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 $0.2\leq z \leq 2.2$ (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 {\it Shape} parameters can be interpreted within a flat-$Λ$CDM model yielding $h=0.6816\pm0.0067$, $Ω_{\rm m}=0.3001\pm0.0057$ and $10^{9}\times A_s= 2.43\pm0.20$ (or $σ_8=0.858\pm0.036$) with a Big Bang Nucleosynthesis prior on the baryon density. Without any external dataset, the BOSS and eBOSS data alone imply $Ω_{\rm m}=0.2971\pm 0.0061$ and $10^{9}\times A_s=2.39^{+0.24}_{-0.43}$ (or $σ_8=0.857\pm0.040$). For models beyond $Λ$CDM, eBOSS data alone (in combination with Planck) constrain the sum of neutrino mass to be $Σm_ν< 0.40$ eV with a BBN prior ($Σm_ν<0.082$ eV) at 95\% CL, the curvature energy density to $Ω_\mathrm{k} = -0.022_{-0.038}^{+0.032}$ ($Ω_\mathrm{k} = 0.0015\pm 0.0016$) and the dark energy equation of state parameter to $w=-0.998_{-0.073}^{+0.085}$ ($w=-1.093_{-0.044}^{+0.048}$) at 68\% CL without a BBN prior.