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L'émission submillimétrique du gaz dans les galaxies taux de refroidissement et formation d'étoiles

Abstract : This PhD thesis presents the most recent study of the warm and dense molecular gas cooling from the emission of the atomic carbone lines and from the emission of the carbone monoxide lines in the interstellar medium of nearby galaxies (D<10Mpc). This work provides us, for the first time, observations of galactic nuclei, performed at frequencies of º =806 GHz and º =809 with the Caltech Submillimeter Observatory. Moreover, using the most to date sophisticated models (PDRs and LVGs models) which reproduce the MIS features, we succeed to derive the physical and chemical properties (kinetic temperature, gas density, FUV radiation field which illuminates interstellar clouds, abundance ratio,...) of the warm and dense molecular gas. This work allows us to increase our understanding on the processes governing the star formation activities. This study also reveals the predominant role of the high-J CO lines (from 12CO(3-2) to 12CO(7-6) which emit at º =345 GHz and º =806 GHz, respectively) and the [CI](3P2-3P1) line (º =809 GHz). These lines should be used as a diagnostic of the gas cooling in the most distant objects, often hardly accessibles. The study of the warm and dense molecular gas not only at low but also at high spatial resolution (obtained with the IRAM-Plateau de Bure interferometer) gives us the opportunity to once more increase our knowledge in the star formation activities by comparing the mid and far IR emissions from the dust with the submillimeter-millimeter emissions from the gas. We point out good correlations between these two well known tracers of the star formation activities in galaxies. All these analyses, the multi-wavelengths studies and the increase of observations in the submillimeter and millimeter lines should be pursue. The interesting results pointed out in this PhD Thesis should be confirmed on more sources, using the next generation of telescopes as ALMA and Herschel.
keyword : molecular gas
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Contributor : Estelle Bayet <>
Submitted on : Friday, December 12, 2008 - 11:25:11 AM
Last modification on : Thursday, December 10, 2020 - 12:36:58 PM
Long-term archiving on: : Thursday, October 11, 2012 - 1:35:10 PM


  • HAL Id : tel-00346731, version 1


Estelle Bayet. L'émission submillimétrique du gaz dans les galaxies taux de refroidissement et formation d'étoiles. Astrophysique [astro-ph]. Université Pierre et Marie Curie - Paris VI, 2006. Français. ⟨tel-00346731⟩



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