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.

cologne database

spectroscopy

hydrogen

microwave

sight-line

ISM: molecules

g10.6-0.4

sagittarius b2

ISM: abundances

submillimeter

molecular clouds

chemistry

Författare

S. L. Qin

Universität zu Köln

P. Schilke

Max Planck-institutet

Universität zu Köln

C. Comito

Max Planck-institutet

T. Moller

Universität zu Köln

R. Rolffs

Max Planck-institutet

Holger Muller

Universität zu Köln

A. Belloche

Max Planck-institutet

K. M. Menten

Max Planck-institutet

D. C. Lis

CalTech

T. G. Phillips

CalTech

E. A. Bergin

University of Michigan

T. A. Bell

CalTech

N. R. Crockett

University of Michigan

G. A. Blake

CalTech

S. Cabrit

LUTH - Laboratoire de l'Univers et de ses Theories

E. Caux

Universite de Toulouse

LUTH - Laboratoire de l'Univers et de ses Theories

C. Ceccarelli

Laboratoire d'Astrophysique de l'Observatoire de Grenoble

J. Cernicharo

CSIC-INTA - Centro de Astrobiologia (CAB)

F. Daniel

LUTH - Laboratoire de l'Univers et de ses Theories

CSIC-INTA - Centro de Astrobiologia (CAB)

M. L. Dubernet

LUTH - Laboratoire de l'Univers et de ses Theories

M. Emprechtinger

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

CSIC-INTA - Centro de Astrobiologia (CAB)

P. F. Goldsmith

Jet Propulsion Laboratory, California Institute of Technology

H. Gupta

Jet Propulsion Laboratory, California Institute of Technology

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

Jet Propulsion Laboratory, California Institute of Technology

S. D. Lord

CalTech

S. Maret

Laboratoire d'Astrophysique de l'Observatoire de Grenoble

P. G. Martin

Canadian Institute for Theoretical Astrophysics

G. J. Melnick

Harvard-Smithsonian Center for Astrophysics

P. Morris

Jet Propulsion Laboratory, California Institute of Technology

J. A. Murphy

Maynooth University

D. A. Neufeld

Johns Hopkins University

V. Ossenkopf

SRON Netherlands Institute for Space Research

Universität zu Köln

L. Pagani

LUTH - Laboratoire de l'Univers et de ses Theories

J. C. Pearson

Jet Propulsion Laboratory, California Institute of Technology

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

SRON Netherlands Institute for Space Research

C. Vastel

LUTH - Laboratoire de l'Univers et de ses Theories

Universite de Toulouse

S. Wang

University of Michigan

H. W. Yorke

Jet Propulsion Laboratory, California Institute of Technology

S. Yu

Jet Propulsion Laboratory, California Institute of Technology

J. Zmuidzinas

CalTech

A. Boogert

CalTech

R. Güsten

Max Planck-institutet

P. Hartogh

MPI für Sonnensystemforschung

N. Honingh

Universität zu Köln

A. Karpov

CalTech

J. Kooi

CalTech

J. M. Krieg

LUTH - Laboratoire de l'Univers et de ses Theories

R. Schieder

Universität zu Köln

M. C. Diez-Gonzalez

Centro Astronómico de Yebes

R. Bachiller

Centro Astronómico de Yebes

J. Martin-Pintado

CSIC-INTA - 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

Jet Propulsion Laboratory, California Institute of Technology

Goutam Chattopadhyay

Jet Propulsion Laboratory, California Institute of Technology

Astronomy and Astrophysics

0004-6361 (ISSN) 1432-0746 (eISSN)

Vol. 521 Art. no. L14 - L14

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201015107