Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS

Felix Aharonian , Hiroki Akamatsu , Fumie Akimoto , Stevenw. Allen , Lorella Angelini , Marc Audard , Hisamitsu Awaki , Magnus Axelsson , Aya Bamba , Marshallw. Bautz , Roger Blandford , Lauraw. Brenneman , Gregoryv. Brown , Esra Bulbul , Edward M. Cackett , Maria Chernyakova , Meng P. Chiao , Paolos. Coppi , Elisa Costantini , Jelle de Plaa , Cor P. de Vries , Jan-Willem den Herder , Chris Done , Tadayasu Dotani , Ken Ebisawa , Megane. Eckart , Teruaki Enoto , Yuichiro Ezoe , Andrewc. Fabian , Carlo Ferrigno , Adamr. Foster , Ryuichi Fujimoto , Yasushi Fukazawa , Maki Furukawa , Akihiro Furuzawa , Massimiliano Galeazzi , Luigic. Gallo , Poshak Gandhi , Margherita Giustini , Andrea Goldwurm (1, 2) , Liyi Gu , Matteo Guainazzi , Yoshito Haba , Kouichi Hagino , Kenji Hamaguchi , Ilanam. Harrus , Isamu Hatsukade , Katsuhiro Hayashi , Takayuki Hayashi , Kiyoshi Hayashida , Junkos. Hiraga , Ann Hornschemeier , Akio Hoshino , Johnp. Hughes , Yuto Ichinohe , Ryo Iizuka , Hajime Inoue , Yoshiyuki Inoue , Manabu Ishida , Kumi Ishikawa , Yoshitaka Ishisaki , Masachika Iwai , Jelle Kaastra , Tim Kallman , Tsuneyoshi Kamae , Jun Kataoka , Satoru Katsuda , Nobuyuki Kawai , Richardl. Kelley , Carolinea. Kilbourne , Takao Kitaguchi , Shunji Kitamoto , Tetsu Kitayama , Takayoshi Kohmura , Motohide Kokubun , Katsuji Koyama , Shu Koyama , Peter Kretschmar , Hansa. Krimm , Aya Kubota , Hideyo Kunieda , Philippe Laurent (1, 2) , Shiu-Hang Lee , Mauricea. Leutenegger , Oliviero. Limousin (2) , Michael Loewenstein , Knoxs. Long , David Lumb , Greg Madejski , Yoshitomo Maeda , Daniel Maier (1, 2) , Kazuo Makishima , Maxim Markevitch , Hironori Matsumoto , Kyoko Matsushita , Dan Mccammon , Brianr. Mcnamara , Missagh Mehdipour , Eric D. Miller , Jon M. Miller , Shin Mineshige , Kazuhisa Mitsuda , Ikuyuki Mitsuishi , Takuya Miyazawa , Tsunefumi Mizuno , Hideyuki Mori , Koji Mori , Koji Mukai , Hiroshi Murakami , Richardf. Mushotzky , Takao Nakagawa , Hiroshi Nakajima , Takeshi Nakamori , Shinya Nakashima , Kazuhiro Nakazawa , Kumikok. Nobukawa , Masayoshi Nobukawa , Hirofumi Noda , Hirokazu Odaka , Anna Ogorzalek , Takaya Ohashi , Masanori Ohno , Takashi Okajima , Naomi Ota , Masanobu Ozaki , Frits Paerels , Stéphane Paltani , Robert Petre , Ciro Pinto , Fredericks. Porter , Katja Pottschmidt , Christophers. Reynolds , Samar Safi-Harb , Shinya Saito , Kazuhiro Sakai , Toru Sasaki , Goro Sato , Kosuke Sato , Rie Sato , Makoto Sawada , Norbert Schartel , Peterj. Serlemtsos , Hiromi Seta , Megumi Shidatsu , Aurora Simionescu , Randallk. Smith , Yang Soong , Łukasz Stawarz , Yasuharu Sugawara , Satoshi Sugita , Andrew Szymkowiak , Hiroyasu Tajima , Hiromitsu Takahashi , Tadayuki Takahashi , Shiníchiro Takeda , Yoh Takei , Toru Tamagawa , Takayuki Tamura , Takaaki Tanaka , Yasuo Tanaka , Yasuyukit. Tanaka , Makotos. Tashiro , Yuzuru Tawara , Yukikatsu Terada , Yuichi Terashima , Francesco Tombesi , Hiroshi Tomida , Yohko Tsuboi , Masahiro Tsujimoto , Hiroshi Tsunemi , Takeshi Go Tsuru , Hiroyuki Uchida , Hideki Uchiyama , Yasunobu Uchiyama , Shutaro Ueda , Yoshihiro Ueda , Shiníchiro Uno , C.Megan Urry , Eugenio Ursino , Shin Watanabe , Norbert Werner , Dan R. Wilkins , Brianj. Williams , Shinya Yamada , Hiroya Yamaguchi , Kazutaka Yamaoka , Norikoy. Yamasaki , Makoto Yamauchi , Shigeo Yamauchi , Tahir Yaqoob , Yoichi Yatsu , Daisuke Yonetoku , Irina Zhuravleva , Abderahmen Zoghbi

1 APC (UMR_7164) - AstroParticule et Cosmologie
2 CEA - Commissariat à l'énergie atomique et aux énergies alternatives

Thanks to its high spectral resolution (∼5 eV at 6 keV), the Soft X-ray Spectrometer (SXS) on board Hitomi enables us to measure the detailed structure of spatially resolved emission lines from highly ionized ions in galaxy clusters for the first time. In this series of papers, using the SXS we have measured the velocities of gas motions, metallicities and the multi-temperature structure of the gas in the core of the Perseus Cluster. Here, we show that when inferring physical properties from line emissivities in systems like Perseus, the resonant scattering effect should be taken into account. In the Hitomi waveband, resonant scattering mostly affects the Fe xxv Heα line (w)—the strongest line in the spectrum. The flux measured by Hitomi in this line is suppressed by a factor of ∼1.3 in the inner ∼30 kpc, compared to predictions for an optically thin plasma; the suppression decreases with the distance from the center. The w line also appears slightly broader than other lines from the same ion. The observed distortions of the w line flux, shape, and distance dependence are all consistent with the expected effect of the resonant scattering in the Perseus core. By measuring the ratio of fluxes in optically thick (w) and thin (Fe xxv forbidden, Heβ, Lyα) lines, and comparing these ratios with predictions from Monte Carlo radiative transfer simulations, the velocities of gas motions have been obtained. The results are consistent with the direct measurements of gas velocities from line broadening described elsewhere in this series, although the systematic and statistical uncertainties remain significant. Further improvements in the predictions of line emissivities in plasma models, and deeper observations with future X-ray missions offering similar or better capabilities to the Hitomi SXS, will enable resonant scattering measurements to provide powerful constraints on the amplitude and anisotropy of cluster gas motions.

Domaines: Astrophysique [astro-ph]

Felix Aharonian, Hiroki Akamatsu, Fumie Akimoto, Stevenw. Allen, Lorella Angelini, et al.. Measurements of resonant scattering in the Perseus Cluster core with Hitomi SXS. Publ.Astron.Soc.Jap., 2018, 70 (2), pp.10. ⟨10.1093/pasj/psx127⟩. ⟨hal-01792586⟩