Shadowing by the Magellanic Bridge: the origin of the 3/4 keV background

The high Galactic latitude 3/4 keV background consists of both extragalactic and Galactic emission with uncertain relative contributions. The surface brightness shows an excess over the extrapolation of the extragalactic power law observed at higher energies which has been attributed to emission from sources as varied as a Galactic halo, the Local Group, diffuse cosmological emission, and a bump in the spectra of discrete cosmological sources. By studying the shadow of an NH enhancement in the Magellanic Bridge, the observed flux can be separated into foreground and background components, which will place clear constraints on a number of models both Galactic, e.g., halo emission is closely linked to the Galactic energy balance, and truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]