XMM-Newton Observations of Two Broad Absorption Line QSOs: Q1246-057 and SBS 1542+541

Abstract

We report on the results of XMM-Newton observations of two broad absorption line quasars (BAL QSOs), Q1246-057 and SBS 1542+541. The unprecedented sensitivity of XMM-Newton allows spectral analysis of these X-ray-weak sources. The X-ray spectral data of these sources can be fitted by a power law with α_X=1.0-1.2 and either a partially covering absorber or an ionized absorber model. Rest-frame UV spectroscopy together with polarimetry favors the model with a partially covering absorber with column density a few times 10²² cm^-2 and a covering fraction of about 0.80. After correcting for absorption, the X-ray loudness of these BAL QSOs appears to be similar to other, unabsorbed quasars. The mystery of X-ray weakness of BAL QSOs appears to be all but solved, with strong absorption being the primary reason. With the available X-ray data, however, the issue of whether BAL QSOs represent highly accreting/younger population of quasars remains unsettled.

Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contribution directly funded by ESA member states and NASA.