The Baryon Acoustic Oscillations (BAO) are one of the most used probes to
understand the accelerated expansion of the Universe. Traditional methods rely
on fiducial model information within their statistical analysis, which may be a
problem when constraining different families of models. The aim of this work is
to provide a method that constrains θBAO​ through a model-independent
and compare parameter estimation of the angular correlation function polynomial
approach, using the covariance matrix from the galaxy sample from thin redshift
bins, with the usual mock sample covariance matrix. We proposed a different
approach to finding the BAO angular feature revisiting previous work in the
literature, we take the bias between the correlation function between the bins
and the whole sample. We used widths of δz=0.002 separation for all
samples as the basis for a sample covariance matrix weighted by the statistical
importance of the redshift bin. We propose a different weighting scheme based
only on random pair counting. We also propose an alternate shift parameter
based only on the data. Each sample belongs to the Sloan Digital Sky Survey
Luminous Red Galaxies (LRG): BOSS1, BOSS2, and eBOSS, with effective redshift
zeff​: 0.35, 0.51, 0.71, respectively, and different numbers of bins with
50, 100, and 200 respectively. In addition, we correct the angular separation
from the polynomial fit (θfit​) that encodes the BAO feature with a
bias function obtained by comparing each bin correlation function with the
correlation function of the whole set. We also tested the same correction
choosing the bin at zeff​ and found that for eBOSS θBAO​ is in 1σ agreement with the Planck 18 model. BOSS1 and BOSS2 θBAO​
agreed in 1σ with the Pantheon+ & SH0​ES FlatΛCDM model, in
tension with Planck 18.Comment: 18 page