The LX-M relation of clusters of galaxies

We present a new measurement of the scaling relation between X-ray luminosity and total mass for 17000 galaxy clusters in the maxBCG cluster sample. Stacking subsamples within fixed ranges of optical richness. N-200, we measure the mean 0.1-2.4 keV X-ray luminosity, (L-X), from the ROSAT All-Sky Survey. The mean mass, (M-200), is measured from weak gravitational lensing of SDSS background galaxies. For 9 <= N-200 < 200, the data are well fitted by a power law, (L-X)/10(42) h(-2) erg s(-1) = [12.6(-1.3)(+1.4) (stat) +/- 1.6 (sys)]((M-200)/10(14)h(-1) M-circle dot)(1.65 +/- 0.13). The slope agrees to within 10 per cent with previous estimates based on X-ray selected catalogues, implying that the covariance in L-X and N-200 at a fixed halo mass is not large. The luminosity intercept is 30 per cent, or 2 nu, lower than that determined from the X-ray flux-limited sample of Reiprich & Bohringer, assuming hydrostatic equilibrium. This slight difference could arise from a combination of Malmquist bias and/or systematic error in hydrostatic mass estimates, both of which are expected. The intercept agrees with that dervied by Stanek et al. using a model for the statistical correspondence between clusters and haloes in a WMAP3 cosmology with power spectrum normalization nu(8) = 0.85. Similar exercises applied to future data sets will allow constraints on the covariance among optical and hot gas properties of clusters at a fixed mass.