Abstract: The light emitted by all galaxies across cosmic time is encoded in the extragalactic background light (EBL), the diffuse background spanning ultraviolet to infrared wavelengths. Through electron positron pair production, the EBL acts as a source of opacity for very-high-energy gamma rays, leaving a distinct attenuation imprint on the spectra of distant sources. In this seminar, I will report on new EBL measurements derived from both the Fermi Large Area Telescope and ground-based Imaging Atmospheric Cherenkov Telescopes. These measurements allow us to constrain the cosmic star formation history and provide an independent measurement of the Hubble constant and cosmic matter density. These results demonstrate that high-energy astrophysics provides competitive cosmological constraints complementary to traditional astronomical surveys.

Speaker Bio: Alberto Dominguez is a Professor at Universidad Complutense de Madrid and a member of IPARCOS. He received his PhD in Astrophysics from Universidad de Sevilla in 2011, focusing on the extragalactic background light (EBL) and gamma-ray astronomy. He held postdoctoral positions at the University of California, Riverside, and Clemson University, USA, before returning to Madrid, where he was a Ramón y Cajal Fellow. His research focuses on gamma-ray cosmology, the EBL, galaxy evolution, and multiwavelength emission from active galaxies, with a focus on the high-energy regime.