Constraining the physics of star formation from CIB-cosmic shear cross-correlations

Abstract

ABSTRACT Understanding the physics of star formation is one of the key problems facing modern astrophysics. The cosmic infrared background (CIB), sourced by the emission from all dusty star-forming galaxies since the epoch of reionization, is a complementary probe to study the star formation history, as well as an important extragalactic foreground for studies of the cosmic microwave background. In this paper, we make high signal-to-noise measurements of the cross-correlation between maps of the CIB from the Planck experiment, and cosmic shear measurements from the Dark Energy Survey and Kilo-Degree Survey. Cosmic shear is a direct tracer of the matter distribution and thus we can use its cross-correlation with the CIB to directly test our understanding of the link between the star formation rate (SFR) density and the matter density. We use our measurements to place constraints on a halo-based model of the SFR that parametrizes the efficiency with which gas is transformed into stars as a function of halo mass and redshift. These constraints are enhanced by using model-independent measurements of the bias-weighted SFR density extracted from the tomographic cross-correlation of galaxies and the CIB. We are able to place constraints on the peak efficiency at low redshifts, $\eta =0.445^{+0.055}_{-0.11}$, and on the halo mass at which this peak efficiency is achieved today log10(M1/M⊙) = 12.17 ± 0.25. Our constraints are in excellent agreement with direct measurements of the SFR density, as well as other CIB-based studies.