Cosmologie

CMB Foreground Studies

Measurements of the Cosmic Microwave Background (CMB) have transformed cosmology into a precision science, and they continue to deliver new insights into the birth and evolution of our Universe. One of the major hurdles in extracting these insights, however, come from "foreground" signals emitted from intervening matter. These spurious emissions can mask and even mimic the primordial CMB, introducing errors into our conclusions.

Pipeline development for next-generation Cosmic Microwave Background observations

The Cosmic Microwave Background (CMB), relic radiation from the hot Big-Bang, carries a wealth of information about physical processes at work in the very early universe, at energies far beyond the reach of man-made particle accelerators. Next generation observatories are poised to further constrain physics beyond the Standard Model of particles and fields, the nature of Dark Matter and Dark Energy, the existence of primordial Gravitational Waves, and the formation of structures. 
 

Scientific exploitation of CMB polarization observation data with the Simons Observatory, CMB-S4 and LiteBIRD

Context. One of the main questions in modern physics concerns the origin of the Universe and the mechanisms at work in the very first moments after the Big Bang. Thanks to the considerable progress made over the past decade, largely driven by the European-led Planck satellite, the stage is set to begin to address this question formally and precisely. In this context, the most promising observational probe is the cosmic microwave background (CMB) and in particular its polarization.

Antenna coupled Kinetic Inductance Detectors for the observation of the Cosmic Microwave Background polarisation

The study of the cold Universe allows us to go back to the origins of our solar system by observing the embryos of stars, or to the origins of the Universe by measuring the polarisation of the Cosmic Microwave Background (CMB). These sub-millimetre and millimetre instruments require the use of superconducting detectors cooled down to 100mK. Kinetic Inductance Detectors (KIDs) are based on superconducting resonators and are about to replace bolometers thanks to their natural frequency multiplexing and ease of production (in their basic form). 

Accelerating Bayesian inference for cosmological pipelines

Summary

The proposed thesis aims to develop and apply a probabilistic programming language written in JAX and using SPMD parallelism on GPUs to scale Bayesian inference tasks on large cosmological datasets. This language has no equivalent on the market and will be a major asset for the scientific community. The thesis will require the development of low-level code and will be led collaboratively following the open-source philosophy.

Modélisation instrumentale, calibration et exploitation des données d’observation de la polarisation du CMB avec le Simons Observatory, dans le cadre du projet européen SciPol (H/F)

Contexte. L'une des principales questions de la cosmologie et de la physique modernes concerne l'origine de l'Univers tel que nous le connaissons aujourd'hui. Grâce aux progrès considérables réalisés au cours de la dernière décennie, en grande partie sous l'impulsion du satellite Planck dirigé par l'Europe, le décor est planté pour commencer à aborder cette question de manière formelle et précise.

Twisting of galaxy orientations and the intrinsic alignment of galaxies

The majority of galaxies appear to be elliptical when projected on the sky. Observations have shown that the shapes of these galaxies align with the tidal matter density field within which they are formed. Therefore the observation of the alignment of galaxies may provide information on this underlying tidal matter density field.
Cosmologie