Molecular Hydrogen in the Quiescent Disk of SW UMa

The FUSE observation has been reduced and a paper has been submitted to ApJ. The analysis has been slow because of the very noisy quality of the data, but we have derived line profile information for O VI and limits to the continuum brightness which place an interesting limit on the white dwarf temperature. The primary results are that a narrow O VI emission component seems to arise from the accretion flow onto the white dwarf itself, in agreement with cooling flow models for the X-ray spectra of low accretion rate dwarf novae. The broad component of the O VI lines is weaker than the observed C IV emission, suggesting that the UV line emission from the disk comes from photoionized plasma. A secondary result is that there is no H-2 fluorescent emission. The upper limits indicate that if molecular gas is present in the disk, it is shielded from Ly alpha photons by a layer of atomic hydrogen on the disk surface. We also derive an upper limit to the continuum level is below that observed by IUE. The limits are compatible with the lower end of the WD temperature range derived from IUE measurements, and they appear to agree with unpublished analysis of HST spectra. The grant has provided partial support for a data aide (Matt Povich) and a postdoc (Alex Lobel). It purchased a computer for M. Menou.