The radio emission is an important observable of quasars, but its relationship to Eigenvector 1 and the [O III] {lambda}5007 Baldwin Effect is not fully understood. We explore these issues based on a sample of 1800 quasars taken from the Sloan Digital Sky Survey Data Release 7. We employ a new approach of selecting subsamples in the plane of fundamental physical parameters of the black hole mass and Eddington ratio, so as to reduce variables and complexity in analyses. Based on these subsamples, we investigate the relationship between radio loudness R and Eigenvector 1 and find that radio loudness is correlated with [O III] {lambda}5007 emission, but has no clear relationship with optical Fe II emission, which indicates that the radio power is probably not a driver of Eigenvector 1 but merely a secondary process. In addition, we also investigate the impact of radio loudness on the Baldwin Effect of [O III] {lambda}5007. We find that when the radio loudness is not strong (log R 2), the Baldwin Effect of [O III] {lambda}5007 becomes weaker or even disappears. We suggest that both radio loudness and luminosity influence the relative strength of [O III].

Cone search capability for table J/MNRAS/514/1595/table1 (The spectral measurements and derived fundamental physical parameters with and without refitting for the corrected sources)