Dehnen-like smoothing wrapper potential¶
- class galpy.potential.DehnenSmoothWrapperPotential(*args, **kwargs)[source]¶
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)[source]¶
Initialize a DehnenSmoothWrapper Potential.
- Parameters:
amp (float, optional) – Amplitude to be applied to the potential (default: 1.).
pot (Potential instance or list thereof, optional) – The amplitude of this will be grown by this wrapper.
tform (float or Quantity, optional) – Start of growth (default: -4.0).
tsteady (float or Quantity, optional) – Time from tform at which the potential is fully grown (default: -tform/2, so the perturbation is fully grown at tform/2).
decay (bool, optional) – If True, decay the amplitude instead of growing it (as 1-grow).
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
2017-06-26 - Started - Bovy (UofT)
2018-10-07 - Added ‘decay’ option - Bovy (UofT)