Widespread galactic CF+ absorption: detection toward W49 with the Plateau de Bure Interferometer

被引:17
作者
Liszt, H. S. [1 ]
Guzman, V. V. [2 ]
Pety, J. [3 ,4 ]
Gerin, M. [3 ,4 ]
Neufeld, D. A. [5 ]
Gratier, P. [6 ,7 ]
机构
[1] Rat Radio Astron Observ, Charlottesville, VA 22903 USA
[2] Harvard Smithsonian Ctr Astrophys, Cambridge, MA 02138 USA
[3] CNRS, UMR 8112, Observ Paris, F-75014 Paris, France
[4] Ecole Normale Super, LERMA LRA, F-75005 Paris, France
[5] Johns Hopkins Univ, Baltimore, MD 21218 USA
[6] Univ Bordeaux, LAB, UMR 5804, F-33270 Floirac, France
[7] CNRS, UMR 5804, LAB, F-33270 Floirac, France
基金
欧洲研究理事会;
关键词
ISM:; molecules; DIFFUSE INTERSTELLAR-MEDIUM; STAR-FORMING REGIONS; COMPARATIVE CHEMISTRY; MOLECULAR-HYDROGEN; TRANSLUCENT; CLOUDS; ABUNDANCE; EMISSION; TRACER; CARBON;
D O I
10.1051/0004-6361/201526232
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
Aims. We study the usefulness of CF+ as a tracer of the regions where C+ and H-2 coexist in the interstellar medium. Methods. We used the Plateau de Bure Interferometer to synthesize CF+ J = 1-0 absorption at 102.6 GHz toward the core of the distant HII region W49N at l = 43.2 degrees, b = 0.0 degrees, and we modeled the fluorine chemistry in diffuse/translucent molecular gas. Results. We detected CF+ absorption over a broad range of velocity showing that CF+ is widespread in the H-2-bearing Galactic disk gas. Conclusions. Originally detected in dense gas in the Orion Bar and Horsehead PDR (Photon-Dominated Region) CF+ was subsequently detected in absorption from diffuse and translucent clouds seen toward BL Lac and 3C 111. Here we showed that CF+ is distributed throughout the diffuse and translucent molecular disk gas with N(CF+)/N(H-2) = 1.5-2.0 x 10(-10), increasing to N(CF+)/N(H-2) = 3.5 x 10(-10) in one cloud at 39 km s(-1) having higher N(H-2) approximate to 3 x 10(21) cm(-2). Models of the fluorine chemistry reproduce the observed column densities and relative abundance of HF, from which CF+ forms, but generally overpredict the column density of CF+ by factors of 1.4-4. We show that a free space photodissociation rate Gamma greater than or similar to 10(-9) s(-1), comparable to that of CH, might account for much of the discrepancy but a recent calculation finds a value about ten times smaller. In the heavily blended and kinematically complex spectra seen toward W49, CF+ absorption primarily traces the peaks of the H2 distribution.
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页数:9
相关论文
共 35 条
[1]  
[Anonymous], 2005, SF2A-2005: Semaine de l'Astrophysique Francaise
[2]   ATOMIC AND MOLECULAR CARBON AS A TRACER OF TRANSLUCENT CLOUDS [J].
Burgh, Eric B. ;
France, Kevin ;
Jenkins, Edward B. .
ASTROPHYSICAL JOURNAL, 2010, 708 (01) :334-341
[3]  
BURTON WB, 1971, ASTRON ASTROPHYS, V10, P76
[4]   First detection of CF+ towards a high-mass protostar [J].
Fechtenbaum, S. ;
Bontemps, S. ;
Schneider, N. ;
Csengeri, T. ;
Duarte-Cabral, A. ;
Herpin, F. ;
Lefloch, B. .
ASTRONOMY & ASTROPHYSICS, 2015, 574
[5]   [C II] absorption and emission in the diffuse interstellar medium across the Galactic plane [J].
Gerin, M. ;
Ruaud, M. ;
Goicoechea, J. R. ;
Gusdorf, A. ;
Godard, B. ;
de Luca, M. ;
Falgarone, E. ;
Goldsmith, P. ;
Lis, D. C. ;
Menten, K. M. ;
Neufeld, D. ;
Phillips, T. G. ;
Liszt, H. .
ASTRONOMY & ASTROPHYSICS, 2015, 573
[6]   Hydride spectroscopy of the diffuse interstellar medium: new clues on the gas fraction in molecular form and cosmic ray ionization rate in relation to H3+ [J].
Gerin, M. ;
Levrier, F. ;
Falgarone, E. ;
Godard, B. ;
Hennebelle, P. ;
Le Petit, F. ;
De Luca, M. ;
Neufeld, D. ;
Sonnentrucker, P. ;
Goldsmith, P. ;
Flagey, N. ;
Lis, D. C. ;
Persson, C. M. ;
Black, J. H. ;
Goicoechea, J. R. ;
Menten, K. M. .
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES, 2012, 370 (1978) :5174-5185
[7]   The tight correlation of CCH and c-C3H2 in diffuse and translucent clouds [J].
Gerin, M. ;
Kazmierczak, M. ;
Jastrzebska, M. ;
Falgarone, E. ;
Hily-Blant, P. ;
Godard, B. ;
De Luca, M. .
ASTRONOMY & ASTROPHYSICS, 2011, 525
[8]   Interstellar CH absorption in the diffuse interstellar medium along the sight-lines to G10.6-0.4 (W31C), W49N, and W51 [J].
Gerin, M. ;
De Luca, M. ;
Goicoechea, J. R. ;
Herbst, E. ;
Falgarone, E. ;
Godard, B. ;
Bell, T. A. ;
Coutens, A. ;
Kazmierczak, M. ;
Sonnentrucker, P. ;
Black, J. H. ;
Neufeld, D. A. ;
Phillips, T. G. ;
Pearson, J. ;
Rimmer, P. B. ;
Hassel, G. ;
Lis, D. C. ;
Vastel, C. ;
Boulanger, F. ;
Cernicharo, J. ;
Dartois, E. ;
Encrenaz, P. ;
Giesen, T. ;
Goldsmith, P. F. ;
Gupta, H. ;
Gry, C. ;
Hennebelle, P. ;
Hily-Blant, P. ;
Joblin, C. ;
Kolos, R. ;
Krelowski, J. ;
Martin-Pintado, J. ;
Monje, R. ;
Mookerjea, B. ;
Perault, M. ;
Persson, C. ;
Plume, R. ;
Salez, M. ;
Schmidt, M. ;
Stutzki, J. ;
Teyssier, D. ;
Yu, S. ;
Contursi, A. ;
Menten, K. ;
Geballe, T. R. ;
Schlemmer, S. ;
Morris, P. ;
Hatch, W. A. ;
Imram, M. ;
Ward, J. S. .
ASTRONOMY & ASTROPHYSICS, 2010, 521
[9]   Molecular absorption lines toward star-forming regions: a comparative study of HCO+, HNC, HCN, and CN [J].
Godard, B. ;
Falgarone, E. ;
Gerin, M. ;
Hily-Blant, P. ;
De Luca, M. .
ASTRONOMY & ASTROPHYSICS, 2010, 520
[10]   The hyperfine structure in the rotational spectrum of CF+ (Research Note) [J].
Guzman, V. ;
Roueff, E. ;
Gauss, J. ;
Pety, J. ;
Gratier, P. ;
Goicoechea, J. R. ;
Gerin, M. ;
Teyssier, D. .
ASTRONOMY & ASTROPHYSICS, 2012, 548