research History

  • Meiji University   School of Science and Technology Department of Physics   Senior Assistant Professor

    2023.4

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  • Rikkyo University   Department of Physics   Assistant Professor

    2021.4 - 2023.3

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  • NASA's Goddard Space Flight Center, Visiting Post-doc Associate

    2018.7 - 2020.12

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  • 理化学研究所   玉川高エネルギー宇宙物理研究室   基礎科学特別研究員

    2018.4 - 2021.3

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  • 日本学術振興会 特別研究員 数物系科学 (DC2)

    2016.4 - 2018.3

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  • ラトガース大学   訪問学生研究員

    2016.1 - 2016.4

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Professional Memberships

Papers

  • Inhomogeneous Stellar Mixing in the Final Hours before the Cassiopeia A Supernova

    Toshiki Sato, Kai Matsunaga, Hiroyuki Uchida, Satoru Katsuda, Koh Takahashi, Hideyuki Umeda, Tomoya Takiwaki, Ryo Sawada, Takashi Yoshida, Ko Nakamura, Yui Kuboike, Paul P. Plucinsky, John P. Hughes

    The Astrophysical Journal   990 ( 2 )   103 - 103   2025.9

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    Publishing type：Research paper (scientific journal)   Publisher：American Astronomical Society  

    Abstract

    Understanding stars and their evolution is a key goal of astronomical research and has long been a focus of human interest. In recent years, theorists have paid much attention to the final interior processes within massive stars, as they can be essential for revealing neutrino-driven supernova mechanisms and other potential transients of massive star collapse. However, it is challenging to observe directly the last hours of a massive star before explosion, since it is the supernova event that triggers the start of intense observational study. Here, we report evidence for a final phase of stellar activity known as a “shell merger,” an intense shell burning in which the O-burning shell swallows its outer C-/Ne-burning shell, deep within the progenitor’s interior moments before the supernova explosion. In the violent convective layer created by the shell merger, Ne, which is abundant in the stellar O-rich layer, is burned as it is pulled inward, and Si, which is synthesized inside, is transported outward. The remnant still preserves some traces of such Ne-rich downflows and Si-rich upflows in the O-rich layer, suggesting that inhomogeneous shell-merger mixing began just hours (≲10<sup>4</sup> s) before its gravitational collapse. Our results provide the first observational evidence that the final stellar burning process rapidly alters the internal structure, leaving a pre-supernova asymmetry. This breaking of spherical symmetry facilitates the explosion of massive stars and influences various supernova and remnant characteristics, including explosion asymmetries and the neutron star’s kick and spin.

    DOI： 10.3847/1538-4357/aded14

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    Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/aded14/pdf

  • Missing Titanium in the Asymmetric Supernova Remnant W 49B

    Toshiki Sato, Makoto Sawada, Keiichi Maeda, John P. Hughes, Brian J. Williams

    The Astrophysical Journal   986 ( 1 )   94 - 94   2025.6

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    Publishing type：Research paper (scientific journal)   Publisher：American Astronomical Society  

    Abstract

    The progenitor of the W 49B supernova remnant is still under debate. One of the candidates is a jet-driven core-collapse supernova. In such a highly asymmetric explosion, a strong α-rich freeze-out is expected in local high-entropy regions, which should enrich elements synthesized by the capture of α-particles such as <sup>44</sup>Ti and <sup>48</sup>Cr (decaying to <sup>44</sup>Ca and <sup>48</sup>Ti, respectively). In the present work, in order to infer the progenitor of the W 49B remnant, we constrain the amount of stable Ti (<sup>48</sup>Ti) synthesized, using Suzaku observations. We found no firm evidence for the Ti line and set the upper limit of M <sub>Ti</sub>/M <sub>Fe</sub> &lt; 9.9 × 10<sup>−4</sup> (99% limit using Xspec/AtomDB) and M <sub>Ti</sub>/M <sub>Fe</sub> &lt; 5.8 × 10<sup>−4</sup> (99% limit using SPEX). Our limits can exclude almost all core-collapse supernova models, suggesting that a Type Ia supernova from a near-Chandrasekhar-mass white dwarf is the most favorable candidate for the origin of W 49B. Future observations with X-ray microcalorimeter missions, such as XRISM, will give us a stronger constraint on the progenitor.

    DOI： 10.3847/1538-4357/add932

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    Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/add932/pdf

  • Measuring the asymmetric expansion of the Fe ejecta of Cassiopeia A with XRISM/Resolve

    Aya Bamba, Manan Agarwal, Jacco Vink, Paul Plucinsky, Yukikatsu Terada, Ehud Behar, Satoru Katsuda, Koji Mori, Makoto Sawada, Hironori Matsumoto, Lia Corrales, Adam Foster, Shin-ichiro Fujimoto, Liyi Gu, Kazuhiro Ichikawa, Kai Matsunaga, Tsunefumi Mizuno, Hiroshi Murakami, Hiroshi Nakajima, Toshiki Sato, Haruto Sonoda, Shunsuke Suzuki, Dai Tateishi, Hiroyuki Uchida, Masahiro Ichihashi, Kumiko Nobukawa, Salvatore Orlando

    Publications of the Astronomical Society of Japan   77 ( Supplement_1 )   S144 - S153   2025.5

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    Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

    Abstract

    The expansion structure of supernova remnants is important for understanding not only how heavy elements are distributed into space, but also how supernovae explode. The ejecta expansion structure of the young core-collapse supernova remnant Cas A is investigated, with Doppler parameter mapping of the Fe–K complex by the Resolve microcalorimeter onboard the X-ray Imaging and Spectroscopy Mission (XRISM). It is found that the Fe ejecta are blueshifted in the south-east and redshifted in the north-west, indicating an incomplete shell structure, similar to intermediate-mass elements (IMEs) such as Si and S. The Fe has a velocity shift of $\sim$1400 and $\sim$2160 km s$^{-1}$ in the north-west and south-east regions, respectively, with the error range of a few hundred km s$^{-1}$. These values are consistent with those for the IMEs in the north-west region, but larger than those for the IMEs in the south-east region, although the large error region prevented us from concluding which component has significantly higher velocity. The line broadening is larger in the center with values of $\sim$2000–3000 km s$^{-1}$, and smaller near the edges of the remnant. The radial profiles of the Doppler shift and broadening of the IMEs and Fe indicate that the Fe ejecta may expand asymmetrically as IME ejecta, although the large error regions do not allow us to confirm this. Moreover, we see little bulk Doppler broadening of the Fe lines in the north-eastern jet region whereas the IME lines exhibit significant broadening. No such narrow lines are detected in the north-west region. These findings suggest an asymmetric expansion of the ejecta potentially driven by large-scale asymmetries originating from the supernova explosion. This interpretation aligns with the large-scale asymmetries predicted by models of neutrino-driven supernova explosions.

    DOI： 10.1093/pasj/psaf041

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  • In-orbit performance of the soft X-ray imaging telescope Xtend aboard XRISM

    Hiroyuki Uchida, Koji Mori, Hiroshi Tomida, Hiroshi Nakajima, Hirofumi Noda, Takaaki Tanaka, Hiroshi Murakami, Hiromasa Suzuki, Shogo Benjamin Kobayashi, Tomokage Yoneyama, Kouichi Hagino, Kumiko Kawabata Nobukawa, Hideki Uchiyama, Masayoshi Nobukawa, Hironori Matsumoto, Takeshi Go Tsuru, Makoto Yamauchi, Isamu Hatsukade, Hirokazu Odaka, Takayoshi Kohmura, Kazutaka Yamaoka, Tessei Yoshida, Yoshiaki Kanemaru, Daiki Ishi, Tadayasu Dotani, Masanobu Ozaki, Hiroshi Tsunemi, Keitaro Miyazaki, Kohei Kusunoki, Yoshinori Otsuka, Haruhiko Yokosu, Wakana Yonemaru, Kazuhiro Ichikawa, Hanako Nakano, Reo Takemoto, Tsukasa Matsushima, Reika Urase, Jun Kurashima, Kotomi Fuchi, Kaito Hayakawa, Masahiro Fukuda, Shun Inoue, Yuma Aoki, Kouta Takayama, Takashi Sako, Marina Yoshimoto, Kohei Shima, Mayu Higuchi, Kaito Ninoyu, Daiki Aoki, Shun Tsunomachi, Takashi Okajima, Manabu Ishida, Yoshitomo Maeda, Takayuki Hayashi, Keisuke Tamura, Rozenn Boissay-Malaquin, Toshiki Sato, Mai Takeo, Asca Miyamoto, Gakuto Matsumoto, Megan E Eckart, Natalie Hell, Maurice A Leutenegger, Kiyoshi Hayashida

