I am a CNRS cosmologist, working at IPAG. Cosmology is that field of physics whose object is the Universe as a whole, its composition, structure and dynamics on large scales, rather than the details of specific objects such as e.g. planets or stars.

There are many ways to do Cosmology, whether you are a more a theoretician, an observer or an instrumentalist, to make it short. I don't like restrictive definitions in general, and I know very few colleagues who would strictly belong to a single one of these categories. As far as I'm concerned, I am "more" an observer, i. e. I "more often" use instruments to collect my own data, but I work in close collaboration with instrumentalists to design and characterize these instruments, in lab and on the observation site. I develop tools to analyze these data, often refered to as "pipelines", because they go all the way from raw instrumental data to final astronomical products, be it maps or e.g. angular power spectra.

Among the many objects you might study in Cosmology (e.g. distant Super Novae, galaxy clusters, old distant galaxies, etc.), over the past years, my main the one I have most studied is the Cosmic Microwave Background (CMB), a.k.a. the 3K fossile radiation. It is the photon bath in which we are immerged, the first light to ever travel over significant distances, a direct relic from the earliest times of the Universe. It is imprinted by the physics of the Big Bang and is a gold mine of information. I also work on galaxy clusters and on the Cosmic Infrared Background, the integrated emission of all distant galaxies. More details may be found in the Research section of this webpage.