galpy.potential.evaluatePotentials¶

Warning

galpy potentials do not necessarily approach zero at infinity. To compute, for example, the escape velocity or whether or not an orbit is unbound, you need to take into account the value of the potential at infinity. E.g., $$v_{\mathrm{esc}}(r) = \sqrt{2[\Phi(\infty)-\Phi(r)]}$$.

galpy.potential.evaluatePotentials(Pot, R, z, phi=None, t=0.0, dR=0, dphi=0)[source]

NAME:

evaluatePotentials

PURPOSE:

convenience function to evaluate a possible sum of potentials

INPUT:

Pot - potential or list of potentials (dissipative forces in such a list are ignored)

R - cylindrical Galactocentric distance (can be Quantity)

z - distance above the plane (can be Quantity)

phi - azimuth (can be Quantity)

t - time (can be Quantity)

dR= dphi=, if set to non-zero integers, return the dR, dphi’t derivative instead

OUTPUT:

Phi(R,z)

HISTORY:

2010-04-16 - Written - Bovy (NYU)