    Publications of the Astronomical Society of Japan   77 ( Supplement_1 )   S23 - S38   2025.5

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    Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

    Abstract

    We present a summary of the in-orbit performance of the soft X-ray imaging telescope Xtend onboard the X-Ray Imaging and Spectroscopy Mission (XRISM), based on in-flight observation data, including first-light celestial objects, calibration sources, and results from the cross-calibration campaign with other currently operating X-ray observatories. XRISM/Xtend has a large field of view of ${38{^{\prime }_{. } }5}$  $\times$  ${38{^{\prime }_{. } }5}$, covering an energy range of 0.4–13 keV, as demonstrated by the first-light observation of the galaxy cluster Abell 2319. It also features an energy resolution of 170–180 eV at 6 keV, which meets the mission requirement and enables us to resolve He-like and H-like Fe K$\alpha$ lines. Throughout the observation during the performance verification phase, we confirm that two issues identified in the Soft X-ray Imager (SXI) onboard the previous Hitomi mission—light leakage and crosstalk events—are addressed and suppressed in the case of Xtend. A joint cross-calibration observation of the bright quasar 3C 273 results in an effective area measured to be $\sim$420 cm$^{2}$ at1.5 keV and $\sim$310 cm$^{2}$ at 6.0 keV, which matches values obtained in ground tests. We also continuously monitor the health of Xtend by analyzing overclocking data, calibration source spectra, and day-Earth observations; the readout noise is stable and low, and contamination is negligible even one year after launch. A low background level compared with other major X-ray instruments onboard satellites, combined with the largest grasp ($\Omega _{\rm eff}\sim 60$ cm$^2$ deg$^2$) of Xtend, will not only support Resolve analysis, but also enable significant scientific results on its own. This includes near-future follow-up observations and transient searches in the context of time-domain and multi-messenger astrophysics.

    DOI： 10.1093/pasj/psaf030

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  • Revisiting the Suzaku spectrum of the Galactic SNR W 49B: Non-detection of iron K-shell charge-exchange emission and refined ejecta–mass ratios of iron-group elements

    Makoto Sawada, Toshiki Sato, Keiichi Maeda, Koki Itonaga

    Publications of the Astronomical Society of Japan   2025.3

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    Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

    Abstract

    The origin of the recombining plasma in several Galactic SNRs has been debated. A plausible mechanism would be a rapid cooling in the past, by either an adiabatic or a conductive process. A recent spectral study of W 49B reported a possible charge-exchange emission due to collisions between the shock-heated ejecta and cold clouds, which could be direct support for the conduction cooling scenario. However, a potentially large systematic uncertainty in the spectral analysis has not been examined. In this paper, we revisit the Suzaku spectrum of W 49B, taking into account the systematic uncertainties in spectral codes and instrumental gain calibration. We find that the previously reported flux of the charge-exchange emission is fully attributable to high-shell transition lines, mainly of dielectronic recombination satellites, that are missing from the spectral codes. We also report refined Fe-group ejecta–mass ratios, which, in comparison to those in the literature, show better agreement with theoretical expectations from nucleosynthesis models, either of Type Ia explosions or spherical core-collapse explosions.

    DOI： 10.1093/pasj/psaf012

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  • XRISM Spectroscopy of the Fe Kα Emission Line in the Seyfert Active Galactic Nucleus NGC 4151 Reveals the Disk, Broad-line Region, and Torus Reviewed

    Marc Audard, Hisamitsu Awaki, Ralf Ballhausen, Aya Bamba, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Gregory V. Brown, Lia Corrales, Elisa Costantini, Renata Cumbee, Maria Diaz Trigo, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Dominique Eckert, Teruaki Enoto, Satoshi Eguchi, Yuichiro Ezoe, Adam Foster, Ryuichi Fujimoto, Yutaka Fujita, Yasushi Fukazawa, Kotaro Fukushima, Akihiro Furuzawa, Luigi Gallo, Javier A. García, Liyi Gu, Matteo Guainazzi, Kouichi Hagino, Kenji Hamaguchi, Isamu Hatsukade, Katsuhiro Hayashi, Takayuki Hayashi, Natalie Hell, Edmund Hodges-Kluck, Ann Hornschemeier, Yuto Ichinohe, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Jelle Kaastra, Timothy Kallman, Erin Kara, Satoru Katsuda, Yoshiaki Kanemaru, Richard Kelley, Caroline Kilbourne, Shunji Kitamoto, Shogo Kobayashi, Takayoshi Kohmura, Aya Kubota, Maurice Leutenegger, Michael Loewenstein, Yoshitomo Maeda, Maxim Markevitch, Hironori Matsumoto, Kyoko Matsushita, Dan McCammon, Brian McNamara, François Mernier, Eric D. Miller, Jon M. Miller, Ikuyuki Mitsuishi, Misaki Mizumoto, Tsunefumi Mizuno, Koji Mori, Koji Mukai, Hiroshi Murakami, Richard Mushotzky, Hiroshi Nakajima, Kazuhiro Nakazawa, Jan Uwe Ness, Kumiko Nobukawa, Masayoshi Nobukawa, Hirofumi Noda, Hirokazu Odaka, Shoji Ogawa, Anna Ogorzalek, Takashi Okajima, Naomi Ota, Stephane Paltani, Robert Petre, Paul Plucinsky, Frederick S. Porter, Katja Pottschmidt, Kosuke Sato, Toshiki Sato, Makoto Sawada, Hiromi Seta, Megumi Shidatsu, Aurora Simionescu, Randall Smith, Hiromasa Suzuki, Andrew Szymkowiak, Hiromitsu Takahashi, Mai Takeo, Toru Tamagawa, Keisuke Tamura

    Astrophysical journal letters   973 ( 1 )   2024.9

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.3847/2041-8213/ad7397

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  • Initial in-orbit operation of the soft x-ray spectrometer Resolve onboard the XRISM satellite

    Yoshitomo Maeda, Ryuichi Fujimoto, Hisamitsu Awaki, Jesus C. Balleza, Kim R. Barnstable, Thomas G. Bialas, Rozenn Boissay-Malaquin, Gregory V. Brown, Edgar R. Canavan, Timothy M. Carnahan, Meng P. Chiao, Brian J. Comber, Elisa Costantini, Renata S. Cumbee, Jan-Willem A. den Herder, Johannes Dercksen, Cor P. de Vries, Michael J. DiPirro, Megan E. Eckart, Yuichiro Ezoe, Carlo Ferrigno, Nathalie Q. S. Gorter, Steven M. Graham, Martin Grim, Leslie S. Hartz, Ryota Hayakawa, Takayuki Hayashi, Natalie Hell, Akio Hoshino, Yuto Ichinohe, Daiki Ishi, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Bryan L. James, Yoshiaki Kanemaru, Richard L. Kelley, Steven J. Kenyon, Caroline A. Kilbourne, Mark O. Kimball, Shunji Kitamoto, Maurice A. Leutenegger, Dan McCammon, Brian J. McLaughlin, Joseph J. Miko, Erik van der Meer, Misaki Mizumoto, Takashi Okajima, Atsushi Okamoto, Stéphane Paltani, Frederick S. Porter, Lillian S. Reichenthal, Kosuke Sato, Toshiki Sato, Yohichi Sato, Makoto Sawada, Keisuke Shinozaki, Russell F. Shipman, Peter J. Shirron, Gary A. Sneiderman, Soong Yang, Richard Szymkiewicz, Andrew E. Szymkowiak, Yoh Takei, Mai Takeo, Tsubasa Tamba, Keisuke Tamura, Masahiro Tsujimoto, Yuusuke Uchida, Stephen Wasserzug, Michael C. Witthoeft, Rob Wolfs, Shinya Yamada, Susumu Yasuda

    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray   53 - 53   2024.8

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    Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

    DOI： 10.1117/12.3013008

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  • Overview and inflight performance of the resolve high-resolution soft X-Ray spectrometer on the X-Ray imaging and spectroscopy mission

