Detection of the rapid variability in the Q2237+0305 quasar
  Rapid intrinsic variability has been detected for the first time in the
Einstein Cross QSO 2237+0305, a radio quiet flat spectrum quasar at z=1.7 that
is quadruply lensed by a foreground galaxy at z=0.04. The observed short-period
event at the time scale of several days and with amplitudes of about 0.1-0.2
mag can be traced in the light curves of the 2004 observing season for all
macroimages and in all the three filters (V, R and I). The accuracy of the
existing estimates of the time delays in Q2237+0305 is insufficient to either
confirm or disprove the estimations of time delays based on the lens models of
this system, especially taking into account the presence of strong microlensing
events. The detected short-period variations in the Q2237+0305 light curves
have made it possible to obtain new estimates of the time delays, which are
more accurate as compared to the earlier determinations by other authors.
