CH+(1-0) and 13CH+(1-0) absorption lines in the direction of massive star-forming regions
Journal article, 2010
We report the detection of the ground-state rotational transition of the methylidyne cation CH+ and its isotopologue (CH+)-C-13 toward the remote massive star-forming regions W33A, W49N, and W51 with the HIFI instrument onboard the Herschel satellite. Both lines are seen only in absorption against the dust continuum emission of the star-forming regions. The CH+ absorption is saturated over almost the entire velocity ranges sampled by the lines-of-sight that include gas associated with the star-forming regions (SFR) and Galactic foreground material. The CH+ column densities are inferred from the optically thin components. A lower limit of the isotopic ratio [(CH+)-C-12]/[(CH+)-C-13]> 35.5 is derived from the absorptions of foreground material toward W49N. The column density ratio, N(CH+)/N(HCO+), is found to vary by at least a factor 10, between 4 and > 40, in the Galactic foreground material. Line-of-sight 12CH+ average abundances relative to total hydrogen are estimated. Their average value, N(CH+)/NH > 2.6 x 10(-8), is higher than that observed in the solar neighborhood and confirms the high abundances of CH+ in the Galactic interstellar medium. We compare this result to the predictions of turbulent dissipation regions (TDR) models and find that these high abundances can be reproduced for the inner Galaxy conditions. It is remarkable that the range of predicted N(CH+)/ N(HCO+) ratios, from 1 to similar to 50, is comparable to that observed.
turbulence
ISM: molecules
astrochemistry
ISM: kinematics and dynamics
Author
E. Falgarone
Ecole Normale Superieure (ENS)
B. Godard
Paris Observatory
J. Cernicharo
CSIC - Instituto de Fisica Fundamental (IFF)
M. de Luca
Ecole Normale Superieure (ENS)
M. Gerin
Paris Observatory
T.G. Phillips
California Institute of Technology (Caltech)
John H Black
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
D. Lis
Jet Propulsion Laboratory, California Institute of Technology
T. A. Bell
Spanish Astrobiology Center (INTA-CSIC)
F. Boulanger
Ecole Normale Superieure (ENS)
A. Coutens
University of Bordeaux
E. Dartois
University Paris-Saclay
P. Encrenaz
Paris Observatory
T. Giesen
University of Kassel
J.R. Goicoechea
CSIC - Instituto de Fisica Fundamental (IFF)
P.F. Goldsmith
Jet Propulsion Laboratory, California Institute of Technology
H. Gupta
National Science Foundation
C. Gry
Laboratoire d'Astrophysique de Marseille
P. Hennebelle
Ecole Normale Superieure (ENS)
E. Herbst
University of Virginia
P. Hily-Blant
Grenoble Alpes University
C. Joblin
National Museum of Botswana
M. Kazmierczak
Netherlands Institute for Space Research (SRON)
R. Kolos
Polish Academy of Sciences
J. Krelowski
University of Rzeszów
J. Martin-Pintado
Instituto Nacional de Tecnica Aeroespacial
Raquel Monje
Jet Propulsion Laboratory, California Institute of Technology
B. Mookerjea
Tata Institute of Fundamental Research
D.A. Neufeld
Johns Hopkins University
M. Perault
Ecole Normale Superieure (ENS)
J. C. Pearson
Jet Propulsion Laboratory, California Institute of Technology
Carina Persson
Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics
R. Plume
University of Calgary
M. Salez
Centre national de la recherche scientifique (CNRS)
M. Schmidt
Polish Academy of Sciences
P. Sonnentrucker
Space Telescope Science Institute (STScI)
J. Stutzki
University of Cologne
D. Teyssier
European Space Agency (ESA)
C. Vastel
Paul Sabatier University
S. Yu
Jet Propulsion Laboratory, California Institute of Technology
K. M. Menten
Max-Planck Institute for Radio Astronomy
T. R. Geballe
Gemini Observatory North
S. Schlemmer
University of Cologne
R. Shipman
Netherlands Institute for Space Research (SRON)
A.G.G.M. Tielens
Leiden University
S. Philipp
Max-Planck Institute for Radio Astronomy
A. Cros
University of Guadalajara
J. Zmuidzinas
California Institute of Technology (Caltech)
L.A. Samoska
Jet Propulsion Laboratory, California Institute of Technology
K. Klein
University of Arizona
A. Lorenzani
Istituto nazionale di astrofisica (INAF)
R. Szczerba
Polish Academy of Sciences
I. Peron
Institut de Radioastronomie Millimétrique (IRAM)
P. Cais
University of Bordeaux
P. Gaufre
Laboratoire d'Astrophysique de Bordeaux
L. Ravera
Institut de Recherche en Astrophysique et Planétologie (IRAP)
P. Morris
California Institute of Technology (Caltech)
S. Lord
California Institute of Technology (Caltech)
P. Planesas
Spanish National Observatory (OAN)
A. Cros
Institut de Recherche en Astrophysique et Planétologie (IRAP)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 521 1 L15Subject Categories
Astronomy, Astrophysics and Cosmology
Roots
Basic sciences
DOI
10.1051/0004-6361/201015109