Variability of Bl-Lacertae Objects at X-Ray and Other Frequencies
Pollock, A. M. T.; Robson, E. I.; Brand, P. W. J. L.; Bregman, J. L.
United Kingdom, United States
Abstract
EXOSAT observations reveal that daily X-ray variability appears to be a common property of high luminosity BL Lac objects. Results are reported for PKS0735+178, OM280(=1147+245), OQ530(=1418+546), OV-236 (=1921-293) and OJ287(=0851+202). In OJ287, for which we have the most extensive coverage, the amplitude of variability at X-ray frequencies appears to be a factor of a few larger than at longer wavelengths.