Complex organic molecules in the Galactic Centre: the N-bearing family

Abstract

We present an unbiased spectral line survey toward the Galactic Centre (GC)\nquiescent giant molecular cloud (QGMC), G+0.693 using the GBT and IRAM 30$\\,$\ntelescopes. Our study highlights an extremely rich organic inventory of\nabundant amounts of nitrogen (N)-bearing species in a source without signatures\nof star formation. We report the detection of 17 N-bearing species in this\nsource, of which 8 are complex organic molecules (COMs). A comparison of the\nderived abundances relative to H$_2$ is made across various galactic and\nextragalactic environments. We conclude that the unique chemistry in this\nsource is likely to be dominated by low-velocity shocks with X-rays/cosmic rays\nalso playing an important role in the chemistry. Like previous findings\nobtained for O-bearing molecules, our results for N-bearing species suggest a\nmore efficient hydrogenation of these species on dust grains in G+0.693 than in\nhot cores in the Galactic disk, as a consequence of the low dust temperatures\ncoupled with energetic processing by X-ray/cosmic ray radiation in the GC.\n