Speaker
Description
The SRG/eROSITA all-sky survey delivers an unprecedented X-ray scan of the whole sky, which offers a great opportunity for large-scale structure studies. At the same time, the Subaru telescope is amongst the deepest and most powerful optical instruments, which provides a large selection of optically selected galaxy clusters via the detection of the overdensities of the red sequence galaxy population. We present a study focusing on the X-ray properties of optically selected galaxy clusters, leveraging data from the 140 deg2 field eROSITA Final Equatorial Depth Survey (eFEDS) and the Subaru telescope (Nguyen-Dang et al in prep.; Ota et al. 2023). Our analysis encompasses a sample of nearly 1000 optically selected galaxy clusters, offering insights into their X-ray characteristics. Notably, only about 20% of these optically selected clusters are detected in X-rays, motivating the application of stacking analysis to investigate the properties of faint X-ray clusters. Our findings reveal significant differences between the X-ray properties of optically selected clusters and those of X-ray-selected samples. Additionally, we explore the dynamical state of these clusters and establish relationships between their luminosity, richness, and weak-lensing mass. Our results contribute to understanding cluster selection effects and inform cosmological models concerning the formation and evolution of galaxy clusters.
