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  2. 海老沢 研

海老沢 研

Ken Ebisawa

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
J-GLOBAL ID
201801002962836691
researchmap会員ID
B000323419
外部リンク

主にX線天文学の研究をやっています。X線天体のフォローアップとして、地上赤外線観測、電波観測もやってます。ブラックホール、中性子星、白色矮星、AGN、銀河面からのX線放射などに興味を持っています。

宇宙航空研究開発機構（JAXA）・宇宙科学研究所（ISAS）にて、MAXI、XRISMを始めとする天文衛星のデータ処理・解析システムの開発、宇宙科学データアーカイブDARTSの運用を行っています。DARTSにおける全天多波長早見システムJUDO2を開発しました。また、「あかり」のアーカイブデータと他の衛星データを組み合わせ、LiteBIRDなどによる将来の宇宙論精密観測に必要な、銀河系内の赤外線前景放射モデルの作成に取り組んでいます。

 
 

研究キーワード

 2

研究分野

 1

経歴

 4

学歴

 2

委員歴

 4

論文

 291
  • Yutaro Nagai, Teruaki Enoto, Masahiro Tsujimoto, Hiroya Yamaguchi, Yuto Mochizuki, Ehud Behar, Lia Corrales, Paul A Draghis, Ken Ebisawa, Natalie Hell, Timothy R Kallman, Richard L Kelley, Pragati Pradhan, Shinya Yamada, Toshiyuki Azuma, Xiao-Min Tong
    Publications of the Astronomical Society of Japan 2026年3月6日  
  • O Adriani, Y Akaike, K Asano, Y Asaoka, E Berti, P Betti, G Bigongiari, W R Binns, L W Blum, M Bongi, P Brogi, A Bruno, N Cannady, G Castellini, C Checchia, M L Cherry, G Collazuol, G A de Nolfo, K Ebisawa, A W Ficklin, H Fuke, S Gonzi, T G Guzik, T Hams, K Hibino, M Ichimura, M H Israel, K Kasahara, J Kataoka, R Kataoka, Y Katayose, C Kato, Y Kato, N Kawanaka, Y Kawakubo, K Kobayashi, K Kohri, H S Krawczynski, J F Krizmanic, P Maestro, P S Marrocchesi, M Mattiazzi, A M Messineo, J W Mitchell, S Miyake, A A Moiseev, M Mori, N Mori, H M Motz, K Munakata, S Nakahira, M Negro, J Nishimura, S Okuno, J F Ormes, S Ozawa, L Pacini, P Papini, A Picquenot, B F Rauch, S B Ricciarini, K Sakai, T Sakamoto, M Sasaki, Y Shimizu, A Shiomi, P Spillantini, F Stolzi, S Sugita, M Takita, T Tamura, M Teramoto, T Terasawa, S Torii, Y Tsunesada, Y Uchihori, E Vannuccini, J P Wefel, K Yamaoka, S Yanagita, A Yoshida, K Yoshida, W V Zober
    Progress of Theoretical and Experimental Physics 2026(3) 033F01 2026年2月17日  査読有り
    Abstract The 11-yr variation of galactic cosmic-ray flux lags behind the variation of the sunspot number. An average $\sim$1-yr time-lag is expected from the outward propagating solar wind with the frozen-in photospheric magnetic field varying in the solar cycle, and from the inward diffusive transport of cosmic-ray particles. The long-term neutron monitor data, however, show that the time-lag is significantly longer (shorter) in the odd (even) solar cycle. In this paper, we analyze the time-lag in proton and electron fluxes observed by the Calorimetric Electron Telescope (CALET). It is found that the time-lag is similar in proton and electron fluxes during an $A > 0$ polarity epoch of the solar dipole magnetic field. In an even solar cycle 24 including a polarity reversal from $A < 0$ to $A > 0$, on the other hand, it is found that the time-lag of proton (electron) flux variation is significantly shorter (longer) than the average $\sim$1-yr lag by analyzing the combined data with CALET and AMS-02. This is the first observation of the charge-sign dependent time-lag. We demonstrate that these observations can be qualitatively interpreted in terms of different 11-yr time profiles of proton and electron fluxes in $A > 0$ and $A < 0$ epochs expected from the drift effect.
  • 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, Satoshi Eguchi, Teruaki Enoto, 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, Daiki Ishi, 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 Ogorzałek, 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, Takaaki Tanaka, Atsushi Tanimoto, Makoto Tashiro, Yukikatsu Terada, Yuichi Terashima, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi Tsuru, Ayşegül Tümer, Hiroyuki Uchida, Nagomi Uchida, Yuusuke Uchida, Hideki Uchiyama, Shutaro Ueda, Yoshihiro Ueda, Shinichiro Uno, Jacco Vink, Shin Watanabe, Brian J. Williams, Satoshi Yamada, Shinya Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Tomokage Yoneyama, Tessei Yoshida, Mihoko Yukita, Irina Zhuravleva, Matthew Charbonneau, Neo Dizdar, Masashi Fujita, Daisuke Ito, Jessica Martin, Hannah McCall, Helen Russell, John ZuHone
    The Astrophysical Journal 998(2) 210-210 2026年2月11日  
