galpy.df.diskdf.sigma2surfacemass¶

diskdf.sigma2surfacemass(R, romberg=False, nsigma=None, relative=False)[source]¶

NAME:

sigma2surfacemass

PURPOSE:

calculate the product sigma_R^2 x surface-mass at R by marginalizing over velocity

INPUT:

R - radius at which to calculate the sigma_R^2 x surfacemass density (can be Quantity)

OPTIONAL INPUT:

nsigma - number of sigma to integrate the velocities over

KEYWORDS:

romberg - if True, use a romberg integrator (default: False)

OUTPUT:

sigma_R^2 x surface-mass at R

HISTORY:

2010-03-XX - Written - Bovy (NYU)