Characterizing the Hot Halos of Galaxy Groups and Clusters with X-ray and SZ Observations
Abstract
X-ray observations have been used to characterize the gaseous halos of galaxy groups and clusters, but many of the derived quantities assume the gas is in hydrostatic equilibrium. While this assumption can be applied to relaxed systems, it becomes invalid for those not in a virialized state. Accordingly, there will be a spread in the amount of relaxation for galaxy groups/clusters within various mass bins. We evaluate this distribution by cross-correlating X-ray data with observations of the Sunyaev-Zel’dovich (SZ) effect. This study uses data from the ROSAT All-Sky Survey (RASS) near the north ecliptic pole, where the satellite attained its deepest exposure, and the SZ maps from the Planck mission. These two independent probes of the same hot gas allow us to estimate various group/cluster properties, such as the baryon fraction and the variation in gas mass spanning a halo mass range of 1013-1015 solar masses. In addition, we will catalog and inspect any groups/clusters with a detected SZ signal that are not identified in the RASS dataset; some of these objects may call for deeper X-ray observations in the future.
- Publication:
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AAS/High Energy Astrophysics Division
- Pub Date:
- March 2019
- Bibcode:
- 2019HEAD...1710706P