THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1
The compact primary in the X-ray binary Cygnus X-1 was the first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, and for the orbital inclination angle of the binary. Building on these results, which are based on our favo...
| Main Authors: | , , , , , , , , , |
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| Format: | Article |
| Language: | en_US |
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Institute of Physics/American Astronomical Society
2015
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| Online Access: | http://hdl.handle.net/1721.1/95710 |
| _version_ | 1826214037594046464 |
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| author | Gou, Lijun McClintock, Jeffrey E. Reid, Mark J. Orosz, Jerome A. Steiner, James F. Narayan, Ramesh Xiang, Jingen Arnaud, Keith A. Davis, Shane W. Remillard, Ronald A |
| author2 | MIT Kavli Institute for Astrophysics and Space Research |
| author_facet | MIT Kavli Institute for Astrophysics and Space Research Gou, Lijun McClintock, Jeffrey E. Reid, Mark J. Orosz, Jerome A. Steiner, James F. Narayan, Ramesh Xiang, Jingen Arnaud, Keith A. Davis, Shane W. Remillard, Ronald A |
| author_sort | Gou, Lijun |
| collection | MIT |
| description | The compact primary in the X-ray binary Cygnus X-1 was the first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, and for the orbital inclination angle of the binary. Building on these results, which are based on our favored (asynchronous) dynamical model, we have measured the radius of the inner edge of the black hole's accretion disk by fitting its thermal continuum spectrum to a fully relativistic model of a thin accretion disk. Assuming that the spin axis of the black hole is aligned with the orbital angular momentum vector, we have determined that Cygnus X-1 contains a near-extreme Kerr black hole with a spin parameter a * > 0.95 (3σ). For a less probable (synchronous) dynamical model, we find a * > 0.92 (3σ). In our analysis, we include the uncertainties in black hole mass, orbital inclination angle, and distance, and we also include the uncertainty in the calibration of the absolute flux via the Crab. These four sources of uncertainty totally dominate the error budget. The uncertainties introduced by the thin-disk model we employ are particularly small in this case given the extreme spin of the black hole and the disk's low luminosity. |
| first_indexed | 2024-09-23T15:58:48Z |
| format | Article |
| id | mit-1721.1/95710 |
| institution | Massachusetts Institute of Technology |
| language | en_US |
| last_indexed | 2024-09-23T15:58:48Z |
| publishDate | 2015 |
| publisher | Institute of Physics/American Astronomical Society |
| record_format | dspace |
| spelling | mit-1721.1/957102022-10-02T05:28:45Z THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 Gou, Lijun McClintock, Jeffrey E. Reid, Mark J. Orosz, Jerome A. Steiner, James F. Narayan, Ramesh Xiang, Jingen Arnaud, Keith A. Davis, Shane W. Remillard, Ronald A MIT Kavli Institute for Astrophysics and Space Research Remillard, Ronald Alan The compact primary in the X-ray binary Cygnus X-1 was the first black hole to be established via dynamical observations. We have recently determined accurate values for its mass and distance, and for the orbital inclination angle of the binary. Building on these results, which are based on our favored (asynchronous) dynamical model, we have measured the radius of the inner edge of the black hole's accretion disk by fitting its thermal continuum spectrum to a fully relativistic model of a thin accretion disk. Assuming that the spin axis of the black hole is aligned with the orbital angular momentum vector, we have determined that Cygnus X-1 contains a near-extreme Kerr black hole with a spin parameter a * > 0.95 (3σ). For a less probable (synchronous) dynamical model, we find a * > 0.92 (3σ). In our analysis, we include the uncertainties in black hole mass, orbital inclination angle, and distance, and we also include the uncertainty in the calibration of the absolute flux via the Crab. These four sources of uncertainty totally dominate the error budget. The uncertainties introduced by the thin-disk model we employ are particularly small in this case given the extreme spin of the black hole and the disk's low luminosity. Smithsonian Institution (Smithsonian Endowment Funds) United States. National Aeronautics and Space Administration (NASA grant DD0-11049X) United States. National Aeronautics and Space Administration (NASA grant DD1-12054X) United States. National Aeronautics and Space Administration (NASA grant NNX11AD08G) 2015-02-27T14:20:27Z 2015-02-27T14:20:27Z 2011-12 2011-06 Article http://purl.org/eprint/type/JournalArticle 0004-637X 1538-4357 http://hdl.handle.net/1721.1/95710 Gou, Lijun, Jeffrey E. McClintock, Mark J. Reid, Jerome A. Orosz, James F. Steiner, Ramesh Narayan, Jingen Xiang, Ronald A. Remillard, Keith A. Arnaud, and Shane W. Davis. “THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1.” The Astrophysical Journal 742, no. 2 (November 9, 2011): 85. © 2011 American Astronomical Society. en_US http://dx.doi.org/10.1088/0004-637X/742/2/85 Astrophysical Journal Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. application/pdf Institute of Physics/American Astronomical Society American Astronomical Society |
| spellingShingle | Gou, Lijun McClintock, Jeffrey E. Reid, Mark J. Orosz, Jerome A. Steiner, James F. Narayan, Ramesh Xiang, Jingen Arnaud, Keith A. Davis, Shane W. Remillard, Ronald A THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 |
| title | THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 |
| title_full | THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 |
| title_fullStr | THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 |
| title_full_unstemmed | THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 |
| title_short | THE EXTREME SPIN OF THE BLACK HOLE IN CYGNUS X-1 |
| title_sort | extreme spin of the black hole in cygnus x 1 |
| url | http://hdl.handle.net/1721.1/95710 |
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