Recent 18cm VLBA images of the ultraluminous IR galaxies UGC5101 and NGC7469 are presented. In combination with 15GHz and 22GHz VLA A-array images of these two objects, we have spatial information on all scales down to about 6 milliarcseconds. The VLBA images show several bright knots of emission which are generally slightly resolved, and an overall structure which is quasi-linear, with total extent about 45 pc. In addition, there is diffuse emission to the SE in UGC5101 which can be identified with a shoulder of emission seen in the 0.1 arcsecond resolution VLA images. This forms the start of a ridgeline of emission that can be traced out to over 1 arcsecond, and the overall structure of the source is therefore suggestive of a curved jet morphology. Based on energetic arguments, the resolved knots argue against a supernova interpretation of the parsec-scale emission in luminous IR galaxies, and at least in UGC5101, the overall structure suggests that a major portion of the radio emission from this galaxy is AGN-related.
American Astronomical Society Meeting Abstracts
- Pub Date:
- December 1995