Catalog of strong MgII absorbers

A geometrical explanation for this discrepancy has been suggested: the ratio of the beam size of the source to the characteristic size of an MgII absorption system can influence the observed MgII equivalent width, if these two sizes are comparable.

We investigate whether the differing beam sizes of the continuum source and broad-line region of Sloan Digital Sky Survey (SDSS) quasars produce a discrepancy between the incidence of strong MgII absorbers illuminated by the quasar continuum region and those of absorbers illuminated by both continuum and broad-line region light.