galpy.df.evolveddiskdf.sigmaRT¶

evolveddiskdf.
sigmaRT
(R, t=0.0, nsigma=None, deg=False, epsrel=0.01, epsabs=1e05, phi=0.0, grid=None, gridpoints=101, returnGrid=False, surfacemass=None, meanvR=None, meanvT=None, hierarchgrid=False, nlevels=2, integrate_method='dopr54_c')[source]¶ NAME:
sigmaRTPURPOSE:
calculate the radialtangential covariance of the velocity distribution at (R,phi)INPUT:
R  radius at which to calculate the moment (can be Quantity)
phi= azimuth (rad unless deg=True; can be Quantity)
t= time at which to evaluate the DF (can be a list or ndarray; if this is the case, list needs to be in descending order and equally spaced) (can be Quantity)
surfacemass, meanvR, meavT= if set use this precalculated surfacemass and mean vR and vT
nsigma  number of sigma to integrate the velocities over (based on an estimate, so be generous)
deg= azimuth is in degree (default=False); do not set this when giving phi as a Quantity
epsrel, epsabs  scipy.integrate keywords (the integration calculates the ration of this vmoment to that of the initial DF)
grid= if set to True, build a grid and use that to evaluate integrals; if set to a gridobjects (such as returned by this procedure), use this grid
gridpoints= number of points to use for the grid in 1D (default=101)
returnGrid= if True, return the grid object (default=False)
hierarchgrid= if True, use a hierarchical grid (default=False)
nlevels= number of hierarchical levels for the hierarchical grid
integrate_method= orbit.integrate method argument
OUTPUT:
covariance of vR and vTHISTORY:
20110331  Written  Bovy (NYU)