Generalized emergent dark energy in the late-time Universe

Abstract

ABSTRACT We investigate a new type of dark energy model called the generalized emergent dark energy (GEDE) model which encodes either phenomenologically emergent dark energy that has no effective presence in the early times and emerges strongly in late times or the standard model of cosmology Lambda cold dark matter ($\Lambda$CDM). We test this new brand dark energy model and compare it with the standard model of cosmology $\Lambda$CDM using the final baryon acoustic oscillation (BAO) uncorrelated measurements in the effective redshift range $0.106 \le z \le 2.33$ of different surveys after two decades of dedicated spectroscopic observation combined with the compressed form of the Pantheon sample of Type Ia supernovae, the observational $H(z)$ measurements based on differential age method, and the recent Hubble constant value measurement from the Hubble Space Telescope and the SH0ES Team in 2022 as an additional Gaussian prior. In the GEDE model fit yields the cosmological parameters $\Omega _{m}=0.2713 \pm 0.0142$ and $\Omega _{\Lambda }=0.7245 \pm 0.0126$ for BAO + R22. Combining BAO with the observational $H(z)$ measurements based on the differential age method, and the Pantheon Type Ia supernova, the Hubble constant yields 69.92 $\pm$ 1.17 km s$^{-1}$ Mpc$^{-1}$ and the sound horizon gives 145.97 $\pm$ 2.44 Mpc. We perform the Akaike information criteria, Bayesian information criterion, and Bayesian evidence to compare the GEDE and $\Lambda$CDM models and see that $\Lambda$CDM has a better performance without the inclusion of early-time observations as the cosmic microwave background.