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 ∼4×106(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.