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Burke CJ, Shen Y, Blaes O, Gammie CF, Horne K, Jiang YF, Liu X, McHardy IM, Morgan CW, Scaringi S, Yang Q. A characteristic optical variability time scale in astrophysical accretion disks. Science 2021; 373:789-792. [PMID: 34385395 DOI: 10.1126/science.abg9933] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 06/11/2021] [Indexed: 12/30/2022]
Abstract
Accretion disks around supermassive black holes in active galactic nuclei produce continuum radiation at ultraviolet and optical wavelengths. Physical processes in the accretion flow lead to stochastic variability of this emission on a wide range of time scales. We measured the optical continuum variability observed in 67 active galactic nuclei and the characteristic time scale at which the variability power spectrum flattens. We found a correlation between this time scale and the black hole mass extending over the entire mass range of supermassive black holes. This time scale is consistent with the expected thermal time scale at the ultraviolet-emitting radius in standard accretion disk theory. Accreting white dwarfs lie close to this correlation, suggesting a common process for all accretion disks.
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Affiliation(s)
- Colin J Burke
- Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Center for AstroPhysical Surveys, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Yue Shen
- Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA. .,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Omer Blaes
- Department of Physics, University of California, Santa Barbara, CA 93106, USA
| | - Charles F Gammie
- Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,Illinois Center for Advanced Study of the Universe, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Keith Horne
- School of Physics and Astronomy, University of St. Andrews, Fife KY16 9SS, UK
| | - Yan-Fei Jiang
- Center for Computational Astrophysics, Flatiron Institute, New York, NY 10010, USA
| | - Xin Liu
- Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Ian M McHardy
- Department of Physics and Astronomy, University of Southampton, Southampton SO17 1BJ, UK
| | | | - Simone Scaringi
- Department of Physics, University of Durham, Durham DH1 3LE, UK
| | - Qian Yang
- Department of Astronomy, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA.,National Center for Supercomputing Applications, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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Lira P, Arevalo P. How massive is that black hole? Science 2021; 373:734-735. [PMID: 34385378 DOI: 10.1126/science.abk3451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Affiliation(s)
- Paulina Lira
- Department of Astronomy, Faculty of Physical and Mathematical Science, University of Chile, Santiago, Chile.
| | - Patricia Arevalo
- Department of Physics and Astronomy, University of Valparaiso, Valparaiso, Chile.
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