Cosmologie

Inflationary non-Gaussianities in the CMB and large-scale structure

Inflation is an important theory of the primordial universe that explains amongst other things the origin of the fluctuations observed in the cosmic microwave background (CMB) and of the large-scale structure of the galaxy distribution. However, there are many different inflation models and one of the challenges of modern cosmology is to find ways to distinguish these models at the level of their predictions for observables, in order to confront them with experimental data.

Galaxy evolution in cluster and proto-clusters at z>1.5

One of the major challenges in the field of galaxy formation and evolution is to understand how early-type galaxy (ETG) star formation is quenched in the first epoch of their assembly. At present, deep space
imaging and spectroscopy observations give us the opportunity to answer this question as never before.

Cosmology dependence on the covariance of galaxy clusters in Rubin/LSST

The covariance of galaxy clusters is an important element when constraining cosmology with galaxy clusters. However its computation is costly in computational resources, especially when it depends on cosmology. We propose an evaluation of the impact on the cosmological parameters when the modeling of the cluster covariance is simplified. This is one of the projects for the preparation of the LSST-DESC cluster cosmology framework.

Dection of the Global 21cm Signal With REACH

The 21 cm HI transition offers a window onto the reionization history of the universe and the formation of the first generation of stars and quasars, when the universe was still metal poor. The global 21 cm signal consists of the non-Galactic distortion of the CMB blackbody radiation through absorption or emission by HI (atomic hydrogen) depending on whether the HI spin temperature is less or greater than the CMB temperature. Recently the EDGES experiment has detected a large signal that appears incompatible with existing theoretical models.
Cosmologie