Hubble-Lemaitre residuals and ages for Pantheon SNe

Their precision derives from empirical correlations, now measured from >1000 SNe Ia, between their luminosities, light-curve shapes, colors, and most recently with the stellar mass of their host galaxy. As mass correlates with other galaxy properties, alternative parameters have been investigated to improve SN Ia standardization though none have been shown to significantly alter the determination of cosmological parameters.

We re-examine a recent claim, based on 34 SN Ia in nearby passive host galaxies, of a 0.05mag/Gyr dependence of standardized SN Ia luminosity on host age, which, if extrapolated to higher redshifts, would be a bias up to 0.25mag, challenging the inference of dark energy. We reanalyze this sample of hosts using both the original method and a Bayesian hierarchical model and find after a fuller accounting of the uncertainties the significance of a dependence on age to be <=2{sigma} and ~1{sigma} after the removal of a single poorly sampled SN Ia.