Interacting dark energy constraints from the full-shape analyses of BOSS DR12 and DES Year 3 measurements

TL;DR

This paper investigates interacting dark energy models, specifically Dark Scattering, using combined data from DES Y3, BOSS DR12, and Planck PR4, demonstrating improved constraints without relying on CMB data alone.

Contribution

It introduces a comprehensive analysis combining multiple large-scale structure probes and a normalising flow approach to constrain Dark Scattering models, enhancing parameter estimation accuracy.

Findings

Combined probes reduce projection effects and tighten constraints.

Joint analysis aligns posterior maxima closer to best-fit values.

Method weakens priors sensitivity of nuisance parameters.

Abstract

Dark Scattering (DS) is an interacting dark energy model characterised by pure momentum exchange between dark energy and dark matter. It is phenomenologically interesting because it is unconstrained by CMB data and can alleviate the $S_8$ tension. We derive constraints on cosmological and DS parameters using three two-point correlation functions (3$\times$2pt) from the Dark Energy Survey third year data release (DES Y3). We then add information from the multipoles of the galaxy power spectrum combined with Baryonic Acoustic Oscillation (BAO) measurements using the twelfth data release of the Baryon Oscillation Spectroscopic Survey (BOSS DR12) and external BAO measurements. We compare results from the direct combination of the probes with the joint posterior distribution calculated with a normalising flow approach. Additionally, we run a CMB analysis with the Planck Public Release 4 (PR4) for comparison of the cosmological constraints. Overall, we find that the combination of probes allows minimising the projection effects and improves constraints without the need to include CMB information. It brings the marginalised posterior maxima closer to the corresponding best-fit values and weakens the sensitivity to the priors of the spectroscopic modelling nuisance parameters. These findings are highly relevant in light of forthcoming data of surveys like DESI, Euclid, and Rubin.