Testing Gravity Using Large-Scale Redshift-Space Distortions
  We use Luminous Red Galaxies from the Sloan Digital Sky Survey II to test the
cosmological structure growth in two alternatives to the standard LCDM+GR
cosmological model. We compare observed three-dimensional clustering in SDSS
DR7 with theoretical predictions for the standard vanilla LCDM+GR model,
Unified Dark Matter cosmologies and the normal branch DGP. In computing the
expected correlations in UDM cosmologies, we derive a parameterized formula for
the growth factor in these models. For our analysis we apply the methodology
tested in Raccanelli et al. 2010 and use the measurements of Samushia et al.
2011, that account for survey geometry, non-linear and wide-angle effects and
the distribution of pair orientation. We show that the estimate of the growth
rate is potentially degenerate with wide-angle effects, meaning that extremely
accurate measurements of the growth rate on large scales will need to take such
effects into account. We use measurements of the zeroth and second order
moments of the correlation function from SDSS DR7 data and the Large Suite of
Dark Matter Simulations, and perform a likelihood analysis to constrain the
parameters of the models. Using information on the clustering up to r_max = 120
Mpc/h, and after marginalizing over the bias, we find, for UDM models, a speed
of sound < 6.1e-4, and, for the nDGP model, a cross-over scale r_c > 340 Mpc,
at 95% confidence level.
