Letter | Published:

Strong disk winds traced throughout outbursts in black-hole X-ray binaries

Nature volume 554, pages 6972 (01 February 2018) | Download Citation


Recurring outbursts associated with matter flowing onto compact stellar remnants (such as black holes, neutron stars and white dwarfs) in close binary systems provide a way of constraining the poorly understood accretion process. The light curves of these outbursts are shaped by the efficiency of angular-momentum (and thus mass) transport in the accretion disks, which has traditionally been encoded in a viscosity parameter, α. Numerical simulations1,2,3 of the magneto-rotational instability that is believed to be the physical mechanism behind this transport yield values of α of roughly 0.1–0.2, consistent with values determined from observations of accreting white dwarfs4. Equivalent viscosity parameters have hitherto not been estimated for disks around neutron stars or black holes. Here we report the results of an analysis of archival X-ray light curves of 21 outbursts in black-hole X-ray binaries. By applying a Bayesian approach to a model of accretion, we determine corresponding values of α of around 0.2–1.0. These high values may be interpreted as an indication either of a very high intrinsic rate of angular-momentum transport in the disk, which could be sustained by the magneto-rotational instability only if a large-scale magnetic field threads the disk5,6,7, or that mass is being lost from the disk through substantial outflows, which strongly shape the outburst in the black-hole X-ray binary. The lack of correlation between our estimates of α and the accretion state of the binaries implies that such outflows can remove a substantial fraction of the disk mass in all accretion states and therefore suggests that the outflows correspond to magnetically driven disk winds rather than thermally driven ones, which require specific radiative conditions8.

Access optionsAccess options

Rent or Buy article

Get time limited or full article access on ReadCube.

from $8.99

All prices are NET prices.


  1. 1.

    , , , & Convection causes enhanced magnetic turbulence in accretion disks in outburst. Astrophys. J. 787, 1 (2014)

  2. 2.

    , , , & Dwarf nova outbursts with magnetorotational turbulence. Mon. Not. R. Astron. Soc. 462, 3710–3726 (2016)

  3. 3.

    , , & Impact of convection and resistivity on angular momentum transport in dwarf novae. Astron. Astrophys. (2017)

  4. 4.

    & The viscosity parameter and the properties of accretion disc outbursts in close binaries. Astron. Astrophys. 545, A115 (2012)

  5. 5.

    , & The magnetorotational instability as a jet launching mechanism. Astron. Astrophys. 550, A61 (2013)

  6. 6.

    & Local study of accretion disks with a strong vertical magnetic field: magnetorotational instability and disk outflow. Astrophys. J. 767, 30–48 (2013)

  7. 7.

    , , & Accretion disc dynamo activity in local simulations spanning weak-to-strong net vertical magnetic flux regimes. Mon. Not. R. Astron. Soc. 457, 857–874 (2016)

  8. 8.

    & Coronae and winds from irradiated disks in x-ray binaries. Astrophys. J. 807, 107–116 (2015)

  9. 9.

    An accretion model for the outbursts of U Geminorum stars. Publ. Astron. Soc. Jpn 26, 429–436 (1974)

  10. 10.

    & On the elusive cause of cataclysmic variable outbursts. Astron. Astrophys. 104, 10–12 (1981)

  11. 11.

    Accretion in cataclysmic binaries. IV. Accretion disks in dwarf novae. Acta Astron. 34, 161–189 (1984)

  12. 12.

    , & On the evolution of accretion disc flow in cataclysmic variables – I. The prospect of a limit cycle in dwarf nova systems. Mon. Not. R. Astron. Soc. 205, 359–375 (1983)

  13. 13.

    & Thermal instability accretion disk model for the X-ray transient A0620−00. Astrophys. J. 343, 229–240 (1989)

  14. 14.

    Accretion Disks in Compact Stellar Systems (World Scientific, 1993)

  15. 15.

    Cataclysmic Variable Stars Ch. 3, 126–215 (Cambridge Univ. Press, 1995)

  16. 16.

    , , & Watchdog: a comprehensive all-sky database of galactic black hole x-ray binaries. Astrophys. J. Suppl. Ser. 222, 15 (2016)

  17. 17.

    On the accretion instability in soft x-ray transients. Astrophys. J. 464, L139–L141 (1996)

  18. 18.

    & Instability, turbulence, and enhanced transport in accretion disks. Rev. Mod. Phys. 70, 1–53 (1998)

  19. 19.

