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 redshift‐space 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 Ωm= 0.27. Our analysis hence indicates that this model provides a self‐consistent description of the growth of cosmic structure through large‐scale 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 quasi‐linear growth of structure including empirical models, fitting formulae calibrated to N‐body simulations, and perturbation theory techniques. We extract the first measurements of the power spectrum of the velocity divergence field, Pθθ(k), as a function of redshift (under the assumption that , where g is the galaxy overdensity field), and demonstrate that the WiggleZ galaxy–mass cross‐correlation is consistent with a deterministic (rather than stochastic) scale‐independent 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 distance–redshift measures such as supernovae and baryon acoustic oscillations.

Measuring the growth of matter fluctuations with third-order galaxy correlations

“…Note that measurements from RSD directly constrain f × D and not f . Nevertheless, under some assumptions we can also infer f from RSD and the typical errors found on SDSS, BOSS and WiggleZ are around 15-20% (Cabré and Gaztañaga 2009;Blake et al 2011;Tojeiro et al 2012), which are comparable to the ones we find here.…”

Observational probes of cosmic acceleration

“…A predecessor to BOSS, the WiggleZ project on the Anglo-Australian 3.9-m telescope, recently completed a spectroscopic survey of 240,000 emission line galaxies out to z = 1.0 (Blake et al, 2011a). The Hyper Suprime-Cam (HSC) facility on the Subaru telescope will have wide-area imaging capabilities comparable to DES and Pan-STARRS, and it is likely to devote substantial fractions of its time to weak lensing surveys.…”

“…Finally, for current data we take WMAP CMB errors, Union2 SN errors, and the BAO data and errors described in §4.2. We adopt the RSD errors reported by Blake et al (2011a) from WiggleZ (see §7.2). We also include a 3% error on H 0 , and a 4% error on σ 8 Ω 0.4 m to represent clusters and weak lensing (see §6.2).…”

“…42). Recent observational analyses include the measurement of Guzzo et al (2008) from the VIMOS-VLT Deep Survey (VVDS), f (z) = 0.91 ± 0.36 at z ≈ 0.8, the measurement of Samushia et al (2012) from SDSS DR7, obtaining ∼ 10% constraints on f (z)σ 8 (z) at z = 0.25 and z = 0.37, the measurement of Blake et al (2011a) from the WiggleZ survey, obtaining ∼ 10% constraints in each of four redshift bins from z = 0.1 to z = 0.9, the measurement of Reid et al (2012) from BOSS, obtaining a ∼ 8% constraint at z = 0.57, and the local measurement of Beutler et al (2012) from the 6dFGS, obtaining a ∼ 13% constraint at z = 0.067. All of these measurements assume ΛCDM geometry when inferring f (z)σ 8 (z), and their derived growth parameters are consistent with ΛCDM predictions.…”

Analytic rotating black-hole solutions in N-dimensional f(T) gravity

“…The accelerated expansion of our Universe is confirmed by many separated cosmological experiments [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. This expansion can be explained in GR by taking into account the dark energy component in the total energy of our Universe.…”