Gaussian processes provide a method for extracting cosmological information from observations without assuming a cosmological model. We carry out cosmography—mapping the time evolution of the cosmic expansion—in a model-independent manner using kinematic variables and a geometric probe of cosmology. Using the state of the art supernova distance data from the Union2.1 compilation, we constrain, without any assumptions about dark energy parametrization or matter density, the Hubble parameter and deceleration parameter as a function of redshift. Extraction of these relations is tested successfully against models with features on various coherence scales, subject to certain statistical cautions.

• Received 16 April 2012

DOI:https://doi.org/10.1103/PhysRevD.85.123530