Preprint typeset using LATEX style emulateapj v. 5/2/11 THE DIFFUSE GALACTIC FAR-ULTRAVIOLET SKY

We present an all sky map of the diffuse Galactic far ultraviolet (1344-1786 Å) background using GALEX data, covering 65 % of the sky with 11.79 arcmin2 pixels. We investigate the dependence of the background on Galactic coordinates, finding that a standard cosecant model of intensity is not a valid fit. Furthermore, we compare our map to Galactic all sky maps of 100 µm emission, NHI column, and Hα intensity. We measure a consistent low level FUV intensity at zero-points for other Galactic quantities, indicating a 300 CU non-scattered isotropic component to the diffuse FUV. There is also a linear relationship between FUV and 100 µm emission below 100 µm values of 8 MJy/sr. We find a similar linear relationship between FUV and NHI below 10 21 cm−2. The relationship between FUV and Hα intensity has no such constant cutoff. For all Galactic quantities, the slope of the linear portion of the relationship decreases with Galactic latitude. A modified cosecant model, taking into account dust scattering asymmetry and albedo, is able to accurately fit the diffuse FUV at latitudes above 20◦. The best fit model indicates an albedo, a, of 0.62 ± 0.04 and a scattering asymmetry function, g, of 0.78 ± 0.05. Deviations from the model fit may indicate regions of excess FUV emission from fluorescence or shock fronts, while low latitude regions with depressed FUV emission are likely the result of self-shielding dusty clouds. Subject headings: ISM: general, scattering, ultraviolet: ISM 1