Speaker
Description
Clusters of galaxies are usually not described by simple symmetric beta models. Their morphologies are important for a number of reasons. Many physical processes talking place inside or between clusters impacts their morphology. For example, merging clusters create disturbed morphologies and cool core clusters containing AGN feedback have steeply-peaked surface brightness profiles. It is therefore important to have a good understanding of cluster morphology distributions to study their evolution and physical processes. In addition, cluster morphology impacts how they are selected in surveys such as the eROSITA all-sky survey, as it becomes easier or harder to distinguish them from point sources or background fluctuations. We describe the results of our analysis of the morphology of over 12 thousand clusters from the first eROSITA all-sky survey (eRASS1). We develop new forward-modelled parameters for characterising how disturbed clusters are, including a "slosh" parameter. We also apply existing measurements of disturbance, including concentration and inner density slopes, to our sample of clusters, taking account of the instrument PSF and background when possible. The result of this is a catalogue of parameters for each detected cluster in eRASS1. We model how these parameters impact the selection of clusters in the survey. We investigate the underlying scaling relation of several of these parameters, taking into account the effects of selection. We develop a new combined disturbance parameter. We compare our findings to previous analyses of the morphology of clusters.
