宇宙物理学研究系

鈴木 寛大

スズキ ヒロマサ  (Hiromasa Suzuki)

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 特任助教

連絡先
hiromasa050701gmail.com
研究者番号
50915402
ORCID ID
 https://orcid.org/0000-0002-8152-6172
J-GLOBAL ID
202301003397839297
researchmap会員ID
R000055343

外部リンク

高エネルギー宇宙、特に宇宙線(宇宙の放射線)、超新星が生む高温プラズマ、中性子星などの観測をしています。そのための装置開発も行います。


委員歴

 2

論文

 52
  • Hirofumi Noda, Mio Aoyagi, Koji Mori, Hiroshi Tomida, Hiroshi Nakajima, Takaaki Tanaka, Hiromasa Suzuki, Hiroshi Murakami, Hiroyuki Uchida, Takeshi Go Tsuru, Keitaro Miyazaki, Kohei Kusunoki, Yoshiaki Kanemaru, Yuma Aoki, Kumiko K. Nobukawa, Masayoshi Nobukawa, Kohei Shima, Marina Yoshimoto, Kazunori Asakura, Hironori Matsumoto, Tomokage Yoneyama, Shogo B. Kobayashi, Kouichi Hagino, Hideki Uchiyama, Kiyoshi Hayashida
    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray 226-226 2024年8月21日  
  • Keisuke Tamura, Takayuki Hayashi, Rozenn Boissay-Malaquin, Takashi Okajima, Toshiki Sato, Megan E. Eckart, Maurice A. Leutenegger, Tahir Yaqoob, Koji Mori, Manabu Ishida, Yoshitomo Maeda, Hiroshi Tomida, Hiroshi Nakajima, Hirofumi Noda, Hiroyuki Uchida, Hiromasa Suzuki, Shogo B. Kobayashi, Tomokage Yoneyama, Kouichi Hagino, Kumiko K. Nobukawa, Takaaki Tanaka, Hiroshi Murakami, Hideki Uchiyama, Masayoshi Nobukawa, Tessei Yoshida, Hironori Matsumoto, Takeshi Go Tsuru, Makoto Yamauchi, Isamu Hatsukade, Hirokazu Odaka, Takayoshi Kohmura, Kazutaka Yamaoka, Yoshiaki Kanemaru, Junko S. Hiraga, Tadayasu Dotani, Masanobu Ozaki, Hiroshi Tsunemi, Keitaro Miyazaki, Kohei Kusunoki, Yoshinori Otsuka, Haruhiko Yokosu, Wakana Yonematsu, Kazuhiro Ichikawa, Hanako Nakano, Reo Takemoto, Tsukasa Matsushima, Yoh Asahina, Masahiro Fukuda, Marina Yoshimoto, Kohei Shima, Mio Aoyagi, Yuma Aoki, Yamato Ito, Daiki Aoki, Kaito Fujisawa, Yasuyuki Shimizu, Mayu Higuchi, Kiyoshi Hayashida, Aurora Simionescud, Eric Miller, Laura Brenneman
    Space Telescopes and Instrumentation 2024: Ultraviolet to Gamma Ray 59-59 2024年8月21日  
  • Takatoshi Ko, Hiromasa Suzuki, Kazumi Kashiyama, Hiroyuki Uchida, Takaaki Tanaka, Daichi Tsuna, Kotaro Fujisawa, Aya Bamba, Toshikazu Shigeyama
    The Astrophysical Journal 2024年7月1日  
  • Hiroumi Matsuhashi, Kouichi Hagino, Aya Bamba, Ayaki Takeda, Masataka Yukumoto, Koji Mori, Yusuke Nishioka, Takeshi Go Tsuru, Mizuki Uenomachi, Tomonori Ikeda, Masamune Matsuda, Takuto Narita, Hiromasa Suzuki, Takaaki Tanaka, Ikuo Kurachi, Takayoshi Kohmura, Yusuke Uchida, Yasuo Arai, Shoji Kawahito
    Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment 1064 169426-169426 2024年7月  
