The role of dust reddening in observational cosmology and supernova calibration

ABSTRACT:

Modern observational cosmology suffers from worrying unsolved puzzles (i.e., Hubble tension) that can point towards the existence of unaccounted systematic biases in the observations, particularly related to the calibration of standard candles in the local distance ladder, such as Cepheids and supernovae.

In the case of type Ia supernovae (SNe Ia), this is further hinted at by the existence of a mass-step, a well-documented discrepancy between the calibrated luminosities of SNe Ia originating in low- and high-mass galaxies, which might indicate that different galaxy populations occur in different rungs of the distance ladder.

In this talk, I will discuss some attempts to improve SN Ia calibration, focusing mainly on a more detailed description of dust reddening. Furthermore, I will explore to what extent host galaxy dust data can be leveraged to improve the SN calibration.