The Dark Energy Survey Supernova Program: An updated measurement of the Hubble constant using the Inverse Distance Ladder

Abstract

We measure the current expansion rate of the Universe, Hubble's constant $H_0$, by calibrating the absolute magnitudes of supernovae to distances measured by Baryon Acoustic Oscillations. This `inverse distance ladder' technique provides an alternative to calibrating supernovae using nearby absolute distance measurements, replacing the calibration with a high-redshift anchor. We use the recent release of 1829 supernovae from the Dark Energy Survey spanning $0.01<z<1.13$ anchored to the recent Baryon Acoustic Oscillation measurements from DESI spanning $0.30<z_{\mathrm{eff}}<2.33$. To trace cosmology to $z=0$, we use the third-, fourth- and fifth-order cosmographic models, which, by design, are agnostic about the energy content and expansion history of the universe. With the inclusion of the higher-redshift DESI-BAO data, the third-order model is a poor fit to both data sets, with the fourth-order model being preferred by the Akaike Information Criterion. Using the fourth-order cosmographic model, we find $H_0=67.19_{-0.64}^{+0.66}\mathrm{km}{\mathrm{s}}^{-1}{\mathrm{Mpc}}^{-1}$, in agreement with the value found by Planck without the need to assume Flat-$\hat{I}›$CDM. However the best-fitting expansion history differs from that of Planck, providing continued motivation to investigate these tensions.