The 2dF Galaxy Redshift Survey: hierarchical galaxy clustering

Baugh, C. M. ; Croton, D. J. ; Gaztañaga, E. ; Norberg, P. ; Colless, M. ; Baldry, I. K. ; Bland-Hawthorn, J. ; Bridges, T. ; Cannon, R. ; Cole, S. ; Collins, C. ; Couch, W. ; Dalton, G. ; De Propris, R. ; Driver, S. P. ; Efstathiou, G. ; Ellis, R. S. ; Frenk, C. S. ; Glazebrook, K. ; Jackson, C. ; Lahav, O. ; Lewis, I. ; Lumsden, S. ; Maddox, S. ; Madgwick, D. ; Peacock, J. A. ; Peterson, B. A. ; Sutherland, W. ; Taylor, K.

In: Monthly Notices of the Royal Astronomical Society, 2004, vol. 351, no. 2, p. L44-L48

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    We use the Two-Degree Field Galaxy Redshift Survey (2dFGRS) to test the hierarchical scaling hypothesis: namely, that the p-point galaxy correlation functions can be written in terms of the two-point correlation function or variance. This scaling is expected if an initially Gaussian distribution of density fluctuations evolves under the action of gravitational instability. We measure the volume-averaged p-point correlation functions using a counts-in-cells technique applied to a volume-limited sample of 44 931 L* galaxies. We demonstrate that L* galaxies display hierarchical clustering up to order p= 6 in redshift space. The variance measured for L* galaxies is in excellent agreement with the predictions from a Λ-cold dark matter N-body simulation. This applies to all cell radii considered, 0.3 < (R/h−1 Mpc) < 30. However, the higher order correlation functions of L* galaxies have a significantly smaller amplitude than is predicted for the dark matter for R < 10 h−1 Mpc. This disagreement implies that a non-linear bias exists between the dark matter and L* galaxies on these scales. We also show that the presence of two rare, massive superclusters in the 2dFGRS has an impact on the higher-order clustering moments measured on large scales