Cosmologie

Réfrigérateur à dilution sans fluide en circulation

L’étude de l’Univers froid nous permet de remonter aux origines, que ce soit celles de notre système solaire avec l’observation des embryons d’étoiles ou celles de l’Univers avec la mesure de la polarisation du rayonnement fossile. Ces instruments d’observations dans les domaines sub-millimétrique et millimétrique nécessitent l’utilisation de détecteurs supraconducteurs refroidis jusqu’à 100mK. Ceci rend ces expériences particulièrement complexes à mettre en oeuvre, en particulier au niveau système.

Probing dark energy with multi-survey joint analyses: shear measurement with machine learning.

During the last decade, cosmology has entered a precision era, leading to the prevalence of the standard cosmological model, ΛCDM. Nevertheless, the main ingredient of this model, dark energy, while dominating the energy budget of the Universe, remains mysterious and its comprehension is the current Graal of the domain. The next generation of cosmological surveys, among which Large Synoptic Survey Telescope (LSST) & Euclid, both starting in 2022, are a major step toward in observational cosmology toward the parametrization of dark energy.

Cosmic Microwave Background Observations for Large-Scale Structure Studies

The Planck mission and the current generation of ground-based cosmic microwave background (CMB) experiments (e.g., the Atacama Cosmology Telescope and the South Pole Telescope) have ushered in a new era of large-scale structure (LSS) studies. With arcminute resolution at frequencies around 100 GHz, CMB observatories probe the distribution of ionized gas in the circumgalactic medium (CGM) and the intergalactic medium (IGM) through the Sunyaev-Zeldovich (SZ) effects, the total mass distribution through gravitational lensing of the CMB and dust emission associated with

Détecteurs multi-fréquences pour l’observation de la polarisation du rayonnement fossile

L’étude des fluctuations polarisées du rayonnement fossile à 3K (Cosmic Microwave Background, CMB) apparaît aujourd’hui comme une voie incontournable pour progresser dans notre compréhension de l’Univers. Après Planck, la communauté européenne s’implique actuellement dans la petite mission spatiale japonaise LiteBird. Des études sont également en cours en préparation d’une grande mission spatiale dédiée à la caractérisation complète de la polarisation du ciel sub-millimétrique et millimétrique en vue de l’appel d’offre ESA M6 ou d’une collaboration avec l’Inde. 

Cosmic Microwave Background Observations for Large-Scale Structure Studies

The Planck mission and the current generation of ground-based cosmic microwave background (CMB) experiments (e.g., the Atacama Cosmology Telescope and the South Pole Telescope) have ushered in a new era of large-scale structure (LSS) studies. With arcminute resolution at frequencies around 100 GHz, CMB observatories probe the distribution of ionized gas in the circumgalactic medium (CGM) and the intergalactic medium (IGM) through the Sunyaev-Zeldovich (SZ) effects, the total mass distribution through gravitational lensing of the CMB and dust emission associated with

Probing the Universe’s beginning and testing fundamental physics with Simons Array and Simons Observatory cosmic microwave background polarization data sets.

Context. One of the main questions of modern cosmology and physics concerns the origin of the Universe, its structure and its evolution, as we observe today. Thanks to the tremendous progress made in the last decade, in big part driven by the Europe-led satellite mission Planck, the stage has been set to start addressing this kind of questions for the first time in a meaningful way.

Cosmologie