Abstract:
We have used data from the Galaxy Evolution Explorer to study the different components of the diffuse ultraviolet background in the region between the Galactic latitudes 70◦–80◦. We find an offset at zero dust column density (E(B − V) = 0) of 240 ± 18 photon units in the FUV (1539 Å) and 394 ± 37 photon units in the NUV (2316 Å). This is approximately half of the total observed radiation with the remainder divided between an extragalactic component of 114 ± 18 photon units in the FUV and 194 ± 37 photon units in the NUV and starlight scattered by Galactic dust at high latitudes. The optical constants of the dust grains were found
to be a = 0.4 ± 0.1 and g = 0.8 ± 0.1 (FUV) and a = 0.4 ± 0.1 and g = 0.5 ± 0.1 (NUV). We cannot differentiate between a Galactic or extragalactic origin for the zero-offset but can affirm that it is not from any known source.
