McGuire, Brett A. and Loomis, Ryan A. and Charness, Cameron M. and Corby, Joanna F. and Blake, Geoffrey A. and Hollis, Jan M. and Lovas, Frank J. and Jewell, Philip R. and Remijan, Anthony J. (2012) Interstellar Carbodiimide (HNCNH): A New Astronomical Detection from the GBT PRIMOS Survey via Maser Emission Features. Astrophysical Journal Letters, 758 (2). Art. No. L33. ISSN 2041-8205 http://resolver.caltech.edu/CaltechAUTHORS:20121116-110039972
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In this work, we identify carbodiimide (HNCNH), which is an isomer of the well-known interstellar species cyanamide (NH_(2)CN), in weak maser emission, using data from the Green Bank Telescope PRIMOS survey toward Sgr B2(N). All spectral lines observed are in emission and have energy levels in excess of 170 K, indicating that the molecule likely resides in relatively hot gas that characterizes the denser regions of this star-forming region. The anticipated abundance of this molecule from ice mantle experiments is ~10% of the abundance of NH_(2)CN, which in Sgr B2(N) corresponds to ~2 × 10^(13) cm^(–2). Such an abundance results in transition intensities well below the detection limit of any current astronomical facility and, as such, HNCNH could only be detected by those transitions which are amplified by masing.
|Additional Information:||© 2012 American Astronomical Society. Received 2012 August 9; accepted 2012 September 7; published 2012 October 1. All authors dedicate this work to Lewis E. Snyder who pioneered the astronomical detection of molecules at radio frequencies. B.A.M. gratefully acknowledges funding by an NSF Graduate Research Fellowship, and M. Emprechtinger for helpful discussions regarding masers.We thank the anonymous referee for very helpful comments. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.|
|Subject Keywords:||astrochemistry; ISM: clouds; ISM: individual objects (Sagittarius B2(N)); ISM: molecules|
|Official Citation:||Interstellar Carbodiimide (HNCNH): A New Astronomical Detection from the GBT PRIMOS Survey via Maser Emission Features Brett A. McGuire et al. 2012 ApJ 758 L33|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Jason Perez|
|Deposited On:||16 Nov 2012 19:33|
|Last Modified:||27 Dec 2012 03:01|
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