Invited Presentation

Cosmological Insights from SZE and X-ray Selected Cluster Samples: SPT, RASS and Prospects for eROSITA

Author(s): Joe Mohr (LMU)

Presenter: Joe Mohr (LMU-Munich)

Large solid angle multiwavelength surveys are a boon to studies of rare, massive galaxy clusters and their use for tests of cosmology and structure formation. In the 2500 deg^2 overlap region between the South Pole Telescope SPT-SZ survey and the Dark Energy Survey (DES), we are defining new cluster samples extending to redshifts z~1.7, characterizing the cluster halo masses using weak lensing, studying the time and mass variation of the cluster baryon content and constraining cosmological parameters. In the 5000 deg^2 overlap region of the ROSAT X-ray All Sky Survey (RASS) and DES, we have applied a new tool called MCMF to create a catalog of 2000 (mostly new) X-ray selected galaxy clusters. A crucial development is the removal of contamination caused by random superpositions of non-cluster X-ray sources with optical clusters. This sample is ~7x larger than published RASS samples over the same area, and it extends to redshift z~1. We validate the contamination and selection function for this sample, finding that the X-ray luminosity functions constructed within redshift bins extending to z=0.9 are in good agreement with expectations from externally calibrated scaling relations and cosmological parameters. These developments on the SZE and X-ray side help set the stage for the analysis of the new eROSITA cluster sample that should enable much deeper and higher precision studies than with RASS samples and that will deliver SPT mass scale clusters (>2x10^14Msun) out to z~1 over the whole sky. We highlight some cosmological studies possible for the eROSITA sample in combination with DES, HSC, Euclid and LSST weak lensing for mass calibration.