【4.21; Seminar】2025年粒子天体物理全国重点实验室系列学术报告 #6：Identification of X-ray extended galaxy clusters and the research of dark matter halos

时间/Time：4月21日周一上午10:00/ 21 Apr. Monday 10:00

地点/Location：主楼419会议室/Meeting Room 419, Main Building

线上会议/Online Meeting：腾讯会议 377-323-760

报告人/Speaker：徐伟伟/ Dr. Weiwei Xu

题目/Title：Identification of X-ray extended galaxy clusters and the research of dark matter halos

主持人/Host：陈勇/ Dr. Yong CHEN

日程/schedule：Report 40 min; Question 30 min

摘要/Abstract: To explain the well-known tension between cosmological parameter constraints obtained from the primary cosmic microwave background (CMB) and those drawn from X-ray-selected galaxy cluster samples identified with early data, we propose a possible explanation for the incompleteness of detected clusters being higher than estimated, and suggest that certain types of galaxy groups or clusters may have been overlooked in previous works. In this talk, I will present our projects to identify galaxy clusters with especially extended X-ray surface brightness distributions, using a dedicated algorithm optimized for extended sources. We creat a new X-ray-selected catalog of extended galaxy clusters from the XMM-SERVS data, called the XVXGC catalog (Xu+24b), as well as an X-ray selected catalog of extended galaxy clusters from the ROSAT All-Sky Survey data, called the RXGCC catalog (Xu+22, Xu+18). In our catalogs, we find that the newly detected clusters with the Intra-Cluster Medium (ICM) are systematically fainter and exhibit flatter surface brightness profiles than previously ICM-detected clusters. In addition, we stack the weak lensing signal of multiple halos with the galaxy-galaxy lensing (gglens) method, to constraint the average profile of halos, such as the concentration-mass relation ((c-M relation, Xu+21), and the splashback radius for halos (Xu+24a), and find consistent results with the simulation.

报告人简介/Bibliography: Dr. Xu is now working as an assistant researcher in National Astronomical Observatories, Chinese Academy of Sciences(NAOC), after her three years postdoc at KIAA at Peking University. She received her PhD in 2019 from NAOC. From 2016 to 2018, Weiwei visited the Argelander Institute for Astronomy, University of Bonn. Her research interests include X-ray research about galaxy clusters and the weak lensing effect of their dark matter halos.