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The anatomy of the Orion B giant molecular cloud: A local template for studies of nearby galaxies

hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
dc.contributor.authorPETY, Jérôme
hal.structure.identifierHarvard-Smithsonian Center for Astrophysics [CfA]
dc.contributor.authorGUZMÁN, Viviana
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
hal.structure.identifierUniversité Grenoble Alpes [2016-2019] [UGA [2016-2019]]
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorORKISZ, Jan
hal.structure.identifierNational Radio Astronomy Observatory [NRAO]
dc.contributor.authorLISZT, Harvey S.
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
dc.contributor.authorGERIN, Maryvonne
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
dc.contributor.authorBRON, Emeric
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorBARDEAU, Sébastien
hal.structure.identifierConsejo Superior de Investigaciones Cientificas [España] = Spanish National Research Council [Spain] [CSIC]
dc.contributor.authorGOICOECHEA, Javier
hal.structure.identifierAMOR 2016
dc.contributor.authorGRATIER, P.
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
dc.contributor.authorLE PETIT, Franck
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
dc.contributor.authorLEVRIER, François
hal.structure.identifierHarvard-Smithsonian Center for Astrophysics [CfA]
dc.contributor.authorOBERG, Karin I.
hal.structure.identifierLaboratoire d'Etude du Rayonnement et de la Matière en Astrophysique [LERMA]
dc.contributor.authorROUEFF, Evelyne
hal.structure.identifierInstituto de RadioAstronomía Milimétrica [IRAM]
dc.contributor.authorSIEVERS, Albrecht
dc.date.issued2017
dc.identifier.issn0004-6361
dc.description.abstractEnContext. Molecular lines and line ratios are commonly used to infer properties of extra-galactic star forming regions. The new generation of millimeter receivers almost turns every observation into a line survey. Full exploitation of this technical advancement in extra-galactic study requires detailed bench-marking of available line diagnostics.Aims. We aim to develop the Orion B giant molecular cloud (GMC) as a local template for interpreting extra-galactic molecular line observations.Methods. We use the wide-band receiver at the IRAM-30 m to spatially and spectrally resolve the Orion B GMC. The observations cover almost 1 square degree at 26′′ resolution with a bandwidth of 32 GHz from 84 to 116 GHz in only two tunings. Among the mapped spectral lines are the 12CO, 13CO, C18O, C17O, HCN, HNC, 12CN, C2H, HCO+, N2H+(1−0), and 12CS, 32SO, SiO, c - C3H2, CH3OH (2−1) transitions.Results. We introduce the molecular anatomy of the Orion B GMC, including relationships between line intensities and gas column density or far-UV radiation fields, and correlations between selected line and line ratios. We also obtain a dust-traced gas mass that is less than approximately one third the CO-traced mass, using the standard XCO conversion factor. The presence of over-luminous CO can be traced back to the dependence of the CO intensity on UV illumination. As a matter of fact, while most lines show some dependence on the UV radiation field, CN and C2H are the most sensitive. Moreover, dense cloud cores are almost exclusively traced by N2H+. Other traditional high-density tracers, such as HCN(1−0), are also easily detected in extended translucent regions at a typical density of ~500 H2 cm-3. In general, we find no straightforward relationship between line critical density and the fraction of the line luminosity coming from dense gas regions.Conclusions. Our initial findings demonstrate that the relationships between line (ratio) intensities and environment in GMCs are more complicated than often assumed. Sensitivity (i.e., the molecular column density), excitation, and, above all, chemistry contribute to the observed line intensity distributions, and they must be considered together when developing the next generation of extra-galactic molecular line diagnostics of mass, density, temperature, and radiation field.
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enAstrophysics - Astrophysics of Galaxies
dc.subject.engalaxies: ISM
dc.subject.enISM: clouds
dc.subject.enHII regions
dc.subject.enradio lines: galaxies
dc.subject.enastrochemistry
dc.title.enThe anatomy of the Orion B giant molecular cloud: A local template for studies of nearby galaxies
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/201629862
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
dc.subject.halPhysique [physics]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
dc.identifier.arxiv1611.04037
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA98
bordeaux.volume599
bordeaux.peerReviewedoui
hal.identifierhal-01400616
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-01400616v1
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