def mass_tot(self, rho0, Ra, Rs):
        """
        total mass within the profile
        :param rho0:
        :param Ra:
        :param Rs:
        :return:
        """
        Ra, Rs = self._sort_ra_rs(Ra, Rs)
        sigma0 = self.rho2sigma(rho0, Ra, Rs)
        m_tot = 2 * np.pi * sigma0 * Ra * Rs
        return m_tot