Evolution of the Galaxy Luminosity Function at z < 0.3
Jon Loveday, University of Sussex
I will present measurements of the redshift-dependent luminosity
function and the comoving radial density of galaxies in the Sloan
Digital Sky Survey Data Release 1 (SDSS DR1). Both measurements
indicate
that the apparent number density of bright galaxies increases by a
factor ~3 as redshift increases from z=0 to z=0.3. This result is
robust
to the assumed cosmology, to the details of the K-correction and to
direction on the sky. These observations are most naturally
explained by
significant evolution in the luminosity and/or number density of
galaxies at redshifts z < 0.3. Such evolution is also consistent
with
the steep number-magnitude counts seen in the APM Galaxy Survey,
without
the need to invoke a local underdensity in the galaxy distribution.