Magnetic Field Structures In and Around Seyfert Galaxy Outflows

Abstract

We present radio polarimetric images of 12 Seyfert and low-ionization nuclear emission-line region (LINER) galaxies belonging to the Centre for Astrophysics +12 μm sample exhibiting kiloparsec-scale radio outflows (KSRs). These observations have been carried out at 10 GHz with the Karl G. Jansky Very Large Array in D array and at 1.4 GHz with the BnA → A array configurations. We find signatures of organized magnetic (B) field structures in the cores, jets, and lobes of these galaxies. The linear polarization fraction varies from a few percent in the cores to 47% ± 18% in the lobes. The inferred B fields are toroidal in the cores of several sources making them consistent with the presence of either a sheath-like or a wind-like component surrounding the jet. The in-band spectral index images typically show the presence of flat/inverted spectrum cores and steep spectrum lobes. Radio cores with flatter spectra are found to have lower Eddington ratios, while the steeper ones have higher. A strong correlation is observed between the Seyfert/LINER radio outflow properties and the mass of the supermassive black holes; correlations with Eddington ratios are weaker. We find signatures of jet-medium interaction and both positive and negative active galactic nuclei (AGN) feedback in these sources. Overall, our study indicates that radio-quiet AGN with KSRs possess radio outflows driven by magnetic fields anchored to their black hole—accretion disk systems, which significantly impact their environments.