Consistency among distance measurements: transparency, BAO scale and accelerated expansion

Abstract

We explore consistency among different distance measures, includingSupernovae Type Ia data, measurements of the Hubble parameter, anddetermination of the Baryon acoustic oscillation scale. We present newconstraints on the cosmic transparency combining H(z) data together with thelatest Supernovae Type Ia data compilation. This combination, in the context ofa flat ΛCDM model, improves current constraints by nearly an order ofmagnitude although the constraints presented here are parametric rather thannon-parametric. We re-examine the recently reported tension between the Baryonacoustic oscillation scale and Supernovae data in light of possible deviationsfrom transparency, concluding that the source of the discrepancy may mostlikely be found among systematic effects of the modelling of the low redshiftdata or a simple ∼ 2-σ statistical fluke, rather than in exoticphysics. Finally, we attempt to draw model-independent conclusions about therecent accelerated expansion, determining the acceleration redshift to bezacc = 0.35+0.20−0.13 (1-σ).