SHADOWING BY THE MAGELLANIC BRIDGE: THE ORIGIN OF THE 3/4 KEV BACKGROUND

At high Galactic latitudes the 3/4 keV background consists of both extragalacticand Galactic emission with uncertain relative contributions. The spectrum showsan excess over the extrapolation of the extragalactic power law observed athigher energies which has been attributed to emission from sources as varied asa Galactic halo, the Local Group, diffuse cosmological emission, and a bump orupturn in the spectra of discrete cosmological sources. By studying the shadowof an NH enhancement in the Magellanic Bridge, the observed flux can beseparated into foreground and background components placing clear constraints onboth Galactic (e.g., halo emission is linked to the Galactic energy balance andenvironment) and cosmological (e.g., the structure of the universe) models. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]