Cosmologie

Measurement of CMB B-mode polarisation with the LiteBIRD satellite mission: development of innovative data analysis techniques.

The Cosmic Microwave Background (CMB) radiation is a relic emission from 380 000 years after the Big-Bang at the time of decoupling between matter and radiation. The small CMB temperature and polarisation fluctuations, induced by quantum perturbation generated in the early Universe, contain precious information about the physics of the primordial Universe and its physical content. Several experiments, including the Planck satellite mission of ESA have measured those perturbations with high accuracy, leading to per cent precision on the determination of cosmological parameters.

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.

Diffuse gas in LSST clusters

Galaxy clusters are the most massive dark matter halos in the Universe. They host galaxies, gas, dust and dark matter.
 
Recently, cluster diffuse gas has provided important information about the feedback activity of their galaxies and gas accretion from filaments.
 
The Legacy Survey of Space and Time (LSST; https://www.lsst.org/about) will detect hundreds of thousands of clusters, which can be used to constraint cosmology and study galaxy evolution.
 

Cosmology with Rayleigh scattering of the CMB

Rayleigh scattering of the Cosmic Microwave Background (CMB) is a less studied yet potentially powerful probe of the recombination history. Scattering of CMB photons off neutral species right after recombination presents a distinctive $\nu^4$ scaling with frequency as well as a strong correlation with the primary CMB. These unique features should facilitate its detection by the next generation of CMB experiments.

SciPol internship

We are proposing a L3 internship to evaluate our ability to characterize instrumental parameters (in particular intensity-to-polarization and cross-polarization effects) within an updated component separation framework. This internship would be part of the global effort undertaken by the SciPol project: https://scipol.in2p3.fr/

Optimisation du système de contrôle et d’acquisition d’une expérience de détection du rayonnement fossile à 10GHz.

Le rayonnement fossile à 3K est la première lumière de l’Univers et a été émis environ 380000 ans après le Big Bang. Il possède un spectre de corps noir avec une température d’environ 2.73K et peut ainsi être observé dans la gamme de longueurs d’onde millimétriques. Le rayonnement fossile fait l’objet d’intenses recherches en cosmologie observationnelle, en particulier au niveau de la polarisation qui renfermerait les traces de l’inflation, une phase d’expansion exponentielle de l’Univers aux tous premiers instants.

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.

Cosmologie