  • F. Aharonian, F. Ait Benkhali, J. Aschersleben, H. Ashkar, M. Backes, A. Baktash, V. Barbosa Martins, J. Barnard, R. Batzofin, Y. Becherini, D. Berge, K. Bernlöhr, B. Bi, M. Böttcher, C. Boisson, J. Bolmont, M. de Bony de Lavergne, J. Borowska, F. Bradascio, M. Breuhaus, R. Brose, A. Brown, F. Brun, B. Bruno, T. Bulik, C. Burger-Scheidlin, T. Bylund, S. Caroff, S. Casanova, R. Cecil, J. Celic, M. Cerruti, T. Chand, S. Chandra, A. Chen, J. Chibueze, O. Chibueze, G. Cotter, J. Damascene Mbarubucyeye, I. D. Davids, J. Djuvsland, A. Dmytriiev, V. Doroshenko, K. Egberts, S. Einecke, J. P. Ernenwein, G. Fontaine, M. Füßling, S. Funk, S. Gabici, S. Ghafourizadeh, G. Giavitto, D. Glawion, J. F. Glicenstein, J. Glombitza, P. Goswami, G. Grolleron, L. Haerer, J. A. Hinton, T. L. Holch, M. Holler, D. Horns, M. Jamrozy, F. Jankowsky, V. Joshi, I. Jung-Richardt, E. Kasai, K. Katarzyński, R. Khatoon, B. Khélifi, W. Kluźniak, N. Komin, K. Kosack, D. Kostunin, R. G. Lang, S. Le Stum, F. Leitl, A. Lemière, J. P. Lenain, F. Leuschner, A. Luashvili, J. Mackey, R. Marx, A. Mehta, M. Meyer, A. Mitchell, R. Moderski, A. Montanari, E. Moulin, M. de Naurois, J. Niemiec, P. O’Brien, S. Ohm, L. Olivera-Nieto, E. de Ona Wilhelmi, M. Ostrowski, S. Panny, R. D. Parsons, S. Pita, D. A. Prokhorov
    Astronomy and Astrophysics 683 2024年3月1日  
    Most γ-ray detected active galactic nuclei are blazars with one of their relativistic jets pointing towards the Earth. Only a few objects belong to the class of radio galaxies or misaligned blazars. Here, we investigate the nature of the object PKS 0625−354, its γ-ray flux and spectral variability and its broad-band spectral emission with observations from H.E.S.S., Fermi-LAT, Swift-XRT, and UVOT taken in November 2018. The H.E.S.S. light curve above 200 GeV shows an outburst in the first night of observations followed by a declining flux with a halving time scale of 5.9 h. The γγ-opacity constrains the upper limit of the angle between the jet and the line of sight to ∼10◦. The broad-band spectral energy distribution shows two humps and can be well fitted with a single-zone synchrotron self Compton emission model. We conclude that PKS 0625−354, as an object showing clear features of both blazars and radio galaxies, can be classified as an intermediate active galactic nuclei. Multi-wavelength studies of such intermediate objects exhibiting features of both blazars and radio galaxies are sparse but crucial for the understanding of the broad-band emission of γ-ray detected active galactic nuclei in general.

