Abstract

I will present some results of our wide field survey brown dwarf search. Brown dwarfs are in many ways the link between stars and planets and their atmospheres, dominated by broad molecular absorption bands, are closer to planetary atmospheres than to stellar one. We are looking for ultracool brown dwarfs, whose effective temperature is below 700K, using Wircam and MegaCam cameras on the CFHT telescope. Brown dwarfs stands out among the millions of sources on the images because of their extremely red colours. Our objectives are to constrain ultracool atmosphere physics by finding a large sample of cool objects and to put the first constraints on the ultracool brown dwarf mass function.

After a general introduction to brown dwarfs and wide fields surveys, I will describe our brown dwarfs selection techniques and present the spectra of some of the coolest brown dwarfs known to science.