code: def targetSigma2(self,R,log=False):
          
          return self._surfaceSigmaProfile.sigma2(R,log=log)
docs: NAME:
  
             targetSigma2
  
          PURPOSE:
  
             evaluate the target Sigma_R^2(R)
  
          INPUT:
  
              R - radius at which to evaluate (can be Quantity)
  
          OUTPUT:
  
             target Sigma_R^2(R)
  
             log - if True, return the log (default: False)
  
          HISTORY:
  
             2010-03-28 - Written - Bovy (NYU)