VOYAGER-2 UVS SPECTRA OF THE VELA SUPERNOVA REMNANT

We report low resolution far-ultraviolet spectra of the Vela supernova remnant obtained with the Voyager 2 Ultraviolet Spectrometer. The areas we observed include filaments on the extreme southeastern limb of the remnant and the northern limb. We also show Hα and [O III] optical CCD interference filter images of the southeast filaments as an aid to interpreting the UV data. Emission line features at 980 and 1035 Å dominate the 500-1700 Å spectra from Voyager. By analogy with the Cygnus Loop, we identify the sub-Lyα Voyager emissions as primarily C III λ977 and O VI λλ32, 1038. This is the first detection of O VI emission from the Vela supernova remnant. The O VI:C III ratio in the regions of Vela we have observed are generally lower than those seen in the Cygnus Loop, suggesting a lower fraction of intermediate velocity (160-300 km s-1) shocks are present in these regions of Vela in comparison with the Cygnus Loop. We briefly discuss some reasons for these differences. © 1995 American Astronomical Society.