    Abstract The XRISM/Resolve microcalorimeter directly measured the gas velocities in the core of the Virgo Cluster, the closest example of active galactic nucleus (AGN) feedback in a cluster. This proximity allows us to resolve the kinematic impact of feedback on scales down to 5 kpc. Our spectral analysis reveals a high velocity dispersion of km s −1 near the AGN, which steeply declines to ∼60 km s −1 between 5 and 25 kpc in the northwest direction. The observed line-of-sight bulk velocity in all regions is broadly consistent with the central galaxy, M87, with a mild trend toward blueshifted motions at larger radii. Systematic uncertainties have been carefully assessed and do not affect the measurements. The central velocities, if attributed entirely to isotropic turbulence, correspond to a transonic intracluster medium at sub-6 kpc scales with 3D Mach number and a nonthermal pressure fraction of . Simple models of weak shocks and sound waves and calculations assuming isotropic turbulence both support the hypothesis that the velocity field reflects a mix of shock-driven expansion and turbulence. Compared to other clusters observed by XRISM to date, M87’s central region stands out as the most kinematically disturbed, exhibiting both the highest velocity dispersion and the largest 3D Mach number, concentrated at the smallest physical scales.
  • Marc Audard, Hisamitsu Awaki, Ralf Ballhausen, Aya Bamba, Ehud Behar, Rozenn Boissay-Malaquin, Laura Brenneman, Gregory V. Brown, Lia Corrales, Elisa Costantini, Renata Cumbee, María Díaz Trigo, Chris Done, Tadayasu Dotani, Ken Ebisawa, Megan E. Eckart, Dominique Eckert, Satoshi Eguchi, Teruaki Enoto, 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, Daiki Ishi, 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, Takaaki Tanaka, Atsushi Tanimoto, Makoto Tashiro, Yukikatsu Terada, Yuichi Terashima, Yohko Tsuboi, Masahiro Tsujimoto, Hiroshi Tsunemi, Takeshi G. Tsuru, Ayşegül Tümer, Hiroyuki Uchida, Nagomi Uchida, Yuusuke Uchida, Hideki Uchiyama, Yoshihiro Ueda, Shinichiro Uno, Jacco Vink, Shin Watanabe, Brian J. Williams, Satoshi Yamada, Shinya Yamada, Hiroya Yamaguchi, Kazutaka Yamaoka, Noriko Yamasaki, Makoto Yamauchi, Shigeo Yamauchi, Tahir Yaqoob, Tomokage Yoneyama, Tessei Yoshida, Mihoko Yukita, Ian Drury, Julie Hlavacek-Larrondo, Julian Meunier, Kostas Migkas, Lior Shefler, Phillip C. Stancil, Nhut Truong, Shutaro Ueda, Benjamin Vigneron, John ZuHone, Congyao Zhang, Annie Heinrich, Irina Zhuravleva, Elena Bellomi
    Nature 650(8101) 309-313 2026年1月28日  
  • Fatima Zaidouni, Erin Kara, Peter Kosec, Ehud Behar, Richard Mushotzky, Michael Koss, A. Juráňová, Elias Kammoun, Laura W. Brenneman, Joheen Chakraborty, Ken Ebisawa, Megan E. Eckart, Andrew C. Fabian, Yasushi Fukazawa, Javier A. García, Liyi Gu, Megan Masterson, Shoji Ogawa, Takashi Okajima, Stéphane Paltani, Daniele Rogantini, Yuichi Terashima, Brian J. Williams, Satoshi Yamada
    The Astrophysical Journal Letters 997(1) L26-L26 2026年1月19日  
    Abstract We present the first XRISM/Resolve observations of the active galactic nucleus NGC 1365, obtained in 2024 February and July. NGC 1365 is known for rapid transitions between Compton-thick and Compton-thin states, along with strong absorption from a highly ionized wind. During our observations, the source was found in a persistent low-flux state, characterized by a decrease in hard-X-ray luminosity and significant line-of-sight obscuration. In this state, XRISM/Resolve reveals clear Fe xxv and Fe xxvi absorption lines together with, for the first time in this source, corresponding emission lines. These features may arise either from reemission from a photoionized wind (P Cygni profile) or from collisionally ionized gas associated with outflow-driven shocks in the interstellar medium. We estimate the wind launch radius to be approximately 10 16 cm (∼10 4 R g ), consistent with the location of the X-ray broadline region. We also resolve a broadened Fe K α line by σ  ∼ 1300 km s −1 , placing it at similar scales to the wind, consistent with radii inferred from disk-broadening models and the variability of the Fe K α broad line. The similarity of the Fe K α profile to the H β wing and broad Pa α width indicates that the X-ray-emitting region is likely cospatial with the optical/infrared broadline region and originates from the same gas.
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MISC

