【学术报告】

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报告题目：Detection of galaxy clusters in X-ray wavelength

报告人：徐伟伟  博士后

报告人单位：北京大学科维理天文与天体物理研究所

报告时间：2019年5月21日（星期二）下午3:00—4:00

报告地点：主楼427会议室

报告语言：中文（英文）

报告摘要： 

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Some indications for tension have long been identified between cosmological constraints obtained from galaxy clusters and primary cosmic microwave background (CMB) measurements. This has been reinforced recently by the Planck collaboration. One possible explanation could be that certain types of galaxy groups or clusters were missed in previous samples, resulting in a higher incompleteness than estimated. In this talk, I will present the project of detecting a hypothetical class of very extended, low-surface-brightness galaxy groups or clusters have been missed in previous X-ray cluster surveys based on the ROSAT All-Sky Survey (RASS). We obtain ~1000 galaxy cluster candidates in almost all-sky region. Besides many known clusters, we also detect a number of new candidates, which are not included in any previous cluster catalogs detected in X-ray band or from Sunyaev-Zel’dovich effect. By the research about a pilot sample in detail, we find some of the new-detected galaxy groups are with low redshift, low mass and flat surface-brightness profile that lie above the nominal flux limits of previous RASS-based cluster catalogs. In this project, we demonstrate that some galaxy groups were indeed missed in previous RASS surveys, possibly due to the flat surface-brightness distributions of this potential new population.

报告人简介：

Dr. Xu is now working as a postdoc in KIAA with Prof. Jianglin Hua. She received her PhD in January 2019 from NAOC, supervised by Prof. Lijun Gou. In 2016, Weiwei received the CAS-DAAD scholarship, with which she spent two years at the Argelander Institute for Astronomy, University of Bonn, working with Prof. Thomas Reiprich on the identification of galaxy clusters in X-ray data. Before that, Weiwei received her B.S degree at Shandong University in 2011, and then a master degree at NAOC in 2014. Her research interests include X-ray research about galaxy cluster, AGN and X-ray binary. In this talk, she will talk about her recent work on ROSAT data about the detection of galaxy clusters.

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本通知也可以在云台学术报告网页看到： 

http://www.ynao.cas.cn/xwzx/xstg/ 

申请安排学术报告的同事请参见台学术报告管理办法： 

http://www.ynao.cas.cn/xwzx/xstg/gzzd/ 

云台邀请团组：

大样本恒星演化组  

邀请方联系人：柳正伟 （18988479252）

5月18日