A Concise Reference to (Projected) Sérsic R 1/ n Quantities, Including Concentration, Profile Slopes, Petrosian Indices, and Kron Magnitudes

Abstract Given the growing use of Sérsic's (1963, 1968) R 1/ n model for describing the stellar distributions in galaxies, and the lack of any single reference that provides the various associated mathematical expressions, we have endeavoured to compile such a resource here. We present the standard intensity profile, and its various guises such as the luminosity, surface-brightness, and aperture–magnitude profile. Expressions to transform the effective surface brightness into the mean effective and central surface brightness are also given, as is the expression to transform between effective radii and exponential scale-lengths. We additionally provide expressions for deriving the ‘concentration’ of an R 1/ n…