title: Detection of nitric oxide in the dark cloud L134N.
abstract: We report the first detection of interstellar nitric oxide (NO) in a cold dark cloud, L134N.  Nitric oxide was observed by means of its two 2 pi 1/2, J = 3/2 --> 1/2, rotational transitions at 150.2 and 150.5 GHz, which occur because of lambda-doubling.  The inferred column density for L134N is N(NO) approximately 5 x 10(14) cm-2 toward the SO peak in that cloud.  This value corresponds to a fractional abundance relative to molecular hydrogen of f(NO) approximately 6 x 10(-8) and is in good agreement with predictions of quiescent cloud ion-molecule chemistry.  NO was not detected toward the dark cloud TMC-1 at an upper limit of f(NO) < or = 3 x 10(-8).
authors.affiliation: Department of Physics and Astronomy, University of Massachusetts, Amherst, USA.
authors.forename: D
authors.initials: D
authors.lastname: McGonagle
authors.forename: L M
authors.initials: LM
authors.lastname: Ziurys
authors.forename: W M
authors.initials: WM
authors.lastname: Irvine
authors.forename: Y C
authors.initials: YC
authors.lastname: Minh
mesh_terms: D055580:Astronomical Phenomena; D001256:Astronomy; D002244:Carbon / Q000032:analysis; D005118:Extraterrestrial Environment; D008956:Models, Chemical; D009569:Nitric Oxide / Q000032:analysis*; D010100:Oxygen / Q000032:analysis; D013057:Spectrum Analysis
chemical_list: D009569:Nitric Oxide; D002244:Carbon; D010100:Oxygen