BAL QSOs are notoriously faint X-ray sources, presumably due to extreme intrinsic absorption. However, several objects have begun to appear through the obscuration with recent X-ray observations by Chandra and ASCA. Where enough counts are present for X-ray spectroscopy, the signatures of absorption are clear. The evidence is also mounting that the absorbers are more complicated than previous simple models assumed; current absorber models need to be extended to the high-luminosity, high-velocity, and high-ionization regime appropriate for BAL QSOs.
Categories: astro-ph
