High-redshift galaxies
Frontiers are always fascinating and full of discoveries. A crucial way to understand galaxy evolution is to find and study the first galaxies whose stars shone when the universe was less than 1-2 Gyrs old. These are the most distant objects we can see in observations carried out for tens of hours by top technology instruments such as the Hubble Space Telescope and ESO Very Large Telescope. And yet these distant galaxies mostly appear as tiny, faint bunches of pixels in our images! I study the primeval galaxies to understand how they evolved and grew in size, how their stars “cleared” the fog of neutral hydrogen that permeated the universe in its early history, how dust and metals formed within them. I am proud of carrrying out these studies as a member of outstanding collaborations gathering colleagues from the whole world: CANDELS, VUDS, VANDELS, Frontier Fields, each one studying the distant universe under a different perspective.
Image analysis algorithms for extragalactic surveys
Astronomers’ laboratory is the universe, where observations are the only experiments we can do. As any observational astronomer I have to spend much time to design, carry out and analyse these experiments. The objects in the sky emit light at many wavelengths, and we have to find the best way to measure this light on observations carried out by different instruments in space or on earth, and to assemble this information in catalogues of sky sources. I am member of important collaborations whose aim is to devise new ways to analyse data from present and future instruments: the ASTRODEEP project, and the “cataloguing” unit OU-MER of the ESA mission EUCLID that in a few years from now will observe a great portion of the sky from space. Also, we need to fight against enemies such as noise and poor resolution that prevents us to mine the information from our “pictures” of the sky: this brought me to explore the fascinating world of mathematics and of the methods for optimizing the resolution and the “depth” of our observations.