A study on the long term periodicities among the Xray binaries: Two new superorbital periods

Long term behaviours of a few selected Xray binaries are studied on the basis of RXTEASM archive covering a period of ∼13 years of continuous Xray data. Two new superorbital periods seem to be revealed for the GX3540 and X Persei systems as 8.7 years and 345 days, respectively. Although the X Persei system has two strongest peaks in its power density spectrum at 15.7 years and at 345 days, the latter is much more plausible. The GX3540 system also has few additional periodicities appeared in different time intervals © 2010 WILEYVCH Verlag GmbH & Co. KGaA, Weinheim