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  2. 藤本 龍一

藤本 龍一

フジモト リュウイチ  (Ryuichi Fujimoto)

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
東京工業大学 理学院 特定教授
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．

研究キーワード

 6

研究分野

 2

経歴

 8
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学歴

 4

委員歴

 2

受賞

 2

論文

 155

MISC

 129
  • 佐藤浩介, 大橋隆哉, 石崎欣尚, 江副祐一郎, 山田真也, 山崎典子, 満田和久, 石田学, 前田良知, 田原譲, 三石郁之, 藤本龍一, 鶴剛, 太田直美, 大里健, 中島真也
    日本天文学会年会講演予稿集 2018 225 2018年8月20日  
  • Alle, S.W., Aharonian, F., Akamatsu, H., Akimoto, F., Allen, S.W., Angelini, L., Audard, M., Awaki, H., Axelsson, M., Bamba, A., Bautz, M.W., Blandford, R., Brenneman, L.W., Brown, G.V., Bulbul, E., Cackett, E.M., Chernyakova, M., Chiao, M.P., Coppi, P.S., Costantini, E., De Plaa, J., De Vries, C.P., Den Herder, J.-W., Done, C., Dotani, T., Ebisawa, K., Eckart, M.E., Enoto, T., Ezoe, Y., Fabian, A.C., Ferrigno, C., Foster, A.R., Fujimoto, R., Fukazawa, Y., Furuzawa, A., Galeazzi, M., Gallo, L.C., Gandhi, P., Giustini, M., Goldwurm, A., Gu, L., Guainazzi, M., Haba, Y., Hagino, K., Hamaguchi, K., Harrus, I.M., Hatsukade, I., Hayashi, K., Hayashi, T., Hayashida, K., Hiraga, J.S., Hornschemeier, A., Hoshino, A., Hughes, J.P., Ichinohe, Y., Iizuka, R., Inoue, H., Inoue, Y., Ishida, M., Ishikawa, K., Ishisaki, Y., Iwai, M., Kaastra, J., Kallman, T., Kamae, T., Kataoka, J., Katsuda, S., Kawai, N., Kelley, R.L., Kilbourne, C.A., Kitaguchi, T., Kitamoto, S., Kitayama, T., Kohmura, T., Kokubun, M., Koyama, K., Koyama, S., Kretschmar, P., Krimm, H.A., Kubota, A., Kunieda, H., Laurent, P., Lee, S.-H., Leutenegger, M.A., Limousin, O.O., Loewenstein, M., Long, K.S., Lumb, D., Madejski, G., Maeda, Y., Maier, D., Makishima, K., Markevitch, M., Matsumoto, H., Matsushita, K., Mccammon, D., Mcnamara, B.R., Mehdipour, M., Miller, E.D., Miller, J.M., Mineshige, S., Mitsuda, K., Mitsuishi, I., Miyazawa, T., Mizuno, T., Mori, H., Mori, K., Mukai, K., Murakami, H., Mushotzky, R.F., Nakagawa, T., Nakajima, H., Nakamori, T., Nakashima, S., Nakazawa, K., Nobukawa, K.K., Nobukawa, M., Noda, H., Odaka, H., Ohashi, T., Ohno, M., Okajima, T., Ota, N., Ozaki, M., Paerels, F., Paltani, S., Petre, R., Pinto, C., Porter, F.S., Pottschmidt, K., Reynolds, C.S., Safi-Harb, S., Saito, S., Sakai, K., Sasaki, T., Sato, G., Sato, K., Sato, R., Sawada, M., Schartel, N., Serlemtsos, P.J., Seta, H., Shidatsu, M., Simionescu, A., Smith, R.K., Soong, Y., Stawarz, Ł., Sugawara, Y., Sugita, S., Szymkowiak, A., Tajima, H., Takahashi, H., Takahashi, T., Takeda, S., Takei, Y., Tamagawa, T., Tamura, T., Tanaka, T., Tanaka, Y., Tanaka, Y.T., Tashiro, M.S., Tawara, Y., Terada, Y., Terashima, Y., Tombesi, F., Tomida, H., Tsuboi, Y., Tsujimoto, M., Tsunemi, H., Suru, T.G., Uchida, H., Uchiyama, H., Uchiyama, Y., Ueda, S., Ueda, Y., Uno, S., Urry, C.M., Ursino, E., Watanabe, S., Werner, N., Wilkins, D.R., Williams, B.J., Yamada, S., Yamaguchi, H., Yamaoka, K., Yamasaki, N.Y., Yamauchi, M., Yamauchi, S., Yaqoob, T., Yatsu, Y., Yonetoku, D., Zhuravleva, I., Zoghbi, A., Nakaniwa, N.
    Publications of the Astronomical Society of Japan 70(2) 2018年  
