XRISM Forecast for the Coma Cluster: Stormy, with a Steep Power Spectrum

XRISM Collaboration; Audard, Marc; Awaki, Hisamitsu; Ballhausen, Ralf; Bamba, Aya; Behar, Ehud; Boissay-Malaquin, Rozenn; Brenneman, Laura; Brown, Gregory V.; Corrales, Lia; Costantini, Elisa; Cumbee, Renata; Diaz Trigo, Maria; Done, Chris; Dotani, Tadayasu; Ebisawa, Ken; Eckart, Megan E.; Eckert, Dominique; Eguchi, Satoshi; Enoto, Teruaki; Ezoe, Yuichiro; Foster, Adam; Fujimoto, Ryuichi; Fujita, Yutaka; Fukazawa, Yasushi; Fukushima, Kotaro; Furuzawa, Akihiro; Gallo, Luigi; García, Javier A.; Gu, Liyi; Guainazzi, Matteo; Hagino, Kouichi; Hamaguchi, Kenji; Hatsukade, Isamu; Hayashi, Katsuhiro; Hayashi, Takayuki; Hell, Natalie; Hodges-Kluck, Edmund; Hornschemeier, Ann; Ichinohe, Yuto; Ishi, Daiki; Ishida, Manabu; Ishikawa, Kumi; Ishisaki, Yoshitaka; Kaastra, Jelle; Kallman, Timothy; Kara, Erin; Katsuda, Satoru; Kanemaru, Yoshiaki; Kelley, Richard; Kilbourne, Caroline; Kitamoto, Shunji; Kobayashi, Shogo; Kohmura, Takayoshi; Kubota, Aya; Leutenegger, Maurice; Loewenstein, Michael; Maeda, Yoshitomo; Markevitch, Maxim; Matsumoto, Hironori; Matsushita, Kyoko; McCammon, Dan; McNamara, Brian; Mernier, François; Miller, Eric D.; Miller, Jon M.; Mitsuishi, Ikuyuki; Mizumoto, Misaki; Mizuno, Tsunefumi; Mori, Koji; Mukai, Koji; Murakami, Hiroshi; Mushotzky, Richard; Nakajima, Hiroshi; Nakazawa, Kazuhiro; Ness, Jan-Uwe; Nobukawa, Kumiko; Nobukawa, Masayoshi; Noda, Hirofumi; Odaka, Hirokazu; Ogawa, Shoji; Ogorzałek, Anna; Okajima, Takashi; Ota, Naomi; Paltani, Stéphane; Petre, Robert; Plucinsky, Paul; Porter, Frederick S.; Pottschmidt, Katja; Sato, Kosuke; Sato, Toshiki; Sawada, Makoto; Seta, Hiromi; Shidatsu, Megumi; Simionescu, Aurora; Smith, Randall; Suzuki, Hiromasa; Szymkowiak, Andrew; Takahashi, Hiromitsu; Takeo, Mai; Tamagawa, Toru; Tamura, Keisuke; Tanaka, Takaaki; Tanimoto, Atsushi; Tashiro, Makoto; Terada, Yukikatsu; Terashima, Yuichi; Tsuboi, Yohko; Tsujimoto, Masahiro; Tsunemi, Hiroshi; Tsuru, Takeshi; Tümer, Ayşegül; Uchida, Hiroyuki; Uchida, Nagomi; Uchida, Yuusuke; Uchiyama, Hideki; Ueda, Shutaro; Ueda, Yoshihiro; Uno, Shinichiro; Vink, Jacco; Watanabe, Shin; Williams, Brian J.; Yamada, Satoshi; Yamada, Shinya; Yamaguchi, Hiroya; Yamaoka, Kazutaka; Yamasaki, Noriko; Yamauchi, Makoto; Yamauchi, Shigeo; Yaqoob, Tahir; Yoneyama, Tomokage; Yoshida, Tessei; Yukita, Mihoko; Zhuravleva, Irina; Fabian, Andrew; Nelson, Dylan; Okabe, Nobuhiro; Pillepich, Annalisa; Potter, Cicely; Regamey, Manon; Sakai, Kosei; Shishido, Mona; Truong, Nhut; Wik, Daniel R.; ZuHone, John

