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Molecular line survey of the high-mass star-forming region NGC 6334I with Herschel/HIFI and the Submillimeter Array

Zernickel, A. and Schilke, P. and Schmiedeke, A. and Lis, D. C. and Brogan, C. L. and Ceccarelli, C. and Comito, C. and Emprechtinger, M. and Hunter, T. R. and Möller, T. (2012) Molecular line survey of the high-mass star-forming region NGC 6334I with Herschel/HIFI and the Submillimeter Array. Astronomy and Astrophysics, 546 . Art. No. A87. ISSN 0004-6361.

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Aims. We aim at deriving the molecular abundances and temperatures of the hot molecular cores in the high-mass star-forming region NGC 6334I and consequently deriving their physical and astrochemical conditions. Methods. In the framework of the Herschel guaranteed time key program CHESS (Chemical HErschel Surveys of Star forming regions), NGC 6334I is investigated by using the Heterodyne Instrument for the Far-Infrared (HIFI) aboard the Herschel Space Observatory. A spectral line survey is carried out in the frequency range 480–1907 GHz, and further auxiliary interferometric data from the Submillimeter Array (SMA) in the 230 GHz band provide spatial information for disentangling the different physical components contributing to the HIFI spectrum. The spectral lines in the processed Herschel data are identified with the aid of former surveys and spectral line catalogs. The observed spectrum is then compared to a simulated synthetic spectrum, assuming local thermal equilibrium, and best fit parameters are derived using a model optimization package. Results. A total of 46 molecules are identified, with 31 isotopologues, resulting in about 4300 emission and absorption lines. High-energy levels (E_u > 1000 K) of the dominant emitter methanol and vibrationally excited HCN (ν_2 = 1) are detected. The number of unidentified lines remains low with 75, or <2% of the lines detected. The modeling suggests that several spectral features need two or more components to be fitted properly. Other components could be assigned to cold foreground clouds or to outflows, most visible in the SiO and H_(2)O emission. A chemical variation between the two embedded hot cores is found, with more N-bearing molecules identified in SMA1 and O-bearing molecules in SMA2. Conclusions. Spectral line surveys give powerful insights into the study of the interstellar medium. Different molecules trace different physical conditions like the inner hot core, the envelope, the outflows or the cold foreground clouds. The derived molecular abundances provide further constraints for astrochemical models.

Item Type:Article
Related URLs:
URLURL TypeDescription
Schilke, P.0000-0003-2141-5689
Lis, D. C.0000-0002-0500-4700
Brogan, C. L.0000-0002-6558-7653
Ceccarelli, C.0000-0001-9664-6292
Hunter, T. R.0000-0001-6492-0090
Additional Information:© 2012 ESO. Article published by EDP Sciences. Received 12 June 2012; Accepted 25 August 2012. Published online 11 October 2012. This work was carried out within the Collaborative Research Council 956, funded by the Deutsche Forschungsgemeinschaft (DFG). C. Ceccarelli acknowledges the financial support from the French spatial agency CNES and the Agence Nationale pour la Recherche (ANR), France (project FORCOMS, contracts ANR-08-BLAN-022). Support for this work was provided by NASA through an award issued by JPL/Caltech. HIFI has been designed and built by a consortium of institutes and university departments from across Europe, Canada and the United States under the leadership of SRON Netherlands Institute for Space Research, Groningen, The Netherlands and with major contributions from Germany, France and the US. Consortium members are: Canada: CSA, U. Waterloo; France: CESR, LAB, LERMA, IRAM; Germany: KOSMA, MPIfR, MPS; Ireland, NUI Maynooth; Italy: ASI, IFSI-INAF, Osservatorio Astrofisico di Arcetri-INAF; Netherlands: SRON, TUD; Poland: CAMK, CBK; Spain: Observatorio Astronómico Nacional (IGN), Centro de Astrobiología (CSIC-INTA). Sweden: Chalmers University of Technology – MC2, RSS & GARD; Onsala Space Observatory; Swedish National Space Board, Stockholm University – Stockholm Observatory; Switzerland: ETH Zurich, FHNW; USA: Caltech, JPL, NHSC. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA.
Funding AgencyGrant Number
Deutsche Forschungsgemeinschaft (DFG)UNSPECIFIED
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Agence Nationale pour la Recherche (ANR)ANR-08-BLAN-022
Subject Keywords:submillimeter: ISM; line: identification; astrochemistry; ISM: molecules; ISM: abundances; stars: formation
Record Number:CaltechAUTHORS:20121130-095011051
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Official Citation:Molecular line survey of the high-mass star-forming region NGC 6334I with Herschel/HIFI and the Submillimeter Array A. Zernickel, P. Schilke, A. Schmiedeke, D. C. Lis, C. L. Brogan, C. Ceccarelli, C. Comito, M. Emprechtinger, T. R. Hunter and T. Möller A&A 546 A87 (2012)
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:35747
Deposited By: Jason Perez
Deposited On:30 Nov 2012 18:27
Last Modified:09 Mar 2020 13:18

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