We report the detection of the ( 1,1 ) and ( 2,2 ) metastable lines of ammonia ( NH _ { 3 } ) in the molecular cloud associated with the Wolf–Rayet ( WR ) nebula NGC 2359 .
Besides the CO and H _ { 2 } , this is the first molecule detected in the environs of a WR star .
Width ( \Delta V _ { 1 / 2 } = 3 km s ^ { -1 } ) and radial velocity ( V _ { LSR } \sim 54 km s ^ { -1 } ) indicate that the NH _ { 3 } lines arises from the molecular cloud which is interacting with the WR star .
The rotational temperature derived from the ( 1,1 ) and ( 2,2 ) line intensity ratios is about 30 K , significantly larger than the typical kinetic temperature of the ambient gas of \sim 10 K. The derived NH _ { 3 } abundance is \sim 10 ^ { -8 } .
Linewidth , abundance and kinetic temperature can be explained if NH _ { 3 } is released from dust grain mantles to the gas phase by shocks produced by the expansion of the bubble created by the WR stellar wind .
We briefly discuss the implications of the detection of warm NH _ { 3 } associated with a WR star in connection to the hot NH _ { 3 } emission detected in the Galactic Center and in the nuclei of external galaxies .