Caltech Faint Galaxy Redshift Survey. XVI. The Luminosity Function for Galaxies in the Region of the Hubble Deep Field–North toz = 1.5

We have carried out a study of the luminosity function (henceforth LF) ofgalaxies in the region of the HDF-North using our very complete redshiftcatalog. We solve for the LF at four rest frame wavelengths from 0.24 to 2.2mu.We find that the LFs for quiescent galaxies have shallow faint end slopes,while those of galaxies with detectable emission lines have steeper faint endslopes. Furthermore these slopes are independent of redshift out to z=1.05 foreach galaxy spectral grouping and agree well with comparable localdeterminations. We find that galaxies with strong absorption lines becomebrighter with z with Q \sim 0.6 at all rest frame bands studied here, where Q =\Delta{\rm{log}}[L^*(z)]/\Delta{z}, while galaxies with detectable emissionlines (i.e. star forming galaxies) show a smaller change in L^* with redshiftat all bands, Q ~ 0.3, with Q becoming significantly larger at rest frame2400A. Passive evolution models of galaxies are in reasonable agreement withthese results for absorption line dominated galaxies, while plausible starformation histories can reproduce the behavior of the emission line galaxies.We find the co-moving number density and stellar mass in galaxies to beapproximately constant out to z~1.05, and with more uncertainty, to z~1.3. Themajor epoch(s) of star formation and of galaxy formation must have occurredeven earlier. (abridged)Comment: Slightly revised to conform to version accepted by the ApJ. Added an appendix and a figure, and small improvements/clarifications to the text in place