code: def meanvT(self,R,romberg=False,nsigma=None,phi=0.):
          
          return self._vmomentsurfacemass(R,0,1,romberg=romberg,nsigma=nsigma)\
              /self.surfacemass(R,romberg=romberg,nsigma=nsigma,
                                use_physical=False)
docs: NAME:
  
             meanvT
  
          PURPOSE:
  
             calculate <vT> at R by marginalizing over velocity
  
          INPUT:
  
             R - radius at which to calculate <vT> (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:
  
             <vT> at R
  
          HISTORY:
  
             2011-03-30 - Written - Bovy (NYU)