SPI images the sky at energies from hard X-rays to soft gamma-rays
All-sky maps of the gamma-ray continuum emission demonstrate that the spectrometer SPI on INTEGRAL can trace
the contributions of diffuse and point-like emission from the hard X-ray into the soft gamma-ray regime
(see also
ESA Science News Release SNR 23-2003, and the POM August 2004).
This picture shows 6 all sky images obtained with SPI across the energy range between 20 keV and 500 keV.
Below 100 keV the population of galactic point sources,
mainly X-ray binaries is most prominent (~ 60 sources below 50 keV and ~ 25 sources in the 50 - 100 keV
range). No diffuse emission is visible in the reconstructions, indicating a rather low intensity level.
In the 200-300 keV band a diffuse and structured emission band along the galactic plane replaces the point
sources in this region, possibly originating from faint and unresolved point source emission. Above 300 keV
the picture changes drastically and the 300-500 keV image is clearly dominated by emission of the Galactic bulge,
and is very similar in morphology to that of the 511 keV line (see POM November 2004).
Crab and Cyg X-1 are prominent point sources detected in this range.
Credit: The SPI Team; J. Knödlseder et al., ESA SP-662 (Proc. 6th INTEGRAL workshop), in press, 2006
