What is the median angular size of the microjansky population?
The angular size of the radio sources provides an important clue to the physical mechanism(s) driving the radio emission. Radio sources within galaxies are invariably associated with either a massive central engine (i.e., black hole) or star-formation. Those sources powered by a central engine have angular dimension of about one milliarcsec whereas those associated with star-formation are similar in extent to the optical galaxy, typically a few arcsec. In winter 1997, we completed deep observations centered on the Hubble Deep Field at 1.4 GHz using the VLA. These observations cover about one degree (FWHM) and have an angular resolution of 1.8 arcsec, combining the benefits of a wide field survey without significant loss of resolution. We are in the process of reducing the data and we hope to present images by the end of 1998. Our expected final rms noise will be about 7 µJy. The VLA 20 cm data will also be combined with those collected from the MERLIN radio telescope in Great Britain (