    We report a Hitomi observation of IGR J16318-4848, a high-mass X-ray binary<br /> system with an extremely strong absorption of N_H~10^{24} cm^{-2}. Previous<br /> X-ray studies revealed that its spectrum is dominated by strong fluorescence<br /> lines of Fe as well as continuum emission. For physical and geometrical insight<br /> into the nature of the reprocessing material, we utilize the high spectroscopic<br /> resolving power of the X-ray microcalorimeter (the soft X-ray spectrometer;<br /> SXS) and the wide-band sensitivity by the soft and hard X-ray imager (SXI and<br /> HXI) aboard Hitomi. Even though photon counts are limited due to unintended<br /> off-axis pointing, the SXS spectrum resolves Fe K{\alpha_1} and K{\alpha_2}<br /> lines and puts strong constraints on the line centroid and width. The line<br /> width corresponds to the velocity of 160^{+300}_{-70} km s^{-1}. This<br /> represents the most accurate, and smallest, width measurement of this line made<br /> so far from any X-ray binary, much less than the Doppler broadening and shift<br /> expected from speeds which are characteristic of similar systems. Combined with<br /> the K-shell edge energy measured by the SXI and HXI spectra, the ionization<br /> state of Fe is estimated to be in the range of Fe I--IV. Considering the<br /> estimated ionization parameter and the distance between the X-ray source and<br /> the absorber, the density and thickness of the materials are estimated. The<br /> extraordinarily strong absorption and the absence of a Compton shoulder<br /> component is confirmed. These characteristics suggest reprocessing materials<br /> which are distributed in a narrow solid angle or scattering primarily with warm<br /> free electrons or neutral hydrogen.
  • Aharonian, F., Akamatsu, H., Akimoto, F., Allen, S.W., Angelini, L., Audard, M., Awaki, H., Axelsson, M., Bamba, A., Bautz, M.W., Blandford, R., Brenneman, L.W., Brown, G.V., Bulbul, E., Cackett, E.M., Chernyakova, M., Chiao, M.P., Coppi, P.S., Costantini, E., De Plaa, J., De Vries, C.P., Den Herder, J.-W., Done, C., Dotani, T., Ebisawa, K., Eckart, M.E., Enoto, T., Ezoe, Y., Fabian, A.C., Ferrigno, C., Foster, A.R., Fujimoto, R., Fukazawa, Y., Furuzawa, A., Galeazzi, M., Gallo, L.C., Gandhi, P., Giustini, M., Goldwurm, A., Gu, L., Guainazzi, M., Haba, Y., Hagino, K., Hamaguchi, K., Harrus, I.M., Hatsukade, I., Hayashi, K., Hayashi, T., Hayashida, K., Hiraga, J.S., Hornschemeier, A., Hoshino, A., Hughes, J.P., Ichinohe, Y., Iizuka, R., Inoue, H., Inoue, Y., Ishida, M., Ishikawa, K., Ishisaki, Y., Iwai, M., Kaastra, J., Kallman, T., Kamae, T., Kataoka, J., Katsuda, S., Kawai, N., Kelley, R.L., Kilbourne, C.A., Kitaguchi, T., Kitamoto, S., Kitayama, T., Kohmura, T., Kokubun, M., Koyama, K., Koyama, S., Kretschmar, P., Krimm, H.A., Kubota, A., Kunieda, H., Laurent, P., Lee, S.-H., Leutenegger, M.A., Limousin, O., Loewenstein, M., Long, K.S., Lumb, D., Madejski, G., Maeda, Y., Maier, D., Makishima, K., Markevitch, M., Matsumoto, H., Matsushita, K., McCammon, D., McNamara, B.R., Mehdipour, M., Miller, E.D., Miller, J.M., Mineshige, S., Mitsuda, K., Mitsuishi, I., Miyazawa, T., Mizuno, T., Mori, H., Mori, K., Mukai, K., Murakami, H., Mushotzky, R.F., Nakagawa, T., Nakajima, H., Nakamori, T., Nakashima, S., Nakazawa, K., Nobukawa, K.K., Nobukawa, M., Noda, H., Odaka, H., Ohashi, T., Ohno, M., Okajima, T., Ota, N., Ozaki, M., Paerels, F., Paltani, S., Petre, R., Pinto, C., Porter, F.S., Pottschmidt, K., Reynolds, C.S., Safi-Harb, S., Saito, S., Sakai, K., Sasaki, T., Sato, G., Sato, K., Sato, R., Sawada, M., Schartel, N., Serlemtsos, P.J., Seta, H., Shidatsu, M., Simionescu, A., Smith, R.K., Soong, Y., Stawarz, L., Sugawara, Y., Sugita, S., Szymkowiak, A., Tajima, H., Takahashi, H., Takahashi, T., Takeda, S., Takei, Y., Tamagawa, T., Tamura, T., Tanaka, T., Tanaka, Y., Tanaka, Y.T., Tashiro, M.S., Tawara, Y., Terada, Y., Terashima, Y., Tombesi, F., Tomida, H., Tsuboi, Y., Tsujimoto, M., Tsunemi, H., Tsuru, T.G., Uchida, H., Uchiyama, H., Uchiyama, Y., Ueda, S., Ueda, Y., Uno, S., Urry, C.M., Ursino, E., Watanabe, S., Werner, N., Wilkins, D.R., Williams, B.J., Yamada, S., Yamaguchi, H., Yamaoka, K., Yamasaki, N.Y., Yamauchi, M., Yamauchi, S., Yaqoob, T., Yatsu, Y., Yonetoku, D., Zhuravleva, I., Zoghbi, A., Uchida, Y.
