The galaxy luminosity function at z <= 0.05: Dependence on morphology

We investigate the dependence of the local galaxy luminosity function on mo rphology using 5404 galaxies from the recently enlarged Second Southern Sky Redshift Survey (SSRS2). Over the range -22 less than or equal to M-B less than or equal to - 14 (H-0 = 100 km s(-1) Mpc(-1)), the luminosity functio n of early-type galaxies is well fitted by a Schechter function with parame ters M-* = -19.37(-0.11)(+0.10), alpha = -1.00(-0.09)(+0.09), and phi(*) = 4.4 +/- 0.8 x 10(-3) Mpc(-3). The spiral luminosity function is very simila r and is well fitted by the parameters M-* = -19.43(-0.08)(+0.08), alpha = -1.11(-0.06)(+0.07), and phi(*) = 8.0 +/- 1.4 x 10(-3) Mpc(-3) over the sam e range in absolute magnitude. The flat faint end of the early-type luminos ity function is consistent with earlier measurements from the CfA Redshift Survey (Marzke et al.) but is significantly steeper than the slope measured in the Stromlo-APM survey (Loveday et al.). Combined with the increased no rmalization of the overall LF measured from intermediate-redshift surveys, the flat faint-end slope of the E/S0 LF produces no-evolution models that r eproduce the deep Hubble Space Telescope (HST) counts of early-type galaxie s remarkably well. However, the observed normalization of the SSRS2 LF is c onsistent with the low value measured in other local redshift surveys. The cause of this lo-redshift anomaly remains unknown. The luminosity function of irregular and peculiar galaxies in the SSRS2 is very steep: M-* -19.78(- 0.50)(+0.40) alpha = -1.81(-0.24)(+0.24), and phi(*) = 0.2 +/- 0.08 x 10(-3 ) Mpc(-3). The steep slope at the faint end is consistent with the LFs meas ured for Sm-Im galaxies in the CfA survey, UV-selected galaxies (Treyer et al.), star-forming held galaxies (Bromley et al.), and the bluest galaxies in the SSRS2 (Marzke & da Costal. As shown by Driver, Windhorst, & Griffith s, the steep LF reduces the observed excess of faint irregulars over no-evo lution predictions but cannot explain it entirely.