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Etude des propriétés d'émission des poussières du Milieu Interstellaire

Abstract : My thesis work is focused on the study of the interstellar matter, essentially the submillimeter emission of dust grains and also the evolution of their properties, from the diffuse medium to the dense medium, in our Galaxy as well as the Large Magellanic Cloud.
I took part in the development of a submillimeter dust emission model and I adjusted his parameters so as to reproduce the observational facts. This model takes into account the amorphous nature of the grains. It considers a disordered charge distribution at the macroscopic scale, and a distribution of two level systems at the microscopic scale.
I compared the emissivity of grains in atomic regions (HI) and molecular (CO) of our Galaxy. I showed that the slope and the level of the emissivities of grains increase notably in the majority of the dense regions of our Galaxy, in the range 100-550 Μm. The conclusions of this work confirm the idea of grains coagulation.
Then I concentrated on the study of dust in the Large Magellanic Cloud (LMC). I evidenced for the first time a lower abundance of the dust in the LMC. Morever my results show that the spatial variations of the dust composition and of the radiation field accross this galaxy are governed by present and past stars formation activity. To finish I focused on the possible interpretations of the observed differences between the atomic and molecular phases
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Submitted on : Thursday, January 24, 2008 - 3:06:38 PM
Last modification on : Thursday, October 15, 2020 - 4:07:06 AM
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  • HAL Id : tel-00216111, version 1

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Déborah Paradis. Etude des propriétés d'émission des poussières du Milieu Interstellaire. Astrophysique [astro-ph]. Université Paul Sabatier - Toulouse III, 2007. Français. ⟨tel-00216111⟩

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