The eROSITA Final Equatorial-Depth Survey (eFEDS)
I. Chiu, V. Ghirardini, Ang Liu, S. Grandis, Esra Bülbül, Y. E. Bahar, Johan Comparat, S. Bocquet, N. Clerc, Matthias Klein, Teng Liu, Xiangchong Li, Hironao Miyatake, J. J. Mohr, Surhud More, Masamune Oguri, N. Okabe, F. Pacaud, M. E. Ramos-Ceja, T. H. Reiprich, T. Schrabback, Keiichi Umetsu
Abstract
We present the first weak-lensing mass calibration and X-ray scaling relations of galaxy clusters and groups selected in the eROSITA Final Equatorial Depth Survey (eFEDS) observed by Spectrum Roentgen Gamma/eROSITA over a contiguous footprint with an area of ≈140 deg 2 , using the three-year (S19A) weak-lensing data from the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey. In this work, we study a sample of 434 optically confirmed galaxy clusters (and groups) at redshift 0.01 ≲ z ≲ 1.3 with a median of 0.35, of which 313 systems are uniformly covered by the HSC survey to enable the extraction of the weak-lensing shear observable. In a Bayesian population modeling, we perform a blind analysis for the weak-lensing mass calibration by simultaneously modeling the observed count rate η and the shear profile g + of individual clusters through the count-rate-to-mass-and-redshift ( η - M 500 -z) relation and the weak-lensing-mass-to-mass-and-redshift ( M WL - M 500 -z) relation, respectively, while accounting for the bias in these observables using simulation-based calibrations. As a result, the count-rate-inferred and lensing-calibrated cluster mass is obtained from the joint modeling of the scaling relations, as the ensemble mass spanning a range of 10 13 h -1 M ⊙ ≲ M 500 ≲ 10 15 h -1 M ⊙ with a median of ≈10 14 h -1 M ⊙ for the eFEDS sample. With the mass calibration, we further model the X-ray observable-to-mass-and-redshift relations, including the rest-frame soft-band and bolometric luminosity ( L X and L b ), the emission-weighted temperature T X , the mass of intra-cluster medium M g , and the mass proxy Y X , which is the product of T X and M g . Except for L X with a steeper dependence on the cluster mass at a statistically significant level, we find that the other X-ray scaling relations all show a mass trend that is statistically consistent with the self-similar prediction at a level of ≲1.7σ. Meanwhile, all these scaling relations show no significant deviation from the self-similarity in their redshift scaling. Moreover, no significant redshift-dependent mass trend is present. This work demonstrates the synergy between the eROSITA and HSC surveys in preparation for the forthcoming first-year eROSITA cluster cosmology.