    Richard L. Kelley, Hisamitsu Awaki, Jesus C. Balleza, Kim R. Barnstable, Thomas G. Bialas, Rozenn Boissay-Malaquin, Gregory V. Brown, Edgar R. Canavan, Timothy M. Carnahan, Meng P. Chiao, Brian J. Comber, Elisa Costantini, Renata S. Cumbee, Jan-Willem A. den Herder, Johannes Dercksen, Cor de Vries, Michael J. DiPirro, Megan E. Eckart, Yuichiro Ezoe, Carlo Ferrigno, Ryuichi Fujimoto, Nathalie Q. S. Gorter, Steven M. Graham, Martin Grim, Leslie S. Hartz, Ryota Hayakawa, Takayuki Hayashi, Natalie Hell, Akio Hoshino, Yuto Ichinohe, Daiki Ishi, Manabu Ishida, Kumi Ishikawa, Yoshitaka Ishisaki, Bryan L. James, Yoshiaki Kanemaru, Steven J. Kenyon, Caroline A. Kilbourne, Mark O. Kimball, Shunji Kitamoto, Maurice A. Leutenegger, Yoshitomo Maeda, Dan McCammon, Brian J. McLaughlin, Joseph J. Miko, Erik van der Meer, Misaki Mizumoto, Takashi Okajima, Atsushi Okamoto, Stéphane Paltani, Frederick S. Porter, Lillian S. Reichenthal, Kosuke Sato, Toshiki Sato, Yohichi Sato, Makoto Sawada, Keisuke Shinozaki, Russell F. Shipman, Peter J. Shirron, Gary A. Sneiderman, Soong Yang, Richard Szymkiewicz, Andrew E. Szymkowiak, Yoh Takei, Mai Takeo, Tsubasa Tamba, Keisuke Tamura, Masahiro Tsujimoto, Yuusuke Uchida, Stephen Wasserzug, Michael C. Witthoeft, Rob Wolfs, Shinya Yamada, Susumu Yasuda

    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray   55 - 55   2024.8

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    Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

    DOI： 10.1117/12.3017731

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  • Pre- and post-launch operation of the soft x-ray spectrometer Resolve on board the XRISM satellite

    Kosuke Sato, Yoshitaka Ishisaki, Richard L. Kelley, Hisamitsu Awaki, Jesus C. Balleza, Kim R. Barnstable, Thomas G. Bialas, Rozenn Boissay-Malaquin, Gregory V. Brown, Edgar R. Canavan, Renata S. Cumbee, Timothy M. Carnahan, Meng P. Chiao, Brian J. Comber, Elisa Costantini, Jan-Willem A. den Herder, Johannes Dercksen, Cor de Vries, Michael J. DiPirro, Megan E. Eckart, Yuichiro Ezoe, Carlo Ferrigno, Ryuichi Fujimoto, Nathalie Q. S. Gorter, Steven M. Graham, Martin Grim, Leslie S. Hartz, Ryota Hayakawa, Takayuki Hayashi, Natalie Hell, Akio Hoshino, Yuto Ichinohe, Daiki Ishi, Manabu Ishida, Kumi Ishikawa, Bryan L. James, Yoshiaki Kanemaru, Steven J. Kenyon, Caroline A. Kilbourne, Mark O. Kimball, Shunji Kitamoto, Maurice A. Leutenegger, Yoshitomo Maeda, Dan McCammon, Brian J. McLaughlin, Joseph J. Miko, Erik van der Meer, Misaki Mizumoto, Takashi Okajima, Atsushi Okamoto, Stéphane Paltani, Frederick S. Porter, Lillian S. Reichenthal, Toshiki Sato, Yohichi Sato, Makoto Sawada, Keisuke Shinozaki, Russell F. Shipman, Peter J. Shirron, Gary A. Sneiderman, Soong Yang, Richard Szymkiewicz, Andrew E. Szymkowiak, Yoh Takei, Mai Takeo, Tsubasa Tamba, Keisuke Tamura, Masahiro Tsujimoto, Yuusuke Uchida, Stephen Wasserzug, Michael C. Witthoeft, Rob Wolfs, Shinya Yamada, Susumu Yasuda, Seiji Yoshida

    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray   232 - 232   2024.8

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    Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

    DOI： 10.1117/12.3019327

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  • Application of transition-edge sensor for micro-X-ray fluorescence measurements and micro-X-ray absorption near edge structure spectroscopy: a case study of uranium speciation in biotite obtained from uranium mine

    Takumi Yomogida, Tadashi Hashimoto, Takuma Okumura, Shinya Yamada, Hideyuki Tatsuno, Hirofumi Noda, Ryota Hayakawa, Sayuri Takatori, Shinji Okada, Tadaaki Isobe, Takahiro Hiraki, Toshiki Sato, Yuichi Toyama, Yuto Ichinohe, Oki Sekizawa, Kiyofumi Nitta, Yuichi Kurihara, Shigeru Fukushima, Tomoya Uruga, Yoshihiro Kitatsuji, Yoshio Takahashi

    The Analyst   2024

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    Publishing type：Research paper (scientific journal)   Publisher：Royal Society of Chemistry (RSC)  

    In this study, we successfully applied a transition-edge sensor (TES) spectrometer as a detector for microbeam X-ray measurements from a synchrotron X-ray light source in hard X-ray region to determine...

    DOI： 10.1039/d4an00059e

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  • Examining Neutrino–Matter Interactions in the Cassiopeia A Supernova

    Toshiki Sato, Takashi Yoshida, Hideyuki Umeda, John P. Hughes, Keiichi Maeda, Shigehiro Nagataki, Brian J. Williams

    The Astrophysical Journal   2023.9

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.3847/1538-4357/ace7c1

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  • Richardson–Lucy Deconvolution with a Spatially Variant Point-spread Function of Chandra: Supernova Remnant Cassiopeia A as an Example

    Yusuke Sakai, Shinya Yamada, Toshiki Sato, Ryota Hayakawa, Ryota Higurashi, Nao Kominato

    The Astrophysical Journal   951 ( 1 )   59 - 59   2023.7

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    Publishing type：Research paper (scientific journal)   Publisher：American Astronomical Society  

    Abstract

    Richardson–Lucy (RL) deconvolution is one of the classical methods widely used in X-ray astronomy and other areas. Amid recent progress in image processing, RL deconvolution still leaves much room for improvement under realistic situations. One direction is to include the positional dependence of a point-spread function (PSF), so-called RL deconvolution with a spatially variant PSF (RL<sub>sv</sub>). Another is the method of estimating a reliable number of iterations and their associated uncertainties. We developed a practical method that incorporates the RL<sub>sv</sub> algorithm and the estimation of uncertainties. As a typical example of bright and high-resolution images, the Chandra X-ray image of the supernova remnant Cassiopeia A was used in this paper. RL<sub>sv</sub> deconvolution enables us to uncover the smeared features in the forward/backward shocks and jet-like structures. We constructed a method to predict the appropriate number of iterations using statistical fluctuation of the observed images. Furthermore, the uncertainties were estimated by error propagation from the last iteration, which was phenomenologically tested with the observed data. Thus, our method is a practically efficient framework to evaluate the time evolution of the remnants and their fine structures embedded in high-resolution X-ray images.

    DOI： 10.3847/1538-4357/acd9b3

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    Other Link： https://iopscience.iop.org/article/10.3847/1538-4357/acd9b3/pdf

  • High-sensitive XANES analysis at Ce L2-edge for Ce in bauxites using transition-edge sensors: Implications for Ti-rich geological samples

    Wenshuai Li, Shinya Yamada, Tadashi Hashimoto, Takuma Okumura, Ryota Hayakawa, Kiyofumi Nitta, Oki Sekizawa, Hiroki Suga, Tomoya Uruga, Yuto Ichinohe, Toshiki Sato, Yuichi Toyama, Hirofumi Noda, Tadaaki Isobe, Sayuri Takatori, Takahiro Hiraki, Hideyuki Tatsuno, Nao Kominato, Masaki Ito, Yusuke Sakai, Hajime Omamiuda, Akiko Yamaguchi, Takumi Yomogida, Hikaru Miura, Makoto Nagasawa, Shinji Okada, Yoshio Takahashi

    Analytica Chimica Acta   1240   340755 - 340755   2023.2

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    Publishing type：Research paper (scientific journal)   Publisher：Elsevier BV  

    DOI： 10.1016/j.aca.2022.340755

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  • Status of resolve instrument onboard x-ray imaging and spectroscopy mission (XRISM)

