Search for chaos in neutron star systems: Is Cyg X-3 a black hole?

Abstract

The accretion disk around a compact object is a nonlinear general relativistic system involving magnetohydrodynamics. Naturally the question arises whether such a system is chaotic (deterministic) or stochastic (random) which might be related to the associated transport properties whose origin is still not confirmed. Earlier, the black hole system GRS 1915+105 was shown to be low dimensional chaos in certain temporal classes. However, so far such nonlinear phenomena have not been studied fairly well for neutron stars which are unique for their magnetosphere and kHz quasi-periodic oscillation (QPO). On the other hand, it was argued that the QPO is a result of nonlinear magnetohydrodynamic effects in accretion disks. If a neutron star exhibits chaotic signature, then what is the chaotic/correlation dimension? We analyze RXTE/PCA data of neutron stars Sco X-1 and Cyg X-2, along with the black hole Cyg X-1 and the unknown source Cyg X-3, and show that while Sco X-1 and Cyg X-2 are low dimensional chaotic systems, Cyg X-1 and Cyg X-3 are stochastic sources. Based on our analysis, we argue that Cyg X-3 may be a black hole.

9 pages including 6 figures; to appear in The Astrophysical Journal

References in corpus (6)

• Is there a link between the neutron-star spin and the frequency of the kilohertz quasi-periodic oscillations?
• A non subjective approach to the GP algorithm for analysing noisy time series
• Effects of the stellar wind on X-ray spectra of Cygnus X-3
• Epicyclic Oscillations of Fluid Bodies: Newtonian Nonslender Torus
• Higher order nonlinearity in accretion disks: QPOs of black hole and neutron star sources and their spin
• The aperiodic broad-band X-ray variability of Cygnus X-3

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• Revisiting Evidence of Chaos in X-ray Light Curves: The Case of GRS 1915+105
• Correlating nonlinear properties with spectral states of RXTE data: Possible observational evidences for four different accretion modes around compact objects
• Classification of Close Binary Stars Using Recurrence Networks
• Observational evidences for spinning black holes: A proof of general relativity for spacetime around rotating black holes
• A search for chaos in the optical light curve of a blazar: W2R 1926+42
• Correlating nonlinear time series and spectral properties of IGR J17091-3624: Is it similar to GRS 1915+105?