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Exposing the plural nature of molecular clouds

dc.contributor.authorROBITAILLE, J.-F.
hal.structure.identifierInstitut de Recherches sur les lois Fondamentales de l'Univers [IRFU]
dc.contributor.authorMOTTE, F.
hal.structure.identifierCEREG [CEREG]
dc.contributor.authorSCHNEIDER, N.
hal.structure.identifierIstituto di Astrofisica e Planetologia Spaziali - INAF [IAPS]
dc.contributor.authorELIA, D.
hal.structure.identifierFORMATION STELLAIRE 2019
dc.contributor.authorBONTEMPS, Sylvain
dc.date.issued2019
dc.identifier.issn0004-6361
dc.description.abstractEnWe present the Multiscale non-Gaussian Segmentation (MnGSeg) analysis technique. This wavelet-based method combines the analysis of the probability distribution function (PDF) of map fluctuations as a function of spatial scales and the power spectrum analysis of a map. This technique allows us to extract the non-Gaussianities identified in the multiscaled PDFs usually associated with turbulence intermittency and to spatially reconstruct the Gaussian and the non-Gaussian components of the map. This new technique can be applied on any data set. In the present paper, it is applied on a Herschel column density map of the Polaris flare cloud. The first component has by construction a self-similar fractal geometry similar to that produced by fractional Brownian motion (fBm) simulations. The second component is called the coherent component, as opposed to fractal, and includes a network of filamentary structures that demonstrates a spatial hierarchical scaling (i.e. filaments inside filaments). The power spectrum analysis of the two components proves that the Fourier power spectrum of the initial map is dominated by the power of the coherent filamentary structures across almost all spatial scales. The coherent structures contribute increasingly from larger to smaller scales, without producing any break in the inertial range. We suggest that this behaviour is induced, at least partly, by inertial-range intermittency, a well-known phenomenon for turbulent flows. We also demonstrate that the MnGSeg technique is itself a very sensitive signal analysis technique that allows the extraction of the cosmic infrared background (CIB) signal present in the Polaris flare submillimetre observations and the detection of a characteristic scale for 0.1 ≲ l ≲ 0.3 pc. The origin of this characteristic scale could partly be the transition of regimes dominated by incompressible turbulence versus compressible modes and other physical processes, such as gravity.
dc.description.sponsorshipGENeration et Evolution des Structures du milieu InterStellaire - ANR-16-CE92-0035
dc.language.isoen
dc.publisherEDP Sciences
dc.subject.enAstrophysics - Astrophysics of Galaxies
dc.subject.enISM: structure
dc.subject.enturbulence
dc.subject.enmethods: data analysis
dc.subject.enmethods: statistical
dc.subject.entechniques: image processing
dc.subject.enISM: general
dc.title.enExposing the plural nature of molecular clouds
dc.title.enExtracting filaments and the cosmic infrared background against the true scale-free interstellar medium
dc.typeArticle de revue
dc.identifier.doi10.1051/0004-6361/201935545
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]
bordeaux.journalAstronomy and Astrophysics - A&A
bordeaux.pageA33
bordeaux.volume628
bordeaux.peerReviewedoui
hal.identifierhal-02145485
hal.version1
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-02145485v1
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