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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 E.
hal.structure.identifierInstituto de Física Fundamental [Madrid] [IFF]
dc.contributor.authorGOICOECHEA, Javier R.
hal.structure.identifierNational Radio Astronomy Observatory [Charlottesville] [NRAO]
dc.contributor.authorLISZT, Harvey S.
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorGRATIER, Pierre
hal.structure.identifierLERMA Cergy [LERMA]
dc.contributor.authorBESLIC, 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, Mathilde
hal.structure.identifierChalmers University of Technology [Gothenburg, Sweden]
dc.contributor.authorORKISZ, Jan H.
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 G.
hal.structure.identifierInstitut de RadioAstronomie Millimétrique [IRAM]
dc.contributor.authorDE SOUZA MAGALHAES, Victor
hal.structure.identifierInstitut de recherche en astrophysique et planétologie [IRAP]
dc.contributor.authorZAKARDJIAN, Antoine
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.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, Viviana V.
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.identifierAstrophysique
dc.contributor.authorLEVRIER, François
hal.structure.identifierCalifornia Institute of Technology [CALTECH]
dc.contributor.authorLIS, Dariusz C.
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 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]
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
dc.identifier.issn0004-6361
dc.description.abstractEnContext. Robust radiative transfer techniques are requisite for efficiently extracting the physical and chemical information from molecular rotational lines.Aims. 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.Methods. 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.Results. 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.Conclusions. 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.description.sponsorshipAnalyse Détaillée du Milieu Inter-Stellaire - ANR-21-CE31-0010
dc.language.isoen
dc.publisherEDP Sciences
dc.rights.urihttp://creativecommons.org/licenses/by/
dc.subject.enradiative transfer
dc.subject.enmethods: data analysis
dc.subject.enmethods: statistical
dc.subject.enISM: clouds
dc.subject.enISM: general
dc.subject.enline: profiles
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.identifier.doi10.1051/0004-6361/202449148
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA255
bordeaux.volume686
bordeaux.peerReviewedoui
hal.identifierhal-04619550
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-04619550v1
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