The Durham / UKST Galaxy Redshift Survey - II . The Field Galaxy Luminosity Function

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 × 10(hMpc) 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 (hMpc). 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 normalisation to be estimated, φ∗ = (1.7 ± 0.3) × 10 (hMpc). 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 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.