The subarcsecond radio structure in NGC 1068 .1. Observations and results

We present the results of new and archival multifrequency MERLIN and VLA observations of the hybrid starburst/Seyfert galaxy NGC 1068, with emphasis on the subarcsecond radio ''triple'' and its associated synchrotron-emitting jet. These results include measurements of the radio continuum spectrum and trajectory of the radio jet, the sizes and minimum energy properties of the compact features, and linear polarization at 22 GHz. Between v = 1.4 and 22 GHz the northeastern and central components (NE and C) have steep spectra: a = -1.04 +/- 0.05 and -0.67 +/- 0.04, respectively (S-nu proportional to nu(2)). The spectrum of the subarcsecond jet flattens locally at components NE and C, implying either compression or reacceleration. The southern component (S) has a very flat spectrum, a = -0.08 +/- 0.05 between 1.4 and 22 GHz. The brightness temperatures of the compact features making up component S (subcomponents S1 and S2) are low, T-b similar to 3 x 10(5) K at 5 GHz. The radio jet bends abruptly at component C from an initial P.A. similar to 12 degrees to P.A. similar to 30 degrees. Contrary to the findings of Ulvestad, Neff, & Wilson (1987), we find no evidence for a gradual, C-shaped bending of the radio jet. The minimum pressures of the compact features are comparable to those of the surrounding narrow-line region. We report similar to 4-5 sigma detections of linear polarization in the directions of components NE and S. The polarization is detected at 22 GHz with 0''.25 resolution, but not in the more sensitive 15 GHz data with 0''.13 resolution. This result indicates that there may be substantial Faraday depolarization toward or within the subarcsecond radio structure.