    Yoshitaka Ishisaki, Richard L. Kelley, Hisamitsu Awaki, Jesus C. Balleza, Kim R. Barnstable, Thomas G. Bialas, Rozenn Boissay-Malaquin, Gregory V. Brown, Edgar R. Canavan, Renata S. Cumbee, Timothy M. Carnahan, Meng P. Chiao, Brian J. Comber, Elisa Costantini, Jan-Willem A. den Herder, Johannes Dercksen, Cor P. de Vries, Michael J. DiPirro, Megan E. Eckart, Yuichiro Ezoe, Carlo Ferrigno, Ryuichi Fujimoto, Nathalie Gorter, Steven M. Graham, Martin Grim, Leslie S. Hartz, Ryota Hayakawa, Takayuki Hayashi, Natalie Hell, Akio Hoshino, Yuto Ichinohe, Manabu Ishida, Kumi Ishikawa, Bryan L. James, Steven J. Kenyon, Caroline A. Kilbourne, Mark O. Kimball, Shunji Kitamoto, Maurice A. Leutenegger, Yoshitomo Maeda, Dan McCammon, Joseph J. Miko, Misaki Mizumoto, Takashi Okajima, Atsushi Okamoto, Stephane Paltani, Frederick S. Porter, Kosuke Sato, Toshiki Sato, Makoto Sawada, Keisuke Shinozaki, Russell Shipman, Peter J. Shirron, Gary A. Sneiderman, Yang Soong, Richard Szymkiewicz, Andrew E. Szymkowiak, Yoh Takei, Keisuke Tamura, Masahiro Tsujimoto, Yuusuke Uchida, Stephen Wasserzug, Michael C. Witthoeft, Rob Wolfs, Shinya Yamada, Susumu Yasuda

    Space Telescopes and Instrumentation 2022: Ultraviolet to Gamma Ray   2022.8

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    Publishing type：Research paper (international conference proceedings)   Publisher：SPIE  

    DOI： 10.1117/12.2630654

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  • X-Ray Studies of the Inverted Ejecta Layers in the Southeast Area of Cassiopeia A

    Tomoya Tsuchioka, Toshiki Sato, Shinya Yamada, Yasunobu Uchiyama

    The Astrophysical Journal   2022.6

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    Publishing type：Research paper (scientific journal)  

    DOI： 10.3847/1538-4357/ac6e63

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  • X-ray hot spots in the eastern ear of the supernova remnant W 50 and the microquasar SS 433 system

    Ryota Hayakawa, Shinya Yamada, Hirotaka Suda, Yuto Ichinohe, Ryota Higurashi, Haruka Sakemi, Mami Machida, Takumi Ohmura, Satoru Katsuda, Hideki Uchiyama, Toshiki Sato, Hiroki Akamatsu, Magnus Axelsson

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   74 ( 3 )   510 - 520   2022.6

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    Language：English   Publishing type：Research paper (scientific journal)  

    DOI： 10.1093/pasj/psac011

    Web of Science

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  • Discovery of stable titanium at the northeastern jet of Cassiopeia A: Need for a weak jet mechanism?

    Takuma Ikeda, Yasunobu Uchiyama, Toshiki Sato, Ryota Higurashi, Tomoya Tsuchioka, Shinya Yamada

    Publications of the Astronomical Society of Japan   74 ( 2 )   334 - 342   2022.4

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    Publishing type：Research paper (scientific journal)   Publisher：Oxford University Press (OUP)  

    Abstract

    The origin of the jet-like structures observed in Cassiopeia A is still unclear, although it seems to be related to its explosion mechanism. X-ray observations of the characteristic structures could provide us useful information on the explosive nucleosynthesis via the observation of elements, which is a unique approach to understand its origin. We here report the discovery of shocked stable Ti, which is produced only at the inner region of exploding stars, in the northeast jet of Cassiopeia A using the 1 Ms deep observation with the Chandra X-ray observatory. The observed Ti coexists with other intermediate-mass elements (e.g., Si, S, Ar, Ca) and Fe at the tip of the X-ray jet structure. We found that its elemental composition is explained well with the production by the incomplete Si burning regime, indicating that the formation process of the jet structure was sub-energetic at the explosion (the peak temperature during the nuclear burning must be ≲5 × 109 K at most). Thus, we conclude that the energy source that formed the jet structure was not the primary engine for the supernova explosion. Our results are useful to limit the power of the jet-structure formation process, and a weak jet mechanism with low temperature may be needed to explain it.

    DOI： 10.1093/pasj/psab130

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  • Spatially Resolved RGS Analysis of Kepler's Supernova Remnant

    Tomoaki Kasuga, Jacco Vink, Satoru Katsuda, Hiroyuki Uchida, Aya Bamba, Toshiki Sato, John P. Hughes

    Astrophysical Journal   915 ( 1 )   2021.7

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    DOI： 10.3847/1538-4357/abff4f

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  • Discovery of a highly neutronized ejecta clump in the type ia supernova remnant 3C397 Reviewed

    Yuken Ohshiro, Hiroya Yamaguchi, Shing Chi Leung, Ken'ichi Nomoto, Toshiki Sato, Takaaki Tanaka, Hiromichi Okon, Robert Fisher, Robert Petre, Brian J. Williams

    Astrophysical Journal Letters   913 ( 2 )   2021.6

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    DOI： 10.3847/2041-8213/abff5b

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  • On the Origin of the Asymmetry of the Ejecta Structure and Explosion of G350.1-0.3 Reviewed

    Tomoya Tsuchioka, Yasunobu Uchiyama, Ryota Higurashi, Hiroyoshi Iwasaki, Shumpei Otsuka, Shinya Yamada, Toshiki Sato

    ASTROPHYSICAL JOURNAL   912 ( 2 )   2021.5

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    DOI： 10.3847/1538-4357/abf2bd

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  • High-entropy ejecta plumes in Cassiopeia A from neutrino-driven convection Reviewed

    Toshiki Sato, Keiichi Maeda, Shigehiro Nagataki, Takashi Yoshida, Brian Grefenstette, Brian J. Williams, Hideyuki Umeda, Masaomi Ono, John P. Hughes

    Nature   592 ( 7855 )   537 - 540   2021.4

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    DOI： 10.1038/s41586-021-03391-9

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  • From supernova to supernova remnant: Comparison of thermonuclear explosion models Reviewed

    Gilles Ferrand, Donald C. Warren, Masaomi Ono, Shigehiro Nagataki, Friedrich K. Röpke, Ivo R. Seitenzahl, Florian Lach, Hiroyoshi Iwasaki, Toshiki Sato

    Astrophysical Journal   906 ( 2 )   2021.1

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    DOI： 10.3847/1538-4357/abc951

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  • Formation pathway for lonely stripped-envelope supernova progenitors: Implications for Cassiopeia A Reviewed

    Ryosuke Hirai, Toshiki Sato, Philipp Podsiadlowski, Alejandro Vigna-Gómez, Ilya Mandel

    Monthly Notices of the Royal Astronomical Society   499 ( 1 )   1154 - 1170   2020.11

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    DOI： 10.1093/mnras/staa2898

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  • A Subsolar Metallicity Progenitor for Cassiopeia A, the Remnant of a Type IIb Supernova Reviewed

    Toshiki Sato, Takashi Yoshida, Hideyuki Umeda, Shigehiro Nagataki, Masaomi Ono, Keiichi Maeda, Ryosuke Hirai, John P. Hughes, Brian J. Williams, Yoshitomo Maeda

    ASTROPHYSICAL JOURNAL   893 ( 1 )   2020.4

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    DOI： 10.3847/1538-4357/ab822a

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  • An ejecta kinematics study of kepler's supernova remnant with high-resolution chandra hetg spectroscopy Reviewed

    Matthew J. Millard, Jayant Bhalerao, Sangwook Park, Toshiki Sato, John P. Hughes, Patrick Slane, Daniel Patnaude, David Burrows, Carles Badenes

    Astrophysical Journal   893 ( 2 )   2020.4

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    DOI： 10.3847/1538-4357/ab7db1

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  • A Nucleosynthetic Origin for the Southwestern Fe-rich Structure in Kepler's Supernova Remnant Reviewed

    Toshiki Sato, Eduardo Bravo, Carles Badenes, John P. Hughes, Brian J. Williams, Hiroya Yamaguchi

    ASTROPHYSICAL JOURNAL   890 ( 2 )   2020.2

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    DOI： 10.3847/1538-4357/ab6aa2

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  • Concept for an X-ray telescope system with an angular resolution booster Reviewed

    Yoshitomo Maeda, Ryo Iizuka, Takayuki Hayashi, Toshiki Sato, Nozomi Nakaniwa, Mai Takeo, Hitomi Suzuki, Manabu Ishida, Shiro Ikeda, Mikio Morii

    Publications of the Astronomical Society of Japan   71 ( 5 )   2019.10

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    DOI： 10.1093/pasj/psz081

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  • Genus Statistic Applied to the X-Ray Remnant of SN 1572: Clues to the Clumpy Ejecta Structure of Type Ia Supernovae Reviewed

    Toshiki Sato, John P. Hughes, Brian J. Williams, Mikio Morii

    ASTROPHYSICAL JOURNAL   879 ( 2 )   2019.7

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    DOI： 10.3847/1538-4357/ab24db

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  • Concept for an X-ray telescope system with an angular resolution booster Reviewed

    Maeda, Y., Iizuka, R., Hayashi, T., Sato, T., Nakaniwa, N., Takeo, M., Suzuki, H., Ishida, M., Ikeda, S., Morii, M.

