A Caltech Library Service

The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe

Hawkins, Ed and Maddox, Steve and Cole, Shaun and Lahav, Ofer and Madgwick, Darren S. and Norberg, Peder and Peacock, John A. and Baldry, Ivan K. and Baugh, Carlton M. and Bland-Hawthorn, Joss and Bridges, Terry and Cannon, Russell and Colless, Matthew and Collins, Chris and Couch, Warrick and Dalton, Gavin and De Propris, Roberto and Driver, Simon P. and Efstathiou, George and Ellis, Richard S. and Frenk, Carlos S. and Glazebrook, Karl and Jackson, Carole and Jones, Bryn and Lewis, Ian and Lumsden, Stuart and Percival, Will and Peterson, Bruce A. and Sutherland, Will and Taylor, Keith (2003) The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe. Monthly Notices of the Royal Astronomical Society, 346 (1). pp. 78-96. ISSN 0035-8711.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


We present a detailed analysis of the two-point correlation function, ξ (σ, π), from the 2dFGalaxy Redshift Survey (2dFGRS). The large size of the catalogue, which contains ∼220 000 redshifts, allows us to make high-precision measurements of various properties of the galaxy clustering pattern. The effective redshift at which our estimates are made is zₛ ≈ 0.15, and similarly the effective luminosity, Lₛ ≈ 1.4L∗. We estimate the redshift-space correlation function, ξ (s), from which we measure the redshift-space clustering length, s₀ = 6.82 ± 0.28 h⁻¹ Mpc. We also estimate the projected correlation function, Ξ(σ), and the real-space correlation function, ξ (r ), which can be fit by a power law (r/r₀)−γ r₀ , with r₀ = 5.05 ± 0.26 h⁻¹ Mpc, γ r = 1.67 ± 0.03. For r ≳ 20 h⁻¹ Mpc, ξ drops below a power law as, for instance, is expected in the popular Λ cold dark matter model. The ratio of amplitudes of the real- and redshift-space correlation functions on scales of 8–30 h⁻¹ Mpc gives an estimate of the redshift-space distortion parameter β. The quadrupole moment of ξ (σ, π) on scales 30–40 h⁻¹ Mpc provides another estimate of β. We also estimate the distribution function of pairwise peculiar velocities, f (v), including rigorously the significant effect due to the infall velocities, and we find that the distribution is well fit by an exponential form. The accuracy of our ξ (σ, π) measurement is sufficient to constrain a model, which simultaneously fits the shape and amplitude of ξ (r) and the two redshift-space distortion effects parametrized by β and velocity dispersion, a. We find β = 0.49 ± 0.09 and a= 506 ± 52 km s⁻¹, although the best-fitting values are strongly correlated. We measure the variation of the peculiar velocity dispersion with projected separation, a(σ), and find that the shape is consistent with models and simulations. This is the first time that β and ƒ(v) have been estimated from a self-consistent model of galaxy velocities. Using the constraints on bias from recent estimates, and taking account of redshift evolution, we conclude that β (L=L*, z= 0) = 0.47 ± 0.08, and that the present-day matter density of the Universe, Ω_m≈ 0.3, consistent with other 2dFGRS estimates and independent analyses.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Norberg, Peder0000-0002-5875-0440
Baugh, Carlton M.0000-0002-9935-9755
Bland-Hawthorn, Joss0000-0001-7516-4016
Colless, Matthew0000-0001-9552-8075
Ellis, Richard S.0000-0001-7782-7071
Additional Information:© 2003 RAS. Accepted 2003 August 1. Received 2003 May 11; in original form 2002 December 17. The 2dFGRS has been made possible through the dedicated efforts of the staff of the Anglo-Australian Observatory, both in creating the 2dF instrument and in supporting it on the telescope. We thank Nelson Padilla, Andrew Benson, Sarah Bridle, Yipeng Jing, Xiaohu Yang and Robert Smith for providing their results in electronic form. We also thank the referee for valuable comments.
Subject Keywords:surveys, galaxies: distances and redshifts, galaxies: statistics, cosmological parameters, large-scale structure of Universe
Issue or Number:1
Record Number:CaltechAUTHORS:20200708-151733120
Persistent URL:
Official Citation:Ed Hawkins, Steve Maddox, Shaun Cole, Ofer Lahav, Darren S. Madgwick, Peder Norberg, John A. Peacock, Ivan K. Baldry, Carlton M. Baugh, Joss Bland-Hawthorn, Terry Bridges, Russell Cannon, Matthew Colless, Chris Collins, Warrick Couch, Gavin Dalton, Roberto de Propris, Simon P. Driver, George Efstathiou, Richard S. Ellis, Carlos S. Frenk, Karl Glazebrook, Carole Jackson, Bryn Jones, Ian Lewis, Stuart Lumsden, Will Percival, Bruce A. Peterson, Will Sutherland, Keith Taylor, The 2dF Galaxy Redshift Survey: correlation functions, peculiar velocities and the matter density of the Universe, Monthly Notices of the Royal Astronomical Society, Volume 346, Issue 1, November 2003, Pages 78–96,
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:104287
Deposited By: Rebecca Minjarez
Deposited On:09 Jul 2020 15:30
Last Modified:09 Jul 2020 15:30

Repository Staff Only: item control page