Angular Baryon Acoustic Oscillation measure atz=2.225 from the SDSS quasar survey

Abstract

Following a quasi model-independent approach we measure the transversal BAO mode at high redshift using the two-point angular correlation function (2PACF). The analyses done here are only possible now with the quasar catalogue from the twelfth data release (DR12Q) from the Sloan Digital Sky Survey, because it is spatially dense enough to allow the measurement of the angular BAO signature with moderate statistical significance and acceptable precision. Our analyses with quasars in the redshift interval z ∈ [2.20, 2.25] produce the angular BAO scale θ BAO = 1.77 • ± 0.31 • with a statistical significance of 2.12 σ (i.e., 97% confidence level), calculated through a likelihood analysis performed using the theoretical covariance matrix sourced by the analytical power spectra expected in the ΛCDM concordance model. Additionally, we show that the BAO signal is robust -although with less statistical significance-under diverse bin-size choices and under small displacements of the quasars' angular coordinates. Finally, we also performed cosmological parameter analyses comparing the θ BAO predictions for wCDM and w(a)CDM models with angular BAO data available in the literature, including the measurement obtained here, jointly with CMB data. The constraints on the parameters Ω M , w 0 and w a are in excellent agreement with the ΛCDM concordance model.

The scale of homogeneity in the local Universe with the ALFALFA catalogue

“…where n g is the number of objects in the data sample, and the third estimator, that is based on the Landy-Szalay (LS) two-point angular correlation function [52,53],…”

The transverse baryonic acoustic scale from the SDSS DR11 galaxies

“…As extensively discussed in Ref. [16] (see also [17,18]), the application of the 2PACF to the data usually exhibits more than a single bump which, in general, is due to systematic effects present in the galaxy catalogs. Previously in the literature (see, e.g., [15]), the usual procedure to identify which one corresponds to the real BAO scale was to compare the bump scales observed in the 2PACF with the prediction of the standard cosmology obtained from Eqs.…”

Bayesian comparison of interacting scenarios

“…We focus on background data such as type Ia supernovae through the Joint Light-curve Analysis (JLA) compilation [17] and through the Pantheon sample [18]; baryon acoustic oscillation data from 6dFGS [19], SDSS-MGS [20], BOSS-LOWZ [21], BOSS-CMASS [21], BOSS-DR12 [22], eBOSS [23,24] and BOSS-Lyα [25]; the cosmic chronometers reported in reference [30] and the angular scale of the sound horizon at the last scattering [31]. Furthermore, we independently consider BAO measurements obtained by the angular separation between pairs of galaxies [26][27][28][29]. In what follows, we briefly present each one of these datasets.…”

“…In this paper, we study the observational viability of different classes of interacting scenarios, including both linear and non-linear interaction terms. In order to observationally distinguish between the different models we perform a Bayesian model selection analysis using current data of type Ia supernova (SN Ia) [17,18], measurements of the baryon acoustic oscillation (BAO) from the 6dFGS [19], SDSS-MGS [20], BOSS-LOWZ [21], BOSS-CMASS [21], BOSS-DR12 [22], eBOSS [23,24] and BOSS-Lyα [25] surveys, along with BAO measurements obtained from SDSS-DR7 [26], SDSS-DR10 [27], SDSS-DR11 [28], SDSS-DR12Q [29]; measurements of the expansion rate from cosmic chronometers [30] and the estimate of the sound horizon scale at the last scattering reported by the Planck collaboration [31]. We find weak and moderate evidence against some of the interacting scenarios studied with respect to ΛCDM when the full joint analysis is considered.…”