Constraints on dark energy dynamics and spatial curvature from Hubble parameter and baryon acoustic oscillation data

Abstract

We use all available baryon acoustic oscillation distance measurements and Hubble parameter data to constrain the cosmological constant Λ, dynamical dark energy, and spatial curvature in simple cosmological models. We find that the consensus spatially flat ΛCDM model provides a reasonable fit to the data, but depending on the Hubble constant prior and cosmological model, it can be a little more than 1σ away from the best-fit model, which can favor mild dark energy dynamics or non-flat spatial hypersurfaces.

Quasar X-ray and UV flux, baryon acoustic oscillation, and Hubble parameter measurement constraints on cosmological model parameters

“…The marginalized one-dimensional best-fit parameter values with 1σ error bars are given in Table 3. These results are consistent with those of Ryan et al (2018). The slight differences between the two sets of results are the consequence of the different analysis techniques used.…”

Evidence against Ryskin’s model of cosmic acceleration

“…This is very similar to the methods employed in Refs. [14,15]; see those papers for details regarding the form that the χ 2 function takes when it is computed within each model and for each data set. The prior function, π(p n ), is necessary to deal with the nuisance parameters Ω m0 and Ω b h 2 that enter the analysis through the calculation of the sound horizon r S (see above).…”

“…The main difference between this first analysis method and the analyses of [14,15] is that I do not compare the best-fitting value of H 0 or the minimum value of χ 2 in Ryskin's model directly to any other models (although the best-fitting H 0 can be compared to the measurements of H 0 made by Refs. [11] and [13]; see below).…”

“…The H(z) data are listed in Ref. [15]; see that paper for a description. The BAO data are listed in Ref.…”

“…For the BAO data, the measured quantities are a set of distances D H (z), D M (z), and D V (z) (defined and described in Refs. [5,14,15]) and H(z), scaled by the value that the sound horizon r S takes at the drag epoch. This latter quantity depends on the homogeneous part of the dimensionless matter density parameter (Ω m0 ), the Hubble constant (H 0 ), the dimensionless baryon density parameter (Ω b h 2 ), and the CMB temperature (T CMB ), thereby making r S a model-dependent quantity.…”