This mosaic image, built with exposures obtained by the IBIS/ISGRI instrument on board ESA’s Integral gamma-ray observatory, provides another view of the Galactic centre region.

Differently from the previous image, this view was built with all exposures taken during the 1.5 years of Integral’s Galactic bulge monitoring, thus providing an ‘average’ view of the area.

By comparing this view with the previous one, it is possible to observe the highly variable nature of the sources.

In particular, the sources and the positions marked in white are almost permanently visible, while those marked in red are known ‘transient’ sources, that is sources more often ‘off’ than ‘on’.

The source called 1E 1740.7-2942 is normally the brightest source in the Galactic Centre region. It is a well-known black-hole candidate, as well as a micro-quasar source. The massive black hole at the very centre of our Galaxy, Sagittarius A* (or Sgr A*), is very close to source marked as ‘1’, corresponding to IGR J17456-2901.

The image covers a sky area of 4.3x2 degrees, and it is centred on (0, -0.5) degrees in Galactic coordinates.