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

TL;DR

This paper introduces a model-agnostic analysis of Sloan Digital Sky Survey data covering 10 billion years of cosmic evolution, enabling flexible interpretation of cosmological parameters without assuming a specific model.

Contribution

It presents the first comprehensive, model-independent clustering analysis of BOSS and eBOSS data, including BAO, RSD, and transfer function signatures, extending beyond standard methods.

Findings

Consistent constraints on cosmological parameters within flat-ΛCDM.

Independent data imply Ω_m ≈ 0.297 and σ_8 ≈ 0.857.

Constraints on neutrino mass, curvature, and dark energy equation of state.

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-$\alpha$ BAO measurements, the clustering BAO, RSD and {\it Shape} parameters can be interpreted within a flat-$\Lambda$CDM model yielding $h=0.6816\pm0.0067$, $\Omega_{\rm m}=0.3001\pm0.0057$ and $10^{9}\times A_s= 2.43\pm0.20$ (or $\sigma_8=0.858\pm0.036$) with a Big Bang Nucleosynthesis prior on the baryon density. Without any external dataset, the BOSS and eBOSS data alone imply $\Omega_{\rm m}=0.2971\pm 0.0061$ and $10^{9}\times A_s=2.39^{+0.24}_{-0.43}$ (or $\sigma_8=0.857\pm0.040$). For models beyond $\Lambda$CDM, eBOSS data alone (in combination with Planck) constrain the sum of neutrino mass to be $\Sigma m_\nu< 0.40$ eV with a BBN prior ($\Sigma m_\nu <0.082$ eV) at 95\% CL, the curvature energy density to $\Omega_\mathrm{k} = -0.022_{-0.038}^{+0.032}$ ($\Omega_\mathrm{k} = 0.0015\pm 0.0016$) 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.