Voyager far-ultraviolet observations of globular clusters

We report on the observations of nine globular clusters carried out by the Voyager ultraviolet spectrometers (UVSs). Three of the observed clusters, M 13, NGC 6752, and M70, exhibit an intense far-ultraviolet (FUV) spectrum do wn to the Lyman limit. However, the spectrum obtained for NGC 6752 is heavi ly contaminated by the nearby star HD 177999 for wavelengths longward of 12 00 Angstrom. For M70 the Voyager spectrum is completely dominated by the B3 star HD 172535. The FUV spectral energy distribution of M13 confirms resul ts from the Ultraviolet Imaging Telescope that the main contributors to the FUV emission are hot sdB stars. M13's integrated spectrum resembles that o f an sdB star of T-eff approximate to 28,000 K. For two clusters, M92 and M 5, UVS detected a weak signal, making it difficult to reach any conclusion on the underlying hot components of the systems. Four clusters, M15, NGC 22 98, NGC 6656, and NGC 6793, were observed but not detected. In some cases i t was possible to identify a weak stellar spectrum, which, however, very li kely originates from foreground FUV emitters not related to the systems. Fo r the nondetected clusters we provide upper limits on the FUV flux.