ar X iv : a st ro - p h / 01 05 45 0 v 1 2 5 M ay 2 00 1 Measuring large - scale structure with the 2 dF Galaxy Redshift Survey

The 2dF Galaxy Redshift Survey is the first to measure more than 100,000 redshifts. This allows precise measurements of many of the key statistical measures of galaxy clustering, in particular redshift-space distortions and the large-scale power spectrum. This paper presents the current 2dFGRS results in these areas. Redshiftspace distortions are detected with a high degree of significance, confirming the detailed Kaiser distortion from large-scale infall velocities, and measuring the distortion parameter β = 0.43 ± 0.07. The power spectrum is measured to < ∼ 10% accuracy for k > 0.02 hMpc, and is well fitted by a CDM model with Ωmh = 0.20 ± 0.03 and a baryon fraction of 0.15± 0.07. I AIMS AND DESIGN OF THE 2DFGRS The large-scale structure in the galaxy distribution is widely seen as one of the most important relics from an early stage of evolution of the universe. The 2dF Galaxy Redshift Survey (2dFGRS) was designed to build on previous studies of this structure, with the following main aims: 1. To measure the galaxy power spectrum P (k) on scales up to a few hundred Mpc, bridging the gap between the scales of nonlinear structure and measurements from the the cosmic microwave background (CMB). 2. To measure the redshift-space distortion of the large-scale clustering that results from the peculiar velocity field produced by the mass distribution. ∗) The 2dF Galaxy Redshift Survey team: Matthew Colless (ANU), John Peacock (ROE), Carlton M. Baugh (Durham), Joss Bland-Hawthorn (AAO), Terry Bridges (AAO), Russell Cannon (AAO), Shaun Cole (Durham), Chris Collins (LJMU), Warrick Couch (UNSW), Nicholas Cross (St Andrews), Gavin Dalton (Oxford), Kathryn Deeley (UNSW), Roberto De Propris (UNSW), Simon Driver (St Andrews), George Efstathiou (IoA), Richard S. Ellis (Caltech), Carlos S. Frenk (Durham), Karl Glazebrook (JHU), Carole Jackson (ANU), Ofer Lahav (IoA), Ian Lewis (AAO), Stuart Lumsden (Leeds), Steve Maddox (Nottingham), Darren Madgwick (IoA), Peder Norberg (Durham), Will Percival (ROE), Bruce Peterson (ANU), Will Sutherland (ROE), Keith Taylor (Caltech) FIGURE 1. The 2dFGRS fields (small circles) superimposed on the APM catalogue area (dotted outlines of Sky Survey plates). There are approximately 140,000 galaxies in the 75◦×15◦ southern strip centred on the SGP, 70,000 galaxies in the 75◦ × 7.5◦ equatorial strip, and 40,000 galaxies in the 100 randomly-distributed 2dF fields covering the whole area of the APM catalogue in the