A Substellar Mass Function for Alpha Per
  We present a deep, wide-field optical survey of the young stellar cluster Alpha Per, in which we have discovered a large population of candidate brown dwarfs. Subsequent infrared photometric follow-up shows that the majority of them are probable or possible members of the cluster, reaching to a minimum mass of 0.035 Msun. We have used this list of members to derive the luminosity and mass functions of the substellar population of the cluster (alpha=0.59+-0.05) and compared its slope to the value measure for the Pleiades. This comparison indicates that the two cluster mass functions are, indeed, very similar. 
David Barrado y Navascues (1), Jerome Bouvier (2), John R. Stauffer   (3), Nicolas Lodieu (4), Mark J. McCaughrean (4) ((1) ...