Temperature Structure in the Perseus Cluster Core Observed with Hitomi
Creators: name: Hitomi Collaboration
name: Aharonian, Felix
name: Akamatsu, Hiroki
name: Akimoto, Fumie
name: Allen, Steven W.
name: Angelini, Lorella
name: Audard, Marc
name: Awaki, Hisamitsu
name: Axelsson, Magnus
name: Bamba, Aya
name: Bautz, Marshall W.
name: Blandford, Roger
name: Brenneman, Laura W.
name: Brown, Gregory V.
name: Bulbul, Esra
name: Cackett, Edward M.
name: Chernyakova, Maria
name: Chiao, Meng P.
name: Coppi, Paolo S.
name: Costantini, Elisa
name: de Plaa, Jelle
name: de Vries, Cor P.
name: Herder, Jan-Willem den
name: Done, Chris
name: Dotani, Tadayasu
name: Ebisawa, Ken
name: Eckart, Megan E.
name: Enoto, Teruaki
name: Ezoe, Yuichiro
name: Fabian, Andrew C.
name: Ferrigno, Carlo
name: Foster, Adam R.
name: Fujimoto, Ryuichi
name: Fukazawa, Yasushi
name: Furukawa, Maki
name: Furuzawa, Akihiro
name: Galeazzi, Massimiliano
name: Gallo, Luigi C.
name: Gandhi, Poshak
name: Giustini, Margherita
name: Goldwurm, Andrea
name: Gu, Liyi
name: Guainazzi, Matteo
name: Haba, Yoshito
name: Hagino, Kouichi
name: Hamaguchi, Kenji
name: Harrus, Ilana M.
name: Hatsukade, Isamu
name: Hayashi, Katsuhiro
name: Hayashi, Takayuki
name: Hayashida, Kiyoshi
name: Hiraga, Junko S.
name: Hornschemeier, Ann
name: Hoshino, Akio
name: Hughes, John P.
name: Ichinohe, Yuto
name: Iizuka, Ryo
name: Inoue, Hajime
name: Inoue, Yoshiyuki
name: Ishida, Manabu
name: Ishikawa, Kumi
name: Ishisaki, Yoshitaka
name: Iwai, Masachika
name: Kaastra, Jelle
name: Kallman, Tim
name: Kamae, Tsuneyoshi
name: Kataoka, Jun
name: Kato, Yuichi
name: Katsuda, Satoru
name: Kawai, Nobuyuki
name: Kelley, Richard L.
name: Kilbourne, Caroline A.
name: Kitaguchi, Takao
name: Kitamoto, Shunji
name: Kitayama, Tetsu
name: Kohmura, Takayoshi
name: Kokubun, Motohide
name: Koyama, Katsuji
name: Koyama, Shu
name: Kretschmar, Peter
name: Krimm, Hans A.
name: Kubota, Aya
name: Kunieda, Hideyo
name: Laurent, Philippe
name: Lee, Shiu-Hang
name: Leutenegger, Maurice A.
name: Limousin, Olivier
name: Loewenstein, Michael
name: Long, Knox S.
name: Lumb, David
name: Madejski, Greg
name: Maeda, Yoshitomo
name: Maier, Daniel
name: Makishima, Kazuo
name: Markevitch, Maxim
name: Matsumoto, Hironori
name: Matsushita, Kyoko
name: McCammon, Dan
name: McNamara, Brian R.
name: Mehdipour, Missagh
name: Miller, Eric D.
name: Miller, Jon M.
name: Mineshige, Shin
name: Mitsuda, Kazuhisa
name: Mitsuishi, Ikuyuki
name: Miyazawa, Takuya
name: Mizuno, Tsunefumi
name: Mori, Hideyuki
name: Mori, Koji
name: Mukai, Koji
name: Murakami, Hiroshi
name: Mushotzky, Richard F.
name: Nakagawa, Takao
name: Nakajima, Hiroshi
name: Nakamori, Takeshi
name: Nakashima, Shinya
name: Nakazawa, Kazuhiro
name: Nobukawa, Kumiko K.
name: Nobukawa, Masayoshi
name: Noda, Hirofumi
name: Odaka, Hirokazu
name: Ohashi, Takaya
name: Ohno, Masanori
name: Okajima, Takashi
name: Ota, Naomi
name: Ozaki, Masanobu
name: Paerels, Frits
name: Paltani, Stéphane
name: Petre, Robert
name: Pinto, Ciro
name: Porter, Frederick S.
