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

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 $μ$m and 17 $μ$m PAH features, where after subtracting the disk, the velocity field matches that of high-ionisation potential lines such as [NeVI] (7.65 $μ$m, IP = 158 eV). Finally, we fail to detect kinematics of the 6.2 $μ$m PAH due to an altered intrinsic profile while the the 3.3 $μ$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.

Figures (11)

• Figure 1: The first four principal components of the 3.3 $\mu$m PAH for NGC 7582. Each row shows each component, where the higher components contain progressively less information held within the original data cube. The left panels show the tomograms which show the spatial distribution of the eigenspectra in the right panels. The first component describes the rest frame emission of the feature while the second component shows a redshifted/blueshifted feature on either side of the nucleus, indicative of rotation. The higher order components contain extra information on the velocity field and/or variations in the intrinsic profile of the PAH feature. The contours overlaid on the tomograms show the first principal component. Note that the colour scale for each of the tomograms is not velocity but rather a correlation coefficient of how strongly each eigenspectrum maps onto the spatial dimensions. The vertical dashed grey lines show the wavelength where the second eigenspetrum crosses zero, showing the kinematic centre. Note that the smooth line between 3.29 - 3.30 $\mu$m that can be seen in the Eigenspectra is due to the masking of the Pf$\delta$ line.
• Figure 2: Velocity maps of each spectral feature for each galaxy. From left to right we show [NeVI] (7.65 $\mu$m), H$_2$ S(5) (6.91 $\mu$m), H$_2$ S(1) (17.03 $\mu$m), 3.3$\mu$m PAH, 11.3 $\mu$m PAH and the 17 $\mu$m PAH. For each galaxy the field of view is the same for each map as well as the velocity scale. We show [NeV] (14.32 $\mu$m) for NGC 7582 as the [NeVI] (7.65 $\mu$m) has a lower signal to noise. The position angle of the major axis of the disk is shown with the solid line while the position angle of the major axis for the outflow is shown with the dashed line. Values are found in Table \ref{['tab:Sample']}. Panels that are blank lack the signal to noise to produce velocity maps.
• Figure 3: Disk modelling and subtraction for NGC 5728. The top left panel shows a three color image constructed from custom filters of MUSE cubes. Blue is a filter centred on [O III] (5028–5095 Å), green is H$\alpha$ (6578–6664 Å) and an $i$ band filter (6430–8630 Å) is shown in red. The white square shows the FOV of the other panels. The middle left panel shows the velocity map of [NeVI] tracing the outflow. The bottom left panel shows the disk model with fixed inclination and position angle constrained from CO and stellar kinematics Shimizu2019. The right panels show the disk subtracted velocity maps for molecular gas (warm S(1) and hot S(5)) as well as the 3.3 $\mu$m PAH (small $\&$ neutral) and the 11.3 $\mu$m PAH (large $\&$ neutral). The major axis of the disk is shown with the solid grey line while the outflow cone is shown with the dashed lines in red and blue for the redshift and blueshift sides of the cone respectively.
• Figure 4: Disk modelling and subtraction for NGC 7582. The top left panel shows a three color image constructed from custom filters of MUSE cubes. Blue is a filter centred on [O III] (5028–5095 Å), green is H$\alpha$ (6578–6664 Å) and an $i$ band filter (6430–8630 Å) is shown in red. The white square shows the FOV of the other panels. The middle left panel shows the velocity map of [NeV] tracing the outflow. The bottom left panel shows the disk model with fixed inclination and position angle. The right panels show the disk subtracted velocity maps for molecular gas (S(5)) as well as the 3.3 $\mu$m PAH (small $\&$ neutral), the 11.3 $\mu$m PAH (large $\&$ neutral) and the 17$\mu$m PAH (large $\&$ neutral). The major axis of the disk is shown with the solid grey line while the outflow cone is shown with the dashed lines in red and blue for the redshift and blueshift sides of the cone respectively.
• Figure 5: Demonstration of the effect of various contributions of the outflow and disk on the resultant velocity map. The top two panels are for NGC 5728 while the bottom two are for NGC 7582. For each object the top row shows the progression from left to right of the velocity map from pure disk to pure outflow. The lower panels show observed velocity maps for various features where the 3.3 PAH on the left shows pure disk while the other features show some mixture of outflow and disk.