Flip-flop states in X-ray binaries and changing-state AGN

Abstract

We show that the flip-flop transitions in X-ray binaries (rapid cycling between different spectral states which are sometimes seen near the global state transition) show a series of analogies to the changing state phenomena (rapid changes in the emission line properties that seem to be driven by changes in the central engine) in active galactic nuclei (AGN). Specifically, (1) the timescales for the transitions scale approximately linearly with mass and (2) both phenomena occur at a few percent of the Eddington luminosity. Because most accretion physics is expected to be scale-free, it is likely that these represent two manifestations of the same phenomena. Demonstrating this would allow the use of a much wider range of observational techniques, on a much wider range of characteristic timescales, and provide a clearer pathway toward understanding these rapid transitions than is currently available. We discuss potential means to establish the connection more firmly, and to use the combination of the observational advantages of both classes of systems to develop a better understanding of the phenomenon.

Figures (2)

• Figure 1: Top: the WISE light curve for the recurring CSAGN, J002311.06+003517.5, reported in wang25DongLAMOSTsample, chosen because it shows the relevant state change and return most clearly of the recurring state change objects. For the black hole mass of approximately $10^9 M_\odot$, the faint state lasts the equivalent of about 3 seconds for a stellar mass black hole, and is one of the fastest objects in the sample of DongLAMOSTsample in terms of during relative to black hole mass. Bottom: RXTE data from the source XTE J1859+226, first reported in 2004AA...426..587C. Here, sharp changes in count rate are seen in association with changes in the Fourier power spectrum; in the fainter states, there is strong aperiodic variability and no clear QPO, while in the brighter states, there is a clear QPO and little or no aperiodic variability. The upper axis label gives the time in units re-scaled to a typical CSAGN with a black hole mass of $10^{7.5} M_\odot$.
• Figure 2: A cartoon illustrating the evolution of the jets in response to the state transitions. Phase (a) represents the system after it has been in a hard state for an extended period of time, and established its quasi-equilibrium configuration with stochastic variability due to internal shocks. Phase (b) represents the system after it has settled into a soft state, so that the part of the jet far from the black hole is largely unchanged, but the part near the black hole is missing. Phase (c) represents the system shortly after it re-enters a hard state, so that the new jet (in green) has started to form and has internal shocking taking place, but it has not yet re-connected with the old jet. Phase (d) represents the system shortly after the new jet reconnects with the old jet, with the orange region representing the location where the excess energy of the new jet is suddenly dissipated.