The Effect of Helium Sedimentation on Chandra X-ray Observations of Galaxy Clusters Abell 1835 and Abell 2204
Abstract
Recent theoretical studies predict that the inner regions of galaxy clusters are enriched by the sedimentation of Helium (He) ions into the cluster core. However, since He produces no lines at X-ray emitting temperatures, cluster masses are generally derived under the assumption that the He abundance is fixed at the Solar abundance value. In this talk we will present observational measurements of the effect of He sedimentation on X-ray derived galaxy cluster masses using high signal-to-noise Chandra X-ray observations of galaxy clusters Abell 2204 and Abell 1835. We use physically motivated analytic models of the density and temperature profile of the intra cluster medium (ICM), assuming that the gas is in hydrostatic equilibrium and has a polytropic equation of state (Bulbul et al. 2009, arXiv: 0911.2827). We model the shape of the He sedimentation profile in clusters using the simulations presented by Peng & Nagai (2009).
- Publication:
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AAS/High Energy Astrophysics Division #11
- Pub Date:
- March 2010
- Bibcode:
- 2010HEAD...11.3416B