The X-Ray Variability of PKS:2155-304 - a Power Spectrum Analysis
Maraschi, L.; Tagliaferri, G.; Stella, L.; Treves, A.; Morini, M.
Netherlands, Italy
Abstract
The bright BL Lac object PKS 2155-304 was observed with EXOSAT 9 times between 1983 and 1985 for a total of 80 hours. During some observations the source appeared stable, while during others, flare-like activity was observed, the intensity doubling in less than an hour. Here we present a power spectrum analysis of the 3 brightest observations. Significant power is found between - 5 x 10-5 and - 2 x 10-3 Hz. Power spectra obtained from the 1-7 keV light curves, using standard Fourier techniques, have an average power-law slope of - -1.5. We find evidence that the power spectrum is affected by low-frequency leakage.