Speaker
Description
In this study, we cross-match the cluster catalog selected by the red-sequence Matched-filter Probabilistic Percolation algorithm (redMaPPer) from the Dark Energy Survey year 3 data (DES-Y3) with the first galaxy cluster catalog from the SRG/eROSITA all sky survey (eRASS:1). The main objective is to investigate the contamination level of the optically selected cluster sample using X-ray selected clusters by eROSITA. Out of 869,335 redMaPPer clusters, 617,859 fall within the eROSITA survey area. By decoupling the real match and random match components in the cross-matching, we calculate the detection fractions of redMaPPer clusters across 5×3 measured richness and redshift bins. We find that 2,124 out of 36,877 (~6%) redMaPPer clusters with measured richness λ>20 are detected in the eROSITA primary cluster catalog. To predict the richness-dependent detection fractions, we utilize the hierarchical Bayesian cluster population model framework, within which we apply a projection optical error model to account for the impact of correlated structures, masking, and percolation on the mapping between intrinsic and measured richness, and employ the posteriors on the richness–mass scaling relation parameters from cosmology analysis of eROSITA to forward model the detection probabilities of redMaPPer clusters.
