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C18O, 13CO, and 12CO abundances and excitation temperatures in the Orion B molecular cloud

hal.structure.identifierPhyTI [PhyTI]
dc.contributor.authorROUEFF, Antoine
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
dc.contributor.authorGERIN, Maryvonne
hal.structure.identifierFORMATION STELLAIRE 2020
dc.contributor.authorGRATIER, Pierre
hal.structure.identifierAstrophysique
dc.contributor.authorLEVRIER, François
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
dc.contributor.authorPETY, Jérôme
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
dc.contributor.authorGAUDEL, Mathilde
hal.structure.identifierInstituto de Física Fundamental [Madrid] [IFF]
dc.contributor.authorGOICOECHEA, Javier
hal.structure.identifierOnsala Space Observatory [OSO]
dc.contributor.authorORKISZ, Jan
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorDE SOUZA MAGALHAES, Victor
hal.structure.identifierSignal et Communications [IRIT-SC]
dc.contributor.authorVONO, Maxime
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorBARDEAU, Sébastien
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
dc.contributor.authorBRON, Emeric
hal.structure.identifierGIPSA - Signal Images Physique [GIPSA-SIGMAPHY]
dc.contributor.authorCHANUSSOT, Jocelyn
hal.structure.identifierCentre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 [CRIStAL]
dc.contributor.authorCHAINAIS, Pierre
hal.structure.identifierPontificia Universidad Católica de Chile [UC]
dc.contributor.authorGUZMAN, Viviana V.
hal.structure.identifierInstitut de recherche en astrophysique et planétologie [IRAP]
dc.contributor.authorHUGHES, Annie
hal.structure.identifierOnsala Space Observatory [OSO]
dc.contributor.authorKAINULAINEN, Jouni
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
dc.contributor.authorLANGUIGNON, David
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
hal.structure.identifierLaboratoire Univers et Théories [LUTH (UMR_8102)]
dc.contributor.authorLE BOURLOT, Jacques
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
hal.structure.identifierLaboratoire Univers et Théories [LUTH (UMR_8102)]
dc.contributor.authorLE PETIT, Franck
hal.structure.identifierNational Radio Astronomy Observatory [Charlottesville] [NRAO]
dc.contributor.authorLISZT, Harvey S.
hal.structure.identifierCanadian Institute for Theoretical Astrophysics [CITA]
dc.contributor.authorMARCHAL, Antoine
hal.structure.identifierAstrophysique Interprétation Modélisation [AIM (UMR_7158 / UMR_E_9005 / UM_112)]
dc.contributor.authorMIVILLE-DESCHÊNES, Marc-Antoine
hal.structure.identifierCardiff University
dc.contributor.authorPERETTO, Nicolas
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique et Atmosphères = Laboratory for Studies of Radiation and Matter in Astrophysics and Atmospheres [LERMA]
dc.contributor.authorROUEFF, Evelyne
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorSIEVERS, Albrecht
dc.date.issued2021-01
dc.identifier.issn0004-6361
dc.description.abstractEnContext. CO isotopologue transitions are routinely observed in molecular clouds for the purpose of probing the column density of the gas and the elemental ratios of carbon and oxygen, in addition to tracing the kinematics of the environment.Aims. Our study is aimed at estimating the abundances, excitation temperatures, velocity field, and velocity dispersions of the three main CO isotopologues towards a subset of the Orion B molecular cloud, which includes IC 434, NGC 2023, and the Horsehead pillar.Methods. We used the Cramer Rao bound (CRB) technique to analyze and estimate the precision of the physical parameters in the framework of local-thermodynamic-equilibrium (LTE) excitation and radiative transfer with added white Gaussian noise. We propose a maximum likelihood estimator to infer the physical conditions from the 1–0 and 2–1 transitions of CO isotopologues. Simulations show that this estimator is unbiased and proves efficient for a common range of excitation temperatures and column densities (Tex > 6 K, N > 1014−1015  cm−2).Results. Contrary to general assumptions, the various CO isotopologues have distinct excitation temperatures and the line intensity ratios between different isotopologues do not accurately reflect the column density ratios. We find mean fractional abundances that are consistent with previous determinations towards other molecular clouds. However, significant local deviations are inferred, not only in regions exposed to the UV radiation field, but also in shielded regions. These deviations result from the competition between selective photodissociation, chemical fractionation, and depletion on grain surfaces. We observe that the velocity dispersion of the C18O emission is 10% smaller than that of 13CO. The substantial gain resulting from the simultaneous analysis of two different rotational transitions of the same species is rigorously quantified.Conclusions. The CRB technique is a promising avenue for analyzing the estimation of physical parameters from the fit of spectral lines. Future works will generalize its application to non-LTE excitation and radiative transfer methods.
dc.description.sponsorshipMIAI @ Grenoble Alpes - ANR-19-P3IA-0003
dc.language.isoen
dc.publisherEDP Sciences
dc.rights.urihttp://creativecommons.org/licenses/by-nc-nd/
dc.subject.enISM: molecules
dc.subject.enISM: clouds
dc.subject.enradiative transfer
dc.subject.enmethods: data analysis
dc.subject.enmethods: statistical
dc.title.enC18O, 13CO, and 12CO abundances and excitation temperatures in the Orion B molecular cloud
dc.title.enAnalysis of the achievable precision in modeling spectral lines within the approximation of the local thermodynamic equilibrium
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/202037776
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
dc.subject.halInformatique [cs]
dc.identifier.arxiv2005.08317
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.volume645
bordeaux.issueA26
bordeaux.peerReviewedoui
hal.identifierhal-02570214
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02570214v1
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