Observational Results of a Multi-telescope Campaign in Search of Interstellar Urea [(NH_2)_2CO]
Abstract
In this paper, we present the results of an observational search for gas phase urea [(NH_2)_2CO] observed toward the Sgr B2(N-LMH) region. We show data covering urea transitions from ~100 GHz to 250 GHz from five different observational facilities: the Berkeley-Illinois-Maryland-Association (BIMA) Array, the Combined Array for Research in Millimeter-wave Astronomy (CARMA), the NRAO 12 m telescope, the IRAM 30 m telescope, and the Swedish-ESO Submillimeter Telescope (SEST). The results show that the features ascribed to urea can be reproduced across the entire observed bandwidth and all facilities by best-fit column density, temperature, and source size parameters which vary by less than a factor of two between observations merely by adjusting for telescope-specific parameters. Interferometric observations show that the emission arising from these transitions is cospatial and compact, consistent with the derived source sizes and emission from a single species. Despite this evidence, the spectral complexity of both (NH_2)_2CO and of Sgr B2(N) makes the definitive identification of this molecule challenging. We present observational spectra, laboratory data, and models, and discuss our results in the context of a possible molecular detection of urea.
Additional Information
© 2014 The American Astronomical Society. Received 2013 July 15; accepted 2014 January 10; published 2014 February 19. We thank the anonymous referee for very helpful comments which improved the quality of this manuscript. B.A.M. gratefully acknowledges G. A. Blake for his support, and funding by an NSF Graduate Research Fellowship. H.-L.K. and B.J.M. gratefully acknowledge funding by a UIUC Critical Research Initiative. We acknowledge support from the Laboratory for Astronomical Imaging at the University of Illinois and NSF AST 99-81363 and AST 02-28953. Support for CARMA construction was derived from the states of California, Illinois, and Maryland, the James S. McDonnell Foundation, the Gordon and Betty Moore Foundation, the Kenneth T. and Eileen L. Norris Foundation, the University of Chicago, the Associates of the California Institute of Technology, and the National Science Foundation. Ongoing CARMA development and operations are supported by the National Science Foundation under a cooperative agreement, and by the CARMA partner universities. The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc.Attached Files
Published - 0004-637X_783_2_77.pdf
Submitted - 1401.4483v1.pdf
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Additional details
- Alternative title
- Observational Results of a Multi-telescope Campaign in Search of Interstellar Urea [(NH2)2CO]
- Eprint ID
- 46280
- Resolver ID
- CaltechAUTHORS:20140616-125336516
- NSF Graduate Research Fellowship
- UIUC Critical Research Initiative
- AST 99-81363
- NSF
- AST 02-28953
- NSF
- Created
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2014-06-16Created from EPrint's datestamp field
- Updated
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2021-11-10Created from EPrint's last_modified field