Title: X-ray in Galaxy Groups: Physical Origins, Redshift Evolution, and Tensions Between Simulations and Observations

Speaker: 郑云亮

Institute: 上海交通大学

Host: 高玉龙

Time: 2026.1.13 周二 10:00 - 11:30

Location: 睿智楼三楼会议室

Abstract: We use the first eROSITA all-sky survey to investigate the contributions of AGN and extended gas to total X-ray luminosity of galaxy groups. We find a correlation between the X-ray luminosity of central AGN and extended gas. However, once we account for the potential offset, their correlation becomes less prominent. By comparing the observational results with predictions from cosmological simulations, we find that many simulations systematically overestimate the X-ray luminosities of galaxy groups, and that differences in feedback implementations lead to markedly different redshift evolutions of the X-ray emission. Regardless of the feedbacks adopted, the AGN accretion rate is tightly correlated with the properties of the hot gas within the halo, which is qualitatively consistent with the observational evidence. AGN feedback also induces angular dependence in the hot gas: compared to the equatorial directions, the gas along the polar directions is hotter and exhibits a more vigorous baryon cycle.

Bio: 郑云亮，上海交通大学博士后，主要从事星系形成演化、暗物质晕特性及星系团X射线观测等天体物理前沿研究。2015-2021年在中国科学院上海天文台获得天体物理学博士学位，期间在中国科学技术大学完成联合培养，并自2022年起在上海交大开展博士后工作。研究聚焦于星系群团的X射线多波段性质，擅长结合观测数据（如DESI星系群、eROSITA巡天）与数值模拟开展系统性分析。目前他主持中国博士后科学基金项目，致力于通过eROSITA全天空巡天数据揭示星系团X射线辐射机制。已发表多篇高水平论文（如MNRS、ApJ等期刊）。