Masses of galaxy clusters and groups in eFEDS

In a joint selection on X-ray and optical observables, the sample contains 455 clusters within a redshift range of 0.1 < z < 1.2, of which 177 systems are covered by the public data from the Hyper Suprime-Cam (HSC) survey that enables uniform weak-lensing cluster mass constraints.

With minimal assumptions, at each cluster redshift we empirically model (1) the scaling relations between the cluster halo mass and the observables, which include the X-ray count rate, the optical richness, and the weak-lensing mass, and (2) the X-ray selection in terms of the completeness function C. Using the richness distribution of the clusters, we directly measure the X-ray completeness and adopt those measurements as informative priors for the parameters of C. In a blinded analysis, we obtain the cosmological constraints {omega}_m_=0.245^+0.048^_-0.058_, {sigma}_8_=0.833^+0.075^_-0.063_, and S_8_ = {sigma}_8_({omega}_m_/0.3)^0.3^ = 0.791^+0.028^_-0.031_ in a flat LCDM cosmology.