Metallicity evolution in quasars
  Broad-band spectra of active galaxies contain a wide range of information
that help reveal the nature and activity of the central continuum source and
their immediate surroundings. Understanding the evolution of metals in the
spectra of Active Galactic Nuclei (AGN) and linking them with the various
fundamental black hole (BH) parameters, for example, BH mass, the bolometric
luminosity of the source, its accreting power, can help address the connection
between the growth of the BH across cosmic time. We investigate the role of
selected metallicity indicators utilizing the rich spectroscopic database of
emission lines covering a wide range in redshift in the recent spectroscopic
data release of Sloan Digital Sky Survey (SDSS). We make careful filtering of
the parent sample to prepare a pair of high-quality, redshift-dependent
sub-samples and present the first results of the analysis here. To validate our
findings from the simple correlations, we execute and evaluate the performance
of a linear dimensionality reduction technique - principal component analysis
(PCA), over our sub-samples and present the projection maps highlighting the
primary drivers of the observed correlations. The projection maps also allow us
to isolate peculiar sources of potential interest.
