An empirical approach to the extragalactic background light from AEGIS galaxy SED-type fractions

TL;DR

This paper introduces a novel observational method to empirically determine the evolving extragalactic background light spectrum across a wide wavelength range, providing new insights into galaxy evolution and gamma-ray astronomy.

Contribution

It presents a new observational approach to derive the EBL spectrum directly from galaxy SED-type fractions over a broad redshift range, without relying on models.

Findings

The local EBL is well constrained from UV to mid-IR wavelengths.

Multiple independent methods agree on the EBL intensity level.

Pop III stars likely do not significantly contribute to the local EBL.

Abstract

The extragalactic background light (EBL) is of fundamental importance both for understanding the entire process of galaxy evolution and for gamma-ray astronomy. However, the overall spectrum of the EBL between 0.1 and 1000 microns has never been determined directly neither from observed luminosity functions (LFs), over a wide redshift range, nor from any multiwavelength observation of galaxy spectral energy distributions (SEDs). The evolving, overall spectrum of the EBL is derived here utilizing a novel method based on observations only. It is emphasized that the local EBL seems already well constrained from the UV up to the mid-IR. Since different independent methodologies such as direct measurement, galaxy counts, gamma-ray attenuation and realistic EBL modelings point towards the same EBL intensity level. A relevant contribution from Pop III stars to the local EBL seems unlikely.