Current constraints on the cosmic growth history

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Abstract
We present constraints on the cosmic growth history with recent cosmological data, allowing for deviations from $\Lambda${}CDM as might arise if cosmic acceleration is due to modifications to general relativity or inhomogeneous dark energy. We combine measures of the cosmic expansion history, from Type~1a supernovae, baryon acoustic oscillations, and the cosmic microwave background (CMB), with constraints on the growth of structure from recent galaxy, CMB, and weak lensing surveys along with integated Sachs Wolfe-galaxy cross correlations. Deviations from $\Lambda${}CDM are parameterized by phenomenological modifications to the Poisson equation and the relationship between the two Newtonian potentials. We find modifications that are present at the time the CMB is formed are tightly constrained through their impact on the well-measured CMB acoustic peaks. By contrast, constraints on late-time modifications to the growth history, as might arise if modifications are related to the onset of cosmic acceleration, are far weaker, but remain consistent with $\Lambda${}CDM at the 95%~confidence level. For these late-time modifications we find that differences in the evolution on large and small scales could provide an interesting signature by which to search for modified growth histories with future wide angular coverage, large scale structure surveys.