The SRG/eROSITA all-sky survey
N. Okabe, T. H. Reiprich, S. Grandis, I. Chiu, Masamune Oguri, Keiichi Umetsu, Esra Bülbül, Y. E. Bahar, Fabian Balzer, N. Clerc, Johan Comparat, V. Ghirardini, Florian Kleinebreil, Matthias Kluge, Ang Liu, Rogério Monteiro-Oliveira, F. Pacaud, Miriam Ramos Ceja, Jeremy Sanders, Tim Schrabback, R. Seppi, Martin Sommer, Xiaoyuan Zhang
Abstract
We performed individual weak-lensing (WL) mass measurements for 78 eROSITA’s first All-Sky Survey (eRASS1) clusters in the footprint of Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) S19A. We did not adopt priors on the eRASS1 X-ray quantities or assumption of the mass and concentration relation. In the sample, we found three clusters are misassociated with optical counterparts and 12 clusters are poorly fitted with an NFW profile. The average mass for the 12 poor-fit clusters changes from ∼ 10 14 h 70 −1 M ⊙ to ∼ 2 × 10 13 h 70 −1 M ⊙ when lensing contamination from surrounding mass structures is taken into account. The scaling relations between the true mass and cluster richness and X-ray count-rate agree well with the results of the eRASS1 western Galactic hemisphere region based on count-rate-inferred masses, which were calibrated with the HSC-SSP, DES, and KiDS surveys. We developed a Bayesian framework for inferring the mass-concentration relation of the cluster sample, explicitly incorporating the effects of weak-lensing mass calibration in the mass-concentration parameter space. The redshift-dependent mass and concentration relation is in excellent agreement with predictions of dark-matter-only numerical simulations and previous studies using X-ray-selected clusters. Based on the two-dimensional (2D) WL analysis, the offsets between the WL-determined centers and the X-ray centroids for 36 eRASS1 clusters with high WL S/N can be described by two Gaussian components. We find that the miscentering effect with X-ray centroids is smaller than that involving peaks in the galaxy maps. Stacked mass maps support a small miscentering effect, even for clusters with a low WL S/N. The projected halo ellipticity is ⟨ ε ⟩ = 0.45 at M 200 ∼ 4 × 10 14 h 70 −1 M ⊙ , which is in agreement with the results of numerical simulations and previous studies of clusters characterized by masses greater than twice the mass treated here.