Testing the DGP model with ESSENCE

Abstract

Abstract. We use the recent supernova data set from the ESSENCE collaboration combined with data from the Supernova Legacy Survey and nearby supernovae to test the DGP brane world model and its generalisations. Combination of this data with a flatness prior and the position of the peak of the CMB disfavours the DGP model slightly, although does not rule it out significantly. Inclusion of the baryon acoustic peak from the Sloan Digital Sky Survey would rule out the DGP model at the 3σ level, although it is not clear how self consistent this procedure would be without a re-analysis of the survey data in the framework of the DGP cosmology. Generalisations of the DGP model are tested and constraints on relevant parameters obtained.

Cosmological constraints combiningH(z), CMB shift and SNIa observational data

“…Our results are consistent with partially overlapping work (e.g. [20,21]) done previously using different combinations of observations.…”

On model selection forecasting, dark energy and modified gravity

“…Song, Hu & Sawicki (2007) show that the simplest flat DGP model demonstrates a difficulty pointed out by Ishak, Upadye & Spergel (2006), that is, inconsistent parameter values are obtained from different data sets. Also, the DGP model may be in difficulties with the CMB peak and baryon oscillations (Rydbeck, Fairbairn & Goobar 2007) as well as theoretically through the existence of ghosts (Gorbunov, Koyama & Sibiryakov 2006). Here, we concentrate instead on distinguishing modified gravity models from GR using a different feature – that the growth factor is different from that of a quintessence model with the same expansion history.…”

Screening bulk curvature in the presence of large brane tension

“…The Dvali-Gabadadze-Porrati (DGP) model [6], in particular, takes this idea to the extreme and considers our 4D Universe to be embedded in an empty 5D bulk of infinite extent. Despite being observationally disfavored [7][8][9][10], 1 the normal branch of the DGP model is perturbatively ghost-free, in contrast to the selfaccelerating branch [14][15][16][17][18][19], and thus represents a perturbatively consistent infrared modification of gravity in which the graviton has a soft mass.…”