name: Pottschmidt, Katja
name: Reynolds, Christopher S.
name: Safi-Harb, Samar
name: Saito, Shinya
name: Sakai, Kazuhiro
name: Sasaki, Toru
name: Sato, Goro
name: Sato, Kosuke
name: Sato, Rie
name: Sawada, Makoto
name: Schartel, Norbert
name: Serlemtsos, Peter J.
name: Seta, Hiromi
name: Shidatsu, Megumi
name: Simionescu, Aurora
name: Smith, Randall K.
name: Soong, Yang
name: Stawarz, Łukasz
name: Sugawara, Yasuharu
name: Sugita, Satoshi
name: Szymkowiak, Andrew
name: Tajima, Hiroyasu
name: Takahashi, Hiromitsu
name: Takahashi, Tadayuki
name: Takeda, Shiníchiro
name: Takei, Yoh
name: Tamagawa, Toru
name: Tamura, Takayuki
name: Tanaka, Takaaki
name: Tanaka, Yasuo
name: Tanaka, Yasuyuki T.
name: Tashiro, Makoto S.
name: Tawara, Yuzuru
name: Terada, Yukikatsu
name: Terashima, Yuichi
name: Tombesi, Francesco
name: Tomida, Hiroshi
name: Tsuboi, Yohko
name: Tsujimoto, Masahiro
name: Tsunemi, Hiroshi
name: Tsuru, Takeshi Go
name: Uchida, Hiroyuki
name: Uchiyama, Hideki
name: Uchiyama, Yasunobu
name: Ueda, Shutaro
name: Ueda, Yoshihiro
name: Uno, Shiníchiro
name: Urry, C. Megan
name: Ursino, Eugenio
name: Watanabe, Shin
name: Werner, Norbert
name: Wilkins, Dan R.
name: Williams, Brian J.
name: Yamada, Shinya
name: Yamaguchi, Hiroya
name: Yamaoka, Kazutaka
name: Yamasaki, Noriko Y.
name: Yamauchi, Makoto
name: Yamauchi, Shigeo
name: Yaqoob, Tahir
name: Yatsu, Yoichi
name: Yonetoku, Daisuke
name: Zhuravleva, Irina
name: Zoghbi, Abderahmen
Publisher: name: arXiv
Year: 2017
Subjects: subject: High Energy Astrophysical Phenomena (astro-ph.HE)
subject: FOS: Physical sciences
subject: FOS: Physical sciences

description: The present paper investigates the temperature structure of the X-ray emitting plasma in the core of the Perseus cluster using the 1.8--20.0 keV data obtained with the Soft X-ray Spectrometer (SXS) onboard the Hitomi Observatory. A series of four observations were carried out, with a total effective exposure time of 338 ks and covering a central region $\sim7'$ in diameter. The SXS was operated with an energy resolution of $\sim$5 eV (full width at half maximum) at 5.9 keV. Not only fine structures of K-shell lines in He-like ions but also transitions from higher principal quantum numbers are clearly resolved from Si through Fe. This enables us to perform temperature diagnostics using the line ratios of Si, S, Ar, Ca, and Fe, and to provide the first direct measurement of the excitation temperature and ionization temperature in the Perseus cluster. The observed spectrum is roughly reproduced by a single temperature thermal plasma model in collisional ionization equilibrium, but detailed line ratio diagnostics reveal slight deviations from this approximation. In particular, the data exhibit an apparent trend of increasing ionization temperature with increasing atomic mass, as well as small differences between the ionization and excitation temperatures for Fe, the only element for which both temperatures can be measured. The best-fit two-temperature models suggest a combination of 3 and 5 keV gas, which is consistent with the idea that the observed small deviations from a single temperature approximation are due to the effects of projection of the known radial temperature gradient in the cluster core along the line of sight. Comparison with the Chandra/ACIS and the XMM-Newton/RGS results on the other hand suggests that additional lower-temperature components are present in the ICM but not detectable by Hitomi SXS given its 1.8--20 keV energy band.
description: 29 pages, 19 figures, 9 tables. Accepted for publication in PASJ