0620030

The simultaneous optical-to-gamma-rays observations of blazars are key tools in understanding the nature of these sources the mechanisms of the gamma-ray emission and other features such as the origin of the soft X-rays (E < 1 keV) photon deficit often observed in high-z flat-spectrum radio quasars. We therefore ask for two 500 ks observations with INTEGRAL (total requested exposure 2x 500 = 1000 ks) of the two high-redshift blazars PKS B2126-158 (z = 3.268) and PKS B2149-307 (z = 2.345). These observations coupled with simultaneous Swift and GLAST observations will allow us to build the best available optical-to-gamma-rays spectral energy distributions which in turn will be modeled and studied in order to give answers to the above mentioned problems. [truncated! Please see actual data for full text]