# Dehnen-like smoothing wrapper potential¶

class galpy.potential.DehnenSmoothWrapperPotential(amp=1.0, pot=None, tform=-4.0, tsteady=None, decay=False, ro=None, vo=None)

Potential wrapper class that implements the growth of a gravitational potential following Dehnen (2000). The amplitude A applied to a potential wrapped by an instance of this class is changed as

$A(t) = amp\,\left(\frac{3}{16}\xi^5-\frac{5}{8}\xi^3+\frac{15}{16}\xi+\frac{1}{2}\right)$

where

$\begin{split}\xi = \begin{cases} -1 & t < t_\mathrm{form}\\ 2\left(\frac{t-t_\mathrm{form}}{t_\mathrm{steady}}\right)-1\,, & t_\mathrm{form} \leq t \leq t_\mathrm{form}+t_\mathrm{steady}\\ 1 & t > t_\mathrm{form}+t_\mathrm{steady} \end{cases}\end{split}$

if decay=True, the amplitude decays rather than grows as decay = 1 - grow.

__init__(amp=1.0, pot=None, tform=-4.0, tsteady=None, decay=False, ro=None, vo=None)

NAME:

__init__

PURPOSE:

initialize a DehnenSmoothWrapper Potential

INPUT:

amp - amplitude to be applied to the potential (default: 1.)

pot - Potential instance or list thereof; the amplitude of this will be grown by this wrapper

tform - start of growth (can be a Quantity)

tsteady - time from tform at which the potential is fully grown (default: -tform/2, st the perturbation is fully grown at tform/2; can be a Quantity)

decay= (False) if True, decay the amplitude instead of growing it (as 1-grow)

OUTPUT:

(none)

HISTORY:

2017-06-26 - Started - Bovy (UofT)

2018-10-07 - Added ‘decay’ option - Bovy (UofT)