# Spherical Shell Potential¶

class galpy.potential.SphericalShellPotential(amp=1.0, a=0.75, normalize=False, ro=None, vo=None)[source]

Class that implements the potential of an infinitesimally-thin, spherical shell

$\rho(r) = \frac{\mathrm{amp}}{4\pi\,a^2}\,\delta(r-a)$

with $$\mathrm{amp} = GM$$ the mass of the shell.

__init__(amp=1.0, a=0.75, normalize=False, ro=None, vo=None)[source]

NAME:

__init__

PURPOSE:

initialize a spherical shell potential

INPUT:

amp - mass of the shell (default: 1); can be a Quantity with units of mass or Gxmass

a= (0.75) radius of the shell (can be Quantity)

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.; note that because the force is always zero at r < a, this does not work if a > 1

ro=, vo= distance and velocity scales for translation into internal units (default from configuration file)

OUTPUT:

(none)

HISTORY:

2018-08-04 - Written - Bovy (UofT)

2020-03-30 - Re-implemented using SphericalPotential - Bovy (UofT)