The tension in the absolute magnitude of Type Ia supernovae · arXivDesk
2307.02434Jul 5, 2023Invited chapter for the edited book Hubble Constant Tension (Eds. E. Di Valentino and D. Brout, Springer Singapore, expected in 2024)
The tension in the absolute magnitude of Type Ia supernovae
This study aims to elucidate the tension in the Hubble constant (H0), a key metric in cosmology representing the universe's expansion rate. Conflicting results from independent measurements such as the Planck satellite mission and the SH0ES collaboration have sparked interest in exploring alternative cosmological models. We extend the analysis by SH0ES to an arbitrary cosmographic model, obtaining a competitive local H0 determination which only assumes the standard flat Λ
Nearby in the stack
CDM model (
73.14±1.10
km/s/Mpc), and another which only assumes the FLRW metric (
74.56±1.61
km/s/Mpc). The study also stresses the importance of the supernova magnitude calibration (
MB
) in cosmological inference and highlights the tension in
MB
when supernovae are calibrated either by CMB and BAO observations or the first two rungs of the cosmic distance ladder. This discrepancy, independent of the physics involved, suggests that models solely changing the Hubble flow and maintaining a sound horizon distance consistent with CMB, fail to explain the discrepancy between early- and late-time measurements of