The two absorbers τ(wind) and τ(clump) used in the modeling in Sect. 4 (solid lines) where τ(clump) corresponds in cone geometry to jet opening angle 20 deg and wind velocity 2000 km s^-1. The dashed line has opening angle 20 deg and smaller 1000 km s^-1 wind velocity. The two almost coincident dotted lines correspond to a wide cone (40 deg, 2000 km s^-1) and a tube (see the text in Sect. 3).