Extreme synchrotron blazars in outburst: The potentiality of INTEGRAL imaging and spectroscopy

Only similar to 10 blazars have been detected in soft gamma-rays by OSSE an d the PDS, often in Baring state. We investigate the impact of the imaging and spectral capabilities of the IBIS instrument on board INTEGRAL on the s tudy of blazars. The objectives are: 1) to remove ambiguities in the identi fication of some blazars as soft gamma-ray emitters; 2) to determine the sp ectral shape of "extreme synchrotron" blazars, namely sources with high F-X /F-radio ratios, for which the synchrotron component peaks at far UV-soft X -ray frequencies. We expect that in these sources the synchrotron peak shif ts to higher energies during outbursts, making them strong soft gamma-ray e mitters, and therefore possible targets for INTEGRAL wide band X- and gamma -ray spectroscopy.