Late Time Dynamical Dark Energy and the CMB-Distance Ladder Tension

Abstract

The traditional distance ladder measures the standardized peak absolute magnitude M^B of Type Ia supernovae (SNIa). According to the SH0ES collaboration, the distance ladder value of M^B is highly discrepant with the value inferred from the cosmic microwave background (CMB) assuming the LCDM cosmology. This CMB-distance ladder tension is insensitive to the actual late time expansion history of the Universe. To derive a value of the Hubble constant H_0, from M^B requires a cosmological model. However, the magnitude-redshift relation of SNIa provides tight constrains the expansion history. As a consequence, uncertainties in the conversion of M^B into H_0 have no significant impact on the CMB-distance ladder tension. The tentative claim by the Dark Energy Spectroscopic Instrument collaboration for late time evolution of the dark energy equation of state does not alter this conclusion.