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 $\hat{I}›$CDM 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.

10 pages, 1 figure, 1 table; Accepted for Publication in ApJL