The upper image shows the distribution on the sky of four of the main soft
gamma-ray source populations observed in the third INTEGRAL/IBIS survey
catalogue. This newly-released catalog contains 421 sources. Of the known
systems, the low-mass X-ray binaries (LMXB) are old systems mainly
populating the galactic bulge, the high-mass X-ray binaries (HMXB) are
younger systems seen along the galactic plane, and the active galactic
nuclei (AGN) are extragalactic sources seen over the whole sky. Around one
in four of the sources seen by INTEGRAL are unidentified, and their
distribution is also shown.
The lower image shows a false colour image of the central region of our
galaxy. This is a composite image based on all-sky IBIS/ISGRI maps in three
energy windows between 17 and 100 keV and represents the true 'X-ray
colours' of the sources. Red sources are dominated by emission below 30 keV,
while blue sources have harder spectra, emitting strongly above 40 keV.
