The long time-scale X-ray variability of the radio-quiet quasar PG 0804+761.

Presents the results from a study of the timing properties and the energy spectrum of the radio-quiet quasar PG 0804+761, based on monitoring RXTE/PCA observations that lasted for a year. Study of the X-ray variations on time-scales of weeks/months of the most luminous radio-quiet quasar studied so far; Significant variations in the 2 to 10 keV band of an average amplitude of ˜15 per cent; Power spectrum estimation at higher frequencies.