    Publications of the Astronomical Society of Japan   71 ( 5 )   2019

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    DOI： 10.1093/pasj/psz081

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  • Asymmetric expansion of the Fe ejecta in Kepler's supernova remnant Reviewed

    Kasuga Tomoaki, Sato Toshiki, Mori Koji, Yamaguchi Hiroya, Bamba Aya

    Publ. Astron. Soc. Japan   2018.8

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  • Vortical Amplification of the Magnetic Field at an Inward Shock of Supernova Remnant Cassiopeia A Reviewed

    F. Fraschetti, S. Katsuda, T. Sato, J. R. Jokipii, J. Giacalone

    Physical Review Letters   120 ( 25 )   2018.6

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    DOI： 10.1103/PhysRevLett.120.251101

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  • In-flight verification of the calibration and performance of the ASTRO-H (Hitomi) soft x-ray spectrometer Reviewed

    Maurice A. Leutenegger, Marc Audard, Kevin R. Boyce, Gregory V. Brown, Meng P. Chiao, Megan E. Eckart, Ryuichi Fujimoto, Akihiro Furuzawa, Matteo Guainazzi, Daniel Haas, Takayuki Hayashi, Jan-Willem Den Herder, Ryo Iizuka, Manabu Ishida, Yoshitaka Ishisaki, Naomichi Kikuchi, Caroline A. Kilbourne, Shu Koyama, Sho Kurashima, Yoshitomo Maeda, Maxim Markevitch, Dan Mccammon, Kazuhisa Mitsuda, Hideyuki Mori, Nozomi Nakaniwa, Takashi Okajima, Stéphane Paltani, Robert Petre, F. Scott Porter, Kosuke Sato, Toshiki Sato, Makoto Sawada, Peter J. Serlemitsos, Hiromi Seta, Gary Sneiderman, Yang Soong, Satoshi Sugita, Andrew E. Szymkowiak, Yoh Takei, Makoto Tashiro, Yuzuru Tawara, Masahiro Tsujimoto, Cor P. De Vries, Tomomi Watanabe, Shinya Yamada, Noriko Yamasaki

    Journal of Astronomical Telescopes, Instruments, and Systems   4 ( 2 )   2018.4

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    DOI： 10.1117/1.JATIS.4.2.021407

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  • Inflight Calibration of Hitomi Soft X-ray Spectrometer (2) Point Spread Function Reviewed

    Maeda, Yoshitomo, Sato, Toshiki, Hayashi, Takayuki, Iizuka, Ryo, Angelini, Lorella, Asai, Ryota, Furuzawa, Akihiro, Kelley, Richard, Koyama, Shu, Kurashima, Sho, Ishida, Manabu, Mori, Hideyuki, Nakaniwa, Nozomi, Okajima, Takashi, Serlemitsos, Peter J, Tsujimoto, Masahiro, Yaqoob, Tahir

    Publ. Astron. Soc. Japan   70 ( 2 )   2018.4

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  • Hitomi Observations of the LMC SNR N132D: Highly Redshifted X-ray Emission from Iron Ejecta Reviewed

    Hitomi collaboration (including, Toshiki Sato

    Publ. Astron. Soc. Japan   70 ( 2 )   2018.4

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  • Search for Thermal X-ray Features from the Crab nebula with Hitomi Soft X-ray Spectrometer Reviewed

    Hitomi collaboration (including, Toshiki Sato

    Publ. Astron. Soc. Japan   70 ( 2 )   2018.4

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  • Hitomi X-ray Observation of the Pulsar Wind Nebula G21.5-0.9 Reviewed

    Hitomi collaboration (including, Toshiki Sato

    Publ. Astron. Soc. Japan   70 ( 3 )   2018.4

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  • In-flight calibration of Hitomi Soft X-ray Spectrometer. (3) Effective area Reviewed

    Masahiro Tsujimoto, Takashi Okajima, Megan E. Eckart, Takayuki Hayashi, Akio Hoshino, Ryo Iizuka, Richard L. Kelley, Caroline A. Kilbourne, Maurice A. Leutenegger, Yoshitomo Maeda, Hideyuki Mori, Frederick S. Porter, Kosuke Sato, Toshiki Sato, Peter J. Serlemitsos, Andrew Szymkowiak, Tahir Yaqoob

    PUBLICATIONS OF THE ASTRONOMICAL SOCIETY OF JAPAN   70 ( 2 )   2018.3

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    DOI： 10.1093/pasj/psy008

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  • In-orbit performance of the soft X-ray imaging system aboard Hitomi Reviewed

    Nakajima Hiroshi, Maeda Yoshitomo, Uchida Hiroyuki, Tanaka Takaaki, Tsunemi Hiroshi, Hayashida Kiyoshi, Tsuru Takeshi G, Dotani Tadayasu, Nagino Ryo, Inoue Shota, Ozaki Masanobu, Tomida Hiroshi, Natsukari Chikara, Ueda Shutaro, Mori Koji, Yamauchi Makoto, Hatsukade Isamu, Nishioka Yusuke, Sakata Miho, Beppu Tatsuhiko, Honda Daigo, Nobukawa Masayoshi, Hiraga Junko S, Kohmura Takayoshi, Murakami Hiroshi, Nobukawa, Kumiko K, Bamba Aya, Doty John P, Iizuka Ryo, Sato Toshiki, Kurashima Sho, Nakaniwa Nozomi, Asai Ryota, Ishida Manadu, Mori Hideyuki, Soong Yang, Okajima Takashi, Serlemitsos Peter, Tawara Yuzuru, Mitsuishi Ikuyuki, Ishibashi Kazunori, Tamura Keisuke, Hayashi Takayuki, Furuzawa Akihiro, Sugita Satoshi, Miyazawa Takuya, Awaki Hisamitsu, Miller Eric D, Yamaguchi Hiroya

    Publications of the Astronomical Society of Japan   70 ( 2 )   2018.3

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    DOI： 10.1093/pasj/psx116

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  • Ground-based x-ray calibration of the Astro-H/Hitomi soft x-ray telescopes Reviewed

    Ryo Iizuka, Takayuki Hayashi, Yoshitomo Maeda, Manabu Ishida, Kazuki Tomikawa, Toshiki Sato, Naomichi Kikuchi, Takashi Okajima, Yang Soong, Peter J. Serlemitsos, Hideyuki Mori, Takanori Izumiya, Sari Minami

    Journal of Astronomical Telescopes, Instruments, and Systems   4 ( 1 )   2018.1

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    DOI： 10.1117/1.JATIS.4.1.011213

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  • On-ground calibration of the Hitomi Hard X-ray Telescopes Reviewed

    Hideyuki Mori, Takuya Miyazawa, Hisamitsu Awaki, Hironori Matsumoto, Yasunori Babazaki, Ayako Bandai, Tadatsugu Demoto, Akihiro Furuzawa, Yoshito Haba, Takayuki Hayashi, Ryo Iizuka, Kazunori Ishibashi, Manabu Ishida, Naoki Ishida, Masayuki Itoh, Toshihiro Iwase, Hiroyoshi Kato, Hiroaki Kobayashi, Tatsuro Kosaka, Hideyo Kunieda, Shou Kurashima, Daichi Kurihara, Yuuji Kuroda, Yoshitomo Maeda, Yoshifumi Meshino, Ikuyuki Mitsuishi, Yuusuke Miyata, Housei Nagano, Yoshiharu Namba, Yasushi Ogasaka, Keiji Ogi, Takashi Okajima, Shigetaka Saji, Fumiya Shimasaki, Takuro Sato, Toshiki Sato, Naotsugu Shima, Satoshi Sugita, Yoshio Suzuki, Kenji Tachibana, Sasagu Tachibana, Shun'Ya Takizawa, Keisuke Tamura, Yuzuru Tawara, Kazuki Tomikawa, Tatsuharu Torii, Kentaro Uesugi, Koujun Yamashita, Shigeo Yamauchi

