Exploring the Early Universe with Line-Intensity Mapping

Characterizing the early Universe --- when the first stars and galaxies thought responsible for reionization emerged, and the formation of present-day large-scale structure is set in motion --- is among the final frontiers of observational cosmology.  However, the young, faint galaxies that populate this epoch are challenging if not outright impossible to individually resolve with traditional observational techniques.  It is in this regime that we turn to statistical methods, which rely on measuring correlations in the background intensities formed by the integrated emission of all of the objects.

In this talk I describe intensity mapping of galaxies as a strategy for addressing faint and confused galaxy populations.  I will describe how continuum intensity mapping combined with stacking have been used to characterize the clustering of dusty star-forming galaxies.  And I will outline the emergence of line-intensity mapping, a field which targets spectral lines emitted by galaxies (CO, CII, etc.) to tomographically track the growth and evolution of galaxies and cosmic structure.  I will present a Status Report of the field, and the prospects for upcoming observatories including COMAP, SPHEREx, TIME, and CCAT-prime.