Weak Line Quasars at High Redshift: Extremely High Accretion Rate SourcesquestionMark

The Sloan Digital Sky Survey has discovered a remarkable group of virgul100 quasarswith extremely weak emission lines in their restframe opticalUV spectra. Wepropose to extend our XMMNewton observations of such sources and obtain imagingspectroscopy of five quasars of this class with a total exposure time of 102 ks,providing virgul1000 photons per source. This will enable an accurate measurement ofthe hardXray photon index required for a robust determination of the accretionrate in each source. Steep spectral slopes will indicate that high accretionrates may be responsible for the intrinsic weakness of the opticalUV emissionlines. The proposed observations will yield crucial insights about the accretionprocess and broad emission line formation in all active galactic nuclei. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]