We present timing analyses of eight X-ray light curves and one optical/UV light curve of the nova V4743 Sgr ( 2002 ) taken by Chandra and XMM-Newton on days after outburst : 50 ( early hard emission phase ) , 180 , 196 , 302 , 371 , 526 ( super soft source , SSS , phase ) , and 742 and 1286 ( quiescent emission phase ) .
We have studied the multifrequency nature and time evolution of the dominant peak at \sim 0.75 mHz using the standard Lomb-Scargle method and a 2-D sine fitting method .
We found a double structure of the peak and its overtone for days 180 and 196 .
The two frequencies were closer together on day 196 , suggesting that the difference between the two peaks is gradually decreasing .
For the later observations , only a single frequency can be detected , which is likely due to the exposure times being shorter than the beat period between the two peaks , especially if they are moving closer together .
The observations on days 742 and 1286 are long enough to detect two frequencies with the difference found for day 196 , but we confidently find only a single frequency .
We found significant changes in the oscillation frequency and amplitude .
We have derived blackbody temperatures from the SSS spectra , and the evolution of changes in frequency and blackbody temperature suggests that the 0.75-mHz peak was modulated by pulsations .
Later , after nuclear burning had ceased , the signal stabilised at a single frequency , although the X-ray frequency differs from the optical/UV frequency obtained consistently from the OM onboard XMM-Newton and from ground-based observations .
We believe that the late frequency is the white dwarf rotation and that the ratio of spin/orbit period strongly supports that the system is an intermediate polar .