Extensions to ΛCDM at Intermediate Redshifts to Solve the Tensions ?
Z. Sakr
Full text: pdf
Published on: November 08, 2023
Abstract
Models of dark energy or modified gravity that tries to alleviate the tensions on the Hubble constant (H0) and the matter fluctuation parameter (σ8) are usually parameterized as function of either late or early time cosmic evolution. In this work we rather focus on one that could privilege extensions to ΛCDM on intermediate redshifts by mean of a Gaussian-like window function with a free moving centre aGwin combined with a modified gravity parameter μGwin and an extension of the equation of state parameter ωGwin. Using different combinations of the latest available current datasets subject of the discrepancies, such as the cosmic microwave (CMB) background power spectrum, the baryonic acoustic scale (BAO) in galaxy distribution, Weak lensing (WL) shear and galaxy clustering cross correlations and local hubble constant measurements, we investigate whether such model could alleviate each or both H0 and σ8 tensions. We found when combining all probes that the σ8 tension is alleviated while the H0 is reduced with a small preference for a positive ωGwin without a particular preference for a redshift or a μGwin different from its equivalent ΛCDM value. However, if we follow another approach and compare the two sets of the probes subject of discrepancy i.e. CMB+BAO vs WL+local H0, we found that the model is able of solving the σ8 discrepancy at the expense of a enlargement of the constraints, while the Hubble constant discrepancy is not that affected due to the fact that the two likelihood contours are stretched in parallel directions. We conclude that modifying ΛCDM cosmology at intermediate redshifts within our model, and the constraints from the datasets used in this study, are not likely a viable solution to solve both tensions.
DOI: https://doi.org/10.22323/1.436.0262
How to cite

Metadata are provided both in article format (very similar to INSPIRE) as this helps creating very compact bibliographies which can be beneficial to authors and readers, and in proceeding format which is more detailed and complete.

Open Access
Creative Commons LicenseCopyright owned by the author(s) under the term of the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License.