| Institution: | Department of Physics, University of Durham, South Road, Durham DH1 3LE,; School of Physics &Astronomy, University of Nottingham, Nottingham NG7 2RD,; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA,; Department of Physics &Astronomy, Johns Hopkins University, Baltimore, MD 21218-2686, USA,; Anglo-Australian Observatory, PO Box 296, Epping, NSW 2121, Australia,; Research School of Astronomy &Astrophysics, The Australian National University, Weston Creek, ACT 2611, Australia,; Astrophysics Research Institute, Liverpool John Moores University, 12 Quays House, Birkenhead L14 1LD,; Department of Astrophysics, University of New South Wales, Sydney, NSW 2052, Australia,; Department of Physics, University of Oxford, Keble Road, Oxford OX1 3RH,; School of Physics and Astronomy, University of St Andrews, North Haugh, St Andrews, Fife KY6 9SS,; Department of Astronomy, California Institute of Technology, Pasadena, CA 91125, USA,; Department of Physics, University of Leeds, Woodhouse Lane, Leeds LS2 9JT and; Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ |
| Abstract: | We investigate the dependence of galaxy clustering on luminosity and spectral type using the 2dF Galaxy Redshift Survey (2dFGRS). Spectral types are assigned using the principal-component analysis of Madgwick et al. We divide the sample into two broad spectral classes: galaxies with strong emission lines ('late types') and more quiescent galaxies ('early types'). We measure the clustering in real space, free from any distortion of the clustering pattern owing to peculiar velocities, for a series of volume-limited samples. The projected correlation functions of both spectral types are well described by a power law for transverse separations in the range 2<( σ / h -1 Mpc)<15 , with a marginally steeper slope for early types than late types. Both early and late types have approximately the same dependence of clustering strength on luminosity, with the clustering amplitude increasing by a factor of ～2.5 between L * and 4 L *. At all luminosities, however, the correlation function amplitude for the early types is ～50 per cent higher than that of the late types. These results support the view that luminosity, and not type, is the dominant factor in determining how the clustering strength of the whole galaxy population varies with luminosity. |
