Strong X-Ray Absorption in a Broad Absorption Line Quasar: PHL 5200

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Abstract
We present ASCA observations of the z = 1.98 prototype broad absorption line quasar (BALQSO): PHL 5200. The source was detected in both SIS and GIS. A power-law spectrum (αE = 0.6−0.6+0.9) with large intrinsic absorption (NH = 1.3−1.1+2.3 × 1023 cm-2) best describes the spectrum. Excess column density over the local Galactic value is required at the 99% confidence level. This detection suggests that, although BALQSOs are X-ray-quiet, it is strong absorption in the BAL region that makes them appear faint to low-energy X-ray experiments. The required intrinsic absorbing column density is 2-3 orders of magnitude larger than earlier estimates of column densities in BALQSOs. This implies that the BAL systems are much more highly ionized than was previously thought.