Navarro-Frenk-White profile

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The Navarro-Frenk-White profile or NFW profile is a spatial distribution of dark matter predicted from N-body simulations by Julio Navarro, Carlos Frenk and Simon White.[1] The NFW profile is one of the most commonly used model profiles for dark matter halos.[2]

Contents

[edit] Density distribution

In the profile, the density of dark matter in space is given by:

\rho (r) = \frac{\rho_0}{\frac{r}{R}\left(1~+~\frac{r}{R}\right)^2}

Both ρ0 and R are parameters which vary from halo to halo.[2]

[edit] Dark Matter Simulations

The NFW profile is achieved as the equilibrium configuration of dark matter in simulations of collisionless dark matter particles by numerous groups of scientists.[3] Before the dark matter virializes, the distribution of dark matter is not expected to match an NFW profile, and significant substructure is observed in simulations while halos collapse.

[edit] Observations of Halos

The observations of both the Milky Way and M31 may be compatible with the NFW profile for the dark matter halo.[4]

[edit] References

  1. ^ Navarro, Julio F.; Frenk, Carlos S.; White, Simon D. M. (May 10, 1996). "The Structure of Cold Dark Matter Halos". The Astrophysical Journal 463: 563. doi:10.1086/177173. 
  2. ^ a b Bertone, Gianfranco; Hooper, Dan; Silk, Joseph (January 2005). "Particle dark matter: evidence, candidates and constraints". Physics Reports 405 (5-6): 279–390. doi:10.1016/j.physrep.2004.08.031. 
  3. ^ Y. P. Jing (20 May 2000). "The Density Profile of Equilibrium and Nonequilibrium Dark Matter Halos". The Astrophysical Journal 535 (1): 30–36. doi:10.1086/308809. 
  4. ^ Klypin, Anatoly; Zhao, HongSheng; Somerville, Rachel S. (10 July 2002). "ΛCDM-based Models for the Milky Way and M31. I. Dynamical Models". The Astrophysical Journal 573 (2): 597–613. doi:10.1086/340656.