galpy.df.impulse_deltav_hernquist¶
- galpy.df.impulse_deltav_hernquist(v, y, b, w, GM, rs)[source]¶
NAME:
impulse_deltav_hernquist
PURPOSE:
calculate the delta velocity to due an encounter with a Hernquist sphere in the impulse approximation; allows for arbitrary velocity vectors, but y is input as the position along the stream
INPUT:
v - velocity of the stream (nstar,3)
y - position along the stream (nstar)
b - impact parameter
w - velocity of the Hernquist sphere (3)
GM - mass of the Hernquist sphere (in natural units)
rs - size of the Hernquist sphere
OUTPUT:
deltav (nstar,3)
HISTORY:
2015-08-13 SANDERS, using Wyn Evans calculation