A cosmic light-show: the Galactic Bulge as viewed by INTEGRAL
Date: 29 September 2011
Copyright: ESA/C. Carreau; Axel Mellinger; INTEGRAL/IBIS-ISGRI; INTEGRAL Galactic Bulge Monitoring Programme (PI: E. Kuulkers)
This video shows the Galactic Bulge, the central part of our Galaxy, the Milky Way, as monitored by ESA's high-energy space observatory INTEGRAL. The video opens with a panoramic view of the entire sky as seen at visible wavelengths. The plane of the Milky Way stretches across the image (from left to right). The bright, round structure at the centre is the Galactic Bulge, the central region of the Milky Way.
The visible image then fades into an all-sky view captured by INTEGRAL. This image is based on data collected with the IBIS/ISGRI instrument at X-ray wavelengths in the 18-40 keV energy range (in comparison, visible light corresponds to 1.65-3.1 eV). All the sources belong to the Milky Way and are mostly X-ray binary systems that contain either a black hole or a neutron star. Other sources are pulsars and remnants of supernova explosions. The sources were observed by INTEGRAL at wavelengths that cannot be perceived by human eyes, they are therefore represented in false colours. The colours used reflect the characteristics of the sources X-ray emission within the 18-40 keV energy range (as observed by the IBIS/ISGRI instrument).
Next, the video zooms in on the Galactic Bulge. This region is the subject of an observing campaign conducted with INTEGRAL and is monitored regularly. The INTEGRAL spacecraft orbits the Earth every three days and approximately once per revolution takes a 'snapshot' of the Galactic Bulge. The video presents observations made between February 2005 and September 2008. When viewed at these wavelengths, the Galactic Bulge has the appearance of a dramatic cosmic light-show.
The video highlights how some sources of high-energy radiation exhibit distinct changes in their brightness, even over very short periods of time. A number of these sources only shine brightly for a limited period of time - in some cases, they appear as a sudden bright flash and disappear shortly afterwards, whereas others are more persistent.