paper

Common Excitation Patterns of Star Formation, Active Galactic Nuclei, and Shocks in Seyfert Galaxies

arXiv:2609.15913 · doi:10.3847/1538-4357/ae9956

Abstract

The growth of galaxies and their central supermassive black holes is closely connected, yet the net effect of active galactic nuclei (AGN) feedback on host-galaxy star formation remains uncertain. AGN may enhance, suppress, or have little measurable impact on star formation, but distinguishing among these outcomes requires separating star-formation and AGN photoionization from shock excitation, which is expected in AGN-driven outflows but has been difficult to isolate. Here we apply a recently developed theoretical three-dimensional diagnostic diagram, designed to separate star formation, AGN, and shock excitation, to VLT/MUSE IFU observations of nine nearby (z < 0.026) Type 2 Seyfert galaxies. We find a common excitation pattern across the sample: star-forming rings or arcs at projected radii of r~0.8-6 kpc, AGN-photoionized bicones extending to kpc scales, central fast-shock-dominated regions that often extend perpendicular to the AGN bicone, and pure-shock- dominated regions surrounding the central fast shocks and appearing locally within the star-forming rings. Deep Chandra X-ray morphology independently supports this decomposition. The circumnuclear star-forming rings are consistent with bar-driven resonances, although positive AGN feedback may also contribute. The central fast shocks are broadly consistent with AGN jet-ISM interactions, while AGN wind-ISM interactions may also play an important role in galaxies with low-power jets. These results establish central shocks as a common feature of Seyfert galaxies and demonstrate the importance of accounting for shock excitation in AGN feedback studies.

arXiv comment33 pages, 21 figures; published in ApJ

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