Vol 16, No 4

Probing the Missing Baryons via kSZ Stacking

Han Miao, Wei-Peng Lin, Peng-Jie Zhang


Abstract Kinetic Sunyaev-Zel’dovich (kSZ) stacking has great potential to become a powerful probe of missing baryons, due to advances in CMB experiments and galaxy surveys. In this paper, we study kSZ stacking in hydrodynamic simulations with different gastrophysics. We quantify the kSZ stacking signal as a function of halo mass, redshift and projection depth. We compare between different simulations to estimate the impact of gastrophysics such as cooling and supernova feedback. Furthermore, we measure the contribution from warm-hot intergalactic medium (WHIM), which is believed to be the reservoir for most, if not all, missing baryons. We find that the WHIM contribution is significant, at the level of ~ 10%–70%, depending on the angular separation from the stacked halos and other factors. However, contribution from the intracluster medium along the line of sight is in general non-negligible. This complexity requires more detailed and comprehensive analysis on probing the missing baryons with kSZ stacking.


Keywords cosmology: theory — large scale structure — kinetic Sunyaev-Zel’dovich effect — missing baryons

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