    Publications of the Astronomical Society of Japan 70(6) 2018年  
    We present the results from the Hitomi Soft Gamma-ray Detector (SGD)<br /> observation of the Crab nebula. The main part of SGD is a Compton camera, which<br /> in addition to being a spectrometer, is capable of measuring polarization of<br /> gamma-ray photons. The Crab nebula is one of the brightest X-ray / gamma-ray<br /> sources on the sky, and, the only source from which polarized X-ray photons<br /> have been detected. SGD observed the Crab nebula during the initial test<br /> observation phase of Hitomi. We performed the data analysis of the SGD<br /> observation, the SGD background estimation and the SGD Monte Carlo simulations,<br /> and, successfully detected polarized gamma-ray emission from the Crab nebula<br /> with only about 5 ks exposure time. The obtained polarization fraction of the<br /> phase-integrated Crab emission (sum of pulsar and nebula emissions) is (22.1<br /> $\pm$ 10.6)% and, the polarization angle is 110.7$^o$ + 13.2 / $-$13.0$^o$ in<br /> the energy range of 60--160 keV (The errors correspond to the 1 sigma<br /> deviation). The confidence level of the polarization detection was 99.3%. The<br /> polarization angle measured by SGD is about one sigma deviation with the<br /> projected spin axis of the pulsar, 124.0$^o$ $\pm$0.1$^o$.
  • Aharonian, F., Akamatsu, H., Akimoto, F., Allen, S.W., Angelini, L., Audard, M., Awaki, H., Axelsson, M., Bamba, A., Bautz, M.W., Blandford, R., Brenneman, L.W., Brown, G.V., Bulbul, E., Cackett, E.M., Chernyakova, M., Chiao, M.P., Coppi, P.S., Costantini, E., De Plaa, J., De Vries, C.P., Den Herder, J.-W., Done, C., Dotani, T., Ebisawa, K., Eckart, M.E., Enoto, T., Ezoe, Y., Fabian, A.C., Ferrigno, C., Foster, A.R., Fujimoto, R., Fukazawa, Y., Furukawa, M., Furuzawa, A., Galeazzi, M., Gallo, L.C., Gandhi, P., Giustini, M., Goldwurm, A., Gu, L., Guainazzi, M., Haba, Y., Hagino, K., Hamaguchi, K., Harrus, I.M., Hatsukade, I., Hayashi, K., Hayashi, T., Hayashida, K., Hiraga, J.S., Hornschemeier, A., Hoshino, A., Hughes, J.P., Ichinohe, Y., Iizuka, R., Inoue, H., Inoue, Y., Ishida, M., Ishikawa, K., Ishisaki, Y., Iwai, M., Kaastra, J., Kallman, T., Kamae, T., Kataoka, J., Kato, Y., Katsuda, S., Kawai, N., Kelley, R.L., Kilbourne, C.A., Kitaguchi, T., Kitamoto, S., Kitayama, T., Kohmura, T., Kokubun, M., Koyama, K., Koyama, S., Kretschmar, P., Krimm, H.A., Kubota, A., Kunieda, H., Laurent, P., Lee, S.-H., Leutenegger, M.A., Limousin, O., Loewenstein, M., Long, K.S., Lumb, D., Madejski, G., Maeda, Y., Maier, D., Makishima, K., Markevitch, M., Matsumoto, H., Matsushita, K., McCammon, D., McNamara, B.R., Mehdipour, M., Miller, E.D., Miller, J.M., Mineshige, S., Mitsuda, K., Mitsuishi, I., Miyazawa, T., Mizuno, T., Mori, H., Mori, K., Mukai, K., Murakami, H., Mushotzky, R.F., Nakagawa, T., Nakajima, H., Nakamori, T., Nakashima, S., Nakazawa, K., Nobukawa, K.K., Nobukawa, M., Noda, H., Odaka, H., Ohashi, T., Ohno, M., Okajima, T., Ota, N., Ozaki, M