New multiprobe analysis of modified gravity and evolving dark energy

TL;DR

This paper combines multiple large-scale structure and cosmic microwave background data sets with advanced analysis techniques to improve constraints on dark energy parameters and test modifications to gravity, finding stronger evidence for evolving dark energy.

Contribution

It introduces a multiprobe analysis using beyond-Limber angular spectra and EFTofDE framework to tighten constraints on dark energy and modified gravity parameters.

Findings

Improved constraints on (w0, wa) by ~50%.

Increased preference for evolving dark energy from 3.8σ to 4.6σ.

Constraints on EFTofDE parameters αB and αM are compatible with GR at ~2σ.

Abstract

We study the $(w_0, \, w_a)$ parametrization of the dark energy (DE) equation of state, with and without the effective field theory of dark energy (EFTofDE) framework to describe the DE perturbations, parametrized here by the braiding parameter $\alpha_B$ and the running of the Planck mass $\alpha_M$. We combine the EFTofLSS full-shape analysis of the power spectrum and bispectrum of BOSS data with the tomographic angular power spectra $C_\ell^{gg}$, $C_\ell^{\kappa g}$, $C_\ell^{Tg}$ and $C_\ell^{T\kappa}$, where $g$, $\kappa$ and $T$ stand for the DESI luminous red galaxy map, Planck PR4 lensing map and Planck PR4 temperature map, respectively. To analyze these angular power spectra, we go beyond the Limber approximation, allowing us to include large-scale data in $C_\ell^{gg}$. The combination of all these probes with Planck PR4, DESI DR2 BAO and DES Y5 improves the constraint on the 2D posterior distribution of $\{w_0, \, w_a\}$ by $\sim 50 \%$ and increases the preference for evolving dark energy over $\Lambda$ from $3.8 \sigma$ to $4.6 \sigma$. When we remove BAO and supernovae data, we obtain a hint for evolving dark energy at $2.3 \sigma$. Regarding the EFTofDE parameters, we improve the constraints on $\alpha_B$ and $\alpha_M$ by $\sim 40 \%$ and $50 \%$ respectively, finding results compatible with general relativity at $\sim 2 \sigma$. We show that these constraints do not depend on the choice of the BAO and supernovae likelihoods.