Likelihood Methods for Cluster Dark Energy Surveys
  Galaxy cluster counts at high redshift, binned into spatial pixels and binned into ranges in an observable proxy for mass, contain a wealth of information on both the dark energy equation of state and the mass selection function required to extract it. The likelihood of the number counts follows a Poisson distribution whose mean fluctuates with the large-scale structure of the universe. We develop a joint likelihood method that accounts for these distributions. Maximization of the likelihood over a theoretical model that includes both the cosmology and the observable-mass relations allows for a joint extraction of dark energy and cluster structural parameters. 
Wayne Hu, J.D. Cohn