We analyse the large‐scale correlation function of the 6dF Galaxy Survey (6dFGS) and detect a baryon acoustic oscillation (BAO) signal at 105 h−1 Mpc. The 6dFGS BAO detection allows us to constrain the distance–redshift relation at zeff= 0.106. We achieve a distance measure of DV(zeff) = 457 ± 27 Mpc and a measurement of the distance ratio, rs(zd)/DV(zeff) = 0.336 ± 0.015 (4.5 per cent precision), where rs(zd) is the sound horizon at the drag epoch zd. The low‐effective redshift of 6dFGS makes it a competitive and independent alternative to Cepheids and low‐z supernovae in constraining the Hubble constant. We find a Hubble constant of H0= 67 ± 3.2 km s−1 Mpc−1 (4.8 per cent precision) that depends only on the Wilkinson Microwave Anisotropy Probe‐7 (WMAP‐7) calibration of the sound horizon and on the galaxy clustering in 6dFGS. Compared to earlier BAO studies at higher redshift, our analysis is less dependent on other cosmological parameters. The sensitivity to H0 can be used to break the degeneracy between the dark energy equation of state parameter w and H0 in the cosmic microwave background data. We determine that w=−0.97 ± 0.13, using only WMAP‐7 and BAO data from both 6dFGS and Percival et al. (2010). We also discuss predictions for the large‐scale correlation function of two future wide‐angle surveys: the Wide field ASKAP L‐band Legacy All‐sky Blind surveY (WALLABY) blind H i survey (with the Australian Square Kilometre Array Pathfinder, ASKAP) and the proposed Transforming Astronomical Imaging surveys through Polychromatic Analysis of Nebulae (TAIPAN) all‐southern‐sky optical galaxy survey with the UK Schmidt Telescope. We find that both surveys are very likely to yield detections of the BAO peak, making WALLABY the first radio galaxy survey to do so. We also predict that TAIPAN has the potential to constrain the Hubble constant with 3 per cent precision.

We report the final redshift release of the 6dF Galaxy Survey (6dFGS), a combined redshift and peculiar velocity survey over the southern sky (|b| > 10°). Its 136 304 spectra have yielded 110 256 new extragalactic redshifts and a new catalogue of 125 071 galaxies making near‐complete samples with (K, H, J, rF, bJ) ≤ (12.65, 12.95, 13.75, 15.60, 16.75). The median redshift of the survey is 0.053. Survey data, including images, spectra, photometry and redshifts, are available through an online data base. We describe changes to the information in the data base since earlier interim data releases. Future releases will include velocity dispersions, distances and peculiar velocities for the brightest early‐type galaxies, comprising about 10 per cent of the sample. Here we provide redshift maps of the southern local Universe with z≤ 0.1, showing nearby large‐scale structures in hitherto unseen detail. A number of regions known previously to have a paucity of galaxies are confirmed as significantly underdense regions. The URL of the 6dFGS data base is http://www-wfau.roe.ac.uk/6dFGS.

We present a detailed analysis of redshift‐space distortions in the two‐point correlation function of the 6dF Galaxy Survey (6dFGS). The K‐band selected subsample which we employ in this study contains 81 971 galaxies distributed over 17 000 degree2 with an effective redshift zeff= 0.067. By modelling the 2D galaxy correlation function, , we measure the parameter combination f(zeff)σ8(zeff) = 0.423 ± 0.055, where is the growth rate of cosmic structure and σ8 is the rms of matter fluctuations in 8 h−1 Mpc spheres. Alternatively, by assuming standard gravity we can break the degeneracy between σ8 and the galaxy bias parameter b. Combining our data with the Hubble constant prior from Riess et al., we measure σ8= 0.76 ± 0.11 and Ωm= 0.250 ± 0.022, consistent with constraints from other galaxy surveys and the cosmic microwave background data from Wilkinson Microwave Anisotropy Probe 7 (WMAP7). Combining our measurement of fσ8 with WMAP7 allows us to test the cosmic growth history and the relationship between matter and gravity on cosmic scales by constraining the growth index of density fluctuations, γ. Using only 6dFGS and WMAP7 data we find γ= 0.547 ± 0.088, consistent with the prediction of General Relativity. We note that because of the low effective redshift of the 6dFGS our measurement of the growth rate is independent of the fiducial cosmological model (Alcock–Paczynski effect). We also show that our conclusions are not sensitive to the model adopted for non‐linear redshift‐space distortions. Using a Fisher matrix analysis we report predictions for constraints on fσ8 for the Wide‐field Australian SKA Pathfinder telescope L‐band Legacy All‐sky Blind surveY (WALLABY) and the proposed Transforming Astronomical Imaging surveys through Polychromatic Analysis of Nebulae (TAIPAN) survey. The WALLABY survey will be able to measure fσ8 with a precision of 4–10 per cent, depending on the modelling of non‐linear structure formation. This is comparable to the predicted precision for the best redshift bins of the Baryon Oscillation Spectroscopic Survey, demonstrating that low‐redshift surveys have a significant role to play in future tests of dark energy and modified gravity.

Citation for published item:pringoD ghristopher wF nd wgoulsD ghristin nd gollessD wtthew nd wouldD teremy nd irdogduD irin nd tonesD hF reth nd vueyD tohn F nd gmpellD vhln nd plukeD ghristopher tF @PHIRA 9he Tdp qlxy urvey X peulir veloity (eld nd osmogrphyF9D wonthly noties of the oyl estronomil oietyFD RRS @QAF ppF PTUUEPTWUF Further information on publisher's website: Additional information: Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details. ABSTRACTWe derive peculiar velocities for the 6dF Galaxy Survey (6dFGS) and describe the velocity field of the nearby (z < 0.055) Southern hemisphere. The survey comprises 8885 galaxies for which we have previously reported Fundamental Plane data. We obtain peculiar velocity probability distributions for the redshift-space positions of each of these galaxies using a Bayesian approach. Accounting for selection bias, we find that the logarithmic distance uncertainty is 0.11 dex, corresponding to 26 per cent in linear distance. We use adaptive kernel smoothing to map the observed 6dFGS velocity field out to cz ∼ 16 000 km s −1 , and compare this to the predicted velocity fields from the PSCz Survey and the 2MASS Redshift Survey. We find a better fit to the PSCz prediction, although the reduced χ 2 for the whole sample is approximately unity for both comparisons. This means that, within the observational uncertainties due to redshift-independent distance errors, observed galaxy velocities and those predicted by the linear approximation from the density field agree. However, we find peculiar velocities that are systematically more positive than model predictions in the direction of the Shapley and Vela superclusters, and systematically more negative than model predictions in the direction of the Pisces-Cetus Supercluster, suggesting contributions from volumes not covered by the models.