Stacking Weak-Lensing Signals of Sunyaev-Zel'dovich Clusters to Constrain Cluster Physics

We show how to place constraints on cluster physics by stacking the weak-lensing signals from multiple clusters found through the Sunyaev-Zel'dovich (SZ) effect. For a survey that covers about 200 deg² in both SZ and weak-lensing observations, the slope and amplitude of the mass versus SZ luminosity (L_SZ) scaling relation can be measured with few percent error for clusters at z ~ 0.5. This can be used to constrain cluster physics, such as the nature of feedback. For example, we can distinguish a preheated model from a model with a decreased accretion pressure at more than 5 σ. The power to discriminate among different nongravitational processes in the intracluster medium becomes even stronger if we use the central Compton parameter, y₀, which could allow one to distinguish among models with preheating, supernova feedback, and active galactic nucleus feedback at more than 5 σ. Furthermore, by measuring these relations as a function of redshift, it would be possible to directly observe, e.g., the evolution of hot gas in clusters. With this approach, the mass-L_SZ relation can be calibrated and its uncertainties can be quantified, leading to a more robust determination of cosmological parameters from cluster surveys. The mass-L_SZ relation calibrated in this way from a small area of the sky can be used to determine masses of SZ clusters from very large SZ-only surveys and is nicely complementary to other techniques proposed in the literature.