Elliptical disk potential

Like in Kuijken & Tremaine

class galpy.potential.EllipticalDiskPotential(amp=1.0, phib=0.4363323129985824, p=0.0, twophio=0.01, tform=None, tsteady=None, cp=None, sp=None)

Class that implements the Elliptical disk potential of Kuijken & Tremaine (1994) phi(R,phi) = phio (R/Ro)^p cos[2(phi-phib)]

__init__(amp=1.0, phib=0.4363323129985824, p=0.0, twophio=0.01, tform=None, tsteady=None, cp=None, sp=None)

NAME:

__init__

PURPOSE:

initialize an Elliptical disk potential

phi(R,phi) = phio (R/Ro)^p cos[2(phi-phib)]

INPUT:

amp= amplitude to be applied to the potential (default: 1.), see twophio below

tform= start of growth (to smoothly grow this potential

tsteady= time delay at which the perturbation is fully grown (default: 2.)

p= power-law index of the phi(R) = (R/Ro)^p part

Either:

1. phib= angle (in rad; default=25 degree)

   twophio= potential perturbation (in terms of 2phio/vo^2 if vo=1 at Ro=1)

2. cp, sp= twophio * cos(2phib), twophio * sin(2phib)

OUTPUT:

(none)

HISTORY:

2011-10-19 - Started - Bovy (IAS)