A study of temeporal characteristics of selected Cataclysmic Variables: The broad-band noise structure between 2-20 kev

Abstract

We present the preliminary analysis of the band-limited noise structure of Cataclysmic Variables (CVs) in the 220 keV energy band. We have currently analyzed Rossi X-ray Timing Explorer (RXTE) PCA data and derived time series from 30 CVs using the RXTE archive. In general, CVs of different types all show broad band noise which can be fitted with power laws, using exponential cut-offs, and Lorenzians in a similar way to power spectral (noise) characteristics of X-ray Binaries (XRBs). In general terms the power spectra show a power law index of (-)1.2-2. A rather large scale flattening of the power spectra exits in nonmagnetic systems in the low to very low frequency range. We observe that in low and high states/outbursts the noise in the high frequency range and low frequency range is changed. CVs show considerable very low frequency noise. In addition, we have recovered several possible QPOs in the X-ray wavelengths from CVs mainly from Intermediate Polar systems.