The Mass Function of Void Groups as a Probe of the Primordial   non-Gaussianity
  The primordial non-Gaussianity signal, if measured accurately, will allow us to distinguish between different candidate models for the cosmic inflation. Since the galaxy groups located in void regions are rare events, their abundance may be a sensitive probe of the primordial non-Gaussianity. We construct an analytic model for the mass function of void groups in the framework of the extended Press-Schechter theory with non-Gaussian initial conditions and investigate how it depends on the primordial non-Gaussianity parameter. A feasibility study is conducted by fitting the analytic mass function of void groups to the observational results from the galaxy group catalog of the Sloan Digital Sky Survey Data Release 4 with adjusting the primordial non-Gaussianity parameter. 
Hyunmi Song, Jounghun Lee (Seoul Nat'l Univ.)