THAIS LEMOS PORCIUNCULA ALVES

Abstract

he baryonic acoustic oscillations (BAO) are a consequence of the competition between the photons radiation pressure and the gravitational force of the dark matter over the photon-baryon fluid. This phenomenon results in a characteristic scale called sound horizon, which is imprinted on the galaxy distribution. The BAO feature is a standard ruler and can be used to constrain cosmological parameters along with other cosmological probes. Currently, the best estimated value of the sound horizon was inferred by the Planck Collaboration 2018 $r_{s}(z_{d}) = 147,01 \pm 0,26$ Mpc at drag epoch $z_{d} \approx 1060$, using Planck TT,TE,EE+lowE+lensing results. However, this estimate is obtained in the context of the $\Lambda$CDM model, leaving the result vulnerable to systematic errors due to the model assumptions on the early Universe physics. The aim of this work is to determine the sound horizon from low-redshift data in a model-independent way, compare the result with the CMB value and verify possible deviations from the standard physics assumed in the Planck estimate. In order to obtain our estimate we combine the latest type Ia supernovae data from the Pantheon catalog with recent BAO angular measurements. As a result, we find $\Bar{r_{d}} = 146,08 \pm 16,03$ Mpc at redshift $z = 0,54$. Comparing our result with the value obtained at the time of drag epoch by the Planck satellite, we obtained an excellent agreement, with a difference of only $ 0,06 \sigma $.