Using the Baryonic Tully–Fisher Relation to Measure H_o

We explore the use of the baryonic Tully–Fisher relation (bTFR) as a new distance indicator. Advances in near-IR imaging and stellar population models, plus precise rotation curves, have reduced the scatter in the bTFR such that distance is the dominant source of uncertainty. Using 50 galaxies with accurate distances from Cepheids or the tip magnitude of the red giant branch, we calibrate the bTFR on a scale independent of H _o. We then apply this calibrated bTFR to 95 independent galaxies from the SPARC sample, using CosmicFlows-3 velocities, to deduce the local value of H _o. We find H _o = 75.1 ± 2.3 (stat) ±1.5 (sys) km s⁻¹ Mpc⁻¹.