Modeling the Extragalactic Background Light and the Cosmic Star Formation History

TL;DR

This paper introduces an updated, comprehensive model of the extragalactic background light (EBL) that incorporates stellar spectra, dust processes, and cosmic evolution, constrained by diverse observational data.

Contribution

It presents a novel, self-consistent model of the EBL that accounts for star formation, dust, and galaxy evolution, fitted to multiple observational datasets.

Findings

Constraints on star formation rate density up to redshift 10

Estimated dust photon escape fraction over cosmic time

Model results sometimes below observed EBL and gamma-ray absorption limits

Abstract

We present an updated model for the extragalactic background light (EBL) from stars and dust, over wavelengths approximately 0.1 to 1000 $\mu$m. This model uses accurate theoretical stellar spectra, and tracks the evolution of star formation, stellar mass density, metallicity, and interstellar dust extinction and emission in the universe with redshift. Dust emission components are treated self-consistently, with stellar light absorbed by dust reradiated in the infrared as three blackbody components. We fit our model, with free parameters associated with star formation rate and dust extinction and emission, to a wide variety of data: luminosity density, stellar mass density, and dust extinction data from galaxy surveys; and $\gamma$-ray absorption optical depth data from $\gamma$-ray telescopes. Our results strongly constraint the star formation rate density and dust photon escape fraction of the universe out to redshift $z=10$, about 90% of the history of the universe. We find our model result is, in some cases, below lower limits on the $z=0$ EBL intensity, and below some low-$z$ $\gamma$-ray absorption measurements.