Deep Optical Galaxy Counts with the Keck Telescope

We present faint galaxy counts from deep VRI images obtained with the Keck Telescope. These images reach R\27 in median seeing FWHM \ 0. 5--0. 6 arcsec and we detect a integrated galaxy number density of 7\ 10^5 degree^-2, equivalent to 3\ 10^10 galaxies in the observable Universe. In addition we present median galaxy colors as a function of magnitude; bluing trends are visible in all colors to R\ 24. 5. Fainter than R\24. 5, however, the typical \\\ color becomes redder again, \\\ remains constant, and \\\ becomes yet bluer. These trends are consistent with the VRI count slopes, implying a decrease in the V slope at the faintest levels, which our data supports. Taking advantage of our good seeing we also present median half-light radii for faint galaxies, these show a steady decline at fainter magnitudes, leading to an intrinsic half-light radius of \ 0. 2 arcsec for a typical R\25. 5--26 galaxy. Irrespective of the redshift distribution, the extremely high galaxy surface densities and their small intrinsic sizes are consistent with a scenario in which the majority of the very faint field population are dwarf galaxies or sub-galactic units.