AAS 197, January 2001
Session 75. Jets in AGN
Display, Wednesday, January 10, 2001, 9:30am-7:00pm, Exhibit Hall

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[75.09] Multi-Frequency VLBA Observations of a Parsec-Scale Counterjet in NGC 6251

D.L. Jones (JPL/Caltech), A.E. Wehrle (IPAC/JPL/Caltech)

We have observed the nucleus of NGC 6251 with the VLBA and the phased VLA at 1.6, 5.0, 8.4, and 15.3 GHz. At 1.6 GHz we detect a faint, short radio counterjet with a peak brightness of about 1.3 mJy/beam. This is 0.5% of the peak image brightness (0.25 Jy/beam). The counterjet lies along the same position angle as the main jet. The angular resolution at 1.6 GHz is insufficient to tell if there is evidence for free-free absorption at the base of the counterjet, as seen in NGC 4261, but our higher frequency data should clarify this. These data are being analyzed, and we expect to present results from all four frequencies.

This research is being carried out at the Jet Propulsion Laboratory, California Institute of Technology, under contract with the National Aeronautics and Space Administration.

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