 
  
  
   
  Account for selection effects of surveys
   Account for selection effects of surveys 
 
  
       , peak of distribution not seen
 , peak of distribution not seen 
 
  Derive Observable population
   Derive Observable population 
 
  Account for beaming fraction
   Account for beaming fraction 
 
  Total population around 500,000
   Total population around 500,000 

    
 
Figure 19: The observed and derived luminosity functions. From Lyne &
Graham-Smith 1990 [23].