How recent limits on the extragalactic background light constrain the star formation history

Abstract

The cosmic star formation rate density (SFRD) is one of the fundamental quantities of cosmology. The SFRD is intimately connected with the extragalactic background light (EBL), i.e., the diffuse meta-galactic photon field in the ultraviolet to infrared, which is dominated by the emission from stars in galaxies. Directly measuring the EBL is difficult due to dominant foreground emission in our solar system and galaxy. However, stringent upper limits on its density are derived from observations of distant sources of very high energy (VHE; E>100 GeV) gamma-rays. Here, recent strong limits on the EBL density are used derive constraints on the SFRD. The stellar EBL contribution is modeled using detailed spectra from simple stellar population modeling. Dust attenuation and re-emission are included. A wide range of values for the different model parameters is investigated and their impact on the resulting EBL is studied. The EBL modeling is then compared with EBL constraints to derive limits on the SFRD. Here, results from this study are reported and implications for the SFRD are discussed.