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J.C. Howk, K.R. Sembach (Johns Hopkins), B.D. Savage (Wisconsin), E.B. Jenkins (Princeton), S.D. Friedman (Johns Hopkins), FUSE O VI Working Group
We report on the properties of interstellar O VI absorption observed with the Far Ultraviolet Spectroscopic Explorer (FUSE) in the directions of approximately 10 stars in the Large Magellanic Cloud (LMC). O VI is a tracer of hot, collisionally-ionized material (T > 3x105 K). It is unlikely to be created by photoionization since stars produce few photons with the required energy (114 eV). The FUSE data, which have a spectral resolution of ~5,000 (~0 km/s), show O VI 1032 Å\ absorption from both the Milky Way and LMC towards these stars. The LMC absorption is patchy, with column densities in the range \log N({\rm O VI}) = 13.9 to 14.5 (in atoms cm-2), and a mean of 14.3+/-0.3 (s.d.). For comparison, the halo of the Milky Way in this direction shows \log N({\rm O VI}) = 14.4 to 14.5. The LMC absorption is often quite broad (as much as 100 km/sec) and likely contains a significant non-thermal component. We discuss the large-scale distribution of O VI within the LMC and its relationship to other phases of the interstellar medium.
This work is based on data obtained for the Guaranteed Time Team by the NASA-CNES-CSA FUSE mission operated by the Johns Hopkins University. Financial support to U. S. participants has been provided by NASA contract NAS5-32985.