  We have employed natural guide star adaptive optics (AO) on the Keck II
telescope to obtain near-infrared (H and K') images of three field galaxies,
each of redshift greater than 0.5. These are among the highest-redshift
non-active disk galaxies to be imaged with AO. Each of the galaxies was chosen
because it had been observed previously with the Hubble Space Telescope (HST)
Wide Field Planetary Camera 2 (WFPC2) by others. Our AO images in the near
infrared (NIR) closely match both the depth and high spatial resolution of
those optical data. Combining the archival V and I data with our new H and K'
images potentially produces a long wavelength baseline at uniform resolution.
The NIR data probe emission well longward of the 4000-Angstrom break at these
redshifts, and provide stellar fluxes less contaminated by dust. We fit
two-dimensional galaxy bulge-plus-disk models simultaneously in all bands, and
compare stellar-population-synthesis modeling to the photometry of these
separated components. This is an initial foray into combining HST and AO
imaging to produce a high spatial-resolution multi-color dataset for a large
sample of faint galaxies. Our pilot program shows that NIR AO images from large
ground-based observatories, augmented by HST images in the optical, can in
principle provide a powerful tool for the analysis of faint field galaxies.
However, the AO data S/N will have to be increased, and AO PSFs need to be
controlled more carefully than they were here.
