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Detection of amino acetonitrile in Sgr B2(N)

Belloche, A. and Menten, K. M. and Comito, C. and Müller, H. S. P. and Schilke, P. and Ott, J. and Thorwirth, S. and Hieret, C. (2008) Detection of amino acetonitrile in Sgr B2(N). Astronomy and Astrophysics, 482 (1). pp. 179-196. ISSN 0004-6361. https://resolver.caltech.edu/CaltechAUTHORS:BELaanda08

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Abstract

Context. Amino acids are building blocks of proteins and therefore key ingredients for the origin of life. The simplest amino acid, glycine (NH2CH2COOH), has long been searched for in the interstellar medium but has not been unambiguously detected so far. At the same time, more and more complex molecules have been newly found toward the prolific Galactic center source Sagittarius B2. Aims. Since the search for glycine has turned out to be extremely difficult, we aimed at detecting a chemically related species (possibly a direct precursor), amino acetonitrile (NH2CH2CN). Methods. With the IRAM 30 m telescope we carried out a complete line survey of the hot core regions Sgr B2(N) and (M) in the 3 mm range, plus partial surveys at 2 and 1.3 mm. We analyzed our 30 m line survey in the LTE approximation and modeled the emission of all known molecules simultaneously. We identified spectral features at the frequencies predicted for amino acetonitrile lines having intensities compatible with a unique rotation temperature. We also used the Very Large Array to look for cold, extended emission from amino acetonitrile. Results. We detected amino acetonitrile in Sgr B2(N) in our 30 m telescope line survey and conducted confirmatory observations of selected lines with the IRAM Plateau de Bure and the Australia Telescope Compact Array interferometers. The emission arises from a known hot core, the Large Molecule Heimat, and is compact with a source diameter of 2" (0.08 pc). We derived a column density of 2.8 x 10^16 cm^-2, a temperature of 100 K, and a linewidth of 7 km s^-1. Based on the simultaneously observed continuum emission, we calculated a density of 1.7 x 10^8 cm^-3, a mass of 2340 M☉, and an amino acetonitrile fractional abundance of 2.2 x 10^-9. The high abundance and temperature may indicate that amino acetonitrile is formed by grain surface chemistry. We did not detect any hot, compact amino acetonitrile emission toward Sgr B2(M) or any cold, extended emission toward Sgr B2, with column-density upper limits of 6 x 10^15 and 3 x 10^12-14 cm^-2, respectively. Conclusions. Based on our amino acetonitrile detection toward Sgr B2(N) and a comparison to the pair methylcyanide/acetic acid both detected in this source, we suggest that the column density of both glycine conformers in Sgr B2(N) is well below the best upper limits published recently by other authors, and probably below the confusion limit in the 1-3 mm range.


Item Type:Article
Related URLs:
URLURL TypeDescription
http://dx.doi.org/10.1051/0004-6361:20079203DOIArticle
http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/abs/2008/16/aa9203-07/aa9203-07.htmlPublisherArticle
http://dx.doi.org/10.1051/0004-6361:20079203eDOIErratum
http://www.aanda.org/index.php?option=article&access=doi&doi=10.1051/0004-6361:20079203ePublisherErratum
ORCID:
AuthorORCID
Menten, K. M.0000-0001-6459-0669
Müller, H. S. P.0000-0002-0183-8927
Schilke, P.0000-0003-2141-5689
Ott, J.0000-0001-8224-1956
Additional Information:© ESO 2008. (Received 6 December 2007 / Accepted 16 January 2008) We thank the IRAM staff in Grenoble for observing at the PdBI and for their help with the data reduction, the IRAM staff in Granada for service observing in January 2005, and Sergio Martin for providing the reference (off) position for our 30 m observations. We thank John Pearson for his predictions of the first excited state of ethylcyanide, Claus Nielsen for providing transition frequencies of formamide isotopologues, Isabelle Kleiner, Vadim Ilyushin, and Frank Lovas for acetic acid frequencies, and Brian Drouin for his predictions of acetone. H.S.P.M. and the CDMS had been supported initially through the Deutsche Forschungsgemeinschaft (DFG) via the collaborative research grant SFB 494. Recent support is provided by the Bundesministerium für Bildung und Forschung administered through Deutsches Zentrum für Luft- und Raumfahrt (DLR; the German space agency). J.O. is a Jansky Fellow of the National Radio Astronomy Observatory. C.H. is a fellow of the Studienstiftung des deutschen Volkes and member of the International Max-Planck Research School for Radio and Infrared Astronomy. We thank Sheng-Yuan Liu for providing very useful information about the way the flux integration was performed on the BIMA data, and Roberto Neri for helpful discussion about the calibration of the PdBI data.
Errata:A&A 482, 179–196 (2008), DOI: 10.1051/0004-6361:20079203
Funders:
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)SFB 494
Bundesministerium für Bildung und ForschungUNSPECIFIED
Deutsches Zentrum für Luft- und Raumfahrt (DLR)UNSPECIFIED
National Radio Astronomy Observatory, Jansky FellowshipUNSPECIFIED
Studienstiftung des deutschen VolkesUNSPECIFIED
International Max-Planck Research School for Radio and Infrared AstronomyUNSPECIFIED
Subject Keywords:astrobiology -- astrochemistry -- line: identification -- stars: formation -- ISM: individual objects: Sagittarius B2 -- ISM: molecules
Issue or Number:1
Record Number:CaltechAUTHORS:BELaanda08
Persistent URL:https://resolver.caltech.edu/CaltechAUTHORS:BELaanda08
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12945
Collection:CaltechAUTHORS
Deposited By: Archive Administrator
Deposited On:17 Jan 2009 09:31
Last Modified:09 Mar 2020 13:19

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