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L'effet Sunyaev-Zel'dovich
The Sunyaev-Zel'dovich effect: measurement of the distortion of primordial radiation by galaxy clusters

Spécialité

Astrophysique

Niveau d'étude

Bac+5

Formation

Master 2

Unité d'accueil

Candidature avant le

28-02-2018

Durée

4 mois

Poursuite possible en thèse

oui

Contact

IRFAN MELIS
+33 1 69 08 44 63

Résumé/Summary

L'étudiant utilisera les dernières données et techniques d'observation pour produire une carte de l'effet S-Z qui sera utilisée pour vérifier la mesure de la densité de matière dans l'Univers ainsi que sa fluctuation dans le temps.
The student will use the latest observational data and techniques to produce an map of the S-Z effect which will be used to verify the CMB measurement of the matter density within the Universe as well as its fluctuation over time.

Sujet détaillé/Full description

Au cours de leur stage, le stagiaire travaillera sur des cartes astronomiques du CMB et du SZ séparées des émissions galactiques. Cela nécessitera d'apprendre comment interpréter de telles cartes dans l'espace des pixels ainsi que dans le domaine des harmoniques sphériques. Cette analyse mettra à profit des techniques de traitement du signal et des techniques d'optimisation.

L'étudiant développera une compréhension de l'astrophysique au sein de notre galaxie, à la fois des mécanismes d'émissions diffuses et compactes, ainsi que de la cosmologie globale accompagnant la théorie du 'Big Bang' et de l'énergie sombre, modèle standard de l'Univers.
The cosmic microwave background (CMB) is the oldest existing radiation; it was imprinted by the same physical processes which determined the creation, structure and early evolution of the Universe.Measurements of the CMB have enabled the cosmological community to encapsulate their understanding of the Universe simply using six main parameters. Extracting information from the CMB, however, is a more complex affair as certain late-time features, such as galaxies, can distort the CMB signal.
CMB photons which travel through galaxy clusters undergo inverse Compton scattering by the energetic electrons in these hot clusters; this distortion is known as the Sunyaev-Zel'dovich (S-Z) effect.

During the internship, the student will work on astronomical maps of the CMB as seen through the Galaxy, so featuring astrophysical emissions. They will learn how to interpret such maps in pixel space as well as in the spherical harmonic domain. They will utilise signal processing techniques such as sparsity and the wavelet transform and optimisation techniques.

The student will develop an understanding of the astrophysics at play within our Galaxy, both diffuse and compact emission mechanisms, as well as the overall cosmology accompanying the `Big Bang' theory and the dark energy, standard model of the Universe.
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