The Multi-Phase Cold Fountain in M82 Revealed by a Wide, Sensitive Map of the Molecular ISM

Understand

We present a wide area (~ 8 x 8 kpc), sensitive map of CO (2-1) emission around the nearby starburst galaxy M82.

• Molecular gas extends far beyond the stellar disk, including emission associated with the well-known outflow as far as 3 kpc from M82's midplane.
• Kinematic signatures of the outflow are visible in both the CO and HI emission: both tracers show a minor axis velocity gradient and together they show double peaked profiles, consistent with a hot outflow bounded by a cone made of a mix of atomic and molecular gas.
• Combining our CO and HI data with observations of the dust continuum, we study the changing properties of the cold outflow as it leaves the disk.