Cluster Mergers: Chandra Studies of the Most Massive Clusters of Galaxies in the Universe

Speaker: Dr. Christine Jones (Center for Astrophysics | Harvard & Smithsonian)

Date: 2020/1/14, Tuesday, 11 am

Room: Science hall B102

Language: English

Abstract:

Clusters of galaxies are the most massive gravitationally bound structures in the Universe. While most of the mass in clusters is in the form of dark matter, the dominant baryonic component in clusters is the hot X-ray emitting gas. The hot intracluster gas can be detected and mapped directly through its X-ray emission and also through the Sunyaev-Zeldovich effect. In this talk, I will first focus on the Chandra observations of a few particularly interesting clusters of galaxies, including those in the HST Frontier Fields. I will present our understanding of the differences in selecting cluster samples from X-ray missions compared to cluster samples derived from the Planck mission, which are based on the Sunyaev-Zeldovich effect. In particular, there is a higher fraction of clusters in the X-ray samples that are relaxed and centrally peaked in their X-ray emission, compared to a higher fraction of clusters in Planck selected samples that are disturbed systems. 

In addition, I also will review the use of clusters as gravitational lenses to magnify and detect background (high redshift) galaxies. In particular, we have obtained HST observations of 41 massive clusters of galaxies in the HST RELICS (the Reionization Lensing Cluster Survey, PI D. Coe). We have discovered more than 300 redshift 6 to 10 gravitationally lensed galaxy candidates, including the brightest known redshift 6 candidates and the most distant spatially resolved lensed arc at z~10.