Interpreting the cosmic far-infrared background anisotropies using a gas regulator model

Cosmic far-infrared background (CFIRB) is a powerful probe of the history of star formation rate and the connection between baryons and dark matter. In this work, we explore to which extent the CFIRB anisotropies can be reproduced by a simple physical framework for galaxy evolution, the gas regulator (bathtub) model. The model is based on continuity equations for gas, stars, and metals, taking into account cosmic gas accretion, star formation, and gas ejection. Our model not only provides a good fit to the CFIRB power spectra measured by Planck, but also agrees well with the correlation between CFIRB and gravitational lensing, far-infrared galaxy number counts, and bolometric infrared luminosity functions. The strong clustering of CFIRB indicates a large galaxy bias, which corresponds to haloes of mass 10M at z = 2; thus, CFIRB favors strong infrared emission in massive haloes, which is higher than the expectation from the star formation rate. We provide constraints and fitting functions for the cosmic star formation history and the infrared luminosity–halo mass relation.