Position-velocity diagrams of the [N II] λ6583 line for pseudo-slits along the gas filaments W1 and W2 identified in Fig. 2. The x-axis zero position of each filament corresponds to the black cross in Fig. 2. The three curves are the expected disk rotation velocities with the parameters described in Sect. 7.1 and Fig. 2, with colors as listed in the insert. At offsets beyond 10″, the velocities of both filaments are best fit with the i = 25° model. This figure is discussed in Sect. 7.1 but placed here for easy comparison with Fig. 2.