galpy.util.coords.galcenrect_to_vxvyvz

galpy.util.coords.galcenrect_to_vxvyvz(vXg, vYg, vZg, vsun=[0.0, 1.0, 0.0], Xsun=1.0, Zsun=0.0, _extra_rot=True)[source]

NAME:

galcenrect_to_vxvyvz

PURPOSE:

transform rectangular Galactocentric coordinates to XYZ coordinates (wrt Sun) for velocities

INPUT:

vXg - Galactocentric x-velocity

vYg - Galactocentric y-velocity

vZg - Galactocentric z-velocity

vsun - velocity of the sun in the GC frame ndarray[3] (can be array of same length as vXg; shape [3,N])

Xsun - cylindrical distance to the GC (can be array of same length as vXg)

Zsun - Sun’s height above the midplane (can be array of same length as vXg)

_extra_rot= (True) if True, perform an extra tiny rotation to align the Galactocentric coordinate frame with astropy’s definition

OUTPUT:

[:,3]= vx, vy, vz

HISTORY:

2011-02-24 - Written - Bovy (NYU)

2016-05-12 - Edited to properly take into account the Sun’s vertical position; dropped Ysun keyword - Bovy (UofT)

2017-10-24 - Allowed vsun/Xsun/Zsun to be arrays - Bovy (UofT)

2018-04-18 - Tweaked to be consistent with astropy’s Galactocentric frame - Bovy (UofT)