Testing for intrinsic absorption in X-ray hard comma moderately radio-loud comma z>4 RLQs

We propose XMMNewton/EPIC observations of J0741+2520 (35 ks) and J1639+4340 (24ks), two extremely optically luminous (Mi < 29) and moderately radioloudquasars at high redshift (z>4). Exploratory Chandra snapshots show these objectshave larger hardness ratios than is typical for similar RLQs. We will obtainhighquality Xray spectra to determine whether the spectral hardness is due toheavy intrinsic absorption or to an anomalously flat power law slope. The formeroutcome could indicate these are young quasars engaged in the process ofclearing absorbing material from near the nucleus, while the latter outcomewould require either a jetdominated Xray spectrum despite moderate radioloudness or else modified disk/coronal accretion structure at high luminosity. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]