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Optique adaptative, traitement d'image et étude des noyaux actifs de galaxie

Abstract : The objective of this PhD thesis was to optimize AO observations of AGNs with a 8-10m class telescope. Data have been acquired with NaCo at VLT, new image processing techniques have been developped and some original results have been found and published.

Concerning image restoration, a new maximum likelihood method for sub-pixel image registration has been developpe, tested on simulated data and applied to real NaCo data. A MAP deconvolution method called MISTRAL has also been optimized to the case of high contrast imaging and applied to NaCo data. Finally, the classical PSF reconstruction algorithm has been tested on simulated data and I showed that it was not appropriate to the case of faint object observations such as AGNs. Some new methods have been proposed and tested on simulations.

Concerning astronomical studies, three archetypal objects have been intensively observed in the Near-IR using classical imaging as well as spectroscopy and coronagraphy. In the case of NGC 1068, data processing unveiled some new structures with a peculiar morphology, probably linked to the jet. The state of the dust in these structures seems also very peculiar as it may be dominated by a VSG population. In the case of NGC 7469, a pair of micro-spiral arms were unveiled by data processing in the inner 2". The presence of strong H2 emission in the direction of the very central source found thanks to spectroscopy at high resolution is a strong clue favoring the unified scheme of AGNs. Finally, in the case of Arp 220, a group of 3 nuclear sources has been clearly identified at 3.5µm allowing a comprehensive study frm the visible to the radio wavelengths.
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Contributor : Damien Gratadour <>
Submitted on : Tuesday, January 17, 2006 - 9:00:51 PM
Last modification on : Thursday, December 10, 2020 - 11:09:09 AM
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  • HAL Id : tel-00011382, version 1


Damien Gratadour. Optique adaptative, traitement d'image et étude des noyaux actifs de galaxie. Astrophysique [astro-ph]. Université Paris-Diderot - Paris VII, 2005. Français. ⟨tel-00011382⟩



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