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Apport de la haute resolution angulaire sur l'etude des galaxies lointaines : imagerie, optique adaptative et spectroscopie 3D

Abstract : The PhD work presented here is related to the study of distant galaxies, whose studies are required to understand the mecanisms responsibles of galaxy formation. The Hubble Space Telescope has allowed to provide high-resolution images of distant galaxies, thus giving first clues about their morphology. In addition, the 8-10 meters telescopes like the european Very Large Telescope (VLT) located at the ground have given spectroscopic informations about these objects. The combination of all these data shows that there was a burst of star formation in the universe some 8-10 billions years ago, which has since declined. The first part of this thesis deals with morphological studies of distant galaxies from Hubble Space Telescope images. Two galaxy's populations were analysed : luminous compact galaxies (LCG) and luminous infrared galaxies (LIRG), which are both responsible of the star formation decline shown before. Those studies have allowed to build a sequence who could give a scenario of the formation of some galaxies in today's universe. Additional studies have also shown the requirement of a high spectral resolution to compute precise star formation rates in distant galaxies. The second part of this thesis is related to the study of FALCON, a project of new generation spectrograph for the VLT, who will provide high angular and spectral resolution. FALCON's goal is to get the dynamical information of distant galaxies with a spatial resolution of 0.25 arcsec with a sufficient signal-to-noise ratio. This requires to use Adaptive Optics to compensate in real-time for image degradation due to atmospheric turbulence. In order to not suffer from anisoplanatism, FALCON will use atmospheric tomography. This consists in combining measurements from off-axis wavefront-sensors around the galaxy to correct its wavefront by using a deformable mirror, so that its dynamic can be measured. The adaptive optics system has first been studied theoritically. Then the development of a simulation tool has allowed to compute some first performances of such a system on the sky.
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https://tel.archives-ouvertes.fr/tel-00009053
Contributor : Assemat Francois <>
Submitted on : Tuesday, April 19, 2005 - 4:03:28 PM
Last modification on : Wednesday, September 23, 2020 - 4:36:51 AM
Long-term archiving on: : Monday, September 20, 2010 - 12:08:13 PM

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  • HAL Id : tel-00009053, version 2

Citation

Assemat Francois. Apport de la haute resolution angulaire sur l'etude des galaxies lointaines : imagerie, optique adaptative et spectroscopie 3D. Astrophysique [astro-ph]. Université Pierre et Marie Curie - Paris VI, 2004. Français. ⟨tel-00009053v2⟩

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