The bulge of our Galaxy hosts a variety of hard X-ray and gamma-ray point sources. Due to the variability these sources possess on all time scales, the region never looks exactly the same. Frequent and regular observations of the Galactic Bulge during its whole visibility period are performed with INTEGRAL, which started already in AO-3 (PI: Kuulkers).
As a service to the community, light curves in two energy bands and images, both from JEM-X and IBIS/ISGRI are made publicly available at http://isdc.unige.ch/Science/BULGE/.
To demonstrate the dynamic nature of this region we here show JEM-X (3-20 keV; top figure) and IBIS/ISGRI (20-60 keV; bottom figure) mosaic significance images (total exposure time is 69 ksec) focussed on the Galactic Center region during April 2006. Surprisingly, most of the sources were off during that time, including the normally bright well-known black-hole candidate and micro-quasar 1E 1740.7-2942. This is a very different view than the long-term average, see, e.g., in http://integral.esac.esa.int/POMSep2005.html. These findings are part of a paper (http://lanl.arxiv.org/abs/astro-ph/0701244) by Kuulkers et al. accepted for A&A.
Credits: E. Kuulkers (ESA/ESAC) et al.
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