., Paerels, F., Paltani, S., Petre, R., Pinto, C., Porter, F.S., Pottschmidt, K., Reynolds, C.S., Safi-Harb, S., Saito, S., Sakai, K., Sasaki, T., Sato, G., Sato, K., Sato, R., Sawada, M., Schartel, N., Serlemtsos, P.J., Seta, H., Shidatsu, M., Simionescu, A., Smith, R.K., Soong, Y., Stawarz, Ł., Sugawara, Y., Sugita, S., Szymkowiak, A., Tajima, H., Takahashi, H., Takahashi, T., Takeda, S., Takei, Y., Tamagawa, T., Tamura, T., Tanaka, T., Tanaka, Y., Tanaka, Y.T., Tashiro, M.S., Tawara, Y., Terada, Y., Terashima, Y., Tombesi, F., Tomida, H., Tsuboi, Y., Tsujimoto, M., Tsunemi, H., Tsuru, T.G., Uchida, H., Uchiyama, H., Uchiyama, Y., Ueda, S., Ueda, Y., Uno, S., Urry, C.M., Ursino, E., Watanabe, S., Werner, N., Wilkins, D.R., Williams, B.J., Yamada, S., Yamaguchi, H., Yamaoka, K., Yamasaki, N.Y., Yamauchi, M., Yamauchi, S., Yaqoob, T., Yatsu, Y., Yonetoku, D., Zhuravleva, I., Zoghbi, A.
    Publications of the Astronomical Society of Japan 70(2) 2018年  
    The present paper investigates the temperature structure of the X-ray<br /> emitting plasma in the core of the Perseus cluster using the 1.8--20.0 keV data<br /> obtained with the Soft X-ray Spectrometer (SXS) onboard the Hitomi Observatory.<br /> A series of four observations were carried out, with a total effective exposure<br /> time of 338 ks and covering a central region $\sim7&#039;$ in diameter. The SXS was<br /> operated with an energy resolution of $\sim$5 eV (full width at half maximum)<br /> at 5.9 keV. Not only fine structures of K-shell lines in He-like ions but also<br /> transitions from higher principal quantum numbers are clearly resolved from Si<br /> through Fe. This enables us to perform temperature diagnostics using the line<br /> ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of<br /> the excitation temperature and ionization temperature in the Perseus cluster.<br /> The observed spectrum is roughly reproduced by a single temperature thermal<br /> plasma model in collisional ionization equilibrium, but detailed line ratio<br /> diagnostics reveal slight deviations from this approximation. In particular,<br /> the data exhibit an apparent trend of increasing ionization temperature with<br /> increasing atomic mass, as well as small differences between the ionization and<br /> excitation temperatures for Fe, the only element for which both temperatures<br /> can be measured. The best-fit two-temperature models suggest a combination of 3<br /> and 5 keV gas, which is consistent with the idea that the observed small<br /> deviations from a single temperature approximation are due to the effects of<br /> projection of the known radial temperature gradient in the cluster core along<br /> the line of sight. Comparison with the Chandra/ACIS and the XMM-Newton/RGS<br /> results on the other hand suggests that additional lower-temperature components<br /> are present in the ICM but not detectable by Hitomi SXS given its 1.8--20 keV<br /> energy band.
