X-ray properties of DES-Y1 galaxy clusters

We examine the scaling behaviour of X-ray temperatures, T_X_, with optical richness, {lambda}_RM_, for clusters in the redshift range 0.2<z<0.7. X-ray temperatures are obtained from Chandra and XMM observations for 58 and 110 redMaPPer systems, respectively.

Despite non-uniform sky coverage, the T_X_ measurements are >50 per cent complete for clusters with {lambda}_RM_>130. Regression analysis on the two samples produces consistent posterior scaling parameters, from which we derive a combined constraint on the residual scatter, {sigma}_lnT|{lambda}_=0.275+/-0.019. Joined with constraints for T_X_ scaling with halo mass from the Weighing the Giants program and richness-temperature covariance estimates from the LoCuSS sample, we derive the richness-conditioned scatter in mass, {sigma}_lnM|{lambda}_=0.30+/-0.04_(stat)_+/-0.09_(sys)_, at an optical richness of approximately 100.