DEEP HST IMAGING OF DISTANT WEAK RADIO AND FIELD GALAXIES

We present deep Hubble Space Telescope (HST) Wide-Field Camera V- and I-band images of three distant weak radio galaxies with z = 0.311-2.390 and seven field galaxies with z = 0.131-0.58. The images were deconvolved with both the Lucy and multiresolution CLEAN methods, which yield a restoring FWHM of less than or equal to 0 ''.2, (nearly) preserve photons and signal-to-noise ratio at low spatial frequencies, and produce consistent light profiles down to our 2 sigma surface brightness sensitivity limit of V similar to 27.2 and I similar to 25.9 mag arcsec(-2). Multicomponent image modeling was used to provide deconvolution-independent estimates of structural parameters for symmetric galaxies. We present 12-band (m(2750) UBVRlgriJHK) photometry for a subset of the galaxies and bootstrap the unknown FOC/48 zero point at 2750 Angstrom in three independent ways (yielding m(2750) = 21.34 +/- 0.09 mag for 1.0 e(-) s(-1)).

Two radio galaxies with z = 0.311 and 0.528, as well as one field galaxy with z = 0.58, have the colors and spectra of early-type galaxies, and a(1/4)-like light profiles in the HST images. The two at z > 0.5 have little or no color gradients in V-I and are likely giant ellipticals, while the z = 0.311 radio galaxy has a dim exponential disk and is likely an SO. Six of the seven field galaxies have light profiles that indicate (small) inner bulges following a(1/4) laws and outer exponential disks, both with little or no color gradients. These are (early-type) spiral galaxies with z = 0.131-0.528. About half have faint companions or bars. One shows lumpy structure, possibly a merger.

The compact narrow-line galaxy 53W002 at z = 2.390 has less than or equal to 30% +/- 10% of its HST V and I flux in the central kiloparsec (due to its weak AGN). Most of its light (V similar or equal to 23.3) occurs in a symmetric envelope with a regular a(1/4)-like profile of effective radius a similar or equal to 1 ''.1 (similar or equal to 12 kpc for H-0 = 50, q(0) = 0.1). Its (HST) V-I color varies at most from similar to 0.3 mag at a similar or equal to 0 ''.2 to similar to 1.2 mag at a greater than or similar to 0 ''.4, and possibly to greater than or similar to 2.2 mag at a greater than or similar to 1 ''.2. Together with its I-K color (similar or equal to 2.5 mag for a greater than or similar to 1 ''.0-2 ''.0), this is consistent with an aging stellar population similar to 0.3-0.5 Gyr old in the galaxy center (a less than or similar to 2 kpc radius), and possibly similar to 0.5-1.0 Gyr old at a greater than or similar to 10 kpc radius. While its outer part may thus have started to collapse at z = 2.5-4, its inner part still is aligned with its redshifted Ly alpha cloud and its radio axis, possibly caused by star formation associated with the radio jet, or by reflection from its AGN cone.