We model the expansion history of the Universe as a Gaussian process and find constraints on the dark energy density and its low-redshift evolution using distances inferred from the Luminous Red Galaxy and Lyman-alpha data sets of the Baryon Oscillation Spectroscopic Survey, supernova data from the Joint Light-Curve Analysis sample, cosmic microwave background data from the Planck satellite, and local measurement of the Hubble parameter from the Hubble Space Telescope ($\mathsf{H}0$). Our analysis shows that the cosmic microwave background, Luminous Red Galaxy, Lyman-alpha, and Joint Light-Curve Analysis data are consistent with each other and with a $\mathrm{\Lambda }\mathrm{CDM}$ cosmology, but the $\mathsf{H}0$ data are inconsistent at moderate significance. Including the presence of dark radiation does not alleviate the $\mathsf{H}0$ tension in our analysis. While some of these results have been noted previously, the strength here lies in that we do not assume a particular cosmological model. We calculate the growth of the gravitational potential in General Relativity corresponding to these general expansion histories and show that they are well approximated by ${\mathrm{\Omega }}_{\mathrm{m}}^{0.55}$ given the current precision. We assess the prospects for upcoming surveys to measure deviations from $\mathrm{\Lambda }\mathrm{CDM}$ using this model-independent approach.

• Received 29 November 2017

DOI:https://doi.org/10.1103/PhysRevD.97.123501