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Bias versus variance when fitting multi-species molecular lines with a non-LTE radiative transfer model

hal.structure.identifierInstitut des Matériaux, de Microélectronique et des Nanosciences de Provence [IM2NP]
dc.contributor.authorROUEFF, Antoine
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
hal.structure.identifierLERMA Cergy [LERMA]
dc.contributor.authorPETY, Jérôme
hal.structure.identifierLERMA Cergy [LERMA]
dc.contributor.authorGERIN, Maryvonne
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
hal.structure.identifierInstitut des Matériaux, de Microélectronique et des Nanosciences de Provence [IM2NP]
dc.contributor.authorSÉGAL, Léontine
hal.structure.identifierInstituto de Física Fundamental [Madrid] [IFF]
dc.contributor.authorGOICOECHEA, Javier
hal.structure.identifierNational Radio Astronomy Observatory [Charlottesville] [NRAO]
dc.contributor.authorLISZT, Harvey
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorGRATIER, Pierre
hal.structure.identifierLERMA Cergy [LERMA]
dc.contributor.authorBEŠLIĆ, Ivana
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
hal.structure.identifierGIPSA - Signal Images Physique [GIPSA-SIGMAPHY]
dc.contributor.authorEINIG, Lucas
hal.structure.identifierLERMA Cergy [LERMA]
dc.contributor.authorGAUDEL, M.
hal.structure.identifierChalmers University of Technology [Gothenburg, Sweden]
dc.contributor.authorORKISZ, Jan
hal.structure.identifierCentre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 [CRIStAL]
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.authorPALUD, Pierre
hal.structure.identifierInstituto de Física Fundamental [Madrid] [IFF]
dc.contributor.authorSANTA-MARIA, Miriam
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorMAGALHAES, Victor De Souza
hal.structure.identifierInstitut de recherche en astrophysique et planétologie [IRAP]
dc.contributor.authorZAKARDJIAN, Antoine
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorBARDEAU, Sebastien
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.identifierCentre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 [CRIStAL]
dc.contributor.authorCHAINAIS, Pierre
hal.structure.identifierWorcester State University [Worcester]
hal.structure.identifierHarvard-Smithsonian Center for Astrophysics [CfA]
dc.contributor.authorCOUDÉ, Simon
hal.structure.identifierInstitut de recherche en astrophysique et planétologie [IRAP]
dc.contributor.authorDEMYK, Karine
hal.structure.identifierInstituto de Astrofisica [Santiago]
dc.contributor.authorGUZMAN VELOSO, Viviana
hal.structure.identifierInstitut de recherche en astrophysique et planétologie [IRAP]
dc.contributor.authorHUGHES, Annie
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 de Physique Théorique de l'ENS [École Normale Supérieure] [LPTENS]
dc.contributor.authorLEVRIER, François
hal.structure.identifierCalifornia Institute of Technology [CALTECH]
dc.contributor.authorLIS, Dariusz
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.authorBOURLOT, Jacques Le
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.authorLE PETIT, Franck
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
hal.structure.identifierCentre de Recherche en Informatique, Signal et Automatique de Lille - UMR 9189 [CRIStAL]
dc.contributor.authorTHOUVENIN, Pierre-Antoine
dc.date.issued2024-06
dc.identifier.issn0004-6361
dc.description.abstractEnRobust radiative transfer techniques are requisite for efficiently extracting the physical and chemical information from molecular rotational lines.We study several hypotheses that enable robust estimations of the column densities and physical conditions when fitting one or two transitions per molecular species. We study the extent to which simplifying assumptions aimed at reducing the complexity of the problem introduce estimation biases and how to detect them.We focus on the CO and HCO+ isotopologues and analyze maps of a 50 square arcminutes field. We used the RADEX escape probability model to solve the statistical equilibrium equations and compute the emerging line profiles, assuming that all species coexist. Depending on the considered set of species, we also fixed the abundance ratio between some species and explored different values. We proposed a maximum likelihood estimator to infer the physical conditions and considered the effect of both the thermal noise and calibration uncertainty. We analyzed any potential biases induced by model misspecifications by comparing the results on the actual data for several sets of species and confirmed with Monte Carlo simulations. The variance of the estimations and the efficiency of the estimator were studied based on the Cramér-Rao lower bound.Column densities can be estimated with 30% accuracy, while the best estimations of the volume density are found to be within a factor of two. Under the chosen model framework, the peak 12CO(1−0) is useful for constraining the kinetic temperature. The thermal pressure is better and more robustly estimated than the volume density and kinetic temperature separately. Analyzing CO and HCO+ isotopologues and fitting the full line profile are recommended practices with respect to detecting possible biases.Combining a non-local thermodynamic equilibrium model with a rigorous analysis of the accuracy allows us to obtain an efficient estimator and identify where the model is misspecified. We note that other combinations of molecular lines could be studied in the future.
dc.language.isoen
dc.publisherEDP Sciences
dc.rights.urihttp://creativecommons.org/licenses/by/
dc.subject.enISM: molecules
dc.subject.enISM: clouds
dc.subject.enRadiative transfer
dc.subject.enMethods: data analysis
dc.subject.enMethods: statistical
dc.title.enBias versus variance when fitting multi-species molecular lines with a non-LTE radiative transfer model
dc.title.enApplication to the estimation of the gas temperature and volume density
dc.typeArticle de revue
dc.typeData paper
dc.identifier.doi10.1051/0004-6361/202449148
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Astrophysique galactique [astro-ph.GA]
dc.subject.halStatistiques [stat]/Applications [stat.AP]
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA255
bordeaux.volume686
bordeaux.issueJune
bordeaux.peerReviewedoui
hal.identifierhal-04523850
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-04523850v1
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