  We report on a study that finds a positive correlation between black hole
mass and variability amplitude in quasars. Roughly 100 quasars at z<0.75 were
selected by matching objects from the QUEST1 Variability Survey with
broad-lined objects from the Sloan Digital Sky Survey. Black hole masses were
estimated with the virial method using the broad Hbeta line, and variability
was characterized from the QUEST1 light curves. The correlation between black
hole mass and variability amplitude is significant at the 99% level or better
and does not appear to be caused by obvious selection effects inherent to
flux-limited samples. It is most evident for rest frame time lags of the order
a few months up to the QUEST1 maximum temporal resolution of about 2 years. The
correlation between black hole mass and variability amplitude means that the
more massive black holes have larger percentage flux variations. Over 2-3
orders of magnitude in black hole mass, the amplitude increases by
approximately 0.2 mag. A likely explanation for the correlation is that the
more massive black holes are starving and produce larger flux variations
because they do not have a steady inflow of gaseous fuel. Assuming that the
variability arises from changes in the accretion rate Li & Cao [8] show that
flux variations similar to those observed are expected as a consequence of the
more massive black holes having cooler accretion disks.
