Determination of the Local Hubble Constant from Virgo Infall Using TRGB Distances

An independent determination of H0 is crucial given the growing tension between the Hubble constant, H0, derived locally and that determined from the modeling of the cosmic microwave background (CMB) originating in the early universe. In this work, we present a new determination of H0 using velocities and tip of the red giant branch (TRGB) distances to 33 galaxies located between the Local Group and the Virgo cluster. We use a model of the infall pattern of the local Hubble flow modified by the Virgo mass, which is given as a function of the cosmological constants (H0, ΩΛ), the radius of the zero-velocity surface R0, and the intrinsic velocity dispersion, σv. Fitting velocities and TRGB distances of 33 galaxies to the model, we obtain H0 = 65.8 ± 3.5 (stat) ± 2.4 (sys) km s−1 Mpc−1 and R0 = 6.76 ± 0.35 Mpc. Our local H0 is consistent with the global H0 determined from CMB radiation, showing no tension. In addition, we present new TRGB distances to NGC 4437 and NGC 4592, which are located near the zero-velocity surface: D = 9.28 ± 0.39 Mpc and D = 9.07 ± 0.27 Mpc, respectively. Their spatial separation is 0.29 Mpc, suggesting that they form a physical pair.