090275

Stacking of SZ signals (Y) by stellar mass produces a significant signal which has been used to infer the halo gas mass of galaxies. Interpreting the stacked signal assumes the Y distribution (at fixed M*) is narrow symmetric and for a uniform sample of objects. These conditions are violated when stacking in stellar mass bins so one must understand the distribution of Y as a function of galaxy environment (M* gal/M*tot). This cannot be obtained from the weak individual SZ signals but can be inferred from X-ray observations. We propose to complete our X-ray studies of 15 nearby galaxies that were previously used in a stack of SZ signals. We will measure the distribution of Y _X (X-ray analog of SZ) to quantify the dependence of halo gas mass on galaxy environment. [truncated! Please see actual data for full text]