Dark energy studies with the Vera Rubin observatory LSST & Euclid-developing a combined cosmic shear analysis with bayesian neural networks

Project Summary

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, remains mysterious while dominating the energy budget of the Universe. Its comprehension is the current Graal of this domain. The next generation of cosmological surveys, among which Legacy Survey of Space and Time (LSST) of the Vera Rubin Observatory (on the ground) & Euclid (in space), both starting their data taking in 2023, are in that regard the most important projects for the next 10 years.

These surveys, when combined, will map thousands of square degrees of sky in a multiwavelength manner with sub-arcsec resolution. This will result in the detection of several tens of billions of sources, enabling a wide range of astrophysical investigations and providing unprecedented constraints on the nature of dark energy and dark matter. The scope of the PhD topic is at the crossing of the two surveys. More precisely, the PhD topic discussed here is focused on developing analyses for weak gravitational lensing combining the data of LSST and Euclid.

If successful, the implications of this work could drastically reduce the bias on cosmic shear measurements and release an essential tool for observational cosmology to the community. Not to mention that LSST commissioning data will become available for science in 2023, during the PhD thesis, making these studies all the more interesting as the scientific environment will be extremely dynamic and competitive.

LABORATOIRE | ASTROPARTICULE & COSMOLOGIE (u-paris.fr)