    & Black holes in binary systems. Observational appearance. Astron. Astrophys. 24, 337–355 (1973)

  20. 20.

    , & The disc instability model for x-ray transients: evidence for truncation and irradiation. Astron. Astrophys. 373, 251–271 (2001)

  21. 21.

    , & Accretion disc viscosity: how big is alpha? Mon. Not. R. Astron. Soc. 376, 1740–1746 (2007)

  22. 22.

    & Determination of the turbulent parameter in accretion discs: effects of self-irradiation in 4U 1543−47 during the 2002 outburst. Mon. Not. R. Astron. Soc. 468, 4735–4747 (2017)

  23. 23.

    , & Sustained magnetorotational turbulence in local simulations of stratified disks with zero net magnetic flux. Astrophys. J. 713, 52–65 (2010)

  24. 24.

    , & Emergent mesoscale phenomena in magnetized accretion disc turbulence. Mon. Not. R. Astron. Soc. 422, 2685–2700 (2012)

  25. 25.

    et al. Simultaneous Chandra and RXTE spectroscopy of the microquasar H1743−322: clues to disk wind and jet formation from a variable ionized outflow. Astrophys. J. 646, 394–406 (2006)

  26. 26.

    et al. Ubiquitous equatorial accretion disc winds in black hole soft states. Mon. Not. R. Astron. Soc. 422, L11–L15 (2012)

  27. 27.

    The case for massive, evolving winds in black hole x-ray binaries. Adv. Space Res. 52, 732–739 (2013)

  28. 28.

    & Global structure of three distinct accretion flows and outflows around black holes from two-dimensional radiation-magnetohydrodynamic simulations. Astrophys. J. 736, 2 (2011)

  29. 29.

    , & The effects of thermodynamic stability on wind properties in different low-mass black hole binary states. Mon. Not. R. Astron. Soc. 436, 560–569 (2013)

  30. 30.

    , , & Photoionization instability of the Fe K absorbing plasma in the neutron star transient AX J1745.6−2901. Mon. Not. R. Astron. Soc. 472, 2454–2461 (2017)

  31. 31.

    et al. Methods and results of an automatic analysis of a complete sample of Swift-XRT observations of grbs. Mon. Not. R. Astron. Soc. 397, 1177–1201 (2009)

  32. 32.

    et al. An online repository of Swift/XRT light curves of gamma-ray bursts. Astron. Astrophys. 469, 379–385 (2007)

  33. 33.

    & The Crab nebula as a calibration source for x-ray astronomy. Astron. J. 79, 995–999 (1974)

  34. 34.

    & Jets in neutron star x-ray binaries: a comparison with black holes. Mon. Not. R. Astron. Soc. 366, 79–91 (2006)

  35. 35.

    , , & emcee: the MCMC hammer. Publ. Astron. Soc. Jpn 125, 306–312 (2013)

  36. 36.

    & Ensemble samplers with affine invariance. Comm. App. Math. Comp. Sci. 5, 65–80 (2010)

  37. 37.

    & The light curves of soft x-ray transients. Mon. Not. R. Astron. Soc. 293, L42–L48 (1998)

  38. 38.

    , , & Disc instability models for X-ray transients: evidence for evaporation and low a-viscosity? Mon. Not. R. Astron. Soc. 314, 498–510 (2000)

  39. 39.

    , & A new heuristic optimization algorithm: harmony search. Simulation 76, 60–68 (2001)

  40. 40.

    , , & X-ray irradiation in low-mass binary systems. Mon. Not. R. Astron. Soc. 303, 139–147 (1999)

  41. 41.

    The disc instability model of dwarf novae and low-mass x-ray binary transients. New Astron. Rev. 45, 449–508 (2001)

  42. 42.

    , & Reprocessing of x rays in low-mass x-ray binaries. Astron. Astrophys. 314, 484–490 (1996)

  43. 43.

    , , & The origin of the rebrightening in soft x-ray transient outbursts. Mon. Not. R. Astron. Soc. 337, 1329–1339 (2002)

  44. 44.

    et al. Observations of the 599 Hz accreting x-ray pulsar IGR J0029l+5934 during the 2004 outburst and in quiescence. Astrophys. J. 672, 1079–1090 (2008)

  45. 45.

    , , & Interpretation of the 1998 outburst of the unique X-ray transient CI Camelopardalis (XTE j0421+560). Mon. Not. R. Astron. Soc. 369, 355–359 (2006)

  46. 46.

