Brown dwarfs in the pleiades - A deep IJK survey

An area large enough ( 180 arcmin(2)) to put constraints on a possible low mass brown dwarf population in the Pleiades has been surveyed to very faint magnitudes in I, J and K. The completeness limit, I=21.6, corresponds to a mass of 0.01 M. for a cluster age of 70 Myr and 0.035 M. for 120 Myr. The result is consistent with previous investigations at higher masses that the brown dwarf initial mass function is a m(-1), or even less steep, power law. Thus low mass brown dwarfs cannot contribute significantly to the Pleiades' mass. One new possible Pleiades member was found, mass similar to 0.08 M. (age 120Myr).