2009AJ....138..421S

We examine the nature of brightness fluctuations in the UV-Optical spectral region of an ordinary quasar with 894 optical brightness measurements made during the epoch 1993-1999. We find evidence for systematic trends having the character of a pattern of reverberations following an initial disturbance. The initial pulses have brightness increases of the order of 20% and pulse widths of 50 days, and the reverberations have typical amplitudes of 12% with longer mean pulse widths of the order of 80 days and pulse separations of an order of 90 days. The repeat pattern occurs over the same timescales whether the initial disturbance is a brightening or fading. The lags of the pulse trains are comparable to the lags seen previously in reverberation of the broad blueshifted emission lines following brightness disturbances in Seyfert galaxies, when allowance is made for the mass of the central object. In addition to the burst pulse trains, we find evidence for a semiperiodicity with a timescale of two years. These strong patterns of brightness fluctuations suggest a method of discovering quasars from photometric monitoring alone, with data of the quality expected from large brightness monitoring programs such as Pan-STARRS and LSST.