A Concise Reference to (Projected) Sérsic R1/n Quantities, Including Concentration, Profile Slopes, Petrosian Indices, and Kron Magnitudes

A Graham, Simon Peter Driver

Research output: Contribution to journalArticlepeer-review

492 Citations (Scopus)

Abstract

Given the growing use of Sersic'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 profile, and two useful equations for the logarithmic slope of the light-profile are given. Petrosian radii and fluxes are also derived for a range of Sersic profiles and compared with the effective radii and total flux. Similarly, expressions to obtain Kron radii and fluxes are presented as a function of the Sersic index n and the number of effective radii sampled. Illustrative figures are provided throughout. Finally, the core-Sersic model, consisting of an inner power-law and an outer Sersic function, is presented.

Original languageEnglish
Pages (from-to)118-127
JournalPublications of the Astronomical Society of Australia
Volume22
Issue number2
DOIs
Publication statusPublished - Jan 2005

Keywords

  • galaxies : structure
  • galaxies : fundamental parameters
  • methods : analytical
  • methods : data analysis
  • EARLY-TYPE GALAXIES
  • DWARF-ELLIPTIC GALAXIES
  • SURFACE BRIGHTNESS GALAXIES
  • SUPERMASSIVE BLACK-HOLES
  • ON SPIRAL GALAXIES
  • FUNDAMENTAL PLANE
  • DISK GALAXIES
  • GALACTIC DISKS
  • PRELIMINARY CLASSIFICATION
  • LUMINOSITY DISTRIBUTION

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