Later confirmation of the detection of NH2 included several studies about a decade
after the initial detection that didn't resolve the lines as well, including the work of
Goicoechea et al. from 2004. Recently,
Persson et al. performed high resolution
studies of NH2 toward W31C, W49N, W51, and G34.3+0.1 with the
Herschel Space Observatory that provided accurate assessments of
the ortho-to-para ratio of NH2
in those sources.