STScI Preprint #1334

VLBI Observations of Symmetric Parsec-Scale Twin Jets in the Narrow Angle Tail Radio Galaxy NGC 1265 (3C 83.1B)

We present global VLBI observations of the nucleus of the narrow angle tail radio galaxy NGC 1265. We report the discovery of symmetric parsec-scale twin jets which are well aligned with the kpc-scale jets. We also present an archival HST/WFPC2 image of the galaxy which shows an apparently almost edge-on dust disk which is within 10^o of perpendicular to the jet axis. The jets in NGC 1265 are consistent with either (1) relativistic motion near the plane of the sky, (2) non-relativistic motion or (3) a "coaxial" structure with a non-relativistic sheath surrounding a relativistic spine. A study of the properties of the nine large scale sources known so far with twin parsec-scale jets suggest that these sources are more likely to be non-relativistic or only mildly relativistic. We also suggest that at least some sources with symmetric parsec-scale jets have been decelerated on the parsec scales, possibly through interaction with ambient gas or the shock at the sonic radius of a cooling flow. Other sources may be reborn Compact Symmetric Object-type sources propagating out of the galaxy's nuclear ISM. Further proper motion studies of this class of source are needed.

Status:

To appear in: The Astronomical Journal

Affiliations:

¹ Space Telescope Science Institute, 3700 San Martin Drive Baltimore, MD 12128, USA
² Also at University of Maryland, College Park,