SIMBAD references

In this Letter, the broad emission line (BEL) profiles of superluminal quasars with apparent jet velocities β_a>10 (ultraluminal QSOs [ULQSOs]) are studied as a diagnostic of the velocity field of the BEL-emitting gas in quasars. The ULQSOs are useful because they satisfy a very strict kinematical constraint: their parsec-scale jets must be propagating within 12° of the line of sight. We know the orientation of these objects with great certainty. The large BEL FWHM, ∼3000-6000 km/s, in ULQSOs tend to indicate that the BEL gas has a larger component of axial velocity (either random or in a wind) along the jet direction than previously thought.