FLICKERING FAINT GALAXIES - FEW AND FAR BETWEEN

Optical variability in galaxies at high redshift is a tracer of evolut ion in AGN activity, and should provide a useful constraint on models of galaxy evolution, AGN structure, and cosmology. We studied optical variability in multiple deep CCD and photographic surveys of blank fie lds for galaxies with B-j=20-25 mag. Weakly variable objects are far m ore common than strongly variable ones. For objects near B-j=22, 0.74% +/-0.2% vary by 0.026 mag rms or more, over a decade. This is small co mpared with previous claims based on photographic surveys, and also sm all compared with the fraction of bright quasars (approximate to 5% at B-j=20 mag) or Seyferts (approximate to 1% - 2% for B-j < 18). The fr action of objects that vary increases slowly with magnitude. Detection probabilities and error rates were checked by simulations and statist ical analysis of fluctuations of sample sky spots. (C) 1996 American A stronomical Society.