Characterising galaxy clusters’ completeness function in Planck

Abstract

Galaxy cluster number counts are an important probe to constrain cosmological parameters. One of the main ingredients of the analysis is the selection function, and in particular the completeness, associated to the cluster sample one is considering. Incorrectly characterising this function can lead to biases in the cosmological constraints. In this work we study the selection function of the Planck cosmological cluster catalogue. In particular, we detail the case in which the cluster model assumed in the detection method differs from the true galaxy clusters, both in terms of profile and shape. We find that varying the cluster pressure profile has a significant effect on the completeness, with clusters with steeper profiles producing a higher completeness than ones with flatter profiles. On the other hand, cluster shapes seem to have a smaller impact on the completeness.