Hubble constant and sound horizon from the late-time Universe

We measure the expansion rate of recent Universe and calibration scale baryon acoustic oscillation (BAO) from low-redshift data. BAO relies on scale, i.e., sound horizon at end drag epoch $r_d$, which often imposes a prior cosmic microwave background (CMB) measurement Planck satellite. In order to make really independent measurements $H_0$, we leave $r_d$ completely free use data sets combined with 31 observational $H(z)$ data, GW170817 Pantheon sample Type Ia supernovae. $\Lambda$CDM model, get $H_0=68.63^{+1.75}_{-1.77}$ km s$^{-1}$ Mpc$^{-1}$, $r_d=146.85^{+3.29}_{-3.77}$ Mpc. For two model-independent reconstructions $H(z)$, obtain $H_0=68.02\pm1.82$ $r_d=148.18^{+3.36}_{-3.78}$ Mpc in cubic expansion, $H_0=68.58\pm1.76$ $r_d=148.02^{+3.63}_{-3.60}$ polynomial expansion. The values Hubble constant $H_0$ are consistent estimate derived CMB assuming flat but is $2.4\sim2.6$ $\sigma$ tension SH0ES 2019, respectively.