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 b(J) similar to 17, contains similar to 2500 galaxies samp led at a rate of one-in-three, and surveys a similar to 4 x 10(6)(h(-1 ) Mpc)(3) volume of space. The maximum-likelihood parameters for a sta ndard Schechter luminosity function are estimated to be M-bJ = -19.72 +/- 0.09, alpha = -1.14 +/- 0.08 and phi =(1.2 +/- 0.2) x 10(-2)(h(3 ) Mpc(-3)). Attempting to correct for the scatter in the observed magn itudes leads to a flatter faint-end slope, alpha = -1.04 +/- 0.08, whi ch, combined with the different luminosity function shape, causes a hi gher normalization to be estimated, phi =(1.7 +/- 0.3) x 10(-2)(h(3) Mpc(-3)). Neither of these parametric functions provides a good formal fit to the non-parametric estimate of the luminosity function. A comp arison with galaxy luminosity functions from other redshift surveys sh ows good agreement, and the shape of the luminosity function now appea rs to be well defined down to M-bJ similar or equal to 17. There are s ome discrepancies between the different surveys for galaxies fainter t han this absolute magnitude. However, our estimate agrees well with th at from the APM-Stromlo Galaxy Redshift Survey and we measure a fairly flat faint-end slope.