    , & Mining the Aql X-l long-term X-ray light curve. Mon. Not. R. Astron. Soc. 432, 1695–1700 (2013)

  47. 47.

    , , & The nature of very faint x-ray binaries: hints from light curves. Mon. Not. R. Astron. Soc. 447, 3034–3043 (2015)

  48. 48.

    , & Mass transfer during low-mass x-ray transient decays. Mon. Not. R. Astron. Soc. 374, 466–476 (2007)

  49. 49.

    , & Soft x-ray transient light curves as standard candles: exponential versus linear decays. Mon. Not. R. Astron. Soc. 301, 382–388 (1998)

  50. 50.

    & X-ray outbursts of low-mass x-ray binary transients observed in the RXTE era. Astrophys. J. 805, 87 (2015)

  51. 51.

    , & X-ray transients: hyper- or hypo-luminous? Astrophys. J. 801, L4 (2015)

  52. 52.

    , , & The black hole mass distribution in the galaxy. Astrophys. J. 725, 1918–1927 (2010)

Download references


B.E.T. thanks participants of the ‘disks17: Confronting MHD Theories of Accretion Disks with Observations’ programme, held at the Kavli Institute for Theoretical Physics (KITP), for their feedback and comments on this project, especially A. Veledina for advice regarding the analysis of the X-ray light curves and P. Charles for comments on the manuscript. B.E.T., G.R.S. and C.O.H. acknowledge support by NSERC Discovery Grants, and C.O.H. by a Discovery Accelerator Supplement. This research was supported in part by the National Science Foundation under grant number NSF PHY-1125915, via support for KITP. J.-P.L. acknowledges support by the Polish National Science Centre OPUS grant 2015/19/B/ST9/01099. J.-P.L. and G.D. also acknowledge support from the French Space Agency CNES. This research has made use of data, software, and/or web tools obtained from the High Energy Astrophysics Science Archive Research Center (HEASARC), a service of the Astrophysics Science Division at NASA/GSFC and of the Smithsonian Astrophysical Observatory’s High Energy Astrophysics Division, data supplied by the UK Swift Science Data Centre at the University of Leicester, and data provided by RIKEN, JAXA and the MAXI team. This work has also made extensive use of NASA’s Astrophysics Data System (ADS).

Author information


  1. Department of Physics, University of Alberta, CCIS 4-181, Edmonton, Alberta T6G 2E1, Canada.

    • B. E. Tetarenko
    • , C. O. Heinke
    •  & G. R. Sivakoff
  2. Institut d’Astrophysique de Paris, CNRS et Sorbonne Universités, UPMC Paris 06, UMR 7095, 98bis Boulevard Arago, 75014 Paris, France

    • J.-P. Lasota
  3. Nicolaus Copernicus Astronomical Centre, Polish Academy of Sciences, ulica Bartycka 18, 00-716 Warsaw, Poland

    • J.-P. Lasota
  4. Université Grenoble Alpes, CNRS, Institut de Planétologie et d’Astrophysique de Grenoble (IPAG), F-38000 Grenoble, France.

    • G. Dubus


  1. Search for B. E. Tetarenko in:

  2. Search for J.-P. Lasota in:

  3. Search for C. O. Heinke in:

  4. Search for G. Dubus in:

  5. Search for G. R. Sivakoff in:


B.E.T. performed the analysis of the X-ray data, wrote the Markov chain Monte Carlo light-curve-fitting algorithm and performed the light-curve fitting, built the Bayesian hierarchical methodology and wrote the paper. J.-P.L. helped to formulate the analytical version of the irradiated-disk-instability model that was fitted to the X-ray light curves, contributed to the interpretation of the data and assisted in writing the discussion in the paper. C.O.H. assisted in the analysis of the X-ray data and the light-curve-fitting process, and contributed to the interpretation of the data. G.D. contributed to the interpretation of the data and assisted in writing the discussion in the paper. G.R.S. assisted in writing the paper and contributed to the interpretation of the data.

Competing interests

The authors declare no competing financial interests.

Corresponding author

Correspondence to B. E. Tetarenko.

Reviewer Information Nature thanks D. Proga and the other anonymous reviewer(s) for their contribution to the peer review of this work.

Publisher's note: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Extended data

About this article

Publication history







By submitting a comment you agree to abide by our Terms and Community Guidelines. If you find something abusive or that does not comply with our terms or guidelines please flag it as inappropriate.