James Webb Space Telescope Feed Post

JWST Observations of Starbursts: Polycyclic Aromatic Hydrocarbon Emission at the base of the M 82 Galactic Wind

PAH and CO emission compared at the same resolution. The JWST 3.3 µm PAH emission (gray scale) has been convolved to the 1.85'' resolution of the NOEMA CO, presented here as the integrated intensity map (color contours). The contour values are 190, 320, 550, 930, and 1580 K km s-1. The lowest contour corresponds to a column density N(H2) ~ 2 × 1022 cm-2. Partial correspondence is observed between the base of some of the PAH plumes and extra-planar CO emission. Abstract: We present new observations of the central 1 kpc of the M 82 starburst obtained with the James Webb Space Telescope (JWST) near-infrared camera (NIRCam) instrument at a resolution ~0.05"-0.1" (~1-2 pc). The data comprises images in three mostly continuum filters (F140M, F250M, and F360M), and filters that contain [FeII] (F164N), H2 v=1-0 (F212N), and the 3.3 um PAH feature (F335M). We find prominent plumes of PAH emission extending outward from the central starburst region, together with a network of complex filamentary substructure and edge-brightened bubble-like features. The structure of the PAH emission closely resembles that of the ionized gas, as revealed in Paschen alpha and free-free radio emission. We discuss the origin of the structure, and suggest the PAHs are embedded in a combination of neutral, molecular, and photoionized gas.