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_⊙. We have used this list of members to derive the luminosity and mass functions of the substellar population of the cluster (α = 0.59 ± 0.05, when expressed in the mass spectrum form ø ∝ M^(-α)) and compared its slope to the value measure for the Pleiades. This comparison indicates that the two cluster mass functions are, indeed, very similar.