Sérsic profile partially coincident with Einasto profile
Generalizations of the Sérsic profile
The brightest elliptical galaxies often have low-density cores that are not well described by Sérsic's law.  The core-Sérsic family of models was introduced
 to describe such galaxies.  Core-Sérsic models have an additional set of parameters that describe the core. 
Dwarf elliptical galaxies and bulges often have point-like nuclei that are also not well described by Sérsic's law. These galaxies are often fit by a Sérsic model with an added central component representing the nucleus.
The Einasto profile is mathematically identical to the Sérsic profile, except that 
  
    
      
        I
      
    
    {\displaystyle I}
   is replaced by 
  
    
      
        ρ
      
    
    {\displaystyle \rho }
  , the volume density, and 
  
    
      
        R
      
    
    {\displaystyle R}
   is replaced by 
  
    
      
        r
      
    
    {\displaystyle r}
  , the internal (not projected on the sky) distance from the center.
partially overlapping with partially intersecting with partially sharing with partially matching with partially aligning with