Oral Presentation

Matching the XXL and HSC-CAMIRA cluster samples: Lessons in selection bias and cluster astrophysics

Author(s): Jon Willis Miriam Ramos-Ceja Masamune Oguri Fabio Gastaldello

Presenter: Jon Willis (University of Victoria)

We present the results of matching the 151 XXL X-ray selected and 289 HSC-CAMIRA optically selected cluster catalogues within the 20 deg2 common data footprint. In addition, we perform X-ray aperture photometry on clusters from both samples and compare these measures to the optical richness computed for all clusters employing the CAMIRA algorithm. Sixty-five percent of X-ray clusters are matched to CAMIRA clusters above the selection limits of each survey. Of perhaps greater interest are the clusters lying above the nominal selection limits of each survey that remain undetected, i.e. optically rich X-ray clusters undetected by CAMIRA and nominally massive optical clusters undetected by XXL. While selection bias undoubtedly plays a role in this analysis we demonstrate that cluster relaxation state plays a non-negligible role in the detectability of clusters at wavelengths beyond those employed for discovery.