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Arxiv: Molecular gas stratification and disturbed kinematics in the Seyfert galaxy MCG-05-23-16 revealed by JWST and ALMA Published: 11/19/2024 12:31:10 PM Updated: 11/19/2024 12:31:10 PM

Paper abstract: Understanding the processes that drive the morphology and kinematics ofmolecular gas in galaxies is crucial for comprehending star formation and,ultimately, galaxy evolution. Using data obtained with the James Webb SpaceTelescope (JWST) and the Atacama Large Millimeter/submillimeter Array (ALMA),we study the behavior of the warm molecular gas at temperatures of hundreds ofKelvin and the cold molecular gas at tens of Kelvin in the galaxyMCG-05-23-16, which hosts an active galactic nucleus (AGN). Hubble SpaceTelescope (HST) images of this spheroidal galaxy, classified in the optical asS0, show a dust lane resembling a nuclear spiral and a surrounding ring. Thesefeatures are also detected in CO(2-1) and H2, and their morphologies andkinematics are consistent with rotation plus local inward gas motions along thekinematic minor axis in the presence of a nuclear bar. The H2 transitions 0-0S(3), 0-0 S(4), and 0-0 S(5), which trace warmer and more excited gas, showmore disrupted kinematics than 0-0 S(1) and 0-0 S(2), including clumps ofhigh-velocity dispersion (of up to ~ 160 km/s), in regions devoid ofCO(2-1). The kinematics of one of these clumps, located at ~ 350 pcwestward from the nucleus, are consistent with outflowing gas, possibly drivenby localized star formation traced by Polycyclic Aromatic Hydrocarbon (PAH)emission at 11.3 {\mu}m. Overall, we observe a stratification of themolecular gas, with the colder gas located in the nuclear spiral, ring, andconnecting arms, while most warmer gas with higher velocity-dispersion fillsthe inter-arm space. The compact jet, approximately 200 pc in size, detectedwith Very Large Array (VLA) observations, does not appear to significantlyaffect the distribution and kinematics of the molecular gas, possibly due toits limited intersection with the molecular gas disc.