Jun-Qing Xia, Vincenzo Vitagliano, Stefano Liberati, Matteo Viel
We perform a cosmographic analysis using several cosmological observables
such as the Hubble parameter, the luminosity distance moduli and the volume
distance. These quantities are determined using several data sets: the Hubble
parameter as measured from surveys of galaxies, the luminosity distance from
Supernovae and Gamma Ray Bursts data and the Baryonic Acoustic Oscillations as
seen in the power spectra of the distribution of galaxies. Compared to our
previous work, that relied on Supernovae and Gamma Ray Bursts luminosity
distance indicators, the number of observables used is thus larger and span a
very wide redshift range. This data set allows to put constraints on the
cosmographic expansion up to fifth order. We then derive the set of the
cosmographic parameters for several cosmological models (including
$\Lambda$CDM) in order to compare them with our best fit set. Current data do
not allow to discriminate among these competing models; furthermore, we do show
that, even if the upcoming large scale structure probes may substantially
improve the precision with which the lowest cosmographic parameters will be
determined, the degeneracy among alternative cosmological frameworks will still
be relatively large. This seems to suggest that obtaining standard
candles/rulers from very high redshift data (e.g. using cosmic microwave
background) will be of crucial importance for the viability of cosmographic
tests.
View original:
http://arxiv.org/abs/1103.0378
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