Model-agnostic interpretation of 10 billion years of cosmic evolution traced by BOSS and eBOSS data

Abstract

We present the first model-agnostic analysis of the complete set of Sloan Digital Sky Survey III (BOSS) and -IV (eBOSS) catalogues of luminous red galaxy and quasar clustering in the redshift range 0.2 ≤ z ≤ 2.2 (10 billion years of cosmic evolution), which consistently includes the baryon acoustic oscillations (BAO), redshift space distortions (RSD) and the shape of the transfer function signatures, from pre- and post-reconstructed catalogues in Fourier space. This approach complements the standard analyses techniques which only focus on the BAO and RSD signatures, and the full-modeling approaches which assume a specific underlying cosmology model to perform the analysis. These model-independent results can then easily be interpreted in the context of the cosmological model of choice. In particular, when combined with z > 2.1 Ly-α BAO measurements, the clustering BAO, RSD and Shape parameters can be interpreted within a flat-ΛCDM model yielding h = 0.6816 ± 0.0067, Ωm = 0.3001 ± 0.0057 and 109 × As = 2.43 ± 0.20 (or σ 8 = 0.858 ± 0.036) with a Big Bang Nucleosynthesis prior on the baryon density.Without any external dataset, the BOSS and eBOSS data alone imply Ωm = 0.2971 ± 0.0061 and 109 × As = 2.39+0.24 -0.43 (or σ 8 = 0.857 ± 0.040).For models beyond ΛCDM, eBOSS data alone (in combination with Planck) constrain the sum of neutrino mass to be Σmν < 0.40 eV with a BBN prior (Σmν < 0.082 eV) at 95% CL, the curvature energy density to Ωk = -0.022+0.032 -0.038 (Ωk = 0.0015 ± 0.0016) and the dark energy equation of state parameter to w = -0.998+0.085 -0.073 (w = -1.093+0.048 0.044) at 68% CL without a BBN prior.These results are the product of a substantial improvement of the state-of-the-art methodologies and represent the most precise model-agnostic cosmological constrains using spectroscopic large-scale data alone.