Radio Sources near Bright Natural Guide Stars

We present a preliminary survey of 58 radio sources within the isoplanatic patches (r < 25′′) of bright (11 < R < 12) stars suitable for use as natural guide stars with high-order adaptive optics (AO). An optical and near-infrared imaging survey was conducted utilizing tip-tilt corrections in the optical and AO in the near-infrared. Spectral Energy Distributions (SEDs) were fit to the multiband data for the purpose of obtaining photometric redshifts using the Hyperz code (Bolzonella et al. 2000). Several of these photometric redshifts were confirmed with spectroscopy, a result that gives more confidence to the redshift distribution for the whole sample. Additional long-wavelength data from Spitzer, SCUBA, SHARC2, and VLA supplement the optical and near-infrared data. We find the sample generally follows and extends the magnitude-redshift relation found for more powerful local radio galaxies. The survey has identified several reasonably bright (H = 19 − 20) objects at significant redshifts (z > 1) that are now within the capabilities of the current generation of AO-fed integral-field spectrographs. These objects constitute a unique sample that can be used for detailed ground-based AO studies of galactic structure, evolution, and AGN formation at high redshift. Subject headings: galaxies: high-redshift — galaxies: fundamental parameters — galaxies: evolution — galaxies: formation