The WiggleZ Dark Energy Survey: the growth rate of cosmic structure since redshift z=0.9
Abstract
We present precise measurements of the growth rate of cosmic structure for the redshift range 0.1 < z < 0.9, using redshiftspace distortions in the galaxy power spectrum of the WiggleZ Dark Energy Survey. Our results, which have a precision of around 10 per cent in four independent redshift bins, are well fitted by a flat Λ cold dark matter (ΛCDM) cosmological model with matter density parameter Ω_{m}= 0.27. Our analysis hence indicates that this model provides a selfconsistent description of the growth of cosmic structure through largescale perturbations and the homogeneous cosmic expansion mapped by supernovae and baryon acoustic oscillations. We achieve robust results by systematically comparing our data with several different models of the quasilinear growth of structure including empirical models, fitting formulae calibrated to Nbody simulations, and perturbation theory techniques. We extract the first measurements of the power spectrum of the velocity divergence field, P_{θθ}(k), as a function of redshift (under the assumption that ?, where g is the galaxy overdensity field), and demonstrate that the WiggleZ galaxymass crosscorrelation is consistent with a deterministic (rather than stochastic) scaleindependent bias model for WiggleZ galaxies for scales k < 0.3 h Mpc^{1}. Measurements of the cosmic growth rate from the WiggleZ Survey and other current and future observations offer a powerful test of the physical nature of dark energy that is complementary to distanceredshift measures such as supernovae and baryon acoustic oscillations.
 Publication:

Monthly Notices of the Royal Astronomical Society
 Pub Date:
 August 2011
 DOI:
 10.1111/j.13652966.2011.18903.x
 arXiv:
 arXiv:1104.2948
 Bibcode:
 2011MNRAS.415.2876B
 Keywords:

 surveys;
 cosmological parameters;
 largescale structure of Universe;
 Astrophysics  Cosmology and Nongalactic Astrophysics
 EPrint:
 17 pages, 11 figures, accepted for publication by MNRAS