Probing the imprint of interacting dark energy on very large scales

TL;DR

This paper examines how relativistic effects influence the galaxy power spectrum on large scales, especially in models with interacting dark energy, highlighting the importance of including these effects for accurate cosmological constraints.

Contribution

It demonstrates that neglecting relativistic effects can bias the detection and characterization of interacting dark energy in large-scale galaxy surveys.

Findings

Relativistic corrections grow on very large scales in galaxy power spectra.

Ignoring relativistic effects leads to biased constraints on interacting dark energy.

Proper inclusion of relativistic effects is crucial for future large-scale structure analyses.

Abstract

The observed galaxy power spectrum acquires relativistic corrections from lightcone effects, and these corrections grow on very large scales. Future galaxy surveys in optical, infrared and radio bands will probe increasingly large wavelength modes and reach higher redshifts. In order to exploit the new data on large scales, an accurate analysis requires inclusion of the relativistic effects. This is especially the case for primordial non-Gaussianity and for extending tests of dark energy models to horizon scales. Here we investigate the latter, focusing on models where the dark energy interacts non-gravitationally with dark matter. Interaction in the dark sector can also lead to large-scale deviations in the power spectrum. If the relativistic effects are ignored, the imprint of interacting dark energy will be incorrectly identified and thus lead to a bias in constraints on interacting dark energy on very large scales.