Cosmic census: Relative distributions of dark matter, galaxies, and diffuse gas

Abstract

Galaxies, diffuse gas, and dark matter make up the cosmic web that defines the large-scale structure of the Universe. We constrained the joint distribution of these constituents by cross-correlating galaxy samples binned by stellar mass from the Sloan Digital Sky Survey CMASS catalog with maps of lensing convergence and the thermal Sunyaev-Zeldovich (tSZ) effect from the Planck mission. Fitting a halo-based model to our measured angular power spectra (galaxy-galaxy, galaxy-lensing convergence, and galaxy-tSZ) at a median redshift of z = 0.53, we detected variation with stellar mass of the galaxy satellite fraction and galaxy spatial distribution within host halos. We find a tSZ-halo hydrostatic mass bias, bh, such that (1 − bh) = 0.6 ± 0.05, with a hint of a larger bias, bh, at the high stellar mass end. The normalization of the galaxy-cosmic microwave background lensing convergence cross-power spectrum shows that galaxies trace the matter distribution without an indication of stochasticity (A = 0.98 ± 0.09). We forecast that next-generation cosmic microwave background experiments will improve the constraints on the hydrostatic bias by a factor of two and will be able to constrain the small-scale distribution of dark matter, hence informing the theory of feedback processes.