SIX Survey

All-sky surveys at hard X-ray energies (above 15 keV) are best performed with coded-mask instrumens like Swift/BAT and INTEGRAL/IBIS. However, the mask itself absorbes 50% of the incident photons negatively affecting the sensistivty of the observations. As a consequence the detection of astronomical objects is still challenging in this energy range. To solve this problem we have developed a new survey technique that consists in summing the photons from the independent observations of Swift/BAT and INTEGRAL/IBIS improving the overall sensitivity. We call this the SIX Survey that stands for Swift - INTEGRAL X-ray Survey. A descrpiton of the technique can be found HERE.

The image below pictures this survey technique: where the field of view of Swift/BAT (left lower corner) and INTEGRAL/IBIS (right lower corner) overlap (red rectangle) it is possible to sum the photons.

As a result the SIX survey is a factor of ~2 more sensitive than the survey of INTEGRAL/IBIS or Swift/BAT alone. We detect an number of new sources that we follow up best with Chandra. We perform science by studying the evolution of extragalactic sources like AGN and the properties of galactic sources.