Constraining the Extragalactic Background Light (EBL) using the 50-MGC Galaxy Catalog

Abstract

This study quantitatively restricts Olbers’ Paradox by evaluating the intensity of the extragalactic background light (EBL) in the optical B-band. Utilizing the 50-MGC galaxy catalog, we establish the numerical densities and intrinsic luminosities of nearby galaxies. To construct a physical model, the local galactic demography was decoupled into star-forming and quiescent populations, evaluating their distinct stellar content. By applying stellar population synthesis and empirical mass assembly metrics, we modeled the continuous evolution of these populations across cosmic time. The comoving numerical density and mean luminosity functions were integrated over redshift to compute the total radiative flux across varying Hubble parameter values (H0)—representing the Planck, Riess, and GM-UYF frameworks—while maintaining constant matter-energy densities. The results demonstrate that while assuming a constant numerical density and luminosity yields fluxes within observational limits, this approach is severely biased. Conversely, extrapolating local redshift-dependent regressions severely underestimates the optical background. We conclude that incorporating decoupled galactic evolution, alongside a galactic extinction filter (|b|>45), is necessary to reconcile theoretical EBL fluxes with empirical limits, successfully resolving the divergent integral of Olbers’ Paradox.