These images obtained with the SPI instrument onboard INTEGRAL show
the galactic plane in hard continuum X-rays. They are made using Core
Program data from the Galactic Centre Deep Exposure (GCDE) with a total
exposure of 6.1 Ms, using the maximum entropy method.
Coordinates are Galactic. At low energies known sources dominate,
while at higher energies diffuse emission from the interstellar medium
becomes evident. While previous experiments (e.g. OSSE) made scans of
the diffuse emission, this is the first time that actual images of the
diffuse continuum emission in hard X-rays of these energies have been made,
thanks to the imaging capabilities of SPI.
