Testing Cosmic Acceleration from the Late-Time Universe

Abstract

We investigate the accelerated cosmic expansion in the late universe and derive constraints on the values of the cosmic key parameters according to different cosmologies such as ΛCDM, wCDM, and w0waCDM. We select 24 baryon acoustic oscillation (BAO) uncorrelated measurements from the latest galaxy surveys measurements in the range of redshift z∈[0.106,2.33] combined with the Pantheon SNeIa dataset, the latest 33 H(z) measurements using the cosmic chronometers (CCs) method, and the recent Hubble constant value measurement measured by Riess 2022 (R22) as an additional prior. In the ΛCDM framework, the model fit yields Ωm=0.268±0.037 and ΩΛ=0.726±0.023. Combining BAO with Pantheon plus the cosmic chronometers datasets we obtain H0=69.76±1.71 km s−1 Mpc−1 and the sound horizon result is rd=145.88±3.32 Mpc. For the flat wCDM model, we obtain w=−1.001±0.040. For the dynamical evolution of the dark energy equation of state, w0waCDM cosmology, we obtain wa=−0.848±0.180. We apply the Akaike information criterion approach to compare the three models, and see that all cannot be ruled out from the latest observational measurements.

Keywords

• dark energy
• cosmological parameters
• numerical methods