doi:10.3847/2041-8213/add2f6

Published May 20, 2025 | Version Published

Journal Article Open

XRISM Forecast for the Coma Cluster: Stormy, with a Steep Power Spectrum

1. University of Geneva
2. Ehime University
3. University of Maryland, College Park
4. Goddard Space Flight Center
5. University of Tokyo
6. Technion – Israel Institute of Technology
7. University of Maryland, Baltimore
8. Harvard-Smithsonian Center for Astrophysics
9. Lawrence Livermore National Laboratory
10. University of Michigan–Ann Arbor
11. Netherlands Institute for Space Research
12. European Southern Observatory
13. Durham University
14. Institute of Space and Astronautical Science
15. Kumamoto Gakuen University
16. Kyoto University
17. Tokyo Metropolitan University
18. Hiroshima University
19. Fujita Health University
20. Saint Mary's University
21. California Institute of Technology
22. European Space Research and Technology Centre
23. University of Miyazaki
24. RIKEN Nishina Center
25. Leiden University
26. Massachusetts Institute of Technology
27. Saitama University
28. Rikkyo University
29. Tokyo University of Science
30. Shibaura Institute of Technology
31. Osaka University
32. University of Wisconsin–Madison
33. University of Waterloo
34. Research Institute in Astrophysics and Planetology
35. Nagoya University
36. University of Teacher Education Fukuoka
37. Tohoku Gakuin University
38. Kanto Gakuin University
39. European Space Astronomy Centre
40. Kindai University
41. Nara University of Education
42. Tohoku University
43. Nara Women's University
44. High Energy Accelerator Research Organization
45. Meiji University
46. Yale University
47. Konan University
48. Kagoshima University
49. Chuo University
50. Shizuoka University
51. Kanazawa University
52. Nihon Fukushi University
53. University of Amsterdam
54. Johns Hopkins University
55. University of Chicago
56. University of Cambridge
57. Heidelberg University
58. Max Planck Institute for Astronomy
59. University of Utah

The XRISM Resolve microcalorimeter array measured the velocities of hot intracluster gas at two positions in the Coma galaxy cluster: 3′×3′ squares at the center and at 6′ (170 kpc) to the south. We find the line-of-sight velocity dispersions in those regions to be σ_z = 208 ± 12 km s⁻¹ and 202 ± 24 km s⁻¹, respectively. The central value corresponds to a 3D Mach number of M = 0.24 ± 0.015 and a ratio of the kinetic pressure of small-scale motions to thermal pressure in the intracluster plasma of only 3.1% ± 0.4%, at the lower end of predictions from cosmological simulations for merging clusters like Coma, and similar to that observed in the cool core of the relaxed cluster A2029. Meanwhile, the gas in both regions exhibits high line-of-sight velocity differences from the mean velocity of the cluster galaxies, Δv_z = 450 ± 15 km s⁻¹ and 730 ± 30 km s⁻¹, respectively. A small contribution from an additional gas velocity component, consistent with the cluster optical mean, is detected along a sight line near the cluster center. The combination of the observed velocity dispersions and bulk velocities is not described by a Kolmogorov velocity power spectrum of steady-state turbulence; instead, the data imply a much steeper effective slope (i.e., relatively more power at larger linear scales). This may indicate either a very large dissipation scale, resulting in the suppression of small-scale motions, or a transient dynamic state of the cluster, where large-scale gas flows generated by an ongoing merger have not yet cascaded down to small scales.

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Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

