极端扰动星系团样本（eDGeS）：eROSITA选出的并合星系团候选体1eRASS J025859.4-193727的光谱与动力学分析
The extreme Disturbed Galaxy Cluster Sample (eDGeS): Spectroscopy and Dynamical Analysis of the eROSITA-Selected Merging Galaxy Cluster Candidate 1eRASS J025859.4-193727
- University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校）
- International Gemini Observatory, NSF NOIRLab（国际双子座天文台，NSF NOIRLab）
- Cerro Tololo Inter-American Observatory, NSF NOIRLab（塞罗托洛洛美洲际天文台，NSF NOIRLab）
- Observatório Nacional (ON/MCTI)（国家天文台（ON/MCTI））
- Universidad de La Serena（拉塞雷纳大学）
- Max Planck Institute for Extraterrestrial Physics（马普地外物理研究所）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本研究对eROSITA选出的并合星系团候选体1eRASS J025859.4-193727进行光谱与动力学分析，确认51个成员星系，测量其速度弥散度和动力学质量，并结合子团分布与相空间证据推断其为天空平面内的并合事件。
AI中文摘要：
解决诸如星系团并合对星系演化的影响以及暗物质自相互作用截面等开放问题，需要构建一个大型、多样化的扰动星系团样本。对此类样本的一个贡献是极端扰动星系团样本（eDGeS），这是一项针对从互补巡天中选出的大质量扰动及并合星系团的持续光谱研究。在此，我们展示了来自eROSITA选出的子样本（eDGeS-eROSITA）的首批结果：对并合星系团候选体1eRASS J025859.4-193727的动力学状态分析。我们给出了该星系团方向上76个星系的首个光谱红移测量结果，确认其中51个为星系团成员。该星系团呈现的视线方向速度弥散度为$\sigma_{\rm{cl}}=808^{+59}_{-66}~\rm{km~s^{-1}}$，动力学质量为$M_{200}=4.47^{+0.94}_{-0.93} \times 10^{14}~M_{\rm{Sun}}$。虽然星系团在视线方向未显示出亚结构的证据，但成员星系的投影分布揭示了三个子团，其中仅一个子团似乎与星系团的X射线轮廓相关联。相空间分析揭示了很大比例的近期内落成员星系。综合这些证据，表明该星系团并合发生在天空平面内。假设两个质量最大的子团在首次近心点穿越后处于外行（内行）轨道，双体蒙特卡洛模型预测这两个子团在$0.50^{+0.20}_{-0.22}~\rm{Gyr}$（$1.24^{+0.96}_{-0.38}~\rm{Gyr}$）前发生碰撞。
英文摘要：
Addressing open questions such as the effect of galaxy cluster mergers on the evolution of galaxies and the self-interaction cross-section of dark matter requires the construction of a large, diverse sample of disturbed galaxy clusters. One contribution to such a sample is the extreme Disturbed Galaxy Cluster Sample (eDGeS), an ongoing spectroscopic study of massive disturbed and merging galaxy clusters selected from complementary surveys. Here, we present our first results from the eROSITA-selected subsample (eDGeS-eROSITA): a dynamical state analysis for the merging cluster candidate 1eRASS J025859.4-193727. We present the first spectroscopic redshift measurements for 76 galaxies in the direction of the cluster, confirming 51 as cluster members. The cluster displays a line-of-sight velocity dispersion of $σ_{\rm{cl}}=808^{+59}_{-66}~\rm{km~s^{-1}}$ and a dynamical mass of $M_{200}=4.47^{+0.94}_{-0.93} \times 10^{14}~M_{\rm{Sun}}$. While the cluster shows no evidence for substructure along the line of sight, the projected distribution of member galaxies reveals three subclusters, only one of which appears associated with the cluster's X-ray contours. Phase-space analysis reveals a large fraction of recently infallen member galaxies. Together, this evidence suggests a cluster merger along the plane of the sky. Assuming that the two most massive subclusters are on outgoing (incoming) trajectories after their first pericentric passage, a two-body Monte Carlo model predicts that the two subclusters collided $0.50^{+0.20}_{-0.22}~\rm{Gyr}$ ($1.24^{+0.96}_{-0.38}~\rm{Gyr}$) ago.
