NAME:
oortB
PURPOSE:
calculate the Oort function B
INPUT:
R - radius at which to calculate B (/ro)
OPTIONAL INPUT:
nsigma - number of sigma to integrate the velocities over
KEYWORDS:
romberg - if True, use a romberg integrator (default: False)
OUTPUT:
Oort B at R
HISTORY:
2011-04-19 - Written - Bovy (NYU)
BUGS:
could be made more efficient, e.g., surfacemass is calculated multiple times