    Journal of Astronomical Telescopes, Instruments, and Systems   4 ( 1 )   011210-1 - 011210-22   2018.1

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    DOI： 10.1117/1.JATIS.4.1.011210

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  • X-Ray Measurements of the Particle Acceleration Properties at Inward Shocks in Cassiopeia A Reviewed

    Toshiki Sato, Satoru Katsuda, Mikio Morii, Aya Bamba, John P. Hughes, Yoshitomo Maeda, Manabu Ishida, Federico Fraschetti

    ASTROPHYSICAL JOURNAL   853 ( 1 )   2018.1

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    DOI： 10.3847/1538-4357/aaa021

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  • Freely Expanding Knots of X-Ray-emitting Ejecta in Kepler's Supernova Remnant Reviewed

    Toshiki Sato, John P. Hughes

    ASTROPHYSICAL JOURNAL   845 ( 2 )   2017.8

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    DOI： 10.3847/1538-4357/aa8305

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  • Direct Ejecta Velocity Measurements of Tycho's Supernova Remnant Reviewed

    Toshiki Sato, John P. Hughes

    ASTROPHYSICAL JOURNAL   840 ( 2 )   2017.5

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    DOI： 10.3847/1538-4357/aa6f60

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  • Multi-year X-Ray Variations of Iron-K and Continuum Emissions in the Young Supernova Remnant Cassiopeia A Reviewed

    Toshiki Sato, Yoshitomo Maeda, Aya Bamba, Satoru Katsuda, Yutaka Ohira, Ryo Yamazaki, Kuniaki Masai, Hironori Matsumoto, Makoto Sawada, Yukikatsu Terada, John P. Hughes, Manabu Ishida

    ASTROPHYSICAL JOURNAL   836 ( 2 )   2017.2

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    DOI： 10.3847/1538-4357/836/2/225

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  • Reflectivity around the gold L-edges of x-ray reflector of the soft x-ray telescope onboard ASTRO-H

    Yoshitomo Maeda, Naomichi Kikuchi, Sho Kurashima, Manabu Ishida, Ryo Iizuka, Takayuki Hayashi, Takashi Okajima, Hironori Matsumoto, Ikuyuki Mitsuishi, Shigetaka Saji, Toshiki Sato, Sasagu Tachibana, Hideyuki Mori, Finn Christensen, Nicolai Brejnholt, Kiyofumi Nitta, Tomoya Uruga

    OPTICS FOR EUV, X-RAY, AND GAMMA-RAY ASTRONOMY VIII   10399   id. 99053Z   2017

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    DOI： 10.1117/12.2275605

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  • An angular-resolution booster on the broadband X-ray telescope system Reviewed

    Yoshitomo Maeda, Ryo Iizuka, Toshiki Sato, Manabu Ishida, Takayuki Hayashi, Ryoko Nakamura

    OPTICS FOR EUV, X-RAY, AND GAMMA-RAY ASTRONOMY VIII   10399   2017

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    DOI： 10.1117/12.2273466

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  • Atomic scattering factor of the ASTRO-H (Hitomi) SXT reflector around the gold's L edges Reviewed

    Naomichi Kikuchi, Sho Kurashima, Manabu Ishida, Ryo Iizuka, Yoshitomo Maeda, Takayuki Hayashi, Takashi Okajima, Hironori Matsumoto, Ikuyuki Mitsuishi, Shigetaka Saji, Toshiki Sato, Sasagu Tachibana, Hideyuki Mori, Finn Christensen, Nicolai Brejnholt, Kiyofumi Nitta, Tomoya Uruga

    OPTICS EXPRESS   24 ( 22 )   25548 - 25564   2016.10

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    DOI： 10.1364/OE.24.025548

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  • Examining the angular resolution of the ASTRO-H's soft x-ray telescopes Reviewed

    Toshiki Sato, Ryo Iizuka, Manabu Ishida, Naomichi Kikuchi, Yoshitomo Maeda, Sho Kurashima, Nozomi Nakaniwa, Kazuki Tomikawa, Takayuki Hayashi, Hideyuki Mori, Takashi Okajima, Peter J. Serlemitsos, Yang Soong, Takanori Izumiya, Sari Minami

    JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS   2 ( 4 )   2016.10

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    DOI： 10.1117/1.JATIS.2.4.044001

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  • Reflectivity around the gold L-edges of x-ray reflector of the soft x-ray telescope onboard ASTRO-H

    Yoshitomo Maeda, Naomichi Kikuchi, Sho Kurashima, Manabu Ishida, Ryo Iizuka, Takayuki Hayashi, Takashi Okajima, Hironori Matsumoto, Ikuyuki Mitsuishi, Shigetaka Saji, Toshiki Sato, Sasagu Tachibana, Hideyuki Mori, Finn Christensen, Nicolai Brejnholt, Kiyofumi Nitta, Tomoya Uruga

    Proceedings of SPIE - The International Society for Optical Engineering   9905   id. 99053Y   2016

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    DOI： 10.1117/12.2232727

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  • Point spread function of ASTRO-H Soft X-ray Telescope (SXT) Reviewed

    Takayuki Hayashi, Toshiki Sato, Naomichi Kikuchi, Ryo Iizuka, Yoshitomo Maeda, Manabu Ishida, Sho Kurashima, Nozomi Nakaniwa, Takashi Okajima, Hideyuki Mori, Yang Soong, Peter J. Serlemitosos

    SPACE TELESCOPES AND INSTRUMENTATION 2016: ULTRAVIOLET TO GAMMA RAY   9905   2016

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    DOI： 10.1117/12.2232007

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  • In-flight verification of the calibration and performance of the ASTRO-H (Hitomi) Soft X-Ray Spectrometer Reviewed

    Maurice A. Leutenegger, Marc Audard, Kevin R. Boyce, Gregory V. Brown, Meng P. Chiao, Megan E. Eckart, Ryuichi Fujimoto, Akihiro Furuzawa, Matteo Guainazzi, Daniel Haas, Jan-Willem Den Herder, Takayuki Hayashi, Ryo Iizuka, Manabu Ishida, Yoshitaka Ishisaki, Richard L. Kelley, Naomichi Kikuchi, Caroline A. Kilbourne, Shu Koyama, Sho Kurashima, Yoshitomo Maeda, Maxim Markevitch, Dan McCammon, Kazuhisa Mitsuda, Hideyuki Mori, Nozomi Nakaniwa, Takashi Okajima, Stéphane Paltani, Robert Petre, F. Scott Porter, Kosuke Sato, Toshiki Sato, Makoto Sawada, Peter J. Serlemitsos, Hiromi Seta, Gary Sneiderman, Yang Soong, Satoshi Sugita, Andrew E. Szymkowiak, Yoh Takei, Makoto Tashiro, Yuzuru Tawara, Masahiro Tsujimoto, Cor P. De Vries, Tomomi Watanabe, Shinya Yamada, Noriko Yamasaki

    Proceedings of SPIE - The International Society for Optical Engineering   9905   2016

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    DOI： 10.1117/12.2234230

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  • The ASTRO-H SXT performance to the large off-set angles Reviewed

    Toshiki Sato, Ryo Iizuka, Hideyuki Mori, Takayuki Hayashi, Yoshitomo Maeda, Manabu Ishida, Naomichi Kikuchi, Sho Kurashima, Nozomi Nakaniwa, Takashi Okajima, Yang Soong, Peter J. Serlemitosos

    SPACE TELESCOPES AND INSTRUMENTATION 2016: ULTRAVIOLET TO GAMMA RAY   9905   2016

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    DOI： 10.1117/12.2232175

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  • First peek of ASTRO-H Soft X-ray Telescope (SXT) in-orbit performance Reviewed

