Far Ultraviolet Spectroscopic Explorer Survey of Magellanic Cloud Supernova Remnants

We report the progress to date from an ongoing unbiased ultraviolet survey ofsupernova remnants in the Magellanic Clouds using the Far UltravioletSpectroscopic Explorer (FUSE) satellite. This survey is obtaining spectra of arandom large sample of Magellanic Cloud supernova remnants with a broad rangeof radio, optical, and X-ray properties. To date, 39 objects have been observedin the survey (38 in the LMC and one in the SMC) and 15 have been detected, adetection rate of nearly 40%. Our survey has nearly tripled the number ofUV-detected SNRs in the Magellanic Clouds (from 8 to 22). Because of thediffuse source sensitivity of FUSE, upper limits on non-detected objects arequite sensitive in many cases. Estimated total luminosities in O~VI span abroad range from considerably brighter to many times fainter than the inferredsoft X-ray luminosities, indicating that O~VI can be an important and largelyunrecognized coolant in certain objects. We compare the optical and X-rayproperties of the detected and non-detected objects but do not find a simpleindicator for ultraviolet detectability. Non-detections may be due toclumpiness of the emission, high foreground extinction, slow shocks whoseemission gets attenuated by the Magellanic interstellar medium, or acombination of these effects.Comment: 34 pages, 26 figures in 8 separate JPG figure files; the characteristics of individual detected supernova remnants are summarized in an Appendi