Advanced methods and algorithm for high precision astronomical imaging
Description
One of the biggest challenges of modern cosmology is to gain a more precise knowledge of the dark energy and the dark matter nature. Fortunately, the dark matter can be traced directly through its gravitational effect on galaxies shapes. The European Spatial Agency Euclid mission will precisely provide data for such a purpose. A critical step is analyzing these data will be to accurately model the instrument Point Spread Function (PSF), which the focus of this thesis.We developed non parametric methods to reliably estimate the PSFs across an instrument field-of-view, based on unresolved stars images and accounting for noise, under sampling and PSFs spatial variability. At the core of these contributions, modern mathematical tools and concepts such as sparsity. An important extension of this work will be to account for the PSFs wavelength dependency. (author)
Abstract (French)
L'un des challenges majeurs de la cosmologie moderne reside en la nature meme de la matiere et de l'energie noire. La matiere noire peut etre directement tracee a travers son effet gravitationnel sur les formes des galaxies. La mission Euclid de l'Agence Spatiale Europeenne fournira precisement des donnees a cette fin. L'exploitation de telles donnees requiert une modelisation precise de la Fonction d'etalement du Point (FEP) de l'instrument d'observation, ce qui constitue l'objectif de cette these. Nous avons developpe des methodes non-parametriques permettant d'estimer de maniere fiable la FEP sur l'ensemble du champ de vue d'un instrument, a partir d'images non resolues d'etoiles, ceci en tenant compte du bruit, d'un possible sous-echantillonnage des observations et de la variabilite spatiale de la FEP. Ce travail tire avantage d'outils et concepts mathematiques modernes parmi lesquelles la parcimonie. Une extension importante de ce travail serait de prendre en compte la dependance en longueur d'onde de la FEP
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Additional details
Additional titles
- Original title (English)
- Methodes et algorithmes avances pour l'imagerie astronomique de haute precision
Publishing Information
- Imprint Pagination
- 200 p.
- Report number
- FRCEA-TH--9597
INIS
- Country of Publication
- France
- Country of Input or Organization
- France
- INIS RN
- 49053112
- Subject category
- S97: MATHEMATICAL METHODS AND COMPUTING; S79: ASTROPHYSICS, COSMOLOGY AND ASTRONOMY;
- Resource subtype / Literary indicator
- Thesis
- Descriptors DEI
- COSMOLOGY; FACTORIZATION; INVERSE SCATTERING PROBLEM; MATRICES; NONLUMINOUS MATTER
- Descriptors DEC
- MATTER
Optional Information
- Notes
- 188 refs.; Available from the INIS Liaison Officer for France, see the INIS website for current contact and E-mail addresses; Also available from Les Bibliotheques, Universite de Paris-Saclay, Espace Technologique, Immeuble Discovery Route de l'Orme aux Merisiers RD 128, 91190 Saint-Aubin, (France)