NGC 6860, Mrk 915, and MCG -01-24-012-II. Inflowing and outflowing cold molecular gas and the connection with ionized gas in Seyfert galaxies

We present a study of the cold molecular gas kinematics in the inner ∼4–7 kpc (projected sizes) of three nearby Seyfert galaxies with active galactic nucleus (AGN) luminosities of ∼1044 erg s−1 using observations of the CO(2–1) emission line obtained with the Atacama Large Millimeter/submillimeter Array (ALMA) at ∼0.5–0.8″ (∼150–400 pc) spatial resolutions. After modeling the CO profiles with multiple Gaussian components, we detected regions with double-peak profiles that exhibit kinematics distinct from the dominant rotational motion. In NGC 6860, a molecular outflow surrounding the bipolar emission of the [O III] ionized gas is observed extending up to Rout ∼ 560 pc from the nucleus. There is evidence of molecular inflows along the stellar bar, although an alternative scenario involving a decoupled rotation in a circumnuclear disk (CND) can also explain the observed kinematics. Mrk 915 shows double-peak CO profiles along one of its spiral arms. Due to the ambiguous orientation of its disk, part of the CO emission can be interpreted as a molecular gas inflow or an outflow reaching Rout ∼ 2.8 kpc. MCG -01-24-012 has double-peak profiles associated with a CND perpendicular to the [O III] bipolar emission. The CO in the CND is rotating while outflowing within Rout ∼ 3 kpc, with the disturbances possibly being caused by the passage of the ionized gas outflow. Overall, the mass inflow rates are larger than the accretion rate needed to produce the observed luminosities, suggesting that only a fraction of the inflowing gas ends up feeding the central black holes. Although we found signatures of AGN feedback on the cold molecular phase, the mass outflow rates of ∼0.09–3 M⊙ yr−1 indicate an overall weak impact at these AGN luminosities. Nonetheless, we may be witnessing the start of the depletion and ejection of the molecular gas reservoir that has accumulated over time.FullText for HTML: https://doi.org/10.1051/0004-6361/202555306