Hot Molecular Gas in NGC 2024

We present observations of five 12 CO and 13 CO lines in NGC 2024, including the first velocity resolved observations of lines above 1 THz in this object (J = 13–12). We analysed the observations using radiative transfer codes and derived a more consistent model of this complex source. We found that the high-J CO emission stems from a dense (n ~ 10 6 cm -3 ) and hot (~300 K) component, located at the interface of the H II region and the molecular cloud.