Hot gas accretion in cluster outskirts
Abstract
The baryonic content of galaxy clusters grows through the accretion of hot gas over cosmic time. Still at the present epoch accretion processes should be important in the outer regions of clusters, rendering the distribution of X-ray emission clumpy and asymmetric. We present a method based on the azimuthal median to estimate the gas clumping factor and recover unbiased density profiles. We apply this method to a sample of 31 clusters observed with ROSAT/PSPC, and compare with the expectations of hydrodynamical simulations. We also present the results of an XMM mosaic program of the clusters A2142 and Hydra A, in which we discovered accreting substructures around the cluster's virial radius. In particular, we report the XMM discovery of a spectacular X-ray tail in A2142, which we use to set constraints on thermal conduction in the ICM.
- Publication:
-
The X-ray Universe 2014
- Pub Date:
- July 2014
- Bibcode:
- 2014xru..confE..69E