galpy.potential.LinShuReductionFactor¶
- galpy.potential.LinShuReductionFactor(axiPot, R, sigmar, nonaxiPot=None, k=None, m=None, OmegaP=None)[source]¶
NAME:
LinShuReductionFactor
PURPOSE:
Calculate the Lin & Shu (1966) reduction factor: the reduced linear response of a kinematically-warm stellar disk to a perturbation
INPUT:
axiPot - The background, axisymmetric potential
R - Cylindrical radius (can be Quantity)
sigmar - radial velocity dispersion of the population (can be Quantity)
Then either provide:
m= m in the perturbation’s m x phi (number of arms for a spiral)
k= wavenumber (see Binney & Tremaine 2008)
OmegaP= pattern speed (can be Quantity); note that in the usual Lin-Shu formula omega = m x OmegaP
nonaxiPot= a non-axisymmetric Potential instance (such as SteadyLogSpiralPotential) that has functions that return OmegaP, m, and wavenumber
OUTPUT:
reduction factor
HISTORY:
2014-08-23 - Written - Bovy (IAS)