Characterizing Galaxy Cluster Temperature Distributions
Abstract
Galaxy clusters are important tools for cosmology, particularly via their X-ray properties. Additionally, much of the physics of galaxy clusters is complex and not yet well understood. Both are complicated by a wealth of temperature substructure in the ICM, including shocks, X-ray cavities, cooling flows, and cold fronts. We aim to characterize both the shape and width of galaxy cluster temperature distributions, and search for correlations with other cluster properties, including median cluster temperature, luminosity, and size. We use a Markov Chain Monte Carlo analysis which models the ICM as a collection of X-ray emitting smoothed particles of plasma. Each smoothed particle is given its own set of parameters, including temperature, spatial redshift, size, and emission measure. This allows us to measure the width of the temperature distribution, median temperature, total emission measure, and a characteristic cluster radius, as well as to characterize the shape of the temperature distribution. We apply this method to XMM-Newton observations of the HIFLUGCS galaxy cluster sample. We find that the temperature distribution is approximately log normal. Of 53 clusters, 19 have a temperature width consistent with isothermality, the remaining 34 clusters have a temperature width equal to approximately one-fourth of their median temperature.
- Publication:
-
American Astronomical Society Meeting Abstracts #219
- Pub Date:
- January 2012
- Bibcode:
- 2012AAS...21933813F