Growth and Geometry Split in Light of the DES-Y3 Survey

TL;DR

This paper tests the smooth dark energy paradigm using DES-Y1 and Y3 data, splitting parameters to compare growth and geometry, finding no tension in Y1 but some in Y3 likely due to systematics.

Contribution

It introduces a method to separate growth and geometry parameters in DES data, revealing potential tensions and systematic effects in current cosmological measurements.

Findings

No detectable tension in DES-Y1 data.

A 2.6σ tension in ΛCDM and 4.48σ in wCDM with DES-Y3 2x2pt data.

Tension likely caused by residual systematics, not new physics.

Abstract

We test the smooth dark energy paradigm using Dark Energy Survey (DES) Year 1 and Year 3 weak lensing and galaxy clustering data. Within the $\Lambda$CDM and $w$CDM model we separate the expansion and structure growth history by splitting $\Omega_\mathrm{m}$ (and $w$) into two meta-parameters that allow for different evolution of growth and geometry in the Universe. We consider three different combinations of priors on geometry from CMB, SNIa, BAO, BBN that differ in constraining power but have been designed such that the growth information comes solely from the DES weak lensing and galaxy clustering. For the DES-Y1 data we find no detectable tension between growth and geometry meta-parameters in both the $\Lambda$CDM and $w$CDM parameter space. This statement also holds for DES-Y3 cosmic shear and 3x2pt analyses. For the combination of DES-Y3 galaxy-galaxy lensing and galaxy clustering (2x2pt) we measure a tension between our growth and geometry meta-parameters of 2.6$\sigma$ in the $\Lambda$CDM and 4.48$\sigma$ in the $w$CDM model space, respectively. We attribute this tension to residual systematics in the DES-Y3 RedMagic galaxy sample rather than to new physics. We plan to investigate our findings further using alternative lens samples in DES-Y3 and future weak lensing and galaxy clustering datasets.