Universität zu Köln

van der Wiel, M. H. D., van der Tak, F. F. S., Lis, D. C., Bell, T., Bergin, E. A., Comito, C., Emprechtinger, M., Schilke, P., Caux, E., Ceccarelli, C., Baudry, A., Goldsmith, P. F., Herbst, E., Langer, W., Lord, S., Neufeld, D., Pearson, J., Phillips, T., Rolffs, R., Yorke, H., Bacmann, A., Benedettini, M., Blake, G. A., Boogert, A., Bottinelli, S., Cabrit, S., Caselli, P., Castets, A., Cernicharo, J., Codella, C., Coutens, A., Crimier, N., Demyk, K., Dominik, C., Encrenaz, P., Falgarone, E., Fuente, A., Gerin, M., Helmich, F., Hennebelle, P., Henning, T., Hily-Blant, P., Jacq, T., Kahane, C., Kama, M., Klotz, A., Lefloch, B., Lorenzani, A., Maret, S., Melnick, G., Nisini, B., Pacheco, S., Pagani, L., Parise, B., Salez, M., Saraceno, P., Schuster, K., Tielens, A. G. G. M., Vastel, C., Viti, S., Wakelam, V., Walters, A., Wyrowski, F., Edwards, K., Zmuidzinas, J., Morris, P., Samoska, L. A. and Teyssier, D. (2010). Herschel/HIFI observations of spectrally resolved methylidyne signatures toward the high-mass star-forming core NGC 6334I. Astron. Astrophys., 521. LES ULIS CEDEX A: EDP SCIENCES S A. ISSN 0004-6361

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Abstract

Context. In contrast to the more extensively studied dense star-forming cores, little is known about diffuse gas surrounding star-forming regions. Aims. We study the molecular gas in the Galactic high-mass star-forming region NGC 6334I, which contains diffuse, quiescent components that are inconspicuous in widely used molecular tracers such as CO. Methods. We present Herschel/HIFI observations of methylidyne (CH) toward NGC 6334I observed as part of the Chemical HErschel Survey of Star forming regions (CHESS) key program. HIFI resolves each of the six hyperfine components of the lowest rotational transition (J = 3/2-1/2) of CH, observed in both emission and absorption. Results. The CH emission features appear close to the systemic velocity of NGC 6334I, while its measured FWHM linewidth of 3 km s(-1) is smaller than previously observed in dense gas tracers such as NH3 and SiO. The CH abundance in the hot core is similar to 7 x 10(-11), two to three orders of magnitude lower than in diffuse clouds. While other studies find distinct outflows in, e. g., CO and H2O toward NGC 6334I, we do not detect any outflow signatures in CH. At least two redshifted components of cold absorbing material must be present at -3.0 and +6.5 km s(-1) to explain the absorption signatures. We derive a CH column density (N-CH) of 7 x 10(13) and 3 x 10(13) cm(-2) for these two absorbing clouds. We find evidence of two additional absorbing clouds at +8.0 and 0.0 km s(-1), both with N-CH approximate to 2 x 10(13) cm(-2). Turbulent linewidths for the four absorption components vary between 1.5 and 5.0 km s(-1) in FWHM. We constrain the physical properties and locations of the clouds by matching our CH absorbers with the absorption signatures seen in other molecular tracers. Conclusions. In the hot core, molecules such as H2O and CO trace gas that is heated and dynamically influenced by outflow activity, whereas the CH molecule traces more quiescent material. The four CH absorbing clouds have column densities and turbulent properties that are consistent with those of diffuse clouds: two are located in the direct surroundings of NGC 6334, and two are unrelated foreground clouds. Local density and dynamical effects influence the chemical composition of the physical components of NGC 6334, which causes some components to be seen in CH but not in other tracers, and vice versa.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code van der Wiel, M. H. D. UNSPECIFIED UNSPECIFIED UNSPECIFIED van der Tak, F. F. S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lis, D. C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bell, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bergin, E. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Comito, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Emprechtinger, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schilke, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Caux, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Ceccarelli, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Baudry, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Goldsmith, P. F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Herbst, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Langer, W. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lord, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Neufeld, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pearson, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Phillips, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Rolffs, R. UNSPECIFIED UNSPECIFIED UNSPECIFIED Yorke, H. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bacmann, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Benedettini, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Blake, G. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Boogert, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Bottinelli, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cabrit, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Caselli, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Castets, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Cernicharo, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Codella, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Coutens, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Crimier, N. UNSPECIFIED UNSPECIFIED UNSPECIFIED Demyk, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Dominik, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Encrenaz, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Falgarone, E. UNSPECIFIED UNSPECIFIED UNSPECIFIED Fuente, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Gerin, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Helmich, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hennebelle, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Henning, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Hily-Blant, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Jacq, T. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kahane, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Kama, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Klotz, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lefloch, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Lorenzani, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Maret, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Melnick, G. UNSPECIFIED UNSPECIFIED UNSPECIFIED Nisini, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pacheco, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Pagani, L. UNSPECIFIED UNSPECIFIED UNSPECIFIED Parise, B. UNSPECIFIED UNSPECIFIED UNSPECIFIED Salez, M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Saraceno, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Schuster, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Tielens, A. G. G. M. UNSPECIFIED UNSPECIFIED UNSPECIFIED Vastel, C. UNSPECIFIED UNSPECIFIED UNSPECIFIED Viti, S. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wakelam, V. UNSPECIFIED UNSPECIFIED UNSPECIFIED Walters, A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Wyrowski, F. UNSPECIFIED UNSPECIFIED UNSPECIFIED Edwards, K. UNSPECIFIED UNSPECIFIED UNSPECIFIED Zmuidzinas, J. UNSPECIFIED UNSPECIFIED UNSPECIFIED Morris, P. UNSPECIFIED UNSPECIFIED UNSPECIFIED Samoska, L. A. UNSPECIFIED UNSPECIFIED UNSPECIFIED Teyssier, D. UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-495063
DOI:	10.1051/0004-6361/201015096
Journal or Publication Title:	Astron. Astrophys.
Volume:	521
Date:	2010
Publisher:	EDP SCIENCES S A
Place of Publication:	LES ULIS CEDEX A
ISSN:	0004-6361
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language INTERSTELLAR CLOUDS; MOLECULAR CLOUDS; GROUND-STATE; CH; SPECTROSCOPY; REGIONS; MODELS; ABUNDANCES; NGC-6334; I(N) Multiple languages Astronomy & Astrophysics Multiple languages
URI:	http://kups.ub.uni-koeln.de/id/eprint/49506