2025/05/30 by Avila, Felipe, Rivera, Alexander Bonilla, Nunes, Rafael C. +2 · 2 citations
#Cosmology and Nongalactic Astrophysics (astro-ph.CO) #FOS: Physical sciences
paper · doi:10.48550/arxiv.2505.24543
In this work, we perform a statistical inference of the classical background law governing the evolution of the temperature of the cosmic microwave background radiation (CMB), given by T\rm CMB(z) = T0(1 + z). To this end, we employ Gaussian Process (GP) regression techniques to reconstruct the temperature evolution based on two observational datasets: (i) CMB-Sunyaev-Zel'dovich (SZ) cluster measurements and (ii) CMB-interstellar medium (ISM) interaction data. Our analysis reveals interesting results that may suggest potential deviations from the standard temperature-redshift relation, particularly at low redshifts (z < 0.5), where discrepancies up to ∼2σ are observed. Additionally, we identify a mild but noteworthy tension, also at the ∼2σ level, between our GP inferred value of the present-day CMB temperature, T\rm CMB(z=0), and the precise direct measurement from the COBE/FIRAS experiment. We also explore possible phenomenological implications of our findings, including interpretations associated with possible variations in fundamental constants, such as the fine-structure constant α, which could provide a physical explanation for the observed deviations at low redshift.