NFW potential

class galpy.potential.NFWPotential(amp=1.0, a=1.0, normalize=False, conc=None, mvir=None, vo=220.0, ro=8.0, H=70.0, Om=0.3, overdens=200.0, wrtcrit=False)

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, conc=None, mvir=None, vo=220.0, ro=8.0, H=70.0, Om=0.3, overdens=200.0, wrtcrit=False)

NAME:

__init__

PURPOSE:

Initialize a NFW potential

INPUT:

amp - amplitude to be applied to the potential

a - “scale” (in terms of Ro)

normalize - 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.

Alternatively, NFW potentials can be initialized using

conc= concentration

mvir= virial mass in 10^12 Msolar

in which case you also need to supply the following keywords

vo= (220.) velocity unit in km/s

ro= (8.) length unit in kpc

H= (default: 70) Hubble constant in km/s/Mpc

Om= (default: 0.3) Omega matter

overdens= (200) overdensity which defines the virial radius

wrtcrit= (False) if True, the overdensity is wrt the critical density rather than the mean matter density

OUTPUT:

(none)

HISTORY:

2010-07-09 - Written - Bovy (NYU)

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