XRISM 对 Coma 星团的预测：湍流状况，幂率谱较陡
高能天体物理现象
2025-04-30 v1 星系天体物理
摘要
XRISM Resolve 微波热力学阵列在 Coma 星团的两个位置测量了热内星际气体的速度：分别为中心 3'x3' 区域和距离中心 6'（170 kpc）南方的区域。我们发现这些区域的视线速度离散为 sigma_z=208+-12 km/s 和 202+-24 km/s。其中心值对应 3D 马赫数为 M=0.24+-0.015，且小尺度运动动能压强与热力学压强之比仅为 3.1+-0.4%，处于来自 cosmological 模拟预测的合并星团（如 Coma）的下端，且类似于在放松星团 A2029 的热核心中观察到的水平。同时，两个区域的气体都显示出与星团星系平均速度的显著视线速度差异，分别为 Delta v_z=450+-15 km/s 和 730+-30 km/s。在星团中心附近的一条视线上检测到来自星团光学平均速度的额外气体速度分量的小贡献。观察到的速度离散和 bulk 速度的组合不符合稳态湍流的Kolmogorov 速度功率谱；相反，数据暗示有效斜率显著更陕（即在更大线性尺度上有更多功率）。这可能表明小尺度运动被抑制的非常大的耗散尺度，或星团处于瞬态动态状态，由于正在进行的合并尚未将大尺度气体流 cascades 至小尺度。
引用
@article{arxiv.2504.20928,
title = {XRISM forecast for the Coma cluster: stormy, with a steep power spectrum},
author = {XRISM Collaboration and Marc Audard and Hisamitsu Awaki and Ralf Ballhausen and Aya Bamba and Ehud Behar and Rozenn Boissay-Malaquin and Laura Brenneman and Gregory V. Brown and Lia Corrales and Elisa Costantini and Renata Cumbee and Maria Diaz Trigo and Chris Done and Tadayasu Dotani and Ken Ebisawa and Megan E. Eckart and Dominique Eckert and Satoshi Eguchi and Teruaki Enoto and Yuichiro Ezoe and Adam Foster and Ryuichi Fujimoto and Yutaka Fujita and Yasushi Fukazawa and Kotaro Fukushima and Akihiro Furuzawa and Luigi Gallo and Javier A. Garcia and Liyi Gu and Matteo Guainazzi and Kouichi Hagino and Kenji Hamaguchi and Isamu Hatsukade and Katsuhiro Hayashi and Takayuki Hayashi and Natalie Hell and Edmund Hodges-Kluck and Ann Hornschemeier and Yuto Ichinohe and Daiki Ishi and Manabu Ishida and Kumi Ishikawa and Yoshitaka Ishisaki and Jelle Kaastra and Timothy Kallman and Erin Kara and Satoru Katsuda and Yoshiaki Kanemaru and Richard Kelley and Caroline Kilbourne and Shunji Kitamoto and Shogo Kobayashi and Takayoshi Kohmura and Aya Kubota and Maurice Leutenegger and Michael Loewenstein and Yoshitomo Maeda and Maxim Markevitch and Hironori Matsumoto and Kyoko Matsushita and Dan McCammon and Brian McNamara and Francois Mernier and Eric D. Miller and Jon M. Miller and Ikuyuki Mitsuishi and Misaki Mizumoto and Tsunefumi Mizuno and Koji Mori and Koji Mukai and Hiroshi Murakami and Richard Mushotzky and Hiroshi Nakajima and Kazuhiro Nakazawa and Jan-Uwe Ness and Kumiko Nobukawa and Masayoshi Nobukawa and Hirofumi Noda and Hirokazu Odaka and Shoji Ogawa and Anna Ogorzalek and Takashi Okajima and Naomi Ota and Stephane Paltani and Robert Petre and Paul Plucinsky and Frederick S. Porter and Katja Pottschmidt and Kosuke Sato and Toshiki Sato and Makoto Sawada and Hiromi Seta and Megumi Shidatsu and Aurora Simionescu and Randall Smith and Hiromasa Suzuki and Andrew Szymkowiak and Hiromitsu Takahashi and Mai Takeo and Toru Tamagawa and Keisuke Tamura and Takaaki Tanaka and Atsushi Tanimoto and Makoto Tashiro and Yukikatsu Terada and Yuichi Terashima and Yohko Tsuboi and Masahiro Tsujimoto and Hiroshi Tsunemi and Takeshi Tsuru and Aysegul Tumer and Hiroyuki Uchida and Nagomi Uchida and Yuusuke Uchida and Hideki Uchiyama and Shutaro Ueda and Yoshihiro Ueda and Shinichiro Uno and Jacco Vink and Shin Watanabe and Brian J. Williams and Satoshi Yamada and Shinya Yamada and Hiroya Yamaguchi and Kazutaka Yamaoka and Noriko Yamasaki and Makoto Yamauchi and Shigeo Yamauchi and Tahir Yaqoob and Tomokage Yoneyama and Tessei Yoshida and Mihoko Yukita and Irina Zhuravleva and Andrew Fabian and Dylan Nelson and Nobuhiro Okabe and Annalisa Pillepich and Cicely Potter and Manon Regamey and Kosei Sakai and Mona Shishido and Nhut Truong and Daniel R. Wik and John ZuHone},
journal= {arXiv preprint arXiv:2504.20928},
year = {2025}
}
备注
ApJ Letters in press. 14 pages, 8 figures