The monopole moment of the three-point correlation function of the two-degree Field Galaxy Redshift Survey

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We measure the monopole moment of the three-point correlation function on scales 1-70 h -1 Mpc in the two-degree Field Galaxy Redshift Survey (2dFGRS). Volume-limited samples are constructed using a series of integral magnitude bins between M = -18 to -22. Our measurements with a novel edge-corrected estimator represent most, if not all, three-point level monopole or angular averaged information in the catalogue. We fit a perturbative non-linear bias model to a joint data vector formed from the estimated two- and three-point correlation functions. Two different models are used: an analytic model based on Eulerian perturbation theory including bias and redshift distortions and a phenomenological bias model based on the direct redshift space measurements in the large Virgo simulations. To interpret the clustering results, we perform a three-parameter Gaussian maximum-likelihood analysis. In the canonical -21 to -20 volume-limited sample, we find σ 8 = 0.93 -0.2 +0.06, b = 1.04 -0.09 +0.23 and b 2 = -0.06 -0.001 +0.003. Our estimate of σ 8 is robust across the different volume-limited samples constructed. These results, based solely on the large-scale clustering of galaxies, are in excellent agreement with previous analyses using the Wilkinson Anisotropy Probe; this is a spectacular success of the concordance model. We also present two-parameter fits for the bias parameters, which are in excellent agreement with the previous findings of the bias evolution in the 2dFGRS.

Original languageEnglish
Pages (from-to)1363-1370
Number of pages8
JournalMonthly Notices of the Royal Astronomical Society
Issue number4
Publication statusPublished - Oct 1 2005



  • Cosmology: theory
  • Large-scale structure of universe
  • Methods: statistical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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