SUBARCSECOND VLA OBSERVATIONS OF HL TAURI - IMAGING THE CIRCUMSTELLARDISK

We report high-resolution observations of HL Tau at 6 cm, 3.6 cm, and 7 mm using the VLA in B configuration. The new centimeter wavelength d ata are in accord with previous observations-taking into account resol ution and sensitivity-and provide no evidence for time variability. At 7 mm, we have used a ''fast-switching'' calibration technique to part ially overcome the problem of atmospheric phase fluctuations and achie ve subarcsecond angular resolution. The 7 mm image, which is dominated by dust emission, shows a flattened structure with Gaussian deconvolv ed size (0''.75 +/- 0''.1) x (0''.35 +/- 0''.1) [(105 +/- 14) x (50 +/ - 14) AU] and major axis P.A. 125 degrees +/- 10 degrees. This orienta tion is similar to that found at shorter wavelengths and is approximat ely orthogonal to the optical jet axis, consistent with a dusty accret ion disk surrounding the star.