Surface brightness profile for NGC 3348 (dots), with Sersic fit (dashed) and core-Sersic fit (solid). [Figure 11 from Graham & Driver 2005 o-link].
The equation for the core-Sersic profile is:
Where Rb is the break radius between the inner power law (log slope of 
) and the outer Sersic profile. The sharpness of the break is set by 
, and the brightness Ib at Rb can be evaluated from:
