An SZ Temperature Decrement - X-ray Luminosity Relation for Galaxy Clusters

We present the observed relation between ∆TSZ, the cosmic microwave background (CMB) temperature decrement due to the Sunyaev-Zeldovich (SZ) effect, and L, the X-ray luminosity of galaxy clusters. We discuss this relation in terms of the cluster properties, and show that the slope of the observed ∆TSZ−L relation is in agreement with both the L − Te relation based on numerical simulations and X-ray emission observations, and the Mgas−L relation based on observation. The slope of the ∆TSZ−L relation is also consistent with the Mtot − L relation, where Mtot is the cluster total mass based on gravitational lensing observations. This agreement may be taken to imply a constant gas mass fraction within galaxy clusters, however, there are large uncertainties, dominated by observational errors, associated with these relations. Using the ∆TSZ−L relation and the cluster X-ray luminosity function, we evaluate the local cluster contribution to arcminute scale cosmic microwave background anisotropies. The Compton distortion y-parameter produced by galaxy clusters through SZ effect is roughly two orders of magnitude lower than the current upper limit based on FIRAS observations.