On The Stability Of H 0 And The Inverse Distance Ladder

The ‘Inverse Distance Ladder’ uses relative-distance measurements with type Ia supernovae (SNe Ia), anchored to an absolute distance scale from Baryon Acoustic Oscillations (BAO) and the cosmic microwave background (CMB), to provide an alternative measurement for the local expansion rate H0. Using SNe Ia from the Dark Energy Survey and BAO measurements from the Dark Energy Spectroscopic Instrument, we show that the inverse distance ladder is unable to explain the Hubble Tension. To do so, we first show that the suite of systematics considered in cosmology analyses with SNe Ia only move the inferred H0 by <0.1kms−1 Mpc−1, and second, we investigate the scale of redshift-dependent magnitude changes necessary to change the inferred inverse distance ladder H0 from 67 to the local network of distance measurements value of 73, and the impact that this would have on other cosmological inferences with SNe Ia. We find that a change of dμ/dz = 0.2 mag would be necessary to infer an H0 in concordance with local distance measurements, and that this dμ/dz value would result in a Flat ΛCDM ΩM = 0.23, 10σ discrepant with other cosmological probes, indicating that the precision of SNe Ia measurements preclude the necessary redshift evolution for an H0 of 74 kms−1 Mpc−1. Therefore, we conclude that current SN Ia cosmology leaves little freedom for the inverse distance ladder to yield H0 values significantly different from 67 kms−1 Mpc−1.