 127
  • 小川翔司, 金丸善朗, 福島光太郎, 寺田幸功, 寺田幸功, 高橋弘充, 水野恒史, 深沢泰司, 信川正順, 宇野伸一郎, 中澤知洋, 大宮悠希, 大熊佳吾, 内山秀樹, 久保田あや, 田代信, 勝田哲, 本上侑吾, 寺島雄一, 志達めぐみ, 善本真梨那, 高木利紘, 山内茂雄, 太田直美, 山田智史, 坪井陽子, 米山友景, 内田悠介, 江口智士, 谷本敦, 飯塚亮, 海老沢研, 渡辺伸, HOLLAND Matt, YAQOOB Tahir, BALUTA Chris, LOEWENSTEIN Michael, LOEWENSTEIN Michael, MILLER Eric
    日本天文学会年会講演予稿集 2025 2025年  
  • 海老沢研, 厚地凪, BORTOLAMI Marco, 茅根裕司, 海老沢研, 金丸善朗, 栗原明稀, 森口諒介, 望月雄友, 水本岬希, 長野佑哉, 中平聡志, 大間々知輝, 小川翔司, 鈴木寛大, スティーバー サマンサ, 桜井雄基, 丹波翼, 辻本匡弘, 富永愛侑, 高瀬祐介, 高倉隼人, TOMASI Maurizio
    宇宙航空研究開発機構特別資料 JAXA-SP-(Web) (24-001) 2025年  
  • 小川翔司, 金丸善朗, 林克洋, 福島光太郎, 吉田鉄生, 寺田幸功, 田代信, 高橋弘充, 水野恒史, 深沢泰司, 信川正順, 宇野伸一郎, 中澤知洋, 大宮悠希, 大熊佳吾, 内山秀樹, 久保田あや, 勝田哲, 本上侑吾, 寺島雄一, 志達めぐみ, 新居田祐基, 高木利紘, 山内茂雄, 太田直美, 白木天音, 鈴木那梨, 山田智史, 坪井陽子, 米山友景, 内田悠介, 江口智士, 谷本敦, 善本真梨那, 飯塚亮, 内田和海, 海老沢研, 渡辺伸, HOLLAND Matt, YAQOOB Tahir, BALUTA Chris, LOEWENSTEIN Michael, LOEWENSTEIN Michael, MILLER Eric
    日本天文学会年会講演予稿集 2025 2025年  
  • 小林寧々, 小林寧々, 梶浦梨央, 梶浦梨央, 中平聡志, 山本幸生, 内田ヘルベルト陽仁, 海老沢研
    宇宙航空研究開発機構研究開発報告 JAXA-RR-(Web) (23-007) 2024年  
  • 吉田鉄生, 林克洋, 金丸善朗, 小川翔司, 福島光太郎, 寺田幸功, 田代信, 高橋弘充, 水野恒史, 深沢泰司, 阪本菜月, 信川正順, 宇野伸一郎, 中澤知洋, 大宮悠希, 大熊佳吾, 内山秀樹, 久保田あや, 勝田哲, 塩入匠, 本上侑吾, 寺島雄一, 志達めぐみ, 新居田祐基, 高木利紘, 山内茂雄, 太田直美, 白木天音, 鈴木那梨, 北口貴雄, 山田智史, 坪井陽子, 米山友景, 根本登, 内田悠介, 江口智士, 谷本敦, 善本真梨那, 内田和海, 海老沢研, 渡辺伸, 飯塚亮, HOLLAND Matt, YAQOOB Tahir, BALUTA Chris, LOEWENSTEIN Michael, LOEWENSTEIN Michael, MILLER Eric
    日本天文学会年会講演予稿集 2024 2024年  
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講演・口頭発表等

 14
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所属学協会

 1

共同研究・競争的資金等の研究課題

 6
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