MISC

 100
  • XRISM Collaboration
    2024年8月26日  
    We present an initial analysis of the XRISM first-light observation of the supernova remnant (SNR) N132D 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$^{-1}$. The Fe He$\alpha$ lines are, on the other hand, 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 $-1000 \lesssim V_{\rm rs}~[{\rm km s}^{-1}] \lesssim 3300$ (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 N132D. These results demonstrate that high-resolution X-ray spectroscopy is capable of providing constraints on the evolutionary stage, geometry, and velocity distribution of SNRs.
  • XRISM Collaboration
    2024年8月26日  
    We present an analysis of the first two XRISM/Resolve spectra of the well-known Seyfert-1.5 active galactic nucleus in NGC 4151, obtained in December 2023. Our work focuses on the nature of the narrow Fe K$_{\alpha}$ emission line at 6.4 keV, the strongest and most common X-ray line observed in AGN. The total line is found to consist of three components. Even the narrowest component of the line is resolved with evident Fe K$_{\alpha,1}$ (6.404 keV) and K$_{\alpha,2}$ (6.391 keV) contributions in a 2:1 flux ratio, fully consistent with neutral gas with negligible bulk velocity. Subject to the limitations of our models, the narrowest and intermediate-width components are consistent with emission from optically thin gas, suggesting that they arise in a disk atmosphere and/or wind. Modeling the three line components in terms of Keplerian broadening, they are readily associated with (1) the inner wall of the ``torus,'' (2) the innermost optical ``broad line region'' (or, ``X-ray BLR''), and (3) a region with a radius of $r\simeq 100~GM/c^{2}$ that may signal a warp in the accretion disk. Viable alternative explanations of the broadest component include a fast wind component and/or scattering; however, we find evidence of variability in the narrow Fe K$_{\alpha}$ line complex on time scales consistent with small radii. The best-fit models are statistically superior to simple Voigt functions, but when fit with Voigt profiles the time-averaged lines are consistent with a projected velocity broadening of FWHM$=1600^{+400}_{-200}~{\rm km}~{\rm s}^{-1}$. Overall, the resolution and sensitivity of XRISM show that the narrow Fe K line in AGN is an effective probe of all key parts of the accretion flow, as it is currently understood. We discuss the implications of these findings for our understanding of AGN accretion, future studies with XRISM, and X-ray-based black hole mass measurements.
  • Koji Mori, Hiroshi Tomida, Hiroshi Nakajima, Takashi Okajima, Hirofumi Noda, Hiroyuki Uchida, Hiromasa Suzuki, Shogo Benjamin Kobayashi, Tomokage Yoneyama, Kouichi Hagino, Kumiko Nobukawa, Takaaki Tanaka, Hiroshi Murakami, Hideki Uchiyama, Masayoshi Nobukawa, Hironori Matsumoto, Takeshi Tsuru, Makoto Yamauchi, Isamu Hatsukade, Hirokazu Odaka, Takayoshi Kohmura, Kazutaka Yamaoka, Manabu Ishida, Yoshitomo Maeda, Takayuki Hayashi, Keisuke Tamura, Rozenn Boissay-Malaquin, Toshiki Sato, Tessei Yoshida, Yoshiaki Kanemaru, Junko Hiraga, Tadayasu Dotani, Masanobu Ozaki, Hiroshi Tsunemi, Shun Inoue, Ryuishi Azuma, Yuma Aoki, Yoh Asahina, Shotaro Nakamura, Takamitsu Kamei, Masahiro Fukuda, Kazunori Asakura, Marina Yoshimoto, Yuichi Ode, Tomohiro Hakamata, Mio Aoyagi, Kohei shima, Yuma Aoki, Yamato Ito, Daiki Aoki, Kaito Fujisawa, Yasuyuki Shimizu, Mayu Higuchi, Keitaro Miyazaki, Kohei Kusunoki, Yoshinori Otsuka, Haruhiko Yokosu, Wakana Yonemaru, Kazuhiro Ichikawa, Hanako Nakano, Reo takemoto, Tsukasa Matsushima, Kiyoshi Hayashida
    2024年6月28日  
    Xtend is one of the two telescopes onboard the X-ray imaging and spectroscopy mission (XRISM), which was launched on September 7th, 2023. Xtend comprises the Soft X-ray Imager (SXI), an X-ray CCD camera, and the X-ray Mirror Assembly (XMA), a thin-foil-nested conically approximated Wolter-I optics. A large field of view of $38^{\prime}\times38^{\prime}$ over the energy range from 0.4 to 13 keV is realized by the combination of the SXI and XMA with a focal length of 5.6 m. The SXI employs four P-channel, back-illuminated type CCDs with a thick depletion layer of 200 $\mu$m. The four CCD chips are arranged in a 2$\times$2 grid and cooled down to $-110$ $^{\circ}$C with a single-stage