galpy.potential.Potential.phi2deriv

Potential.phi2deriv(R, z, phi=0.0, t=0.0)[source]

NAME:

phi2deriv

PURPOSE:

evaluate the second azimuthal derivative

INPUT:

R - Galactocentric radius (can be Quantity)

Z - vertical height (can be Quantity)

phi - Galactocentric azimuth (can be Quantity)

t - time (can be Quantity)

OUTPUT:

d2Phi/dphi2

HISTORY:

2013-09-24 - Written - Bovy (IAS)