Herschel observations of EXtra-Ordinary Sources (HEXOS): detecting spiral arm clouds by CH absorption lines
Artikel i vetenskaplig tidskrift, 2010
We have observed CH absorption lines (J = 3/2, N = 1 <- J = 1/2, N = 1) against the continuum source Sgr B2(M) using the Herschel/HIFI instrument. With the high spectral resolution and wide velocity coverage provided by HIFI, 31 CH absorption features with different radial velocities and line widths are detected and identified. The narrower line width and lower column density clouds show "spiral arm" cloud characteristics, while the absorption component with the broadest line width and highest column density corresponds to the gas from the Sgr B2 envelope. The observations show that each "spiral arm" harbors multiple velocity components, indicating that the clouds are not uniform and that they have internal structure. This line-of-sight through almost the entire Galaxy offers unique possibilities to study the basic chemistry of simple molecules in diffuse clouds, as a variety of different cloud classes are sampled simultaneously. We find that the linear relationship between CH and H-2 column densities found at lower AV by UV observations does not continue into the range of higher visual extinction. There, the curve flattens, which probably means that CH is depleted in the denser cores of these clouds.
g10.6-0.4
spectroscopy
sagittarius b2
cologne database
chemistry
microwave
submillimeter
molecular clouds
ISM: molecules
hydrogen
sight-line
ISM: abundances
Författare
S. L. Qin
Universität zu Köln
P. Schilke
Max-Planck-Gesellschaft
Universität zu Köln
C. Comito
Max-Planck-Gesellschaft
T. Moller
Universität zu Köln
R. Rolffs
Max-Planck-Gesellschaft
Holger Muller
Universität zu Köln
A. Belloche
Max-Planck-Gesellschaft
K. M. Menten
Max-Planck-Gesellschaft
D. C. Lis
California Institute of Technology (Caltech)
T. G. Phillips
California Institute of Technology (Caltech)
E. A. Bergin
University of Michigan
T. A. Bell
California Institute of Technology (Caltech)
N. R. Crockett
University of Michigan
G. A. Blake
California Institute of Technology (Caltech)
S. Cabrit
LUTH - Laboratoire de l'Univers et de ses Theories
E. Caux
LUTH - Laboratoire de l'Univers et de ses Theories
Université de Toulouse
C. Ceccarelli
Laboratoire d'Astrophysique de l'Observatoire de Grenoble
J. Cernicharo
Centro de Astrobiologia (CAB)
F. Daniel
LUTH - Laboratoire de l'Univers et de ses Theories
Centro de Astrobiologia (CAB)
M. L. Dubernet
LUTH - Laboratoire de l'Univers et de ses Theories
M. Emprechtinger
California Institute of Technology (Caltech)
P. Encrenaz
LUTH - Laboratoire de l'Univers et de ses Theories
E. Falgarone
LUTH - Laboratoire de l'Univers et de ses Theories
M. Gerin
LUTH - Laboratoire de l'Univers et de ses Theories
T. F. Giesen
Universität zu Köln
J. R. Goicoechea
Centro de Astrobiologia (CAB)
P. F. Goldsmith
California Institute of Technology (Caltech)
H. Gupta
California Institute of Technology (Caltech)
E. Herbst
Ohio State University
C. Joblin
LUTH - Laboratoire de l'Univers et de ses Theories
D. Johnstone
National Research Council Canada
W. D. Langer
California Institute of Technology (Caltech)
S. D. Lord
California Institute of Technology (Caltech)
S. Maret
Laboratoire d'Astrophysique de l'Observatoire de Grenoble
P. G. Martin
Institut canadien d'astrophysique théorique
G. J. Melnick
Harvard-Smithsonian Center for Astrophysics
P. Morris
California Institute of Technology (Caltech)
J. A. Murphy
Maynooth University
D. A. Neufeld
Johns Hopkins University
V. Ossenkopf
Universität zu Köln
Netherlands Institute for Space Research (SRON)
L. Pagani
LUTH - Laboratoire de l'Univers et de ses Theories
J. C. Pearson
California Institute of Technology (Caltech)
M. Perault
LUTH - Laboratoire de l'Univers et de ses Theories
R. Plume
University of Calgary
M. Salez
LUTH - Laboratoire de l'Univers et de ses Theories
S. Schlemmer
Universität zu Köln
J. Stutzki
Universität zu Köln
N. Trappe
Maynooth University
F. F. S. van der Tak
Netherlands Institute for Space Research (SRON)
C. Vastel
LUTH - Laboratoire de l'Univers et de ses Theories
Université de Toulouse
S. Wang
University of Michigan
H. W. Yorke
California Institute of Technology (Caltech)
S. Yu
California Institute of Technology (Caltech)
J. Zmuidzinas
California Institute of Technology (Caltech)
A. Boogert
California Institute of Technology (Caltech)
R. Güsten
Max-Planck-Gesellschaft
P. Hartogh
MPI für Sonnensystemforschung
N. Honingh
Universität zu Köln
A. Karpov
California Institute of Technology (Caltech)
J. Kooi
California Institute of Technology (Caltech)
J. M. Krieg
LUTH - Laboratoire de l'Univers et de ses Theories
R. Schieder
Universität zu Köln
M. C. Diez-Gonzalez
Observatorio de Yebes (IGN)
R. Bachiller
Observatorio de Yebes (IGN)
J. Martin-Pintado
Centro de Astrobiologia (CAB)
W. Baechtold
Eidgenössische Technische Hochschule Zürich (ETH)
Michael Olberg
Chalmers, Rymd- och geovetenskap, Onsala rymdobservatorium
L. H. Nordh
Stockholms universitet
J. L. Gill
California Institute of Technology (Caltech)
Goutam Chattopadhyay
California Institute of Technology (Caltech)
Astronomy and Astrophysics
0004-6361 (ISSN) 1432-0746 (eISSN)
Vol. 521 1 Art. no. L14 - L14Ämneskategorier (SSIF 2011)
Astronomi, astrofysik och kosmologi
DOI
10.1051/0004-6361/201015107