Observational constraints on the modification of standard ΛCDM cosmology with dark radiation

Abstract

We revisit a cosmological model modified by an extra “radiation-like” energy component in the Universe, which can be interpreted as many physical phenomena. Here, we derive the constraint on the energy density from this modification with current cosmological observations, including Cosmic Microwave Background, Baryon Acoustic Oscillation, Observational Hubble Parameter data and Type Ia supernovae. Performing a Bayesian analysis gives at 95% confidence level. Our work shows the dark radiation energy is small. Alleviating H 0 tension by introducing this term can also be interpreted as the systematic error caused by the numerical method.