Balmer decrement versus velocity. First two panels – the inner radius is the same, but different positions of the Hα and Hβ disk with respect to the black hole are assumed. The bottom panel shows the cases where the one of the two emitting regions is closer to the central black hole. The inner and outer radii assumed in models are labeled in each panel. The BD points are normalized to the one at  − 4000 km s^-1.