Effects of Type Ia Supernovae Absolute Magnitude Priors on the Hubble Constant Value

Abstract

We systematically explore the influence of the prior of the peak absolute magnitude ( M ) of Type Ia supernovae (SNe Ia) on the measurement of the Hubble constant ( H 0 ) from SNe Ia observations. We consider five different data-motivated M priors, representing varying levels of dispersion, and assume the spatially flat ΛCDM cosmological model. Different M priors lead to relative changes in the mean values of H 0 from 2% to 7%. Loose priors on M yield H 0 estimates consistent with both the Planck 2018 result and the SH0ES result at the 68% confidence level. We also examine the potential impact of peculiar velocity subtraction on the value of H 0 and show that it is insignificant for the SNe Ia observations with redshift z > 0.01 used in our analyses. We also repeat the analysis in the cosmography model and find very similar results. This suggests that our results are robust and model independent.