Double power-law density spherical potential¶

class galpy.potential.TwoPowerSphericalPotential(amp=1.0, a=5.0, alpha=1.5, beta=3.5, normalize=False, ro=None, vo=None)[source]¶

Class that implements spherical potentials that are derived from two-power density models

\[\rho(r) = \frac{\mathrm{amp}}{4\,\pi\,a^3}\,\frac{1}{(r/a)^\alpha\,(1+r/a)^{\beta-\alpha}}\]

__init__(amp=1.0, a=5.0, alpha=1.5, beta=3.5, normalize=False, ro=None, vo=None)[source]¶

Initialize a two-power-density 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.
alpha (float, optional) – Inner power.
beta (float, optional) – Outer power.
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.
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