of 15 quasars per square degree [@Paris]. In fact, the current sample is actually dense enough to allow for the analyses in very thin redshift bins. The methodology followed to retrieve this sample was based in a SDSS pipeline and is fully described in Pâris et al. (2017) [@Paris].

With this exceptional catalogue, DR12Q, we search for a statistically significant angular BAO detection. The DR12Q sample is distributed between two disconnected regions of the sky, so we selected that one containing the largest amount of quasars, that is, the quasars located in the sky patch with $90^{\circ} < \alpha < 270^{\circ}$ (i.e., the North Galactic region), where $\alpha$ is the right ascension in equatorial coordinates; moreover, we first considered the quasar sample in the redshift range $2.20 - 2.80$. After several analyses that considers the large number of quasars (to minimize the statistical noise) in the thinest redshift bin (to minimize the non-linear contributions due to the projection effect, see, e.g., ref. [@Sanchez11]), we finally selected the thin shell: $z \in [2.20, 2.25]$, which contains a total of $10,526$ quasars.

\[sec3\] The two-point correlation functions
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Traditionally, the BAO analyses assume a fiducial cosmology to compute the comoving distance between 