Low-Energy Diffuse X-Rays

Measurements of diffuse cosmic X-rays in the energy region E < 284 eV and 0.5-1 keV show that there is a clear excess over the extrapolated higher-energy power law and that the spatial distribution is not consistent with a purely extragalactic origin. The excess intensity cannot have its origin in interstellar processes unless ionization rates larger than 1(h13 (s H)-1 can be accommodated.