X-RAY-SELECTED GALAXY GROUPS IN BOÖTES

We present the X-ray and optical properties of the galaxy groups selected in the Chandra X-Bootes survey. We used follow-up Chandra observations to better define the group sample and their X-ray properties. Group redshifts were measured from the AGN and Galaxy Evolution Survey spectroscopic data. We used photometric data from the NOAO Deep Wide Field Survey to estimate the group richness (N sub(gals)) and the optical luminosity (L sub(opt)). Exploring the scaling relations built with the X-Bootes sample and comparing these with samples from the literature, we find a break in the L sub(X)-M sub(500) relation at approximately M sub(500) = 5 x 10 super(13) M sub([middot in circle]) (for M sub(500) > 5 x 10 super(13) M sub([middot in circle]), M sub(500) [is proportional to] L super(0.61+ or -0.02)X, while for M sub(500) [< or =, slant] 5 x 10 super(13) M sub([middot in circle]), M sub(500) [is proportional to] L super(0.44+ or -0.05)X). Thus, the mass-luminosity relation for galaxy groups cannot be described by the same power law as galaxy clusters.