Exploring the dynamics of the Coma galaxy cluster by mapping its X-ray emission line profiles with XRISM

@misc{sakai2026exploring,
  title = {{Exploring the dynamics of the Coma galaxy cluster by mapping its X-ray emission line profiles with XRISM}},
  author = {Kosei Sakai and Kazuhiro Nakazawa and Maxim Markevitch and Dominique Eckert and Yuichiro Ezoe and Yuto Ichinohe and Richard Kelley and Richard Mushotzky and Nobuhiro Okabe and Yuki Omiya and Naomi Ota and Cicely Potter and Andrew Szymkowiak and Shunsuke Torii and Nhut Truong and Ayşegül Tümer and Yuusuke Uchida and Dan Wik and Irina Zhuravleva and John ZuHone},
  howpublished = {arXiv},
  year = {2026},
  month = sep,
  doi = {10.48550/arxiv.2609.14264},
  eprint = {2609.14264},
  archivePrefix = {arXiv},
  url = {https://arxiv.org/abs/2609.14264},
}

TY  - UNPB
TI  - Exploring the dynamics of the Coma galaxy cluster by mapping its X-ray emission line profiles with XRISM
AU  - Kosei Sakai
AU  - Kazuhiro Nakazawa
AU  - Maxim Markevitch
AU  - Dominique Eckert
AU  - Yuichiro Ezoe
AU  - Yuto Ichinohe
AU  - Richard Kelley
AU  - Richard Mushotzky
AU  - Nobuhiro Okabe
AU  - Yuki Omiya
AU  - Naomi Ota
AU  - Cicely Potter
AU  - Andrew Szymkowiak
AU  - Shunsuke Torii
AU  - Nhut Truong
AU  - Ayşegül Tümer
AU  - Yuusuke Uchida
AU  - Dan Wik
AU  - Irina Zhuravleva
AU  - John ZuHone
PY  - 2026
DA  - 2026/09/21
PB  - arXiv
DO  - 10.48550/arxiv.2609.14264
UR  - https://arxiv.org/abs/2609.14264
AB  - The intracluster medium (ICM) in merging galaxy clusters exhibits turbulence and bulk flows. Unraveling these components is crucial not only for elucidating the geometry of the cluster mergers, but also for understanding the physics of magnetic field amplification and relativistic particle acceleration. XRISM/Resolve data for two 3'×3' fields in the core of the Coma cluster reveales that the ICM in the central field moves with Δcz = −430~km~s^−1 relative to the cluster galaxy average, while that in the southern field moves with Δcz = −730~km~s^−1 (see \cite{2025ApJ...985L..20X}, hereinafter ``Paper I''). In this paper, we perform a more detailed analysis of these data sets to search for non-Gaussian features in the Fe-K line complex profiles. In the spectra from the northwest (NW) quadrant of the central field, in addition to the main and redshifted ICM components (Δcz = −40 km s^−1) reported in Paper I, we find evidence of another, blueshifted component, moving with Δcz = −1250 km s^−1. For a systematic search for other significant velocity components, we perform a bias-free 3 eV step multi-component fit to the Resolve full-array spectra from the central and southern fields. This search uncovers another redshifted component in the southern field, moving with Δcz ∼ +1230 km s^−1. We estimate the energy densities of the ICM turbulence and bulk motion to be similar to each other and several times greater than the energy density of the cluster's B∼ 5 μG magnetic field.
ER  -