For the 'first light' images INTEGRAL was pointed at Cygnus X-1.
Cygnus X-1 lies about 10000 light years from Earth and is one of
the brightest high-energy emitters in the sky. It was discovered
in the 1960s and is thought to be a black hole, ripping its companion
star to pieces. The companion star, HDE 226868, is a blue supergiant
with a surface temperature of around 31000 K. It orbits the black hole
every 5.6 days. It is a well-known source of high-energy radiation and
provided the ideal test location to fine-tune INTEGRAL's science
instruments. INTEGRAL's four instruments, the Imager on Board the
INTEGRAL Satellite (IBIS), the Spectrometer on INTEGRAL (SPI), the
Optical Monitoring Camera (OMC) and the Joint European X-ray monitor
(JEM-X) all point in the same direction so that they can simultaneously
observe the same celestial objects. This allows their data to be matched
together, producing a greater insight into the nature of the
celestial objects that INTEGRAL will be studying.
Copyright: ESA. Illustration by the INTEGRAL team and ESA/ECF.
