galpy.df.diskdf.sigma2¶
- diskdf.sigma2(R, romberg=False, nsigma=None, phi=0.0)[source]¶
NAME:
sigma2
PURPOSE:
calculate sigma_R^2 at R by marginalizing over velocity
INPUT:
R - radius at which to calculate sigma_R^2 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 at R
HISTORY:
2010-03-XX - Written - Bovy (NYU)