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.

In this, the first in a series of three papers concerning the SuperCOSMOS Sky Survey (SSS), we give an introduction and user guide to the survey programme. We briefly describe other wide‐field surveys and compare them with our own. We give examples of the data, and make a comparison of the accuracies of the various image parameters available with those from the other surveys providing similar data; we show that the SSS data base and interface offer advantages over these surveys. Some science applications of the data are also described and some limitations discussed. The series of three papers constitutes a comprehensive description and user guide for the SSS.