Reflection and noise in the low spectral state of GX 339-4

Abstract

Abstract. We analyze RXTE/PCA observations of GX 339-4 in the low spectral state from 1996-1997 and show that the pattern of its spectral and temporal variability is nearly identical to that of Cyg X-1. In particular, a tight correlation exists between the QPO centroid frequency and the spectral parameters. An increase of the QPO centroid frequency is accompanied with an increase of the amplitude of the reflected component and a steepening the slope of the underlying power law. Fourier frequency resolved spectral analysis showed, that the variability of the reflected component at frequencies higher than ∼1−10 Hz is suppressed in comparison with that of the primary emission.

Fluorescent iron lines as a probe of astrophysical black hole systems

“…As shown in Fig. 21, although the overall correlation was found, it was not as strong as described by the models of Revnivtsev et al [302]. Furthermore, a slightly better correlation was found between amplitude of reflection and soft X-ray flux [52, and Fig.…”

“…Both of these objections have been alleviated to some extent by considering multiple observations of single objects that represent a wide range of flux and spectral slopes. Furthermore, these observations have been fit with a variety of models (that bear in mind possible systematic errors), all of which yield the basic correlation [277,302,52]. The ability to observe GBHC over a very wide variety of accretion rate states has proven crucial for such studies.…”

“…As for the case of NGC 5548, however, the details of the overall correlation are more complicated than any simple model. Analyzing RXTE observations of Cyg X-1 and GX 339−4, Marat Gilfanov, Michael Revnivtsev, and Eugene Churazov used a crude Gaussian convolution of a reflection model (to mimic relativistic effects) to deduce a very strong correlation between spectral slope and amplitude of reflection [277,302]. Furthermore, they found that the width of the Gaussian smearing (or equivalently, the amplitude of the relativistic distortions) increased as the spectrum softened and the reflection amplitude increased.…”

Limits on pair production and multizone Comptonization: the broad-band X/γ-ray spectrum of XTE J1550–564 revisited

“…The energy band used for spectral modelling is 3-20 keV. To extract the spectrum of the fast variability, we follow the procedure described in Revnivstev, Gilfanov & Churazov (1999) and Revnivstev, Gilfanov & Churazov (2001). We extract a light curve for each available channel for each observation and construct a power-density spectrum (PDS).…”

Multi-Wavelength Variability

“…For this reason, the study of spectral-timing in BHXRBs, pioneered by satellites with proportional-counter detectors such Ginga and later RXTE, has necessarily been biased towards studying the power-law in the hard states (e.g. Nowak et al 1999;Revnivtsev et al 2001). In the softer states on the other hand, both the power-law and disc components can be studied and there it is clear that the powerlaw dominates the variability and disc emission seems to be rather stable.…”