2018ApJ...867..149D

We explore the gas morphology and excitation mechanisms of the ionization cones of the Type II Seyfert galaxy NGC 5728. Near-IR and optical data from the SINFONI and MUSE integral field units on the Very Large Telescope are combined with Hubble Space Telescope optical images, Chandra X-ray data, and Very Large Array radio observations. The complex nuclear structure has a star-forming (SF) ring with a diameter of 2 kpc. A radio jet impacts on the interstellar medium at about 200 pc from the nucleus, with the supernova remnants in the SF ring also present. Emission-line ratios of [Fe II] and H II show heavy extinction toward the nucleus, moderate extinction in the SF ring, and reduced extinction in the ionization cones. The active galactic nucleus (AGN) is hidden by a dust bar with up to 19 mag of visual extinction; the dust temperature at the nuclear position is ∼870 K. An X-ray jet is aligned with the ionization cones and associated with high-excitation emission lines of [Si VI] in a coronal line region extending 300 pc from the nucleus. Molecular hydrogen is spatially independent of the cones, concentrated in a disk equatorial to the SF ring, but also showing entrainment along the sides of the bicone. Gas masses for warm and cold H₂, H I, and H II are estimated, and the excitation mechanisms for ionized and molecular gas are elucidated, from both optical (which shows a clean SF-AGN mixing sequence) and infrared diagnostics (which show more complicated, multicomponent excitation regimes).