Low-redshift estimates of the absolute scale of baryon acoustic oscillations

Measurements of the characteristic length scale rs of the baryon acoustic oscillations (BAO) provide a robust determination of the distance-redshift relation. Currently, the best (sub-per cent) estimate of rs at the drag epoch is pro-vided by Cosmic Microwave Background (CMB) observa-tions assuming the validity of the standard ?CDM model at z -1000. Therefore, inferring rs from low-z observations in a model-independent way and comparing its value with CMB estimates provides a consistency test of the standard cosmol-ogy and its assumptions at high -z. In this paper, we address this question and estimate the absolute BAO scale combin-ing angular BAO measurements and type Ia Supernovae data. Our analysis uses two different methods to connect these data sets and finds a good agreement between the low-z estimates of rs with the CMB sound horizon at drag epoch, regardless of the value of the Hubble constant H0 considered. These results highlight the robustness of the standard cosmology at the same time that they also reinforce the need for more precise cosmological observations at low-z.