A complete X-ray and optical view on the absorption in BALQSOs

Streblyanska, A.; Barcons, X.; Carrera, F. J.; Gil-Merino, R.
Bibliographical reference

X-RAY ASTRONOMY 2009; PRESENT STATUS, MULTI-WAVELENGTH APPROACH AND FUTURE PERSPECTIVES: Proceedings of the International Conference. AIP Conference Proceedings, Volume 1248, pp. 513-514 (2010).

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We collect information for 88 broad absorption line quasars (BALQSOs) from the literature and existing catalogues, creating the largest BALQSOs sample analyzed optically and X-ray to date. We performed a full X-ray spectral analysis with different models on the sample of 39 sources with higher number of counts, and an approximate hardness-ratio analysis on the remaining sources. We also investigate the dependence between BALnicity index and different X-ray properties. Using the neutral absorption model, we found that 40% of our BALQSOs have NHn<1022 cm-2, lower than typical X-ray absorption for such objects. However, when we used appropriate for this sources, physically-motivated model for the X-ray absorption in BALQSOs, i.e. ionized absorption, most of the objects (74%) are absorbed. In addition, we confirm a correlation between ionized absorption column density and BAL parameters. There is dependence (at 98% level) that the amount of X-ray absorption is correlated with the strength of high-ionization UV absorption.