093579

We propose to observe the two luminous quasars RBS229 and PG1407+265 at z=0.334and z=0.940 for 230 ks of net exposure time each. Thanks to their brightnessthey offer the unique opportunity to probe the extreme radio-quiet AGNluminosity regimes with NuSTAR. We will study the yet poorly investigatedemission of these objects in the hard X-rays in order to explore the propertiesof their hot coronal environment. Archival XMM-Newton observations showfeatureless continua lacking any contribution from neutral Compton reflectionor absorption which may contaminate the primary power law. Our proposed targetswill provide unique spectral templates to properly infer fluxes and luminositiesas well as assess the detectability of z>6 quasars with present-day and future X-ray facilities. [truncated! Please see actual data for full text]