GATOS N: The first direct kinematic evidence of dusty outflows from AGN via PAH kinematics of local Seyfert galaxies with JWST

TL;DR

This study provides the first direct kinematic evidence of dusty outflows in AGN using JWST observations of PAH features, revealing neutral and large PAHs in outflows of local Seyfert galaxies.

Contribution

It introduces a novel application of PCA tomography to resolve PAH kinematics in AGN outflows, demonstrating the presence of dust in these outflows for the first time.

Findings

PAH velocities match molecular gas and high-ionisation lines.

Outflows are traced by large, neutral PAHs like 11.3 and 17 μm.

6.2 μm PAH kinematics are absent due to profile alterations.

Abstract

We present the first spatially resolved kinematic evidence for dust in the outflows of Active Galactic Nuclei (AGN). We utilise observations from JWST with NIRSpec IFU and MIRI MRS data of 10 local Seyferts and use Principal Component Analysis (PCA) tomography to extract the kinematics of Polycyclic Aromatic Hydrocarbon (PAH) features. PAHs comprise the smallest carbonaceous dust molecules in the Interstellar Medium (ISM), and produce emission features in the infrared providing the potential to measure kinematics. This is however challenging due to their broad shapes and variations in their intrinsic profile, prompting the need for techniques such as PCA tomography. We find that the velocity of the PAHs is similar to the molecular gas as traced by the rotational transitions of H$_2$, where for NGC 5728 and NGC 7582, both disk and outflow are present. We detect the outflow in the kinematics of large and neutral PAHs, namely the 11.3 $\mu$m and 17 $\mu$m PAH features, where after subtracting the disk, the velocity field matches that of high-ionisation potential lines such as [NeVI] (7.65 $\mu$m, IP = 158 eV). Finally, we fail to detect kinematics of the 6.2 $\mu$m PAH due to an altered intrinsic profile while the the 3.3 $\mu$m PAH kinematics purely trace the circumnuclear disk. This suggests the PAHs in the outflow are more neutral and larger than in star-forming regions, consistent with PAH band ratios in previous studies of AGN.