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The magnetic nature of disk accretion onto black holes

Naturevolume 441pages953955 (2006) | Download Citation



Although disk accretion onto compact objects—white dwarfs, neutron stars and black holes—is central to much of high-energy astrophysics, the mechanisms that enable this process have remained observationally difficult to determine. Accretion disks must transfer angular momentum in order for matter to travel radially inward onto the compact object1. Internal viscosity from magnetic processes1,2,3,4 and disk winds5 can both in principle transfer angular momentum, but hitherto we lacked evidence that either occurs. Here we report that an X-ray-absorbing wind discovered in an observation of the stellar-mass black hole binary GRO J1655 - 40 (ref. 6) must be powered by a magnetic process that can also drive accretion through the disk. Detailed spectral analysis and modelling of the wind shows that it can only be powered by pressure generated by magnetic viscosity internal to the disk or magnetocentrifugal forces. This result demonstrates that disk accretion onto black holes is a fundamentally magnetic process.

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We acknowledge conversations with N. Calvet, L. Hartmann, D. Proga and M. Rupen. We are indebted to A. Prestwich, H. Tananbaum and the Chandra staff for help in making this observation possible. We thank B. Lauritsen for editorial insights. This work was supported by NASA through the Chandra guest observer programme (J.M.M.). Author Contributions J.M.M. analysed the Chandra data and wrote most of the paper. J.R. developed the photoionization model. J.M.M., J.R., A.F. and C.R. developed the interpretation of the data. D.S., J.H., M.K. and R.W. contributed insights on X-ray binaries and/or made supporting observations with other instruments. All others discussed the work at length, and contributed to the manuscript.

Author information


  1. Department of Astronomy, University of Michigan, Ann Arbor, 500 Church Street, Michigan, 48109, USA

    • Jon M. Miller
  2. Harvard-Smithsonian Center for Astrophysics, Cambridge, 60 Garden Street, Massachusetts, 02138, USA

    • John Raymond
    •  & Danny Steeghs
  3. Institute of Astronomy, University of Cambridge, Cambridge, CB3 OHA, UK

    • Andy Fabian
  4. Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, 77 Massachusetts Avenue, Massachusetts, 02139, USA

    • Jeroen Homan
  5. Department of Astronomy, University of Maryland, College Park, Maryland, 20742, USA

    • Chris Reynolds
  6. Astronomical Institute Anton Pannekoek, University of Amsterdam, Amsterdam, Kruislaan 403, 1098 SJ, The Netherlands

    • Michiel van der Klis
    •  & Rudy Wijnands


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Reprints and permissions information is available at npg.nature.com/reprintsandpermissions. The authors declare no competing financial interests.

Corresponding author

Correspondence to Jon M. Miller.

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    This file contains Supplementary Figures 1 and 2 and Supplementary Tables. (PDF 340 kb)

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