Voronoi tessellation and non-parametric halo concentration

Meagan Lang, Kelly Holley-Bockelmann, Manodeep Sinha

Research output: Contribution to journalArticlepeer-review


We present and test Tessellation-based Recovery of Amorphous halo Concentrations (TesseRACt), a non-parametric technique for recovering the concentration of simulated dark matter halos using Voronoi tessellation. TesseRACt is tested on idealized N-body halos that are axisymmetric, triaxial, or contain substructure and is compared to traditional least-squares fitting as well as to two non-parametric techniques that assume spherical symmetry. TesseRACt recovers halo concentrations within 3% of the true value regardless of whether the halo is spherical, axisymmetric, or triaxial. Traditional fitting and non-parametric techniques that assume spherical symmetry can return concentrations for non-spherical halos that are systematically off by as much as 10% from the true value. TesseRACt also performs significantly better when there is substructure present outside 0.5 R200. Given that cosmological halos are rarely spherical and often contain substructure, we discuss implications for studies of halo concentration in cosmological N-body simulations including how choice of technique for measuring concentration might bias scaling relations.

Original languageEnglish (US)
Article number152
JournalAstrophysical Journal
Issue number2
StatePublished - Oct 1 2015
Externally publishedYes


  • galaxies: fundamental parameters
  • galaxies: halos
  • methods: numerical

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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