Resolving the Multiphase Outflow, Shock Signatures, and PAHs in the AGN-Starburst Composite ULIRG F10565+2448 with JWST MIRI/MRS

Abstract

We present new James Webb Space Telescope Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer (MRS) observations of the nearby ultra-luminous infrared galaxy F10565+2448. These integral field spectroscopic data reveal an unresolved nuclear outflow in both warm-ionized and warm-molecular gas phases as well as a resolved blueshifted kpc-scale warm-molecular outflow. The unresolved warm-ionized outflow has a mean projected velocity up to $-520$ km/s, while the unresolved warm-molecular outflow is slower at $-150$ km/s. For the resolved warm-molecular outflow, the projected mean velocity ($-280<v_{50}<-110$ km/s) is only slightly faster than the velocity of the disk ($-70<v_{50}<120$ km/s) and as such likely does not exceed the estimated escape velocity of $\gtrsim 300$ km/s. The warm-molecular outflow is slightly hotter ($507\pm 25$K) than the disk ($329\pm 5$K), and displays areas of higher temperature and lower column density that may indicate a shock front, which we explore using the [Fe II] 5.34 $\mu$m/Pf$\alpha$ shock diagnostic. Analysis of the polycyclic aromatic hydrocarbon features reveal trends of ionization and grain size that first decrease with radius up to 1 kpc before increasing up to 3 kpc. These results bolster the picture of F10565+2448 being an AGN-starburst composite where both star formation and AGN-powered phenomena are required to explain the outflow energetics.

22 pages, 14 figures, 2 tables, accepted for publication in ApJ