Statistical analysis of galaxy surveys – III. The non-linear clustering of red and blue galaxies in the 2dFGRS |
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| Authors: | Darren J Croton Peder Norberg Enrique Gaztañaga Carlton M Baugh |
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| Institution: | Department of Astronomy, University of California, Berkeley, CA 94720, USA;SUPA, Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ;Instituto de Ciencias del Espacio (IEEC/CSIC), F. de Ciencies UAB, Torre C5- Par-2a, Bellaterra, 08193 Barcelona, Spain;Institute for Computational Cosmology, Department of Physics, University of Durham, South Road, Durham DH1 3LE |
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| Abstract: | We present measurements of the higher order clustering of red and blue galaxies as a function of scale and luminosity made from the two-degree field galaxy redshift survey (2dFGRS). We use a counts-in-cells analysis to estimate the volume-averaged correlation functions,  , as a function of scale up to the order of p = 5 , and also the reduced void probability function. Hierarchical amplitudes are constructed using the estimates of the correlation functions:  . We find that (i) red galaxies display stronger clustering than blue galaxies at all orders measured; (ii) red galaxies show values of S p that are strongly dependent on luminosity whereas blue galaxies show no segregation in S p within the errors; this is remarkable given the segregation in the variance; (iii) the linear relative bias shows the opposite trend to the hierarchical amplitudes, with little segregation for the red sequence and some segregation for the blue; (iv) faint red galaxies deviate significantly from the 'universal' negative binomial reduced void probabilities followed by all other galaxy populations. Our results show that the characteristic colour of a galaxy population reveals a unique signature in its spatial distribution. Such signatures will hopefully further elucidate the physics responsible for shaping the cosmological evolution of galaxies. |
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| Keywords: | galaxies: statistics cosmology: theory large-scale structure of Universe |
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