Radio jets in NGC 1068 with e-MERLIN and VLA: structure and morphology

TL;DR

This study provides high-resolution radio images of NGC 1068, revealing detailed jet structures, spectral properties, and variability, and links radio jet features with molecular gas outflows observed with ALMA.

Contribution

It presents the first combined e-MERLIN and VLA radio images of NGC 1068's jets, identifying new components and analyzing their spectral and variability properties.

Findings

Detection of a new jet component, S2a.

Observation of flux decrease in component C over years.

Identification of bow shocks in the NE jet lobe.

Abstract

We present new high-sensitivity e-MERLIN and VLA radio images of the prototypical Seyfert 2 galaxy NGC 1068 at 5, 10 and 21 GHz. We image the radio jet, from the compact components NE, C, S1 and S2 to the faint double-lobed jet structure of the NE and SW jet lobes. Furthermore, we map the jet between by combining e-MERLIN and VLA data for the first time. Components NE, C and S2 have steep spectra indicative of optically-thin non-thermal emission domination between 5 and 21 GHz. Component S1, which is where the AGN resides, has a flat radio spectrum. We report a new component, S2a, a part of the southern jet. We compare these new data with the MERLIN and VLA data observed in 1983, 1992 and 1995 and report a flux decrease by a factor of 2 in component C, suggesting variability of this jet component. With the high angular resolution e-MERLIN maps, we detect the bow shocks in the NE jet lobe that coincide with the molecular gas outflows observed with ALMA. The NE jet lobe has enough radio power considered to be responsible for driving out the dense molecular gas observed with ALMA around the same region.