Constraints on cosmological parameters and CMB first acoustic peak in conformal Killing gravity

TL;DR

This paper tests conformal Killing gravity cosmology against multiple datasets, finding consistency with standard cosmology, revealing a significant dark sector density, and supporting a dynamical dark energy model aligned with CMB observations.

Contribution

It introduces a Bayesian analysis of conformal Killing gravity using diverse datasets, highlighting the role of a novel dark sector density and confirming the dynamical nature of dark energy.

Findings

Consistent $H_0$ and $ m \Omega_M$ with $ m \Lambda$CDM.

Significant negative dark sector density $ m \\Omega_D$.

First acoustic peak aligns with Planck data.

Abstract

In the frame of conformal Killing gravity cosmology, we performed a Bayesian analysis on two different datasets of Baryon Acoustic oscillations (DESI and SDSS DR16), two datasets of SNeIa (Pantheon+ and Union3), and using the Cosmic Microwave Background (CMB) Planck likelihood. The results for $H_0$ and $\Omega_M$ in a spatially flat Friedmann-Lema\^itre-Robertson-Walker (FLRW) background are consistent with the $\Lambda$CDM scenario. We obtain a non-negligible negative value for the novel density of dark sector, $\Omega_D$, and its relevance in the evolution of the cosmological observables, thus finding quantitatively what its contribution is on real data to match the standard scenario. The results confirm the dynamical character of dark energy. We also calculate the deceleration parameter $q_0$ and the present time dark energy equation of state parameter $w_0$: the latter belongs to the quintessence regime. The evaluation of the first acoustic peak of CMB places it near to the best value provided by the Planck collaboration. In this scenario, we can conclude that late time and early time data can be successfully matched under the same standard.