Nonlinear Oscillations in the Longterm Evolution of LMC X-3
The black hole binary LMC X-3 exhibits long term intensity variations of a
factor of several hundred, with a characteristic time scale of about one
hundred days. Presumed to be periodic based on HEAO-1 A2 data (Cowley et
al.), RXTE/ASM data reveal a more complex variation, not strictly
periodic. We find that times between successive minima are related by
rational fractions, suggesting a stable clock in the system driving a
nonlinear oscillator. Segments whose lengths are multiples of that clock
are extracted from the RXTE ASM light curve and embedded in a phase space
reconstructed from the data. The flow in this representation is
reminiscent of several well-studied low dimensional dynamical systems.
Phase-space evolution similar to many nonlinear dynamical
systems, and markedly dissimilar to random (or periodic) behavior. Note
suggestion of two unstable fixed points in the flow (FPi).
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