A halo model for baryonic gas: intensity mapping through the end stages of reionization

Intensity mapping of emission lines such as HI, CO and CII has emerged as a novel probe of large scale structure, galaxy formation and the epoch of reionization of the Universe. We develop data driven halo models to describe the distribution of these baryonic tracers, obtaining the best-fitting parameters from a rich sample of low redshift galaxy emission line studies, intermediate redshift intensity mapping experiments, and higher redshift Damped Lyman Alpha (DLA) observations. Our models describe the abundance and clustering of HI, CO and CII across redshifts 0 - 6, and can be used to investigate several aspects of cosmology and astrophysics. In particular, we explore what the recent intensity mapping detections inform us about the evolution of the baryonic gas abundance and clustering across redshifts, and develop sensitivity forecasts for current and planned intensity mapping experiments.