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Physical conditions in the gas phases of the giant HII region LMC-N11: II. Origin of [CII] and fraction of CO-dark gas

hal.structure.identifierAstrophysique Interprétation Modélisation [AIM (UMR7158 / UMR_E_9005 / UM_112)]
dc.contributor.authorLEBOUTEILLER, Vianney
hal.structure.identifierUniversität Heidelberg [Heidelberg] = Heidelberg University
dc.contributor.authorCORMIER, D.
hal.structure.identifierDépartement d'Astrophysique (ex SAP) [DAP]
dc.contributor.authorMADDEN, S. C.
hal.structure.identifierUniversity of Cambridge [UK] [CAM]
dc.contributor.authorGALAMETZ, M.
hal.structure.identifierInstitut de Recherches sur les lois Fondamentales de l'Univers [IRFU]
dc.contributor.authorHONY, S.
hal.structure.identifierAstrophysique Interprétation Modélisation [AIM (UMR7158 / UMR_E_9005 / UM_112)]
dc.contributor.authorGALLIANO, Frédéric
hal.structure.identifierAstrophysique Interprétation Modélisation [AIM (UMR7158 / UMR_E_9005 / UM_112)]
dc.contributor.authorCHEVANCE, M.
dc.contributor.authorLEE, Min-Young
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
dc.contributor.authorBRAINE, J.
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA (UMR_8112)]
dc.contributor.authorPOLLES, F. L.
dc.contributor.authorREQUEÑA-TORRES, M. Angel
dc.contributor.authorINDEBETOUW, R.
hal.structure.identifierUniversity of KwaZulu-Natal [Durban, Afrique du Sud] [UKZN]
dc.contributor.authorHUGHES, A.
hal.structure.identifierUniversity of Cincinnati [UC]
dc.contributor.authorABEL, N.
dc.description.abstractEn(abridged) The ambiguous origin of [CII] 158um in the interstellar medium complicates its use for diagnostics concerning the star-formation rate and physical conditions in photodissociation regions (PDRs). We observed the giant HII region N11 in the Large Magellanic Cloud with SOFIA/GREAT in order to investigate the origin of [CII] to obtain the total H2 gas content, the fraction of CO-dark H2 gas, and the influence of environmental effects such as stellar feedback. We present an innovative spectral decomposition method that allows statistical trends to be derived. The [CII] line is resolved in velocity and compared to HI and CO, using a Bayesian approach to decompose the profiles. A simple model accounting for collisions in the neutral atomic and molecular gas was used in order to derive the H2 column density traced by C+. The profile of [CII] most closely resembles that of CO, but the integrated [CII] line width lies between that of CO and that of HI. Using various methods, we find that [CII] mostly originates from the neutral gas. We show that [CII] mostly traces the CO-dark H2 gas but there is evidence of a weak contribution from neutral atomic gas preferentially in the faintest components. Most of the molecular gas is CO-dark. The fraction of CO-dark H2 gas decreases with increasing CO column density, with a slope that seems to depend on the impinging radiation field from nearby massive stars. Finally we extend previous measurements of the photoelectric-effect heating efficiency, which we find is constant across regions probed with Herschel, with [CII] and [OI] being the main coolants in faint and diffuse, and bright and compact regions, respectively, and with PAH emission tracing the CO-dark H2 gas heating where [CII] and [OI] emit. Our study highlights the importance of velocity-resolved PDR diagnostics and higher spatial resolution for HI observations.
dc.language.isoen
dc.title.enPhysical conditions in the gas phases of the giant HII region LMC-N11: II. Origin of [CII] and fraction of CO-dark gas
dc.typeDocument de travail - Pré-publication
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Instrumentation et méthodes pour l'astrophysique [astro-ph.IM]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Phénomènes cosmiques de haute energie [astro-ph.HE]
dc.identifier.arxiv1911.03280
hal.identifierhal-02380125
hal.version1
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02380125v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.au=LEBOUTEILLER,%20Vianney&CORMIER,%20D.&MADDEN,%20S.%20C.&GALAMETZ,%20M.&HONY,%20S.&rft.genre=preprint


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