Variability in Quasar Light Curves: using quasars as standard candles
  A relation between the variational slope, $s_F$ , and the mean absolute
magnitude, $\langle M \rangle$, in the light curves of 58 spectroscopically
confirmed quasars is measured with a dispersion of 0.15dex. Assuming it holds
for quasars in general, not only does this relation add to our working
knowledge of quasar variability but it also shows great promise at accurately
measuring luminosity distance to a quasar in a model independent way. An
accurate, model independent measure of the luminosity distance would allow
quasars to be added to the cosmic distance ladder, easily extending the ladder
out far beyond the redshifts accessible to type Ia supernovae where
cosmological parameters can be better constrained.
