X-ray Spectra of z>4 Quasars

We propose to harness both the unequalled sensitivity of XMM and its broad energy band to systematically study a sample of 6 high redshift (z>4) quasars. XMM can determine accurately both the absorption column density and the underlying spectral shape of the Xray emission allowing us to resolve intriguing, outstanding questions such as: Is the apparent difference between the Xray spectra of highredshift radioloud and radioquiet quasars real If so, is it explained by intrinsic absorption or by different evolution of the Xray spectrum with redshift What contraints can we place on the Xray spectral evolution with reshift and/or luminosity for each class. What limits can we put on intervening Damped Lyalpha systems and on the Xray Forest. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]