Emission linewidths and QSO black hole mass estimates from the 2dF QSO Redshift Survey

We have used composite spectra generated from more than 22 000 quasi-stellar objects (QSOs) observed during the course of the 2dF and 6dF QSO Redshift Surveys to investigate the relationship between the velocity width of emission lines and QSO luminosity. We find that the velocity widths of the broad emission lines H, H , Mg II, C III] and C IV are correlated with the continuum luminosity, with a significance of more than 99 per cent. Of the major narrow emission lines (