A characteristic optical variability time scale in astrophysical accretion disks
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.
Citation
Burke , C J , Shen , Y , Blaes , O , Gammie , C F , Horne , K , Jiang , Y-F , Liu , X , McHardy , I M , Morgan , C W , Scaringi , S & Yang , Q 2021 , ' A characteristic optical variability time scale in astrophysical accretion disks ' , Science , vol. 373 , no. 6556 , pp. 789-792 . https://doi.org/10.1126/science.abg9933
Publication
Science
Status
Peer reviewed
ISSN
0036-8075Type
Journal article
Rights
Copyright © 2021 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. This work has been made available online in accordance with publisher policies or with permission. Permission for further reuse of this content should be sought from the publisher or the rights holder. This is the author created accepted manuscript following peer review and may differ slightly from the final published version. The final published version of this work is available at www.XXXX.xxx / https://doi.org/10.1126/science.abg9933.
Description
C.J.B. acknowledges support from an Illinois Graduate Survey Science Fellowship. Y.S. was supported by NSF grant AST-2009947. C.F.G. was supported by NSF grants AST-1716327 and OISE-1743747. K.H. was supported by UK STFC grant ST/R000824/1. I.M.M. was supported by UK STFC grant ST/R000638/1. C.W.M. was supported by NSF grant AST-2007680.Collections
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