code: def cBurkPot(self, R, Rs, rho0, r_core):
  
          
          x = R * Rs ** -1
          p = Rs * r_core ** -1
          hx = self._H(x, p)
  
          return 2 * rho0 * Rs ** 3 * hx
docs: :param R: projected distance
          :param Rs: scale radius
          :param rho0: central core density
          :param r_core: core radius