Exploring the Outskirts of Galaxy Clusters
Abstract
A number of recent studies have traced the hot intracluster medium (ICM) to the virial radius in a sizeable sample of galaxy clusters. These results have begun to clarify the thermodynamic conditions at the edge of clusters, constraining models of cluster growth and evolution, yet the observations are challenging and bedeviled by a host of systematic issues due to the very low ICM surface brightness in the cluster outskirts. We are currently embarked on a program to observe a sample of about ten relaxed clusters with Suzaku, fully imaging each cluster to beyond R_200, and leveraging complementary data from XMM-Newton and Chandra. Our results support the idea that the ICM is not in hydrostatic equilibrium in the cluster outskirts, where we see indications of low-entropy substructures and some evidence for azimuthal variations in temperature and surface brightness. I will present the latest results from this project, explore the possible sources of systematic error, and discuss the remarkable ``universality'' of thermodynamic profiles to the outer limits of galaxy clusters.
- Publication:
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AAS/High Energy Astrophysics Division #14
- Pub Date:
- August 2014
- Bibcode:
- 2014HEAD...1411102M