No Small-scale Radio Jets Here: Multiepoch Observations of Radio Continuum Structures in NGC 1068 with the VLBA

Abstract

We present recent Very Long Baseline Array (VLBA) 5 GHz radio observations of the nearby, luminous Seyfert 2 galaxy NGC 1068 for comparison to similar VLBA observations made on 1997 April 26. By cross-correlating the positions of emitting regions across both epochs, we find that spatially resolved extranuclear radio knots in this system have subrelativistic transverse speeds ( v ≲0.1 c ). We discuss sources of the observed knots and how the radio emission relates to additional phases of gas in the central ∼150 pc of this system. We suggest that the most likely explanation for the observed emission is synchrotron radiation formed by shocked host media via interactions between active galactic nucleus winds and the host environment.

Keywords

• Active galactic nuclei
• Radio astronomy
• AGN host galaxies