Approximately half of the Universe's baryons are in a form that has been hard to detect directly. However, the missing component can be traced through the cross-correlation of the thermal Sunyaev-Zeldovich (tSZ) effect with weak gravitational lensing. We build a model for this correlation and use it to constrain the extended baryon component, employing data from the Canada France Hawaii Lensing Survey and the {\it Planck\/} satellite. The measured correlation function is consistent with an isothermal β-model for the halo gas pressure profile, and the 1- and 2-halo terms are both detected at the 4σ level. In addition, we measure the hydrostatic mass bias (1−b)=0.79−0.10+0.07, which is consistent with numerical simulation results and the constraints from X-ray observations. The effective temperature of the gas is found to be in the range (7×105--3×108)\,K, with approximately 50% of the baryons appearing to lie beyond the virial radius of the halos, consistent with current expectations for the warm-hot intergalactic medium.
@article{arxiv.1404.4808,
title = {Probing the diffuse baryon distribution with the lensing-tSZ cross-correlation},
author = {Yin-Zhe Ma and Ludovic Van Waerbeke and Gary Hinshaw and Alireza Hojjati and Douglas Scott and Joe Zuntz},
journal= {arXiv preprint arXiv:1404.4808},
year = {2015}
}