Stirling cooler. Before the launch of XRISM, we conducted a month-long spacecraft thermal vacuum test. The performance verification of the SXI was successfully carried out in a course of multiple thermal cycles of the spacecraft. About a month after the launch of XRISM, the SXI was carefully activated and the soundness of its functionality was checked by a step-by-step process. Commissioning observations followed the initial operation. We here present pre- and post-launch results verifying the Xtend performance. All the in-orbit performances are consistent with those measured on ground and satisfy the mission requirement. Extensive calibration studies are ongoing.
  • Hiromasa Suzuki, Tomokage Yoneyama, Shogo B. Kobayashi, Hirofumi Noda, Hiroyuki Uchida, Kumiko K. Nobukawa, Kouichi Hagino, Koji Mori, Hiroshi Tomida, Hiroshi Nakajima, Takaaki Tanaka, Hiroshi Murakami, Hideki Uchiyama, Masayoshi Nobukawa, Yoshiaki Kanemaru, Yoshinori Otsuka, Haruhiko Yokosu, Wakana Yonemaru, Hanako Nakano, Kazuhiro Ichikawa, Reo Takemoto, Tsukasa Matsushima, Marina Yoshimoto, Mio Aoyagi, Kohei Shima, Yuma Aoki, Yamato Ito, Kaito Fukuda, Honoka Kiyama, Daiki Aoki, Kaito Fujisawa, Yasuyuki Shimizu, Mayu Higuchi, Masahiro Fukuda, Natsuki Sakamoto, Ryuichi Azuma, Shun Inoue, Takayoshi Kohmura, Makoto Yamauchi, Isamu Hatsukade, Hironori Matsumoto, Hirokazu Odaka, Tsunefumi Mizuno, Tessei Yoshida, Yoshitomo Maeda, Manabu Ishida, Takeshi G. Tsuru, Kazutaka Yamaoka, Takashi Okajima, Takayuki Hayashi, Junko S. Hiraga, Masanobu Ozaki, Tadayasu Dotani, Hiroshi Tsunemi, Kiyoshi Hayashida
    2024年6月28日  
    XRISM (X-Ray Imaging and Spectroscopy Mission) is an astronomical satellite with the capability of high-resolution spectroscopy with the X-ray microcalorimeter, Resolve, and wide field-of-view imaging with the CCD camera, Xtend. The Xtend consists of the mirror assembly (XMA: X-ray Mirror Assembly) and detector (SXI: Soft X-ray Imager). The components of SXI include CCDs, analog and digital electronics, and a mechanical cooler. After the successful launch on September 6th, 2023 (UT) and subsequent critical operations, the mission instruments were turned on and set up. The CCDs have been kept at the designed operating temperature of $-110^\circ$C ~after the electronics and cooling system were successfully set up. During the initial operation phase, which continued for more than a month after the critical operations, we verified the observation procedure, stability of the cooling system, all the observation options with different imaging areas and/or timing resolutions, and operations for protection against South Atlantic Anomaly. We optimized the operation procedure and observation parameters including the cooler settings, imaging areas for the specific modes with higher timing resolutions, and event selection algorithm. We summarize our policy and procedure of the initial operations for SXI. We also report on a couple of issues we faced during the initial operations and lessons learned from them.
  • Masahiro Ichihashi, Aya Bamba, Yuichi Kato, Satoru Katsuda, Hiromasa Suzuki, Tomoaki Kasuga, Hirokazu Odaka, Kazuhiro Nakazawa
    2024年5月15日  
    Heating of charged particles via collisionless shocks, while ubiquitous in the universe, is an intriguing yet puzzling plasma phenomenon. One outstanding question is how electrons and ions approach an equilibrium after they were heated to different immediate-postshock temperatures. In order to fill the significant lack of observational information of the downstream temperature-relaxation process, we observe a thermal-dominant X-ray filament in the northwest of SN~1006 with Chandra. We divide this region into four layers with a thickness of 15$^{\prime\prime}$ or 0.16 pc each, and fit each spectrum by a non-equilibrium ionization collisional plasma model. The electron temperature was found to increase toward downstream from 0.52-0.62 keV to 0.82-0.95 keV on a length scale of 60 arcsec (or 0.64 pc). This electron temperature is lower than thermal relaxation processes via Coulomb scattering, requiring some other effects such as plasma mixture due to turbulence and/or projection effects, etc, which we hope will be resolved with future X-ray calorimeter missions such as XRISM and Athena.

担当経験のある科目(授業)

 2

所属学協会

 4

共同研究・競争的資金等の研究課題

 4