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 _ { \odot } .
We have used this list of members to derive the luminosity and mass functions of the substellar population of the cluster ( \alpha =0.59 \pm 0.05 , when expressed in the mass spectrum form \phi \propto 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 .