@Article{Mookerjea_etal2010,
author="Mookerjea, B.
and Giesen, T.
and Stutzki, J.
and Cernicharo, J.
and Goicoechea, J. R.
and De Luca, M.
and Bell, T. A.
and Gupta, H.
and Gerin, M.
and Persson, C. M.
and Sonnentrucker, P.
and Makai, Z.
and Black, J.
and Boulanger, F.
and Coutens, A.
and Dartois, E.
and Encrenaz, P.
and Falgarone, E.
and Geballe, T.
and Godard, B.
and Goldsmith, P. F.
and Gry, C.
and Hennebelle, P.
and Herbst, E.
and Hily-Blant, P.
and Joblin, C.
and Ka<c5><ba>mierczak, M.
and Ko{\l}os, R.
and Kre{\l}owski, J.
and Lis, D. C.
and Martin-Pintado, J.
and Menten, K. M.
and Monje, R.
and Pearson, J. C.
and Perault, M.
and Phillips, T. G.
and Plume, R.
and Salez, M.
and Schlemmer, S.
and Schmidt, M.
and Teyssier, D.
and Vastel, C.
and Yu, S.
and Dieleman, P.
and G{\"u}sten, R.
and Honingh, C. E.
and Morris, P.
and Roelfsema, P.
and Schieder, R.
and Tielens, A. G. G. M.
and Zmuidzinas, J.",
title="Excitation and abundance of C3 in star forming cores. Herschel/HIFI observations of the sight-lines to W31C and W49N",
journal="Astron. Astrophys.",
year="2010",
volume="521",
pages="L13",
optkeywords="HEB mixer applications; HIFI; Herschel; ISM: lines and bands / ISM: molecules / radiative transfer / ISM: individual objects: W49N / ISM: individual objects: W31C",
abstract="We present spectrally resolved observations of triatomic carbon (C3) in several ro-vibrational transitions between the vibrational ground state and the low-energy {\^I}{\textonehalf}2 bending mode at frequencies between 1654--1897 GHz along the sight-lines to the submillimeter continuum sources W31C and W49N, using Herschel{\textquoteright}s HIFI instrument. We detect C3 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 C3 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 (Trot) of {\textasciitilde}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 Trot, we get column densities N(C3) {\textasciitilde} 7--9 {\texttimes} 1014 cm-2 and abundance x(C3) {\textasciitilde} 10-8 with respect to H2. 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(C3) = 10-8, Tkin = 30--50 K, N(C3) = 1.5 {\texttimes} 1015 cm-2 fits the observations reasonably well and provides parameters in very good agreement with the simple excitation analysis.",
optnote="exported from refbase (https://db.rplab.ru/refbase/show.php?record=1099), last updated on Fri, 17 Jun 2016 17:44:19 -0500",
doi="10.1051/0004-6361/201015095",
opturl="https://doi.org/10.1051/0004-6361/201015095"
}