Correlation between the variation of the ionizing continuum and broad
  absorption lines
  In this Letter, we present an analysis of the relation between the
variability of broad absorption lines (BALs) and that of the continuum. Our
sample is multi-epoch observations of 483 quasars by the Sloan Digital Sky
Survey-I/II/III (SDSS-I/II/III). We derive the fractional flux variations of
the continuum and fractional equivalent width (EW) variations for C IV and Si
IV BALs, and explore the correlations between the three. Our results reveal
moderate anticorrelations with high significance level between the fractional
flux variations of the continuum and fractional EW variations for both C IV and
Si IV BALs. We also prove a significant positive correlation between the
fractional EW variations for C IV and Si IV BALs, which is in agreement with
several previous studies. Our discoveries can serve as evidence for the idea:
Change of an ionizing continuum is the primary driver of BAL variability.
