The cooling of atomic and molecular gas in DR21
| dc.contributor.author | JAKOB, H. | |
| dc.contributor.author | KRAMER, C. | |
| dc.contributor.author | SIMON, R. | |
| dc.contributor.author | SCHNEIDER, N. | |
| dc.contributor.author | OSSENKOPF, V. | |
| hal.structure.identifier | Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB] | |
| hal.structure.identifier | Observatoire aquitain des sciences de l'univers [OASU] | |
| hal.structure.identifier | Laboratoire d'Astrophysique de Bordeaux [Pessac] [LAB] | |
| dc.contributor.author | BONTEMPS, Sylvain | |
| dc.contributor.author | GRAF, U. U. | |
| dc.contributor.author | STUTZKI, J. | |
| dc.date.created | 2007 | |
| dc.date.issued | 2007 | |
| dc.identifier.issn | 0004-6361 | |
| dc.description.abstractEn | We present an overview of a high-mass star formation region through the major (sub-)mm, and far-infrared cooling lines to gain insight into the physical conditions and the energy budget of the molecular cloud. We used the KOSMA 3m telescope to map the core ($10'\times 14'$) of the Galactic star forming region DR 21/DR 21 (OH) in the Cygnus X region in the two fine structure lines of atomic carbon CI and four mid-$J$ transitions of CO and $^{13}$CO, and CS $J=7\TO6$. These observations have been combined with FCRAO $J=1\TO0$ observations of $^{13}$CO and C$^{18}$O. Five positions, including DR21, DR21 (OH), and DR21 FIR1, were observed with the ISO/LWS grating spectrometer in the \OI 63 and 145 $\mu$m lines, the \CII 158 $\mu$m line, and four high-$J$ CO lines. We discuss the intensities and line ratios at these positions and apply Local Thermal Equilibrium (LTE) and non-LTE analysis methods in order to derive physical parameters such as masses, densities and temperatures. The CO line emission has been modeled up to J=20. From non-LTE modeling of the low- to high-$J$ CO lines we identify two gas components, a cold one at temperatures of T$_\RM{kin}\sim 30-40$ K, and one with T$_\RM{kin}\sim 80-150$ K at a local clump density of about n(H$_2$)$\sim 10^4-10^6$ cm$^{-3}$. While the cold quiescent component is massive containing typically more than 94 % of the mass, the warm, dense, and turbulent gas is dominated by mid- and high-$J$ CO line emission and its large line widths. The medium must be clumpy with a volume-filling of a few percent. The CO lines are found to be important for the cooling of the cold molecular gas, e.g. at DR21 (OH). Near the outflow of the UV-heated source DR21, the gas cooling is dominated by line emission of atomic oxygen and of CO. | |
| dc.language.iso | en | |
| dc.publisher | EDP Sciences | |
| dc.subject.en | ISM: clouds | |
| dc.subject.en | ISM: abundances | |
| dc.subject.en | Radio lines: ISM | |
| dc.subject.en | Line: profiles | |
| dc.subject.en | Stars: formation | |
| dc.subject.en | ISM: individual objects: DR21 | |
| dc.subject.en | DR21 (OH) | |
| dc.title.en | The cooling of atomic and molecular gas in DR21 | |
| dc.type | Article de revue | |
| dc.subject.hal | Physique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO] | |
| dc.subject.hal | Planète et Univers [physics]/Astrophysique [astro-ph] | |
| dc.identifier.arxiv | astro-ph/0609559 | |
| bordeaux.journal | Astronomy and Astrophysics - A&A | |
| bordeaux.page | 999-1012 | |
| bordeaux.volume | 461 | |
| bordeaux.peerReviewed | oui | |
| hal.identifier | hal-00119895 | |
| hal.version | 1 | |
| hal.popular | non | |
| hal.audience | Non spécifiée | |
| hal.origin.link | https://hal.archives-ouvertes.fr//hal-00119895v1 | |
| bordeaux.COinS | ctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.jtitle=Astronomy%20and%20Astrophysics%20-%20A&A&rft.date=2007&rft.volume=461&rft.spage=999-1012&rft.epage=999-1012&rft.eissn=0004-6361&rft.issn=0004-6361&rft.au=JAKOB,%20H.&KRAMER,%20C.&SIMON,%20R.&SCHNEIDER,%20N.&OSSENKOPF,%20V.&rft.genre=article |
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