Hubble constant and sound horizon from the late-time Universe

We measure the expansion rate of the recent Universe and the calibration scale of the baryon acoustic oscillation (BAO) from low-redshift data. BAO relies on the calibration scale, i.e., the sound horizon at the end of drag epoch r(d), which often imposes a prior of the cosmic microwave background (CMB) measurement from the Planck satellite. In order to make really independent measurements of H-0, we leave r(d) completely free and use the BAO data sets combined with the 31 observational H(z) data, GW170817, and Pantheon sample of Type Ia supernovae. In lambda cold dark matter (Lambda CDM) model, we get H-0 = 68.63(-1.77)(+1.75) km s(-1) Mpc(-1), r(d) = 146.85(-3.77)(+3.29) Mpc. For the two model-independent reconstructions of H(z), we obtain H-0 = 68.02 +/- 1.82 km s(-1) Mpc(-1), r(d) = 148.18(-3.78)(+3.36) Mpc in the cubic expansion, and H-0 = 68.58 +/- 1.76 km s(-1) Mpc(-)1, r(d) = 148.02(-3.60)(+3.63) Mpc in the polynomial expansion. The values of Hubble constant H-0 and sound horizon r(d) are consistent with the estimate derived from the Planck CMB data assuming a flat Lambda CDM model, but H-0 is in 2.4 similar to 2.6 sigma tension with SH0ES 2019, respectively.

Automated summary

This study independently measures the calibration scale of baryon acoustic oscillations (BAO) and the expansion rate of the recent Universe, providing values for the Hubble constant and sound horizon that are consistent with estimates derived from Planck data but show tension with SH0ES 2019.