X-Ray Variability of the BL Lacertae Object PKS 2155-304 in the 0.1--6 keV Range
Maccagni, D.; Maraschi, L.; Tanzi, E. G.; Chiappetti, L.; Wolter, A.; Molteni, D.; Treves, A.; Morini, M.
Italy
Abstract
Observations of the bright BL Lac object PKS 2155 - 304 obtained at 1-6 keV using the ME argon counters and channel-multiplier array at the focus of the Exosat LE telescope, in conjunction with the 0.05-2-keV-bandpass 3000-A Lexan filter, during a total of 30 h in October-November 1983 and November 1984 are reported. The data are presented in tables and graphs and characterized. Findings discussed include an overall variation of a factor of 10, one factor-of-four increase over 4 h, and maximum luminosity variation dL/dt = 2 x 10 to the 42nd erg/s sq for H = 100 km/s Mpc (corresponding to a lower limit of mass of 10 to the 8th solar mass and a gravitational radius of 3 x 10 to the 13th cm). The implications of these results for theoretical models of the X-ray emission source are considered.