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

Abstract

We explore consistency among different distance measures, including Supernovae Type Ia data, measurements of the Hubble parameter, and determination of the Baryon acoustic oscillation scale. We present new constraints on the cosmic transparency combining $H(z)$ data together with the latest Supernova Type Ia data compilation. This combination, in the context of a flat $\Lambda$CDM model, improves current constraints by nearly an order of magnitude. We re-examine the recently reported tension between the Baryon acoustic oscillation scale and Supernovae data in light of possible deviations from transparency, concluding that the source of the discrepancy may most likely be found among systematic effects of the modelling of the low redshift data or a simple $\sim 2-\sigma$ statistical fluke, rather than in exotic physics. Finally, we attempt to draw model-independent conclusions about the recent accelerated expansion, determining the acceleration redshift to be $z_{acc}=0.35_{-0.13}^{+0.20}$ (1-$\sigma$).

15 pages, 7 figures; V2: effect of parameterization discussed, section 4 expanded; matches published version

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