The results presented above are made possible by over three decades of work by the team of scientists and engineers who created a microcalorimeter array for X-rays and overcame enormous setbacks. We gratefully acknowledge the entire XRISM team's effort to build, launch, calibrate, and operate this observatory. We thank the referee for useful comments. Part of this work was supported by the US Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA27344 and by NASA under contracts 80GSFC21M0002 and 80GSFC24M0006 and grants 80NSSC20K0733, 80NSSC18K0978, 80NSSC20K0883, 80NSSC20K0737, 80NSSC24K0678, 80NSSC18K1684, 80NSSC23K0650, and 80NNSC22K1922. Support was provided by JSPS KAKENHI grant Nos. JP23H00121, JP22H00158, JP22H01268, JP22K03624, JP23H04899, JP21K13963, JP24K00638, JP24K17105, JP21K13958, JP21H01095, JP23K20850, JP24H00253, JP21K03615, JP24K00677, JP20K14491, JP23H00151, JP19K21884, JP20H01947, JP20KK0071, JP23K20239, JP24K00672, JP24K17104, JP24K17093, JP20K04009, JP21H04493, JP20H01946, JP23K13154, JP19K14762, JP20H05857, and JP23K03459; the JSPS Core-to-Core Program, JPJSCCA20220002; and the Strategic Research Center of Saitama University. L.C. acknowledges support from NSF award 2205918. C.D. acknowledges support from STFC through grant ST/T000244/1. L.G. acknowledges support from Canadian Space Agency grant 18XARMSTMA. N.O. acknowledges partial support by the Organization for the Promotion of Gender Equality at Nara Women's University. M.S. acknowledges support by the RIKEN Pioneering Project Evolution of Matter in the Universe (r-EMU) and Rikkyo University Special Fund for Research (Rikkyo SFR). A.T. acknowledges support from the Kagoshima University postdoctoral research program (KU-DREAM). S.Y. acknowledges support by the RIKEN SPDR Program. I.Z. acknowledges partial support from the Alfred P. Sloan Foundation through the Sloan Research Fellowship. D.N. acknowledges funding from the Deutsche Forschungsgemeinschaft (DFG) through Emmy Noether Research Group grant No. NE 2441/1-1.

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Is new version of: Discussion Paper: arXiv:2504.20928 (arXiv)

United States Department of Energy
DE-AC52-07NA27344
National Aeronautics and Space Administration
80GSFC21M0002
National Aeronautics and Space Administration
80GSFC24M0006
National Aeronautics and Space Administration
80NSSC20K0733
National Aeronautics and Space Administration
80NSSC18K0978
National Aeronautics and Space Administration
80NSSC20K0883
National Aeronautics and Space Administration
80NSSC20K0737
National Aeronautics and Space Administration
80NSSC24K0678
National Aeronautics and Space Administration
80NSSC18K1684
National Aeronautics and Space Administration
80NSSC23K0650
National Aeronautics and Space Administration
80NNSC22K1922
Japan Society for the Promotion of Science
JP23H00121
Japan Society for the Promotion of Science
JP22H00158
Japan Society for the Promotion of Science
JP22H01268
Japan Society for the Promotion of Science
JP22K03624
Japan Society for the Promotion of Science
JP23H04899
Japan Society for the Promotion of Science
JP21K13963
Japan Society for the Promotion of Science
JP24K00638
Japan Society for the Promotion of Science
JP24K17105
Japan Society for the Promotion of Science
JP21K13958
Japan Society for the Promotion of Science
JP21H01095
Japan Society for the Promotion of Science
JP23K20850
Japan Society for the Promotion of Science
JP24H00253
Japan Society for the Promotion of Science
JP21K03615
Japan Society for the Promotion of Science
JP24K00677
Japan Society for the Promotion of Science
JP20K14491
Japan Society for the Promotion of Science
JP23H00151
Japan Society for the Promotion of Science
JP19K21884
Japan Society for the Promotion of Science
JP20H01947
Japan Society for the Promotion of Science
JP20KK0071
Japan Society for the Promotion of Science
JP23K20239
Japan Society for the Promotion of Science
JP24K00672
Japan Society for the Promotion of Science
JP24K17104
Japan Society for the Promotion of Science
JP24K17093
Japan Society for the Promotion of Science
JP20K04009
Japan Society for the Promotion of Science
JP21H04493
Japan Society for the Promotion of Science
JP20H01946
Japan Society for the Promotion of Science
JP23K13154
Japan Society for the Promotion of Science
JP19K14762
Japan Society for the Promotion of Science
JP20H05857
Japan Society for the Promotion of Science
JP23K03459
Japan Society for the Promotion of Science
JPJSCCA20220002
Saitama University
National Science Foundation
2205918
Science and Technology Facilities Council
ST/T000244/1
Canadian Space Agency
18XARMSTMA
Nara Women's University
RIKEN
Rikkyo University
Kagoshima University
Alfred P. Sloan Foundation
Deutsche Forschungsgemeinschaft
NE 2441/1-1

Accepted: 2025-04-29
Available: 2025-05-19

Published

Caltech groups: Division of Physics, Mathematics and Astronomy (PMA)
Publication Status: Published

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XRISM Forecast for the Coma Cluster: Stormy, with a Steep Power Spectrum

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XRISM Forecast for the Coma Cluster: Stormy, with a Steep Power Spectrum

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