Detection of galaxy luminosity and color evolution.

Recent CCD multi-color imaging of faint galaxies in 12 high- latitude fields reveals strong evidence for color and luminosity evolution. Deep images in several bands from 0.3 to 1micron enable studies of galaxies undergoing evolution at redshifts up to 7. At 27th J mag the sky becomes confusion limited in galaxies. 

Galaxy counts at 25th J magnitude are a factor of 5-15 above no-evolution models. A strong bluing trend is seen for the fainter galaxies, suggesting that the UV excess from massive star formation in these evolving galaxies has been redshifted into the blue band. We compute explicitly the extragalactic background light from the number- magnitude counts. 

We find no evidence of extended primeval objects down to 30 J mag arcsec sup (-2). Mild and continuous evolution of spiral galaxies seems to have occurred. Any bright phase at 3.