Shocked ammonia in the Wolf-Rayet nebula NGC 2359

We report the detection of the (1, 1) and (2, 2) metastable lines of ammoni a (NH3) in the molecular cloud associated with the Wolf-Rayet (W-R) nebula NGC 2359. Besides the CO and H-2, this is the first molecule detected in th e environs of a W-R star. Width (DeltaV(1/2) = km s(-1)) and radial velocit y (V-LSR similar to km s(-1)) indicate that the NH3 lines arise from the mo lecular cloud that is interacting with the W-R star. The rotational tempera ture 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 similar to 10 K. The derived NH3 abundance is similar to 10(-8). Lin e width, abundance, and kinetic temperature can be explained if NH3 is rele ased from dust grain mantles to the gas phase by shocks produced by the exp ansion of the bubble created by the W-R stellar wind. We briefly discuss th e implications of the detection of warm NH3 associated with a W-R star in c onnection to the hot NH3 emission detected in the Galactic center and in th e nuclei of external galaxies.