David Valls-Gabaud
CNRS, Observatoire de Paris, France

Abstract
The S-class MESSIER satellite has been designed to explore the extremely low surface brightness universe at UV and optical wavelengths. The two driving science cases target the mildly- and highly non-linear regimes of structure formation to test two key predictions of the LCDM scenario: (1) the detection of the putative large number of galaxy satellites, and (2) the identification of the filaments of the cosmic web. The science requirements imply challenging instrumentation issues which have only recently been solved. The satellite will drift scan the entire sky in 6 bands covering the 200-1000 nm wavelength range to reach the unprecedented surface brightness levels of 34 mag/arcsec^2 in the optical and 37mag/arcsec^2 in the UV. As usual when uncovering new volumes in parameter space, many important secondary science cases will also result as free by-products and will be discussed in some detail: the actual luminosity function of galaxies, the contribution and role of intracluster light, the fluctuations of the cosmological background radiation at UV and optical wavelengths, the warm molecular hydrogen content of galaxies at z=0.25, time-domain studies of supernovae and tidal disruption events, the chemical enrichment of the interstellar medium through mass loss of red giant stars and the accurate measure of the BAO scale at z=0.7 with over 30 million galaxies detected in Lyman-alpha at this redshift. It will provide the first space-based reference UV-optical photometric catalogue of the entire sky, and synergies with GAIA, EUCLID, LSST and WFIRST will also be discussed.

2019 February 05, 15:00

IA/U.Lisboa
Observatório Astronómico de Lisboa (Seminar room)
Tapada da Ajuda, 1349-018 Lisboa