A substellar mass function for Alpha Persei

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 M-circle dot. 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, when expressed in the mass spectrum form phi proportional to M-alpha) and compared its slope to the value measure for the Pleiades. This comparison indicates that the two cluster mass functions are, indeed, very similar.