Excitation and abundance of C3 in star forming cores Herschel/HIFI observations of the sight-lines to W31C and W49N
Journal article, 2010

We present spectrally resolved observations of triatomic carbon (C-3) in several ro-vibrational transitions between the vibrational ground state and the low-energy nu(2) bending mode at frequencies between 1654-1897 GHz along the sight-lines to the submillimeter continuum sources W31C and W49N, using Herschel's HIFI instrument. We detect C-3 in absorption arising from the warm envelope surrounding the hot core, as indicated by the velocity peak position and shape of the line profile. The sensitivity does not allow to detect C-3 absorption due to diffuse foreground clouds. From the column densities of the rotational levels in the vibrational ground state probed by the absorption we derive a rotation temperature (T-rot) of similar to 50-70 K, which is a good measure of the kinetic temperature of the absorbing gas, as radiative transitions within the vibrational ground state are forbidden. It is also in good agreement with the dust temperatures for W31C and W49N. Applying the partition function correction based on the derived T-rot, we get column densities N(C-3) similar to 7-9 x 10(14) cm(-2) and abundance x(C-3) similar to 10(-8) with respect to H-2. For W31C, using a radiative transfer model including far-infrared pumping by the dust continuum and a temperature gradient within the source along the line of sight we find that a model with x(C-3) = 10(-8), T-kin = 30-50 K, N(C-3) = 1.5 x 10(15) cm(-2) fits the observations reasonably well and provides parameters in very good agreement with the simple excitation analysis.

ISM: individual objects: W31C

g10.6-0.4

dust

ISM: molecules

radiative transfer

individual objects: W49N

spiral-arm clouds

spectroscopy

translucent

irc+10216

interstellar c-3

hii-regions

ISM:

ISM: lines and bands

h-ii-regions

absorption

Author

B. Mookerjea

Tata Institute of Fundamental Research

T. Giesen

University of Cologne

J. Stutzki

University of Cologne

J. Cernicharo

Centro de Astrobiologia (CAB)

J. R. Goicoechea

Centro de Astrobiologia (CAB)

M. de Luca

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

T. A. Bell

California Institute of Technology (Caltech)

H. Gupta

Jet Propulsion Laboratory, California Institute of Technology

M. Gerin

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

Carina Persson

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

P. Sonnentrucker

Johns Hopkins University

Z. Makai

University of Cologne

John H Black

Chalmers, Earth and Space Sciences, Radio Astronomy and Astrophysics

F. Boulanger

Institut d'Astrophysique Spatiale

A. Coutens

University of Toulouse

E. Dartois

Institut d'Astrophysique Spatiale

P. Encrenaz

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

E. Falgarone

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

T. R. Geballe

Gemini Observatory North

B. Godard

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

P. F. Goldsmith

Jet Propulsion Laboratory, California Institute of Technology

C. Gry

Laboratoire d'Astrophysique de Marseille

P. Hennebelle

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

E. Herbst

Ohio State University

P. Hily-Blant

Laboratoire d'Astrophysique de Grenoble

C. Joblin

University of Toulouse

M. Kazmierczak

Uniwersytet Mikołaja Kopernika w Toruniu

R. Kolos

Polish Academy of Sciences

J. Krelowski

Uniwersytet Mikołaja Kopernika w Toruniu

D. C. Lis

California Institute of Technology (Caltech)

J. Martin-Pintado

Centro de Astrobiologia (CAB)

K. M. Menten

Max Planck Society

Raquel Monje

California Institute of Technology (Caltech)

J. C. Pearson

Jet Propulsion Laboratory, California Institute of Technology

M. Perault

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

T. G. Phillips

California Institute of Technology (Caltech)

R. Plume

University of Calgary

M. Salez

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

S. Schlemmer

University of Cologne

M. Schmidt

Polish Academy of Sciences

D. Teyssier

European Space Astronomy Centre (ESAC)

C. Vastel

University of Toulouse

S. Yu

LERMA - Laboratoire d'Etudes du Rayonnement et de la Matiere en Astrophysique et Atmospheres

P. Dieleman

Netherlands Institute for Space Research (SRON)

R. Güsten

Max Planck Society

C. E. Honingh

University of Cologne

P. Morris

California Institute of Technology (Caltech)

P. Roelfsema

Netherlands Institute for Space Research (SRON)

R. Schieder

University of Cologne

Aggm Tielens

Leiden University

J. Zmuidzinas

California Institute of Technology (Caltech)

Astronomy and Astrophysics

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

Vol. 521 1 Article Number: L13 - L13

Subject Categories

Astronomy, Astrophysics and Cosmology

DOI

10.1051/0004-6361/201015095

More information

Latest update

1/28/2020