Measurement of the Weyl potential evolution from the first three years of Dark Energy Survey data

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Main Authors: Tutusaus, Isaac, Bonvin, Camille, Grimm, Nastassia
Format: Preprint
Published: 2023
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author Tutusaus, Isaac
Bonvin, Camille
Grimm, Nastassia
author_facet Tutusaus, Isaac
Bonvin, Camille
Grimm, Nastassia
contents The Weyl potential, which is the sum of the spatial and temporal distortions of the Universe's geometry, provides a direct way of testing the theory of gravity and the validity of the $Λ$CDM (Lambda Cold Dark Matter) model. Here we present measurement of the Weyl potential at four redshifts bins using data from the first three years of observations of the Dark Energy Survey. We find that the measured Weyl potential is 2$σ$, respectively 2.8$σ$, below the $Λ$CDM predictions in the two lowest redshift bins. We show that these low values of the Weyl potential are at the origin of the tension between Cosmic Microwave Background measurements and weak lensing measurements, regarding the parameter $σ_8$ which quantifies the clustering of matter. Interestingly, we find that the tension remains if no information from the Cosmic Microwave Background is used. Dark Energy Survey data on their own prefer a high value of the primordial fluctuations, together with a slow evolution of the Weyl potential. An important feature of our method is that the measurements of the Weyl potential are model-independent and can therefore be confronted with any theory of gravity, allowing efficient tests of models beyond General Relativity.
format Preprint
id arxiv_https___arxiv_org_abs_2312_06434
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Measurement of the Weyl potential evolution from the first three years of Dark Energy Survey data
Tutusaus, Isaac
Bonvin, Camille
Grimm, Nastassia
Cosmology and Nongalactic Astrophysics
The Weyl potential, which is the sum of the spatial and temporal distortions of the Universe's geometry, provides a direct way of testing the theory of gravity and the validity of the $Λ$CDM (Lambda Cold Dark Matter) model. Here we present measurement of the Weyl potential at four redshifts bins using data from the first three years of observations of the Dark Energy Survey. We find that the measured Weyl potential is 2$σ$, respectively 2.8$σ$, below the $Λ$CDM predictions in the two lowest redshift bins. We show that these low values of the Weyl potential are at the origin of the tension between Cosmic Microwave Background measurements and weak lensing measurements, regarding the parameter $σ_8$ which quantifies the clustering of matter. Interestingly, we find that the tension remains if no information from the Cosmic Microwave Background is used. Dark Energy Survey data on their own prefer a high value of the primordial fluctuations, together with a slow evolution of the Weyl potential. An important feature of our method is that the measurements of the Weyl potential are model-independent and can therefore be confronted with any theory of gravity, allowing efficient tests of models beyond General Relativity.
title Measurement of the Weyl potential evolution from the first three years of Dark Energy Survey data
topic Cosmology and Nongalactic Astrophysics
url https://arxiv.org/abs/2312.06434