A FAR ULTRAVIOLET SPECTROSCOPIC EXPLORER SURVEY OF INTERSTELLAR O vi ABSORPTION IN THE SMALL MAGELLANIC CLOUD

We present the results of a Far Ultraviolet Spectroscopic Explorer (FUSE) survey of O vi 1031.93 and 1037.62 absorption toward 18 OB stars in the Small Magellanic Cloud (SMC). The FUSE data are of very high quality, allowing a detailed study of the coronal temperature gas in the SMC.We find that O vi is ubiqui-tous in the SMC, with a detection along every sight line. The average value of the O vi column density in the SMC is loghNðO viÞi 14:53. This value is 1.7 times higher than the average value for the Milky Way halo (perpendicular to the Galactic plane) of logN?ðO viÞ 14:29 found by FUSE, even though the SMC has much lower metallicity than the Galaxy. The column density in the SMC is higher along sight lines that lie close to star-forming regions, in particular NGC 346 in the northern part of the SMC, and to a lesser degree the southwestern complex of H ii regions. This correlation with star formation suggests that local processes have an important effect on the distribution of coronal gas in the SMC. If the sight lines within NGC 346 are excluded, the mean column density for the SMC is logNðO viÞ 14:45, only 1.4 times higher than the Milky Way average. The standard deviation of the column densities for sight lines outside of NGC 346 is 27%, somewhat lower than the deviation seen in the Milky Way halo. The lowest O vi column den-sities, logN(O vi)14.3, occur in the central region and in the southeastern ‘ ‘ wing ’ ’ of the galaxy. Even thes