RELATIVE QUASAR LUMINOSITIES DETERMINED FROM EMISSION-LINE STRENGTHS

Observations of flat radio spectrum QSOs selected from complete samples confirm the strong correlation between continuum luminosity and emission line equivalent width. The r.m.s. scatter about a mean relationship is about 0.6 mag. The data indicate that the luminosity of QSO emission lines increase as the 1/3 power of the continuum luminosity. Unless the zero point of the relationship between emission line equivalent width and continuum luminosity depends on redshift, both the local hypothesis and zero pressure models of the Universe in which qo ≈ 0 are ruled out by the data at about the 99% confidence level. © 1978 Nature Publishing Group.