1999A&A...351..669S

We present the results of [Ne V] λ3426 observations in the Cygnus Loop supernova remnant using the Fabry-Perot spectrophotometer ESOP. The [Ne V] emission was measured at 64 sites throughout the Loop. Emission was detected at 58 of these sites, 48 of the observations have strong signal to noise ratios and are used in the final analysis. We derive the kinematics of this [Ne V] gas mostly along the eastern and western rims of the Cygnus Loop. The eastern rim exhibits large variations in brightness and velocity from place to place, which we relate to projection effects in an inhomogeneous medium. In the western ridge, we observe similar brightness and velocities (all negative). This suggests that either the emitting medium is homogeneous or that the far-side emission (positive velocities) is fully absorbed by the molecular cloud interacting with the supernova remnant. We investigate the non-equilibrium ionization and temperature conditions required to produce the [Ne V] emission line as well as the filling factor of the [Ne V] gas.