AAS 198th Meeting, June 2001
Session 59. Galactic ISM
Display, Wednesday, June 6, 2001, 10:00am-7:00pm, Exhibit Hall

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[59.11] O VI Resonance Line Emission from the Galactic Interstellar Medium toward l = 113.0, b = 70.7

R. L. Shelton (Johns Hopkins Univ.)

We report Far Ultraviolet Spectroscopic Explorer (FUSE) measurements of resonance line emission from diffuse O~{\scriptsize{VI}} in the interstellar medium toward l = 113.0\rm{o}, b = 70.7\rm{o}. The intensities in the 1032 and 1038 Å\ emission lines are approximately 2400 ±500 and 1400 ±400 photons cm-2 s-1 sr-1, respectively. This is the third reported FUSE observation of emission from diffuse O~{\scriptsize{VI}} in the Galactic interstellar medium outside of supernova remnants or superbubbles. The doublet intensity being reported here is about equal to that seen for l = 58\rm{o}, b = 88\rm{o} and is about 80% of that seen for l = 315\rm{o}, b = -41\rm{o}. Each of the observations has examined a high latitude direction, suggesting that the sources of the emission are the Local Bubble surrounding the solar neighborhood, and the Galactic halo.

>From the observed doublet intensity, estimates of the O~{\scriptsize{VI}} column densities for the Local Bubble and Galactic halo, and an isothermal model, we estimate the electron density, thermal pressure, and depth of the emitting region. We conclude that the observed doublet intensity is greater than would be expected from the Local Bubble alone and that the emitting depths are relatively short compared with the size of the Local Bubble and the scale over which O~{\scriptsize{VI}} is distributed in the Galactic halo.

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