Contributed Talk - Splinter eROSITA

Wednesday, 14 September 2022, 16:59   (SFG 0140 / virtual eROSITA)

Cosmological Constraints from Galaxy Clusters and Groups in the eROSITA Final Equatorial Depth Survey

I-Non Chiu; Matthias Klein; Joseph Mohr; Sebastian Bocquet
National Cheng Kung University

We present the first cosmological constraints using the cluster abundance of a sample of eROSITA clusters, which were identified in the eROSITA Final Equatorial Depth Survey (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 a uniform weak-lensing mass calibration. In a framework of empirical modelling and blind analysis, we simultaneously model the cosmology, the X-ray selection, and the observable-to-mass-and-redshift relations with the observables including the X-ray count rate, the optical richness, and the weak-lensing mass. As a result, we deliver cosmological constraints that are in excellent agreement (at a level of < 1 sigma) with the results from the Planck mission, the galaxy-galaxy lensing and clustering analysis of the Dark Energy Survey, and the cluster abundance analysis of the SPT-SZ survey. This work not only presents the first fully self-consistent cosmological constraints obtained in a synergy between wide-field X-ray and weak-lensing surveys, but also demonstrates the success of the empirical modeling in X-ray cluster cosmology studies.