We present results of recurrence analysis of the black hole X-ray binary
Cygnus X-1 using combined observations from the Rossi X-ray Timing Explorer
All-sky Monitor and the Japanese Monitor of All-sky X-ray Image aboard the ISS.
From the time-dependent windowed recurrence plot (RP), we compute ten
recurrence quantities that describe the dynamical behavior of the source and
compare them to the spectral state at each point in time. We identify epochs of
state changes corresponding to transitions into highly deterministic or highly
stochastic dynamical regimes and their correlation to specific spectral states.
We compare k-Nearest Neighbors and Random Forest models for various sizes of
the time-dependent RP. The spectral state in Cygnus X-1 can be predicted with
greater than 95 per cent accuracy for both types of models explored across a
range of RP sizes based solely on the recurrence properties. The primary
features from the RP that distinguish between spectral states are the
determinism, Shannon entropy, and average line length, all of which are
systematically higher in the hard state compared to the soft state. Our results
suggest that the hard and soft states of Cygnus X-1 exhibit distinct dynamical
variability and the time domain alone can be used for spectral state
classification.Comment: 17 pages, 10 figures, 7 tables; Accepted for publication in Monthly
Notices of the Royal Astronomical Societ