X-RAY SPECTRA OF HIGH REDSHIFT QUASARS

We propose to harness both the unequalled sensitivity of XMM and its broadenergy band to systematically study a sample of 9 high redshift(z > 4) quasars,the most luminous, youngest and least studied objects known(4 new observations).XMM can determine accurately both the absorption column density and the Xrayspectral shape allowing us to resolve intriguing, outstanding questions such as:Is the apparent difference between the Xray spectra of highredshift radioloudand radioquiet quasars real? If so, is it explained by intrinsic absorption orby different evolution of the Xray spectrum with redshift? What constraints canwe place on the Xray spectral evolution with redshift and/or luminosity foreach class? What limits can we put on intervening Damped Lyalpha systems? truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]