High-resolution VLA observations of the radio jet in NGC 6251.

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• Bridle, A. H.
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• Willis, A. G.

Abstract

The VLA has been used at resolutions in the 1.15-15 arcsec range at 1370, 1480, 1662, and 4885 MHz, and 50 arcsec at 1446 and 1662 MHz, to observe the jet in the radio galaxy NGC 6251. The jet expands at a variable rate, exhibiting several stages of confinement and reexpansion. A counterjet has been detected over 56 kpc in the direction opposite to that of the main jet. There are large and complex gradients of the Faraday rotation measure, both along and across the jet, which may be due to the presence of a magnetoionic medium that is outside the jet, yet within NGC 6251. The projected magnetic configuration of the jet is dominated by the component parallel to the jet axis for the first 40 kpc from the core. There are significant regions in which the magnetic configuration is dominated by the oblique field components. The implications of these results for the physics of the jet are discussed.