2018ApJ...858..101A

We have used GALEX observations of the north and south Galactic poles to study the diffuse ultraviolet background at locations where the Galactic light is expected to be at a minimum. We find offsets of 230-290 photon units in the far-UV (1531 Å) and 480-580 photon units in the near-UV (2361 Å). Of this, approximately 120 photon units can be ascribed to dust-scattered light and another 110 photon units (190 in the near-UV) to extragalactic radiation. The remaining radiation is, as yet, unidentified and amounts to 120-180 photon units in the far-UV and 300-400 photon units in the near-UV. We find that molecular hydrogen fluorescence contributes to the far-UV when the 100 µm surface brightness is greater than 1.08 MJy sr^–1.