Standard rulers, candles, and clocks from the low-redshift Universe

Understand

We measure the length of the Baryon Acoustic Oscillation (BAO) feature, and the expansion rate of the recent Universe, from low-redshift data only, almost model-independently.

• We make only the following minimal assumptions: homogeneity and isotropy; a metric theory of gravity; a smooth expansion history, and the existence of standard candles (supernov\ae) and a standard BAO ruler.
• The rest is determined by the data, which are compilations of recent BAO and Type IA supernova results.
• Making only these assumptions, we find for the first time that the standard ruler has length $103.9 \pm 2.3\, h^{-1}$ Mpc.