Cosmologie

Conception d’ASICs mixtes durcis aux radiations pour observatoires spatiaux

Context : L'usage de grandes matrices de détecteurs pour l'observation astrophysique, du domaine millimétrique aux rayons X, est aujourd'hui incontournable. Associé aux développements de ces matrices de détecteurs fonctionnant à très basse température, le développement d'une lecture spécifique, multiplexée et faible consommation constitue un enjeu majeur pour les futurs observatoires spatiaux.

Constraints on dark energy from eBOSS lyman-alpha data

The discovery of the accelerated expansion of the Universe was a surprise and remains a mystery. Is it due to a yet misunderstood theory of gravity or fueled by the perplexing dark energy? The BOSS/eBOSS survey is a state-of-the-art experimental effort to shed light on the matter. The PhD candidate will work in the context of the BOSS/eBOSS international collaboration. She/he will use lyman-alpha data to extract the highest-redshift most precise measurements of the Hubble expansion rate and the angular diameter distance to constrain the history of the expansion rate.

Theory and observations of the 21cm line at large redshift

Radio astronomy is undergoing a period of rapid advances because of digital techniques that allow an improvement in sensitivity of several orders of magnitude. The universe nearby and the initial conditions of the universe have now been characterized at great precision thanks to modern galaxy surveys and precision measurements of the cosmic microwave background. But the intermediate epoch, sometimes dubbed the “Dark Ages,” remains largely unexplored. However precision measurements using the 21cm line will allow a detailed three-dimensional characterization of this intermediate epoch.

Zodiacal Emission from Planck, COBE, IRAS and other Satellites

Zodiacal Emission is the emission of infrared radiation by heated particles in our Solar System. The full-sky Zodiacal emission was first mapped over the full-sky by the IRAS satellite, but it has now been detected by COBE, Planck, WISE, and Akari, among others. There has, however, never been an analysis which combined all these experiments. In addition, many earlier analyses were done with computers that are much less powerful than those to which we have access today.

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