The 2dF Galaxy Redshift Survey: spectral types and luminosity functions

We describe the 2dF Galaxy Redshift Survey (2dFGRS) and the current status of the observations, In this exploratory paper, we apply a principal compon ent analysis to a preliminary sample of 5869 galaxy spectra and use the two most significant components to split the sample into five spectral classes . These classes are defined by considering visual classifications of a subs et of the 2dF spectra, and also by comparison with high-quality spectra of local galaxies. We calculate a luminosity function for each of the differen t classes and find that later-type galaxies have a fainter characteristic m agnitude, and a steeper faint-end slope. For the whole sample we find M* = -19.7 (for Ohm = 1, H-0 = 100 km s(-1) Mpc(-1)), alpha = -1.3, phi* = 0.017 , For class 1 ('early-type') we find M* = -19.6; alpha = -0,7, while for cl ass 5 ('late-type') we find M* = -19.0; alpha = -1,7, The derived 2dF lumin osity functions agree well with other recent luminosity function estimates.