Testing the R_h=ct universe jointly with the redshift-dependent expansion rate and angular-diameter and luminosity distances

We use three different data sets, specifically H(z) measurements from cosmic chronometers, the HII-galaxy Hubble diagram, and reconstructed quasar-core angular-size measurements, to perform a joint analysis of three flat cosmological models: the R_h=ct Universe, ΛCDM, and wCDM. For R_h=ct, the 1σ best-fit value of the Hubble constant H₀ is 62.336±1.464km s⁻¹Mpc⁻¹, which matches previous measurements (∼63km s⁻¹Mpc⁻¹) based on best fits to individual data sets. For ΛCDM, our inferred value of the Hubble constant, H₀=67.013±2.578km s⁻¹Mpc⁻¹, is more consistent with the Planck optimization than the locally measured value using Cepheid variables, and the matter density Ω_m=0.347±0.049 similarly coincides with its Planck value to within 1σ. For wCDM, the optimized parameters are H₀=64.718±3.088km s⁻¹Mpc⁻¹, Ω_m=0.247±0.108 and w=−0.693±0.276, also consistent with Planck. A direct comparison of these three models using the Bayesian Information Criterion shows that the R_h=ct universe is favored by the joint analysis with a likelihood of ∼97% versus ≲3% for the other two cosmologies.