Flux and spectral variations of 1E1740.7$-$2942 over the years 2003$-$2012

Manuel Castro, Flavio D'Amico, Francisco Jablonski +1

The black hole system 1E1740.7$-$2942 is usually the brightest hard X-ray source (above 20 keV) near the Galactic Center, but presents some epochs of low emission (be…