Constraints from Cosmography in various parameterizations

Abstract

We use cosmography to present constraints on the kinematics of the Universe without postulating any underlying theoretical model a priori. To this end, we use a Markov Chain Monte Carlo analysis to perform comparisons to the supernova Ia union 2 compilation, combined with the Hubble Space Telescope measurements of the Hubble constant, and the Hubble parameter datasets. The cosmographic approach to our analysis is revisited and extended for new notions of redshift presented as alternatives to the redshift z. Furthermore, we introduce a new set of fitting parameters describing the kinematical evolution of the Universe in terms of the equation of state of the Universe and derivatives of the total pressure. Our results are consistent with the \Lambda CDM model, although alternative models, with nearly constant pressure and no cosmological constant, match the results accurately as well.