The Absorption-Line QSOs

Abstract

Many features of the distribution of emission and absorption line redshifts of QSO spectra and of the distribution of the differences between emission and absorption line redshifts may be due to observational selection. However, it seems significant that all six of the absorption line objects of largest redshift have multiple absorption systems. Observations seem to favor more strongly the hypothesis that the multiple absorption line systems are due to clouds associated with the QSO rather than in the intervening space. The multiple absorption line systems of the QSOs PKS 0237–23, Ton 1530 and 4C 05.34 are discussed. The persistence of the Lyman-α absorption feature and identification of multiple-absorption line systems strongly suggests that unidentified absorption lines shortward of the Lyman-α emission also arise from the Lyman-α transition.