Atomic data and spectral modeling constraints from high-resolution X-ray observations of the Perseus cluster with Hitomi
Authors: Aharonian Hitomi Collaboration, Felix , Akamatsu Hiroki , Akimoto Fumie , Allen Steven W , Angelini Lorella , Audard Marc , Awaki Hisamitsu , Axelsson Magnus , Bamba Aya , Bautz Marshall W , Blandford Roger , Brenneman Laura W , Brown Gregory V , Bulbul Esra , Cackett Edward M , Chernyakova Maria , Chiao Meng P , Coppi Paolo S , Costantini Elisa , de Plaa Jelle , de Vries Cor P , den Herder Jan-Willem , Done Chris , Dotani Tadayasu , Ebisawa Ken , Eckart Megan E , Enoto Teruaki , Ezoe Yuichiro , Fabian Andrew C , Ferrigno Carlo , Foster Adam R , Fujimoto Ryuichi , Fukazawa Yasushi , Furuzawa Akihiro , Galeazzi Massimiliano , Gallo Luigi C , Gandhi Poshak , Giustini Margherita , Goldwurm Andrea , Gu Liyi , Guainazzi Matteo , Haba Yoshito , Hagino Kouichi , Hamaguchi Kenji , Harrus Ilana M , Hatsukade Isamu , Hayashi Katsuhiro , Hayashi Takayuki , Hayashida Kiyoshi , Hell Natalie , Hiraga Junko S , Hornschemeier Ann , Hoshino Akio , Hughes John P , Ichinohe Yuto , Iizuka Ryo , Inoue Hajime , Inoue Yoshiyuki , Ishida Manabu , Ishikawa Kumi , Ishisaki Yoshitaka , Iwai Masachika , Kaastra Jelle , Kallman Tim , Kamae Tsuneyoshi , Kataoka Jun , Katsuda Satoru , Kawai Nobuyuki , Kelley Richard L , Kilbourne Caroline A , Kitaguchi Takao , Kitamoto Shunji , Kitayama Tetsu , Kohmura Takayoshi , Kokubun Motohide , Koyama Katsuji , Koyama Shu , Kretschmar Peter , Krimm Hans A , Kubota Aya , Kunieda Hideyo , Laurent Philippe , Lee Shiu-Hang , Leutenegger Maurice A , Limousin Olivier , Loewenstein Michael , Long Knox S , Lumb David , Madejski Greg , Maeda Yoshitomo , Maier Daniel , Makishima Kazuo , Markevitch Maxim , Matsumoto Hironori , Matsushita Kyoko , McCammon Dan , McNamara Brian R , Mehdipour Missagh , Miller Eric D , Miller Jon M , Mineshige Shin , Mitsuda Kazuhisa , Mitsuishi Ikuyuki , Miyazawa Takuya , Mizuno Tsunefumi , Mori Hideyuki , Mori Koji , Mukai Koji , Murakami Hiroshi , Mushotzky Richard F , Nakagawa Takao , Nakajima Hiroshi , Nakamori Takeshi , Nakashima Shinya , Nakazawa Kazuhiro , Nobukawa Kumiko K , Nobukawa Masayoshi , Noda Hirofumi , Odaka Hirokazu , Ohashi Takaya , Ohno Masanori , Okajima Takashi , Ota Naomi , Ozaki Masanobu , Paerels Frits , Paltani Stéphane , Petre Robert , Pinto Ciro , Porter Frederick S , Pottschmidt Katja , Reynolds Christopher S , Safi-Harb Samar , Saito Shinya , Sakai Kazuhiro , Sasaki Toru , Sato Goro , Sato Kosuke , Sato Rie , Sawada Makoto , Schartel Norbert , Serlemtsos Peter J , Seta Hiromi , Shidatsu Megumi , Simionescu Aurora , Smith Randall K , Soong Yang , Stawarz Łukasz , Sugawara Yasuharu , Sugita Satoshi , Szymkowiak Andrew , Tajima Hiroyasu , Takahashi Hiromitsu , Takahashi Tadayuki , Takeda Shin’ichiro , Takei Yoh , Tamagawa Toru , Tamura Takayuki , Tanaka Takaaki , Tanaka Yasuo , Tanaka Yasuyuki T , Tashiro Makoto S , Tawara Yuzuru , Terada Yukikatsu , Terashima Yuichi , Tombesi Francesco , Tomida Hiroshi , Tsuboi Yohko , Tsujimoto Masahiro , Tsunemi Hiroshi , Tsuru Takeshi Go , Uchida Hiroyuki , Uchiyama Hideki , Uchiyama Yasunobu , Ueda Shutaro , Ueda Yoshihiro , Uno Shin’ichiro , Urry C Megan , Ursino Eugenio , Watanabe Shin , Werner Norbert , Wilkins Dan R , Williams Brian J , Yamada Shinya , Yamaguchi Hiroya , Yamaoka Kazutaka , Yamasaki Noriko Y , Yamauchi Makoto , Yamauchi Shigeo , Yaqoob Tahir , Yatsu Yoichi , Yonetoku Daisuke , Zhuravleva Irina , Zoghbi Abderahmen , Raassen A J J 
Published: February 2018

Abstract
The Hitomi Soft X-ray Spectrometer spectrum of the Perseus cluster, with ∼5 eV resolution in the 2–9 keV band, offers an unprecedented benchmark of the atomic modeling and database for hot collisional plasmas. It reveals both successes and challenges of the current atomic data and models. The latest versions of AtomDB/APEC (3.0.8), SPEX (3.03.00), and CHIANTI (8.0) all provide reasonable fits to the broad-band spectrum, and are in close agreement on best-fit temperature, emission measure, and abundances of a few elements such as Ni. For the Fe abundance, the APEC and SPEX measurements differ by 16%, which is 17 times higher than the statistical uncertainty. This is mostly attributed to the differences in adopted collisional excitation and dielectronic recombination rates of the strongest emission lines. We further investigate and compare the sensitivity of the derived physical parameters to the astrophysical source modeling and instrumental effects. The Hitomi results show that accurate atomic data and models are as important as the astrophysical modeling and instrumental calibration aspects. Substantial updates of atomic databases and targeted laboratory measurements are needed to get the current data and models ready for the data from the next Hitomi-level mission.