Weak lensing, thermal SZ effect and baryons : Implications for ICM gastrophysics and galaxy-galaxy lensing

Abstract: A recent detection of a correlation between gravitational lensing by large scale structure (from CFHTLenS survey) and the thermal Sunyaev-Zeldovich effect (constructed from Planck maps) is discussed. Further theoretical predictions, as well as investigations from hydro simulations, to characterize the origin of the detected signal is described. We demonstrate that a significant proportion of the signal originates from the regions beyond the virial radius of clusters, and that more than half of the baryons in the Universe are in the form of diffuse gas outside halos which is not hot or dense enough to produce a significant tSZ signal or be observed by X-ray experiments. We also demonstrate that future high-resolution tSZ-lensing cross-correlation observations will serve as a powerful tool for discriminating between different galactic feedback models. Higher order statistics that can better discriminate the impact of baryonic feedback and the consequences for galaxy-galaxy lensing measurements on small scales (~ arcminuite) are also investigated.