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B.Y. Welsh, S. Sallmen (UC Berkeley), R. Lallement (CNRS (France))
The latest FUSE observations of the OVI (\lambda1032 Å) emission line indicate a constant surface brightness at high galactic latitudes of 2700 ± 280 LU. This suggests that it is formed locally, most porbably at the conductive interface of the Local Hot Bubble cavity. Emisison intensities of the 0.25 keV soft X-ray background flux measured towards the same lines-of-sight are also of a similar constancy of ~ 10000 x 10-6 counts s-1 arcmin-1. When compared with measurements of the OVI line in absorption the FUSE data are best explained by a scenario in which both the emisison and absorption lines are formed at the neutral boundary to the Local Bubble. These new data enable us to forward a new paradigm for testing models of the local hot cavity which now must explain (a) the low levels of variability in both the OVI and soft X-ray emission intensities for sight-lines > \mid 40 \mid \deg, (b) the observed pressure of P/k ~ 10,000 cm-3 K for the local hot interstellar gas, and (c) the paucity of high ionization line absorption lines observed within the local ISM and the sudden increase in their measured column densities for distances beyond the Local Bubble neutral boundary
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Bulletin of the American Astronomical Society, 34
© 2002. The American Astronomical Soceity.