Correlation between Break Frequency and Power Density Spectrum Slope for the X-ray Source Cygnus X-2: RXTE/PCA Data

Abstract

We present results of RXTE observations of the X-ray source Cyg X-2 during 1996-1999. Its power density spectra in the 0.1-128-Hz band are fitted by a model that takes into account the power-law spectral behavior at frequencies below and above the break frequency, with an introduction of one or more Lorenz lines to describe the peaks of quasi-periodic oscillations that correspond to the horizontal branch of the Z track. The RXTE observations have revealed a positive correlation between the break frequency and the indices of the two parts of the spectrum. The spectrum steepens with increasing break frequency both above and below the break frequency.

7 pages, 2 figures, To be published in Astronomy Letters, Vol. 27, No. 12, 2001, pp. 790-793 (English version by "MAIK Nauka")

References in corpus (1)

• X-ray timing behaviour of Cygnus X-2 at low intensities

Cited by in corpus (1)

• Correlations between X-ray Spectral and Timing Characteristics in Cyg X-2