Mysterious Broad Absorption Line Quasars openParBALQSOsclosePar

Just when we thought that the mystery of broad absorption line quasars issolved, new Chandra observations confront our understanding. Some BALQSOs appearunabsorbed in softXrays and yet are Xray weak. To understand these puzzlingobservations, we propose to observe a Chandra detected radioloud BALQSO forprecision spectroscopy with EPIC PN. With the high quality XMM spectrum we willuncover spectral complexity, if any, which mimics the unabsorbed spectral shapein the crude Chandra data. It would be even more interesting if the spectrumturns out to be truly unabsorbed, as it will completely shake the presenthypothesis that BALQSOs are normal quasars viewed through special sightlines andwill imply that radioloud BALQSOs are a separate class, perhaps related to quasar evolution. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]