Schilke, P. and Lis, D. C. and Phillips, T. G. and Bell, T. A. and Blake, G. A. and Emprechtinger, M. and Latter, W. B. and Lord, S. D. and Morris, P. and Kooi, J. and Karpov, A. and Zmuidzinas, J. and Boogert, A. (2010) Herschel observations of ortho- and para-oxidaniumyl (H_2O^+) in spiral arm clouds toward Sagittarius B2(M). Astronomy and Astrophysics, 521 . Art. No. L11. ISSN 0004-6361. http://resolver.caltech.edu/CaltechAUTHORS:20110111-162129524
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H_2O^+ has been observed in its ortho- and para- states toward the massive star forming core Sgr B2(M), located close to the Galactic center. The observations show absorption in all spiral arm clouds between the Sun and Sgr B2. The average o/p ratio of H_2O^+ in most velocity intervals is 4.8, which corresponds to a nuclear spin temperature of 21 K. The relationship of this spin temperature to the formation temperature and current physical temperature of the gas hosting H_2O^+ is discussed, but no firm conclusion is reached. In the velocity interval 0–60 km s^(−1), an ortho/para ratio of below unity is found, but if this is due to an artifact of contamination by other species or real is not clear.
|Additional Information:||© 2010 ESO. Received 30 May 2010, Accepted 28 June 2010, Published online 01 October 2010. Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA. Appendix (pages 6, 7) is only available in electronic form at http://www.aanda.org. 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 Astrobiologìa (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. Support for this work was provided by NASA through an award issued by JPL/Caltech. CSO is supported by the NSF, award AST- 0540882. H.S.P.M. is very grateful to the Bundesministerium für Bildung und Forschung (BMBF) for financial support aimed at maintaining the Cologne Database for Molecular Spectroscopy, CDMS. This support has been administered by the Deutsches Zentrum für Luft- und Raumfahrt (DLR). We appreciate funding for the ASTRONET Project CATS through the Bundesministerium für Bildung und Forschung (BMBF). We thank an anonymous referee for constructive comments which helped to clarify the discussion in this article.|
|Subject Keywords:||astrochemistry – line: profiles – molecular processes|
|Official Citation:||Herschel observations of ortho- and para-oxidaniumyl (H2O+) in spiral arm clouds toward Sagittarius B2(M) P. Schilke, C. Comito, H. S. P. Müller, E. A. Bergin, E. Herbst, D. C. Lis, D. A. Neufeld, T. G. Phillips, T. A. Bell, G. A. Blake, S. Cabrit, E. Caux, C. Ceccarelli, J. Cernicharo, N. R. Crockett, F. Daniel, M.-L. Dubernet, M. Emprechtinger, P. Encrenaz, E. Falgarone, M. Gerin, T. F. Giesen, J. R. Goicoechea, P. F. Goldsmith, H. Gupta, C. Joblin, D. Johnstone, W. D. Langer, W. B. Latter, S. D. Lord, S. Maret, P. G. Martin, G. J. Melnick, K. M. Menten, P. Morris, J. A. Murphy, V. Ossenkopf, L. Pagani, J. C. Pearson, M. Pérault, R. Plume, S.-L. Qin, M. Salez, S. Schlemmer, J. Stutzki, N. Trappe, F. F. S. van der Tak, C. Vastel, S. Wang, H. W. Yorke, S. Yu, N. Erickson, F. W. Maiwald, J. Kooi, A. Karpov, J. Zmuidzinas, A. Boogert, R. Schieder and P. Zaal A&A 521 L11 (2010) DOI: 10.1051/0004-6361/201015087|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Benjamin Perez|
|Deposited On:||12 Jan 2011 16:17|
|Last Modified:||26 Dec 2012 12:50|
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