Magnetic Field Structures In and Around Seyfert Galaxy Outflows

TL;DR

This study uses radio polarimetric imaging to reveal magnetic field structures and jet interactions in Seyfert and LINER galaxies, showing that magnetic fields influence outflows and feedback in radio-quiet AGN.

Contribution

It provides detailed polarization and spectral analysis of kiloparsec-scale outflows in Seyfert and LINER galaxies, highlighting magnetic field configurations and their role in AGN feedback.

Findings

Magnetic fields are organized in cores, jets, and lobes.

Radio cores with flatter spectra have lower Eddington ratios.

Signatures of jet-medium interaction and AGN feedback are observed.

Abstract

We present radio polarimetric images of 12 Seyfert and Low-Ionization Nuclear Emission-line Region (LINER) galaxies belonging to the Centre for Astrophysics (CfA)+12 micron sample exhibiting kiloparsec-scale radio outflows (KSRs). These observations have been carried out at 10 GHz with Karl G. Jansky Very Large Array (VLA) in D-array and at 1.4 GHz with the BnA$\rightarrow$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 per cent in the cores to $47\pm18$ per cent 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 (SMBHs); correlations with Eddington ratios are weaker. We find signatures of jet-medium interaction and both positive and negative AGN feedback in these sources. Overall, our study indicates that radio-quiet (RQ) AGN with KSRs possess radio outflows driven by magnetic fields anchored to their black holes - accretion disks, which significantly impact their environments.