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Description
We investigate the interstellar medium (ISM) properties of the disk and outflowing gas in the central regions of nine nearby Seyfert galaxies, all characterised by prominent single- or bi-conical outflows. These objects are part of the MAGNUM (Measuring Active Galactic Nuclei Under MUSE Microscope) survey, that aims at probing their physical conditions and ionisation mechanism, by exploiting the unprecedented sensitivity of the Multi Unit Spectroscopic Explorer (MUSE), combined with its spatial and spectral coverage. Specifically, we study the different properties of the gas in the disk and in the outflow with spatially and kinematically resolved maps, by dividing the strongest emission lines in velocity bins. We associate the core of the lines to the disk, consistent with the stellar velocity, and the redshifted and the blueshifted wings to the outflow. We measure the reddening, density, ionisation parameter and dominant ionisation source of the emitting gas for both components in each galaxy. We find that the outflowing gas is characterised by higher values of density and ionisation parameter than the disk, which presents a higher dust extinction. Moreover, we distinguish high- and low-ionisation regions across the portion of spatially resolved narrow line region (NLR) traced by the outflowing gas. The high ionisation regions characterised by the lowest [NII]/H{alpha} and [SII]/H{alpha} line ratios, generally trace the innermost parts along the axis of the emitting cones, where the [SIII]/[SII] line ratio is enhanced, while the low ionisation ones follow the cone edges and/or the regions perpendicular to the axis of the outflows, characterised also by a higher [OIII] velocity dispersion. A possible scenario to explain these features relies on the presence of two distinct population of line emitting clouds: one is optically thin to the radiation and characterised by the highest excitation, while the other, optically thick, is impinged by a filtered - and thus harder - radiation field, which generates strong low-excitation lines. The highest values of [NII]/H{alpha} and [SII]/H{alpha} line ratios may be due to shocks and/or a hard filtered radiation field from the AGN.
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