The Norris Survey of the Corona Borealis Supercluster. II. Galaxy Evolution with Redshift and Environment

We measure the field galaxy luminosity function (LF) as a function of colorand redshift from z = 0 to z = 0.5 using galaxies from the Norris Survey of theCorona Borealis Supercluster. We find that our local r-band LF, when normalizedto counts in high galactic latitude fields, agrees well with the local LFmeasured in the Las Campanas Redshift Survey. Our B-band local LF, however,does not match the B-band LF from the Stromlo/APM survey, having anormalization 1.6 times higher. We see compelling evidence that B-band fieldgalaxy LF evolves with redshift. The evolution is strongest for the populationof star-forming galaxies with [OII]3727 rest-frame equivalent widths greaterthan 10A. The population of red, quiescent galaxies shows no sign of evolutionto z = 0.5. The evolution of the LF which we observe is consistent with thefindings of other faint galaxy redshift surveys. The fraction of galaxies with[OII] emission increases rapidly with redshift, but the fraction of galaxieswith strong Hdelta 4101 absorption, a signature of a burst of star formation,does not. We thus conclude that the star formation in distant galaxies isprimarily long-lived. We also compute the LFs of the Corona Borealis supercluster and the A2069supercluster. The shapes of the two supercluster LFs are broadly similar to theshape of the local LF. However, there are important differences. Bothsupercluster LFs have an excess of very bright galaxies. In addition, there isa suggestion of an upturn in the LF for galaxies fainter than M(B) = -17 mag. (Abridged from the abstract in the paper.)Comment: 28 pages plus 18 pages of figures; accepted for publication in Ap