We present the first interferometric detection of extragalactic NH _ { 3 } ( 6,6 ) emission in the nearby galaxy IC 342 made using the VLA ^ { 5 } .
The data have a resolution of 7.8 ” \times 5.0 ” and trace hot ( T \sim 412 K ) and dense ( > 10 ^ { 4 } cm ^ { -3 } ) molecular gas .
We have covered a 170 ” \times 300 ” area , and detect two very strong line emission peaks , likely associated with the two strongest star formation regions of the central part of the galaxy .
We compare these emission peaks to CO ( 1-0 ) and ( 2-1 ) emission data , which are the most abundant CO transitions and trace spatially extended emission .
The NH _ { 3 } ( 6,6 ) emission is also compared to emission data from three high-density , nitrogen bearing tracers : HNC ( 1-0 ) , HC _ { 3 } N ( 10-9 ) and N _ { 2 } H ^ { + } .
Our results suggest that the molecular mass in the nuclear region of IC 342 has at least two different components , a dense and cold component and a less dense and hotter component .