학술논문
The SRG/eROSITA All-Sky Survey. Optical identification and properties of galaxy clusters and groups in the western galactic hemisphere
Document Type
Working Paper
Author
Kluge, M.; Comparat, J.; Liu, A.; Balzer, F.; Bulbul, E.; Chitham, J. Ider; Ghirardini, V.; Garrel, C.; Bahar, Y. E.; Artis, E.; Bender, R.; Clerc, N.; Dwelly, T.; Fabricius, M. H.; Grandis, S.; Hernández-Lang, D.; Hill, G. J.; Joshi, J.; Lamer, G.; Merloni, A.; Nandra, K.; Pacaud, F.; Predehl, P.; Ramos-Ceja, M. E.; Reiprich, T. H.; Salvato, M.; Sanders, J. S.; Schrabback, T.; Seppi, R.; Zelmer, S.; Zenteno, A.; Zhang, X.
Source
A&A 688, A210 (2024)
Subject
Language
Abstract
The first SRG/eROSITA All-Sky Survey (eRASS1) provides the largest intracluster medium-selected galaxy cluster and group catalog covering the western galactic hemisphere. Compared to samples selected purely on X-ray extent, the sample purity can be enhanced by identifying cluster candidates using optical and near-infrared data from the DESI Legacy Imaging Surveys. Using the red-sequence-based cluster finder eROMaPPer, we measured individual photometric properties (redshift $z_\lambda$, richness $\lambda$, optical center, and BCG position) for 12,000 eRASS1 clusters over a sky area of 13,116 deg$^2$, augmented by 247 cases identified by matching the candidates with known clusters from the literature. The median redshift of the identified eRASS1 sample is $z=0.31$, with 10% of the clusters at $z>0.72$. The photometric redshifts have an accuracy of $\delta z/(1+z)<0.005$ for $0.0595% for $z>0.05$. For these and further quality assessments of the eRASS1 identified catalog, we applied our identification method to a collection of galaxy cluster catalogs in the literature, as well as blindly on the full Legacy Surveys covering 24,069 deg$^2$. Using a combination of these cluster samples, we investigated the velocity dispersion-richness relation, finding $\log(\lambda)=2.401\times\log(\sigma)-5.074$ with an intrinsic scatter of $0.10\pm0.01$ dex. Our main result is the identified eRASS1 cluster catalog with a high purity and a well-defined X-ray selection process, enabling precise cosmological analyses presented in companion papers.
Comment: 36 pages, 23 figures, 6 tables. Accepted for publication in A&A
Comment: 36 pages, 23 figures, 6 tables. Accepted for publication in A&A