Hysteresis in the light curves of soft X-ray transients

By T. Maccarone, P. Coppi. 2002

155 citations recorded by the source corpus.

Using Proportional Counter Array (PCA) data from the Rossi X-Ray Timing Explorer (RXTE), we track the spectral states of the neutron star transient system Aql X-1 through a complete outburst cycle. We find a hard-to-soft state transition during the very early, rising phase of the outburst, and show that there is a hysteresis effect such that the transition back to the hard state occurs at a luminosity ~5 times lower than the hard-to-soft transition. This hysteresis effect rules out the propeller mechanism as the sole cause of state transitions in Aql X-1. Assuming the propeller mechanism only operates at a luminosity equal to or below that of the observed soft-to-hard transition requires that the magnetic field of Aql X-1 be less than 7 × 10 7 G, the lowest neutron star field known to date. To compare the state transition behaviour of Aql X-1 with that found in transient black hole systems, we use RXTE All-Sky Monitor (ASM) data to compute hardness-intensity diagrams for four black hole candidate transients where the ASM data should also give us state information throughout much of the outburst cycles. In all four systems, we find evidence for a hard-to-soft state transition during the rising outburst phase and for the source staying in a soft state down to much lower luminosities during the declining phase, i.e. a hysteresis effect. This similarity suggests a common origin for state transitions in low magnetic field neutron star and black hole systems, and the hysteresis effect rules out the 'strong ADAF (advection-dominated accretion flow) principle' for determining the state of an accretion disc. We discuss the general implications of these observations for current models of state transitions. We note the contrast to previous observations of the non-transient systems Cygnus X-1 and X-3, which do not show a hysteresis effect.

Subfields: Astronomy and Astrophysics

View Paper: https://www.semanticscholar.org/paper/d1045eed76388c04a866532fc61e9bd72561c12f

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Citations in the corpus

A radio-emitting outflow in the quiescent state of A0620−00: implications for modelling low-luminosity black hole binaries (2006, background): “Above this critical luminosity, and allowing for hysteresis effects (Maccarone & Coppi 2003), the systems make a transition to the thermal dominant state, and their core radio emission is quenched below detectable levels.”
The Evolution of Black Hole States (2004, background): “They also suggested that the very-high state and the intermediate state(s) are one and the same state and represent transitions between the low/hard and high/soft states at different luminosities.”
GX 339—4: the distance, state transitions, hysteresis and spectral correlations (2004, background): “The presence of hysteresis in GX 339–4 has been found before by, e.g., Miyamoto et al. (1995), Smith et al. (2002b), Nowak, Wilms & Dove (2002), and by, e.g., Maccarone & Coppi (2003) and Rossi et al. (2004) in some other black-hole and neutron-star binaries.”
X-Ray Properties of Black-Hole Binaries (2006, background): “The hysteresis in transitions to and from the hard state are especially evident in the HID (panel d; see also Maccarone & Coppi 2003).”
Do X-ray binary spectral state transition luminosities vary? (2003, background): “…state transitions occur in quasi-equilibrium states, while the hard-to-soft occur in violently unstable states, there may be instrinsic variations in the hard-to-soft state transition luminosities that do not occur in the soft-to-hard state transition luminosities (Maccarone & Coppi 2003a).”
The 'universal' radio/X-ray flux correlation : the case study of the black hole GX 339-4 (2012, background): “The transition back to the hard state occurred at lower X-ray flux defining an hysteresis cycle (Maccarone & Coppi 2003).”
GRS 1915+105 and the Disc-Jet Coupling in Accreting Black Hole Systems (2004, background): “What is generally observed is a peak in the LS (e.g., Brocksopp et al. 2002, Maccarone & Coppi 2003, Yu et al. 2003).”
A Unified Model for Black Hole X-Ray Binary Jets? (2004, background): “Many – perhaps all – sources which undergo an X-ray outburst have a bright hard state during the rising phase (e.g. Brocksopp et al. 2002; Maccarone & Coppi 2003; Yu et al. 2003; Yu, van der Klis & Fender 2004).”
Global optical/infrared-X-ray correlations in X-ray binaries: quantifying disc and jet contributions (2006, background): “…identified in BHXB transients, and at least one NSXB transient: the hard to soft state transition always occurs at a higher X-ray luminosity than the transition back to the hard state (Maccarone & Coppi 2003; Maccarone, Gallo & Fender 2003; Yu et al. 2003; Fender et al. 2004; Homan & Belloni 2005).”
Modelling the behaviour of accretion flows in X-ray binaries (2007, background): “This effect occurs in all BHB with high enough signal–to–noise to track the transition except for Cyg X-1 (e.g. Maccarone & Coppi 2003).”
Evaluating Spectral Models and the X-Ray States of Neutron Star X-Ray Transients (2007, background): “…& Swank 1997), (2) detailed studies of a large number of observations from a single outburst of a NS X-ray transient (Gierliński & Done 2002b; Maccarone & Coppi 2003b; Maitra & Bailyn 2004), (3) Fourier frequency resolved Xray spectroscopy (Gilfanov et al. 2003; Olive et al. 2003), and (4)…”
WATCHDOG: A COMPREHENSIVE ALL-SKY DATABASE OF GALACTIC BLACK HOLE X-RAY BINARIES (2015, background): “The behavioural pattern often observed during outburst (Maccarone & Coppi 2003; Vadawale et al. 2003) involves the system cycling through a pattern of hard (dominated by Comptonized emission) and soft (dominated by thermal emission) states, where the rise in luminosity at the start of outbursts…”