Observations of the Diffuse Far-Ultraviolet Background with the Far Ultraviolet Spectroscopic Explorer

Abstract

We have used observations taken under the Far Ultraviolet Spectroscopic Explorer (FUSE) S405/505 channel realignment program to explore the diffuse far-ultraviolet (FUV; 1000-1200 Å) radiation field. Of the 71 independent locations in that program, we have observed a diffuse signal in 32, ranging in brightness from 1600 to a maximum of 2.9×10/sup5 photons cm/sup-2 sr/sup-1 s/sup-1 Å/sup-1 in Orion. The FUSE data confirm that the diffuse FUV sky is patchy with regions of intense emission, usually near bright stars, but also with dark regions, even at low Galactic latitudes. We find a weak correlation between the FUV flux and the 100 μm ratio but with wide variations, perhaps due to differences in the local radiation field.