The Durham/UKST Galaxy Redshift Survey - II. The field galaxy luminosity function

Abstract

We present the results for the galaxy luminosity function as estimated from the Durham/UKST Galaxy Redshift Survey. This survey is magnitude-limited to bJ ∼ 17, contains ∼2500 galaxies sampled at a rate of one-in-three, and surveys a ∼4 × 106(h-1 Mpc)3 volume of space. The maximum-likelihood parameters for a standard Schechter luminosity function are estimated to be M*bj = -19.72±0.09, α= -1.14±0.08 and φ* = (1.2±0.2) × 10-2(h3 Mpc-3). Attempting to correct for the scatter in the observed magnitudes leads to a flatter faint-end slope, α= -1.04±0.08, which, combined with the different luminosity function shape, causes a higher normalization to be estimated, φ*=(1.7±0.3) × 10-2(h3 Mpc-3). Neither of these parametric functions provides a good formal fit to the non-parametric estimate of the luminosity function. A comparison with galaxy luminosity functions from other redshift surveys shows good agreement, and the shape of the luminosity function now appears to be well defined down to MbJ ≃ - 17. There are some discrepancies between the different surveys for galaxies fainter than this absolute magnitude. However, our estimate agrees well with that from the APM-Stromlo Galaxy Redshift Survey and we measure a fairly flat faint-end slope.