The X-ray flux variations of CYG X-2.

Abstract

Results of a 47 d observation of Cygnus X-2 by the COS-B X-ray experiment are presented. The observed variability of the X-ray intensity is investigated for the presence of modulation at either the 9.843 d optical period or the 11.23 d X-ray period claimed for this source. Upper limits are given to pulse amplitudes for periods between 1 d and 200 s. Clear dips were observed during the time of highest source intensity, with transitions of up to 40 percent in the source flux in less than 1000-2000 s. It is suggested that the dips may be connected to the reported UV flaring activity.