Global optical/infrared-X-ray correlations in X-ray binaries: quantifying disc and jet contributions

By D. Russell, Robert P. Fender, R. Hynes, C. Brocksopp, J. Homan, Peter G. Jonker, M. M. B. Southampton, Louisiana State Univ., Mssl, Mit and 4 more. 2006

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The optical/near-infrared (OIR) region of the spectra of low-mass X-ray binaries appears to lie at the intersection of a variety of different emission processes. In this paper we present quasi-simultaneous OIR–X-ray observations of 33 XBs in an attempt to estimate the contributions of various emission processes in these sources, as a function of X-ray state and luminosity. A global correlation is found between OIR and X-ray luminosity for low-mass black hole candidate XBs (BHXBs) in the hard X-ray state, of the form LOIR / L 0.6 X . This correlation holds over 8 orders of magnitude in LX and includes data from BHXBs in quiescence and at large distances (LMC and M31). A similar correlation is found in low-mass neutron star XBs (NSXBs) in the hard state. For BHXBs in the soft state, all the near-infrared (NIR) and some of the optical emission is suppressed below the correlation, a behaviour indicative of the jet switching off/on in transition to/from the soft state. We compare these relations to theoretical models of a number of emission processes. We find that X-ray reprocessing in the disc and emission from the jets both predict a slope close to 0.6 for BHXBs, and both contribute to the OIR in BHXBs in the hard state, the jets producing � 90 percent of the NIR emission at high luminosities. X-ray reprocessing dominates the OIR in NSXBs in the hard state, with possible contributions from the jets (only at high luminosity) and the viscously heated disc. We also show that the optically thick jet spectrum of BHXBs extends to near the K-band. OIR spectral energy distributions of 15 BHXBs help us to confirm these interpretations. We present a prediction of the LOIR–LX behaviour of a BHXB outburst that enters the soft state, where the peak LOIR in the hard state rise is greater than in the hard state decline (the well known hysteretical behaviour). In addition, it is possible to estimate the X-ray, OIR and radio luminosity and the mass accretion rate in the hard state quasi-simultaneously, from observations of just one of these wavebands, since they are all linked through correlations. Finally, we have discovered that the nature of the compact object, the mass of the companion and the distance/reddening can be constrained by quasi-simultaneous OIR and X-ray luminosities.

Subfields: Astronomy and Astrophysics, Nuclear and High Energy Physics

View Paper: https://www.semanticscholar.org/paper/441581b8f918c60ce98154aa5b1d88dd87c14c5f

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Citations in the corpus

The 'universal' radio/X-ray flux correlation : the case study of the black hole GX 339-4 (2012, background): “A similarly tight correlation was also found between X-ray and optical/near-infrared (hereafter OIR) emission in a sample of BH candidates (BHC) and also in GX 339−4 over different outbursts (Homan et al. 2005; Russell et al. 2006; Coriat et al. 2009).”
No evidence for black hole spin powering of jets in X-ray binaries (2010, methodology): “In addition to the radio measurements, the decrease in near-infrared jet emission at the transition to the soft X-ray state is also clearly observed, in some cases by up to a factor of 20 (Homan et al. 2005; Russell et al. 2006; see also Russell & Fender 2010).”
Fast infrared variability from a relativistic jet in GX 339-4 (2010, background): “In the hard state of BHs, the jet is expected to dominate the IR emission (Russell et al. 2006, see also 2).”
WATCHDOG: A COMPREHENSIVE ALL-SKY DATABASE OF GALACTIC BLACK HOLE X-RAY BINARIES (2015, background): “Both direct thermal emission from the outer disc (Cantrell et al. 2010; Gelino et al. 2010) and synchrotron emission from a relativistic jet (Gallo et al. 2007; Russell et al. 2006) have been suggested as culprits for this flux contamination.”
Radiatively efficient accreting black holes in the hard state: the case study of H1743-322 (2011, background): “It was subsequently shown that this same correlation also holds between opticalinfrared (OIR) and X-ray fluxes (Homan et al. 2005; Russell et al. 2006, 2007; Coriat et al. 2009).”
VISTA Variables in the Via Lactea (VVV): The public ESO near-IR variability survey of the Milky Way (2009, background): “Fortunately, Xray binaries are usually variable, and their variability ininfrared and X-rays is, for the most part, well correlated (e.g., Russell et al., 2006).”
Rapid optical and X-ray timing observations of GX 339-4: multi-component optical variability in the low/hard state (2010, background): “Several distinct components (including both reprocessed and direct variability) contribute to the optical power of XRBs in general (e.g. Russell et al. 2006).”