Radio detection of nitroxyl /HNO/ - The first interstellar NO bond

Abstract

A spectral line identified as the J(K- K+) = 1(01)-0(00) transition of nitroxyl has been detected in emission from the directions of Sgr B2 and NGC 2024. An abundance ratio of carbon to nitrogen about 1.4 is derived for NGC 2024, which suggests that nitrogen may be as abundant as carbon in molecular clouds. Detection of an unidentified line, U81.505, which may be a weak maser, is also reported along with observations of previously detected transitions of ketene (H2CCO), dimethyl ether (CH3OCH3) and cyanoacetylene (HC3N). The identification of previously reported U81.543 is reduced to either thioformaldehyde (H2CS) or HC2(C-13)N.