NAME:
U
PURPOSE:
return Heliocentric Galactic rectangular x-velocity (aka “U”)
INPUT:
t - (optional) time at which to get U
- obs=[X,Y,Z,vx,vy,vz] - (optional) position and velocity of observer
- (in kpc and km/s) (default=[8.5,0.,0.,0.,235.,0.]) OR Orbit object that corresponds to the orbit of the observer
ro= distance in kpc corresponding to R=1. (default: 8.5)
vo= velocity in km/s corresponding to v=1. (default: 235.)
OUTPUT:
U(t)
HISTORY:
2011-02-24 - Written - Bovy (NYU)
