发表机构
Leiden University; SRON, Space Research Organisation Netherlands; Leiden Observatory, Leiden University; Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo; Waterloo Centre for Astrophysics, Department of Physics and Astronomy, University of Waterloo; Department of Physics, Nagoya University; KMI, Nagoya University; Institute of Space and Astronautical Science (ISAS), Japan Aerospace Exploration Agency (JAXA); INAF - Istituto di Radioastronomia（莱顿大学; 荷兰空间研究组织; 莱顿天文台，莱顿大学; 东京大学宇宙物理与数学 Kavli 研究所（WPI）; 滑铁卢大学天体物理中心，物理与天文学系，滑铁卢大学; 名古屋大学物理学系; 名古屋大学 KMI; 日本宇宙航空研究开发机构 JAXA 宇宙科学研究所 (ISAS); 意大利国家天体物理研究所射电天文研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
利用XRISM对牙刷星系团南部进行167千秒观测，发现至少三个子星系团存在超声速视线速度偏移，表明合并年轻且湍流级联未充分发展。
AI 中文摘要
牙刷星系团（1RXS J0603.3+4214）以其北部的射电遗迹、射电晕和高度扰动的X射线形态而闻名。它展现出冲击驱动和湍流再加速两种特征，其中后者被用来解释其射电晕。然而，合并过程中动能如何在空间尺度上分布到气体运动中仍不清楚。我们利用一次167千秒的XRISM/Resolve观测，探测了该星系团南部X射线最亮区域的星系团内介质（ICM）动力学。我们通过在全阵列和象限子阵列上使用3-8 keV波段内的单组分和多组分热模型拟合光谱进行分析。全阵列光谱倾向于两个ICM组分，其跨声速视线（LOS）速度差为$\Delta v_{\mathrm{bulk}}=1635^{+165}_{-110}$ km s$^{-1}$，而速度弥散则低得多，为$\sigma_{v,1\mathrm{D}}\sim$245-310 km s$^{-1}$。子阵列分析同样显示至少三个象限中存在多个组分，视线方向体速度范围从$-2520^{+295}_{-230}$到$+930^{+70}_{-110}$ km s$^{-1}$。速度弥散保持适中，约为$\sim$215 km s$^{-1}$，对应于在主导观测线展宽尺度上约3-6%的湍流压力支撑。在东北和西南方向探测到较冷气体，其$kT_{\mathrm{NE}}=3.13^{+0.33}_{-0.30}$ keV和$kT_{\mathrm{SW}}=2.32^{+0.43}_{-0.37}$ keV，可能关联于弱引力透镜和光学研究中识别出的第三个北部子星系团。我们的结果表明ICM具有复杂的运动学结构，至少有三个子星系团表现出超声速体速度偏移和更小的速度弥散。这表明合并几何结构具有显著的视线方向分量，并可能表明星系团碰撞相对年轻，湍流级联尚未完全建立。
英文摘要
The Toothbrush Cluster (1RXS J0603.3+4214) is known for its northern radio relic, radio halo, and highly disturbed X-ray morphology. It shows features of both shock-driven and turbulent reacceleration, the latter of which is invoked to explain its radio halo. However, how kinetic energy from the merger is distributed into gas motions across spatial scales remains unclear. We probe the intracluster medium (ICM) dynamics in the southern, X-ray-brightest region of the cluster using a 167 ks XRISM/Resolve observation. We conduct both full-array and quadrant sub-array analyses by fitting the spectra with single and multi-component thermal models in the 3-8 keV band. The full-array spectrum favours two ICM components with a transonic line-of-sight (LOS) velocity difference of $Δv_{\mathrm{bulk}}=1635^{+165}_{-110}$ km s$^{-1}$, while the velocity dispersions are much lower, at $σ_{v,1\mathrm{D}}\sim$245-310 km s$^{-1}$. The sub-array analysis likewise reveals multiple components in at least three quadrants, with LOS bulk velocities ranging from $-2520^{+295}_{-230}$ to $+930^{+70}_{-110}$ km s$^{-1}$. The velocity dispersions remain modest at $\sim$215 km s$^{-1}$, corresponding to a turbulent pressure support of about 3-6% on scales dominating the observed line broadening. Cooler gas is detected in the NE and SW, with $kT_{\mathrm{NE}}=3.13^{+0.33}_{-0.30}$ keV and $kT_{\mathrm{SW}}=2.32^{+0.43}_{-0.37}$ keV, likely associated with a third, northern subcluster identified in weak-lensing and optical studies. Our results indicate a complex ICM kinematic structure, with evidence for at least three subclusters exhibiting supersonic bulk velocity offsets and much smaller velocity dispersions. This shows that the merger geometry has a significant line-of-sight component and may indicate that the cluster collision is relatively young, with the turbulent cascade not yet fully established.
Comments19 pages, 10 figures, Submitted to A&A
