Constraints onH0from the Central Velocity Dispersions of Lens Galaxies

We employ Schwarzschild's method of the orbit modeling to constrain the mass profiles of the central lens galaxies in Q0957+561 and PG 1115+080. We combine the measured, central projected stellar velocity dispersions of these galaxies with the self-similar radial profiles of the rms velocity and of the Gauss-Hermite moment h 4 observed in nearby galaxies for 0 ≲ R ≲ 2 R eff . For Q0957+561, we find a 16% uncertainty in the galaxy mass and formal 2 σ limits on the Hubble constant of H 0 =61 km s -1 Mpc -1 . For PG 1115+080, we find that none of the viable lens models can be ruled out, so that H 0 is not yet strongly constrained by this system.