Excitation and abundance of C3 in star forming cores Herschel/HIFI observations of the sight-lines to W31C and W49N
Artikel i vetenskaplig tidskrift, 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: molecules

hii-regions

h-ii-regions

ISM: lines and bands

ISM:

irc+10216

spiral-arm clouds

spectroscopy

dust

individual objects: W49N

absorption

interstellar c-3

ISM: individual objects: W31C

g10.6-0.4

translucent

radiative transfer

Författare

B. Mookerjea

Tata Institute of Fundamental Research

T. Giesen

Universität zu Köln

J. Stutzki

Universität zu Köln

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

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, Rymd- och geovetenskap, Radioastronomi och astrofysik

P. Sonnentrucker

Johns Hopkins University

Z. Makai

Universität zu Köln

John H Black

Chalmers, Rymd- och geovetenskap, Radioastronomi och astrofysik

F. Boulanger

Institut d'Astrophysique Spatiale

A. Coutens

Université de 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 Telescope

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

Université de Toulouse

M. Kazmierczak

Uniwersytet Mikołaja Kopernika w Toruniu

R. Kolos

Institute of Physical Chemistry of the Polish Academy of Sciences

J. Krelowski

Uniwersytet Mikołaja Kopernika w Toruniu

D. C. Lis

CalTech

J. Martin-Pintado

Centro de Astrobiologia (CAB)

K. M. Menten

Max Planck-institutet

Raquel Rodriguez-Monje

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

CalTech

R. Plume

University of Calgary

M. Salez

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

S. Schlemmer

Universität zu Köln

M. Schmidt

Nicolaus Copernicus Astronomical Center of the Polish Academy of Sciences

D. Teyssier

European Space Astronomy Centre (ESA)

C. Vastel

Université de 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-institutet

C. E. Honingh

Universität zu Köln

P. Morris

CalTech

P. Roelfsema

Netherlands Institute for Space Research (SRON)

R. Schieder

Universität zu Köln

Aggm Tielens

Universiteit Leiden

J. Zmuidzinas

CalTech

Astronomy and Astrophysics

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

Vol. 521 1 Article Number: L13 - L13

Ämneskategorier

Astronomi, astrofysik och kosmologi

DOI

10.1051/0004-6361/201015095