Quasar absorption lines. A review

The paper first reviews the observations of quasar absorption lines, paying particular attention to those objects with multiple redshifts. Recent high-resolution work by Morton and Morton, by Morton and Richstone, by Wingert and by Boksenberg and Sargent has shown that the absorption redshifts frequently are found to split into close pairs or multiples. Boksenberg and Sargent have proposed that this splitting may represent a constant velocity separation between adjacent pairs of redshifts of about 140 km. s⁻¹. Recent observations pertinent to this suggestion are reviewed. The second part of the paper deals with theories concerning the origin of the absorption lines. The existence of the possible magic splitting in redshifts would strongly point to the lines originating in material ejected by the quasar.