NFW potential

class galpy.potential.NFWPotential(amp=1.0, a=1.0, normalize=False, rmax=None, vmax=None, conc=None, mvir=None, vo=None, ro=None, H=70.0, Om=0.3, overdens=200.0, wrtcrit=False)[source]

Class that implements the NFW potential

\[\rho(r) = \frac{\mathrm{amp}}{4\,\pi\,a^3}\,\frac{1}{(r/a)\,(1+r/a)^{2}}\]
__init__(amp=1.0, a=1.0, normalize=False, rmax=None, vmax=None, conc=None, mvir=None, vo=None, ro=None, H=70.0, Om=0.3, overdens=200.0, wrtcrit=False)[source]

Initialize a NFW Potential.

Parameters:

  • amp (float or Quantity, optional) – Amplitude to be applied to the potential (default: 1); can be a Quantity with units of mass or Gxmass.

  • a (float or Quantity, optional) – Scale radius (can be Quantity).

  • normalize (bool or float, optional) – If True, normalize such that vc(1.,0.)=1., or, if given as a number, such that the force is this fraction of the force necessary to make vc(1.,0.)=1.

  • rmax (float or Quantity, optional) – Radius where the rotation curve peak.

  • vmax (float or Quantity, optional) – Maximum circular velocity.

  • conc (float, optional) – Concentration.

  • mvir (float, optional) – virial mass in 10^12 Msolar

  • H (float, optional) – Hubble constant in km/s/Mpc.

  • Om (float, optional) – Omega matter.

  • overdens (float, optional) – Overdensity which defines the virial radius.

  • wrtcrit (bool, optional) – If True, the overdensity is wrt the critical density rather than the mean matter density.

  • ro (float or Quantity, optional) – Distance scale for translation into internal units (default from configuration file).

  • vo (float or Quantity, optional) – Velocity scale for translation into internal units (default from configuration file).

Notes

  • Initialize with one of:

    • a and amp or normalize

    • rmax and vmax

    • conc, mvir, H, Om, overdens, wrtcrit

  • 2010-07-09 - Written - Bovy (NYU)

  • 2014-04-03 - Initialization w/ concentration and mass - Bovy (IAS)

  • 2020-04-29 - Initialization w/ rmax and vmax - Bovy (UofT)