Joint 2D posterior distributions of c₂₀₀ and M₅₀₀ (panel a)), M_E and M₅₀₀ (panel b)), c₂₀₀ and r_s (panel c)), and r_E and θ (panel d)). Contours are at the 68% and 95% levels. Filled green contours show constraints from strong lensing alone and red contours show the constraints when is included as an independent constraint. Crosses show the corresponding maximum likelihood estimates.