Observations of the Diffuse FUV Background with FUSE

We have used observations taken under the FUSE S405/S505 channel realignment program to explore the diffuse 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 photons cm sr s Å to a maximum of 2.9× 10 photons cm sr s Å 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. Subject headings: ultraviolet: ISM, ISM: dust Based on observations made with the NASA-CNES-CSA Far Ultraviolet Spectroscopic Explorer. FUSE is operated for NASA by the Johns Hopkins University under NASA contract NAS5-32985.