Spectroscopic members of COSMOS X-ray systems

The COSMOS X-ray system catalog we use includes 180 X-ray systems to a limiting flux of 1.0x10^-15^erg/cm^2^/s, an order of magnitude deeper than the future e-ROSITA survey. We identify spectroscopic members of these X-ray systems based on the spectroscopic catalog constructed by compiling various spectroscopic surveys including 277 new measurements; 146 X-ray systems are spectroscopically identified groups with more than three spectroscopic members.

We identify 2196 spectroscopic redshifts of member candidates in these X-ray systems. The X-ray luminosity (L_X_)-velocity dispersion ({sigma}_v_) scaling relation of the COSMOS X-ray systems is consistent with that of massive X-ray clusters. One of the distinctive features of the COSMOS survey is that it covers the X-ray luminosity range where poor groups overlap the range for extended emission associated with individual quiescent galaxies.