  • Aharonian, F., Akamatsu, H., Akimoto, F., Allen, S.W., Angelini, L., Audard, M., Awaki, H., Axelsson, M., Bamba, A., Bautz, M.W., Blandford, R., Brenneman, L.W., Brown, G.V., Bulbul, E., Cackett, E.M., Chernyakova, M., Chiao, M.P., Coppi, P.S., Costantini, E., De Plaa, J., De Vries, C.P., Den Herder, J.-W., Done, C., Dotani, T., Ebisawa, K., Eckart, M.E., Enoto, T., Ezoe, Y., Fabian, A.C., Ferrigno, C., Foster, A.R., Fujimoto, R., Fukazawa, Y., Furuzawa, A., Galeazzi, M., Gallo, L.C., Gandhi, P., Giustini, M., Goldwurm, A., Gu, L., Guainazzi, M., Haba, Y., Hagino, K., Hamaguchi, K., Harrus, I.M., Hatsukade, I., Hayashi, K., Hayashi, T., Hayashida, K., Hell, N., Hiraga, J.S., Hornschemeier, A., Hoshino, A., Hughes, J.P., Ichinohe, Y., Iizuka, R., Inoue, H., Inoue, Y., Ishida, M., Ishikawa, K., Ishisaki, Y., Iwai, M., Kaastra, J., Kallman, T., Kamae, T., Kataoka, J., Katsuda, S., Kawai, N., Kelley, R.L., Kilbourne, C.A., Kitaguchi, T., Kitamoto, S., Kitayama, T., Kohmura, T., Kokubun, M., Koyama, K., Koyama, S., Kretschmar, P., Krimm, H.A., Kubota, A., Kunieda, H., Laurent, P., Lee, S.-H., Leutenegger, M.A., Limousin, O., Loewenstein, M., Long, K.S., Lumb, D., Madejski, G., Maeda, Y., Maier, D., Makishima, K., Markevitch, M., Matsumoto, H., Matsushita, K., McCammon, D., McNamara, B.R., Mehdipour, M., Miller, E.D., Miller, J.M., Mineshige, S., Mitsuda, K., Mitsuishi, I., Miyazawa, T., Mizuno, T., Mori, H., Mori, K., Mukai, K., Murakami, H., Mushotzky, R.F., Nakagawa, T., Nakajima, H., Nakamori, T., Nakashima, S., Nakazawa, K., Nobukawa, K.K., Nobukawa, M., Noda, H., Odaka, H., Ohashi, T., Ohno, M., Okajima, T., Ota, N., Ozaki, M., Paerels, F., Paltani, S., Petre, R., Pinto, C., Porter, F.S., Pottschmidt, K., Reynolds, C.S., Safi-Harb, S., Saito, S., Sakai, K., Sasaki, T., Sato, G., Sato, K., Sato, R., Sawada, M., Schartel, N., Serlemtsos, P.J., Seta, H., Shidatsu, M., Simionescu, A., Smith, R.K., Soong, Y., Stawarz, Ł., Sugawara, Y., Sugita, S., Szymkowiak, A., Tajima, H., Takahashi, H., Takahashi, T., Takeda, S., Takei, Y., Tamagawa, T., Tamura, T., Tanaka, T., Tanaka, Y., Tanaka, Y.T., Tashiro, M.S., Tawara, Y., Terada, Y., Terashima, Y., Tombesi, F., Tomida, H., Tsuboi, Y., Tsujimoto, M., Tsunemi, H., Tsuru, T.G., Uchida, H., Uchiyama, H., Uchiyama, Y., Ueda, S., Ueda, Y., Uno, S., Urry, C.M., Ursino, E., Watanabe, S., Werner, N., Wilkins, D.R., Williams, B.J., Yamada, S., Yamaguchi, H., Yamaoka, K., Yamasaki, N.Y., Yamauchi, M., Yamauchi, S., Yaqoob, T., Yatsu, Y., Yonetoku, D., Zhuravleva, I., Zoghbi, A., Raassen, A.J.J.
    Publications of the Astronomical Society of Japan 70(2) 2018年  
    The Hitomi SXS spectrum of the Perseus cluster, with $\sim$5 eV resolution in<br /> the 2-9 keV band, offers an unprecedented benchmark of the atomic modeling and<br /> database for hot collisional plasmas. It reveals both successes and challenges<br /> of the current atomic codes. The latest versions of AtomDB/APEC (3.0.8), SPEX<br /> (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band<br /> spectrum, and are in close agreement on best-fit temperature, emission measure,<br /> and abundances of a few elements such as Ni. For the Fe abundance, the APEC and<br /> SPEX measurements differ by 16%, which is 17 times higher than the statistical<br /> uncertainty. This is mostly attributed to the differences in adopted<br /> collisional excitation and dielectronic recombination rates of the strongest<br /> emission lines. We further investigate and compare the sensitivity of the<br /> derived physical parameters to the astrophysical source modeling and<br /> instrumental effects. The Hitomi results show that an accurate atomic code is<br /> as important as the astrophysical modeling and instrumental calibration<br /> aspects. Substantial updates of atomic databases and targeted laboratory<br /> measurements are needed to get the current codes ready for the data from the<br /> next Hitomi-level mission.
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