Probing the temporal variability of Cygnus X-1 into the soft state

Abstract

Building on results from previous studies of Cygnus~X-1, we analyze Rossi X-ray Timing Explorer (RXTE) data taken when the source was in the soft and transitional spectral states. We look at the power spectrum in the 0.01 -- 50 Hz range, using a model consisting of a cut-off power-law and two Lorentzian components. We are able to constrain the relation between the characteristic frequencies of the Lorentzian components, and show that it is consistent with a power-law relation having the same index (1.2) as previously reported for the hard state, but shifted by a factor ~2. Furthermore, it is shown that the change in the frequency relation seen during the transitions can be explained by invoking a shift of one Lorentzian component to a higher harmonic, and we explore the possible support for this interpretation in the other component parameters. With the improved soft state results we study the evolution of the fractional variance for each temporal component. This approach indicates that the two Lorentzian components are connected to each other, and unrelated to the power-law component in the power spectrum, pointing to at least two separate emission components.

arXiv comment11 pages, 10 figures, 1 electronic table. Accepted for publication in A&A

References in corpus (33)

• Lense-Thirring Precession and QPOs in Low Mass X-Ray Binaries
• RXTE Observation of Cygnus X-1: II. Timing Analysis
• The evolution of the timing properties of the black-hole transient GX 339-4 during its 2002/2003 outburst
• Radiation mechanisms and geometry of Cygnus X-1 in the soft state
• Correlations in the QPO Frequencies of Low Mass X-Ray Binaries and the Relativistic Precession Model
• kHz Quasi Periodic Oscillations in Low Mass X-ray Binaries as Probes of General Relativity in the Strong Field Regime
• The flux-dependent amplitude of broadband noise variability in X-ray binaries and active galaxies
• Soft state of Cygnus X-1: stable disk and unstable corona
• Radiative Processes, Spectral States and Variability of Black-Hole Binaries
• The broad-band power spectra of X-ray binaries
• Spectral Transitions in Cyg X-1 and Other Black Hole X-Ray Binaries
• Simultaneous X-ray and gamma-ray observations of Cyg X-1 in the hard state by Ginga and OSSE
• Are There Three Peaks in the Power Spectra of GX 339-4 and Cyg X-1?
• Long Term Variability of Cyg X-1 I. X-ray spectral-temporal correlations in the hard state
• Understanding the long-term spectral variability of Cygnus X-1 with BATSE and ASM observations
• Temporal Properties of Cygnus X-1 During the Spectral Transitions
• Orbital, precessional and flaring variability of Cygnus X-1
• Tracing the power-law component in the energy spectrum of black hole candidates as a function of the QPO frequency
• Long Term Variability of Cygnus X-1. IV. Spectral Evolution 1999-2004
• Coronal--Temporal Correlations in GX339-4: Hysteresis, Possible Reflection Changes, and Implications for ADAFs
• Long Term Variability of Cyg X-1, II. The rms-Flux Relation
• Broad-band spectra of Cyg X-1 and correlations between spectral characteristics
• Patterns of energy-dependent variability from Comptonization
• RXTE Observation of Cygnus X-1 In Its High State
• Orbital modulation and longer-term variability in the radio emission from Cygnus X-1
• Evolution of the 0.01 - 25 Hz power spectral components in Cygnus X-1
• X-ray temporal properties of XTE J1650-500 during outburst decay
• Understanding Spectral Variability and Time Lags in Accreting Black Holes
• Correlation between radio luminosity and X-ray timing frequencies in neutron star and black hole X-ray binaries
• Energy-dependent variability from accretion flows
• INTEGRAL & RXTE Power Spectra of Cygnus X-1
• Modelling the energy dependencies of X-ray quasi-periodic oscillations in accreting compact objects
• Different kinds of long-term variability from Cygnus X-1

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