    Takashi Okajima, Yang Soong, Peter Serlemitsos, Hideyuki Mori, Larry Olsen, David Robinson, Richard Koenecke, Bill Chang, Devin Hahne, Ryo Iizuka, Manabu Ishida, Yoshitomo Maeda, Toshiki Sato, Naomichi Kikuchi, Sho Kurashima, Nozomi Nakaniwa, Takayuki Hayashi, Kazunori Ishibashi, Takuya Miyazawa, Kenji Tachibana, Keisuke Tamura, Akihiro Furuzawa, Yuzuru Tawara, Satoshi Sugita

    Proceedings of SPIE - The International Society for Optical Engineering   9905   2016

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    DOI： 10.1117/12.2231705

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  • Upgrade of the 30-m x-ray pencil beam line at the Institute of Space and Astronautical Science Reviewed

    Takayuki Hayashi, Toshiki Sato, Naomichi Kikuchi, Sho Kurashima, Nozomi Nakaniwa, Takuro Sato, Ryo Iizuka, Yoshitomo Maeda, Manabu Ishida

    JOURNAL OF ASTRONOMICAL TELESCOPES INSTRUMENTS AND SYSTEMS   1 ( 4 )   2015.10

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    DOI： 10.1117/1.JATIS.1.4.044004

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  • Thermal stress test of the depth-graded platinum/carbon reflectors Reviewed

    Yoshitomo Maeda, Kou Ichihara, Hiroaki Kan, Yu Shionome, Takuro Sato, Toshiki Sato, Takayuki Hayashi, Manabu Ishida, Yoshiharu Namba, Hideaki Takahashi, Takuya Miyazawa, Kazunori Ishibashi, Michito Sakai, Satoshi Sugita, Yoshito Haba, Hironori Matsumoto, Hideyuki Mori

    Journal of Astronomical Telescopes, Instruments, and Systems   1 ( 3 )   id. 034001   2015.7

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    DOI： 10.1117/1.JATIS.1.3.034001

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  • Hard x-ray telescopes to be onboard ASTRO-H Reviewed

    Hisamitsu Awaki, Hideyo Kunieda, Manabu Ishida, Hironori Matsumoto, Yasunori Babazaki, Tadatsugu Demoto, Akihiro Furuzawa, Yoshito Haba, Takayuki Hayashi, Ryo Iizuka, Kazunori Ishibashi, Naoki Ishida, Masayuki Itoh, Toshihiro Iwase, Tatsuro Kosaka, Daichi Kurihara, Yuuji Kuroda, Yoshitomo Maeda, Yoshifumi Meshino, Ikuyuki Mitsuishi, Yuusuke Miyata, Takuya Miyazawa, Hideyuki Mori, Housei Nagano, Yoshiharu Namba, Yasushi Ogasaka, Keiji Ogi, Takashi Okajima, Shigetaka Saji, Fumiya Shimasaki, Takuro Sato, Toshiki Sato, Satoshi Sugita, Yoshio Suzuki, Kenji Tachibana, Sasagu Tachibana, Shunya Takizawa, Keisuke Tamura, Yuzuru Tawara, Tatsuharu Torii, Kentato Uesugi, Koujun Yamashita, Shigeo Yamauchi

    Applied Optics   53 ( 32 )   7664 - 7676   2014.11

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    DOI： 10.1364/AO.53.007664

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  • Upgrade of the thirty-meter x-ray pencil beam line at the institute of space and astronautical science Reviewed

    Takayuki Hayashi, Toshiki Sato, Kazuki Tomikawa, Naomichi Kikuchi, Takuro Sato, Ryo Iizuka, Yoshitomo Maeda, Manabu Ishida

    SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY   9144   2014

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    DOI： 10.1117/12.2055741

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  • Ground-based X-ray calibration of the Astro-H soft X-ray telescopes Reviewed

    Ryo Iizuka, Takayuki Hayashi, Yoshitomo Maeda, Manabu Ishida, Kazuki Tomikawa, Toshiki Sato, Naomichi Kikuchi, Takashi Okajima, Yang Soong, Peter J. Serlemitosos, Hideyuki Mori, Takanori Izumiya, Sari Minami

    SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY   9144   2014

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    Language：English   Publishing type：Research paper (international conference proceedings)  

    DOI： 10.1117/12.2054626

    Web of Science

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  • ASTRO-H Soft X-ray Telescope (SXT) Reviewed

    Yang Soong, Takashi Okajima, Peter J. Serlemitsos, Stephen L. Odell, Brian D. Ramsey, Mikhail V. Gubarev, Manabu Ishida, Yoshitomo Maeda, Ryo Iizuka, Takayuki Hayashi, Yuzuru Tawara, Akihiro Furuzawa, Hideyuki Mori, Takuya Miyazawa, Hideyo Kunieda, Hisamitsu Awaki, Satoshi Sugita, Keisuke Tamura, Kazunori Ishibashi, Takanori Izumiya, Sari Minami, Toshiki Sato, Kazuki Tomikawa, Naomichi Kikuchi, Toshihiro Iwase

    SPACE TELESCOPES AND INSTRUMENTATION 2014: ULTRAVIOLET TO GAMMA RAY   9144   2014

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    Language：English   Publishing type：Research paper (international conference proceedings)  

    DOI： 10.1117/12.2056804

    Web of Science

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  • Assembly of a MEMS-based Wolter type-I X-ray optic toward a future planetary exploration mission Reviewed

    Ikuyuki Mitsuishi, Yuichiro Ezoe, Tomohiro Ogawa, Takuya Kakiuchi, Masahiro Ikuta, Takayuki Hayashi, Toshiki Sato, Takaya Ohashi, Kazuhisa Mitsuda, Kohei Morishita, Kazuo Nakajima

    International Conference on Optical MEMS and Nanophotonics   115 - 116   2013

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    Language：English   Publishing type：Research paper (international conference proceedings)  

    DOI： 10.1109/OMN.2013.6659086

    Scopus

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MISC

  • JEDIミッション(仮称)のサイエンス検討:2030年代の紫外・X線による超新星爆発の即応/待ち受け観測

    内田裕之, 岩切渉, 石崎渉, 内山秀樹, 樫山和巳, 勝田哲, 黄天鋭, 黄天鋭, 佐藤寿紀, 茂山俊和, 鈴木昭宏, 鈴木寛大, 諏訪雄大, 田中周太, 田中孝明, 柘植紀節, 辻直美, 津名大地, 津名大地, 鶴剛, 寺田幸功, 成田拓人, 野田博文, 信川久実子, 信川正順, 馬場彩, 前田啓一, 松永海, 森浩二

    日本天文学会年会講演予稿集   2024   2024

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  • X線による超新星残骸Cassiopeia Aにおける高エントロピー上昇流の発見

    佐藤寿紀, 前田啓一, 長瀧重博, 吉田敬, GREFENSTETTE Brian, WILLIAMS Brian J., 梅田秀之, 小野勝臣, HUGHES John P.

    日本天文学会年会講演予稿集   2021   2021

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  • 高密度な白色矮星を起源とするIa型超新星残骸3C397の重元素分布

    大城勇憲, 大城勇憲, 山口弘悦, 山口弘悦, LEUNG Shing-Chi, 野本憲一, 佐藤寿紀, 田中孝明, 尾近洸行

    日本天文学会年会講演予稿集   2021   2021

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  • 超新星Cassiopeia Aの不完全Si燃焼層での中性子過剰度の推定

    佐藤寿紀, 佐藤寿紀, 佐藤寿紀, 吉田敬, 梅田秀之, 小野勝臣, 長瀧重博, 前田良知, 前田啓一, HUGHES John P., WILLIAMS Brian J.

