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abstract |
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1E 1740.7-2942 - the hardest bright source close to the dynamic Center of our Galaxy - has been systematically studied by GRANAT and OSSE in 1990-1994. The 40-150 keV flux varies from 130 mCrab level to less than 10 mCrab on time scale of months. The hard state is likely to be connected with e-e+ annihilation process. In addition, Mirabel et al. reported the identification of a radio counterpart of 1E1740.7- 2942 and the detection of a double radio jet emanating from it. Moreover, we detected a variation in the jet structure, within a period of 15 months which is in favor of a galactic origin of these jets. The compact radio source at the center of the double jet is time variable in flux and spoctral index and this variability is correlated with the X-ray source. We propose to keep on with this monitoring in radio (mm and cm) and X-gamma ray of the 1E complex to better understand the physics of this region. |
We will use the BATSE Earth occultation technique to produce the first hard X-ray light curves to span time scales of days to years for 3C 273 and other bright AGN, without any pointed CGRO time. This will allow us to probe the long time scales predicted by theory, and determine the characteristic variability time scales. By focusing on sources that have been monitored intensively at lower energies, we can use continuum cross-correlation functions to relate the hard X-rays to other bands, allowing a key test of reprocessing models. We will determine how the spectral slope and cutoff vary as a function of brightness, to test Comptonization and pair production models. Finally,. we will look for an anticorrelation between luminosity and variability. which would yield evidence for isotropic emission. |
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