Strong [O III] Objects Among SDSS Broad-Line Active Galaxies
  We present the results of a spectral principal component analysis on 9046
broad-line AGN from the Sloan Digital Sky Survey. We examine correlations
between spectral regions within various eigenspectra (e.g., between Fe II
strength and H$\beta$ width) and confirm that the same trends are apparent in
spectral measurements, as validation of our technique. Because we found that
our sample had a large range in the equivalent width of [O III] $\lambda$5007,
we divided the data into three subsets based on [O III] strength. Of these,
only in the sample with the weakest equivalent width of [O III] were we able to
recover the known correlation between [O III] strength and full width at half
maximum of H$\beta$ and their anticorrelation with Fe II strength. At the low
luminosities considered here ($L_{5100 \AA}$ of $10^{42}-10^{46}$ erg
s$^{-1}$), interpretation of the principal components is considerably
complicated particularly because of the wide range in [O III] equivalent width.
We speculate that variations in covering factor are responsible for this wide
range in [O III] strength.