    日本天文学会年会講演予稿集   2020   2020

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Presentations

  • X線観測によるケプラーの超新星残骸の明るい塊構造の三次元速度測定

    Sato Toshiki

    日本天文学会秋季年会  2017.9 

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    Language：Japanese   Presentation type：Oral presentation (general)  

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  • In-flight Calibration Status of the Soft X-ray Telescopes (SXTs) onboad the Hitomi Satellite International conference

    Toshiki Sato, lf, Hi, omi's, S

    12th IACHEC meeting  2017.3 

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  • カシオペア A の逆行衝撃波の固有運動とスペクトル変動の調査

    Sato Toshiki

    日本天文学会春季年会  2017.3 

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    Language：Japanese   Presentation type：Oral presentation (general)  

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  • Plasma Study of the Cassiopeia A Supernova Remnant International conference

    Sato Toshiki

    Spectroscopy of Cosmic Plasma in the Era of ASTRO-H  2015.8 

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    Language：English   Presentation type：Oral presentation (general)  

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  • Time variation of Cassiopeia A and a new evidence of the variation International conference

    Sato Toshiki

    COSPAR MOSCOW 2014  2014.8 

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Awards

  • 2015 NASA ’s Robert H. Goddard Exceptional Achievement for Science Team

    2015   NASA  

    Sato Toshiki, ASTRO-H SXT

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  • Best poster prize at 5th ASTRO-H Summer School

    2014   ASTRO-H science working group  

    Sato Toshiki

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  • 2014 NASA's Group Achievement Award

    2014   NASA  

    Sato Toshiki, ASTRO-H SXT

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Research Projects

  • 精密X線観測で迫る超新星内部でのニュートリノ相互作用

    Grant number：23K13128  2023.4 - 2026.3

    日本学術振興会  科学研究費助成事業  若手研究

    佐藤 寿紀

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    Grant amount：\4680000 （ Direct Cost: \3600000 、 Indirect Cost：\1080000 ）

    本研究では、超新星残骸観測を用いた「ニュートリノ相互作用」の観測的検証と将来の観測に向けた装置開発を行う。超新星残骸では、超新星爆発時に合成された元素が高階電離した高温プラズマからのX線を観測できる。「ニュートリノ元素合成」で増加する元素は、ニュートリノ相互作用の検証に有用であり、その観測可能性を過去の我々の研究で示した。XRISM 衛星を用いた精密X線観測で、そのニュートリノ元素合成に関わる微小元素を観測し、超新星爆発時のニュートリノ相互作用の検証を行う。また、将来のより高精度観測を目指したX線望遠鏡開発を行う。

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  • Constraint of the Nuclear Burning Condition in the Deep Core of the Massive Star’s Explosion

    2019.9 - 2021.3

    RIKEN 

    Sato Toshiki

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    Authorship：Principal investigator  Grant type：Competitive

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  • 44Ti専用硬X線望遠鏡で明らかにする銀河系内陽電子の起源

    Grant number：19K14749  2019.4 - 2023.3

    日本学術振興会  科学研究費助成事業 若手研究  若手研究

    佐藤 寿紀

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    Authorship：Principal investigator  Grant type：Competitive

    Grant amount：\4160000 （ Direct Cost: \3200000 、 Indirect Cost：\960000 ）

    本研究では、銀河系内陽電子起源の有力候補として考えられているIa型超新星(Double Detonation model)の観測的証拠を掴むための観測機器の開発と観測研究を行なっている。Ia型超新星モデルの中でも、厚いHe外層の核燃焼の衝撃波で白色矮星の爆発を誘発するタイプのIa型超新星では、その外層の核燃焼時に大量の44Tiが合成されると考えられており、その崩壊時に放出される陽電子が我々の銀河内で供給されている可能性がある。つまり、Ia型超新星で44Tiが合成されている現場を捉えられれば、このIa型超新星の陽電子起源の最も強い証拠になる。
    我々は、この44Ti崩壊γ線(68 keV, 78 keV)の観測精度の飛躍的向上のため、ニューハンプシャー大やNASAと協力し、γ線TESカロリメータと硬X線望遠鏡を組み合わせた気球実験計画を進めている。今年度は米国の気球計画にプロポーザルを提出したが、未採択となったため、次回に向け再度提案書を作成している。硬X線望遠鏡の開発に関しては、多層膜研究をNASA/GSFCで開始した。Ni コーティングを可能にするため、新たなスパッタ装置を導入し、現在その立ち上げ作業を行なっており、次の年度から実際に膜付け研究を行う予定である。
    観測研究に関しては、Ia型超新星の残骸(ケプラーの超新星残骸)の膨張速度を Chandra 衛星のグレーティング観測で測定し、その三次元構造に迫った(Matthew et al. 2020, ApJ)。加えて、Ia型超新星の残骸の構造と超新星シミュレーションの構造を直接比較できる手法を開発した(Sato et al. 2019, ApJ)。これらの構造研究の他にも、超新星残骸内の元素組成に着目し、その爆発機構へ迫る研究を行なった(Sato et al. 2020a,b)。

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  • Ia型超新星の爆発機構解明に向けた観測的三次元モデルの構築

    Grant number：18H05865  2018.8 - 2020.3

    日本学術振興会  科学研究費助成事業 研究活動スタート支援  研究活動スタート支援

    佐藤 寿紀

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    Grant amount：\2210000 （ Direct Cost: \1700000 、 Indirect Cost：\510000 ）

    X線を用いた超新星残骸の観測研究に関して二本の共著論文を査読論文として出版し、一本の主著論文と一本の共著論文を査読誌へ投稿した。また、国際学会での口頭発表一件と天文学会年会でのポスター発表一件を行った。
    本研究ではIa型超新星残骸の三次元的構造から、その爆発機構の解明を目指した。特に、今年度は超新星残骸内に存在する塊状構造に着目し、これらがどのようにして形成されたかを議論するため「ジーナス統計」という手法を世界で初めて超新星残骸の観測研究に適応し、Ia型超新星残骸の三次元流体モデルとの比較を行った。結果として、これらの塊構造は爆発初期から存在していた事が示唆され、その形成過程は爆発機構を議論する上でも非常に重要なプロセスである事を指摘できた。本研究内容に関しては、米国 Astrophysical Journal 誌にて、現在査読中である。
    加えて、Ia型超新星残骸内のドップラー偏移に着目した三次元構造の調査に関連する研究も順調に進める事ができた(Kasuga, Sato+19, PASJ & Millard+19, submitted to ApJ)。これらの結果は今後、三次元超新星モデルとの比較により、爆発機構の同定の重要な情報になりうる。
    その他にも、超新星残骸 Cassiopeia A 内で起こる非熱的放射(宇宙線電子からのシンクロトロン放射)の時間変動に関して、多数の塊状の構造内を衝撃波が伝搬する際の、渦状乱流によって解析的に説明できる事を示し、Physical Review Letters 誌に掲載された(Fraschetti, Katsuda, Sato+18)。

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  • ４４Ｔｉの合成量に基づいた対称・非対称な重力崩壊型超新星爆発の元素合成の解明

    Grant number：16J03448  2016.4 - 2018.3

    日本学術振興会  科学研究費助成事業 特別研究員奨励費  特別研究員奨励費

    佐藤 寿紀

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    Authorship：Principal investigator  Grant type：Competitive

    Grant amount：\1300000 （ Direct Cost: \1300000 ）

    本研究の目的は、重力崩壊型超新星の44Tiの合成量を調査することで、爆発モデルに伴う元 素合成過程を明らかにすることであり、その実現のために、実験・観測の両面から研究を行った。本年度の研究成果を以下の3つに分けて記す。
    (I) 2016年に打ち上げられたひとみ衛星の軌道上キャリブレーションと観測研究を行った。ひとみ衛星に搭載された超精密X線分光システムは、Cassiopeia A内の44Tiが崩壊した後の44ScからのX線輝線検出が期待されていた。しかしながら、Cassiopeia A の観測前に運用停止となってしまったため、他の重力崩壊型超新星の残骸である、カニ星雲、G21.5-0.9、N132Dの観測研究を行った。カニ星雲では、爆発噴出物由来の熱的X線放射をこれまでにない精度で上限値を決める事に成功し、その爆発起源の推定を行った。N132Dに関しては、爆発噴出物の鉄が偏った方向に飛び交っている事を初めて示し、爆発の非対称性を議論する事が出来た。観測結果は、査読論文としてPASJから出版された。
    (II) Cassiopeia A は重力崩壊型超新星であり、本研究の鍵を握る44Tiからの崩壊ガンマ線が硬X線観測で発見されている数少ないサンプルである。今年度私は、この天体内の衝撃波で加速された宇宙線電子からの非熱的放射に着目した研究を行った。本研究では逆行する衝撃波に着目し、通常の前進している順行衝撃波よりも、それらの衝撃波速度が早くなっていることを観測的に初めて明らかにした。この結果は、査読論文(主著)として、APJ誌に掲載された。
    (III) Ia型超新星残骸ティコ、ケプラーの膨張速度をドップラー効果を用いる事で測定することに成功し、その三次元的な空間構造に迫る研究を行った。結果として、ティコとケプラーではそれぞれ対称、非対称な膨張であることがわかって来た。これらの研究内容は、それぞれ2本の査読論文(主著)として、APJ誌に掲載された。

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