Accretion-induced variability links young stellar objects, white dwarfs, and black holes

Abstract

The central engines of disc-accreting stellar-mass black holes appear to be scaled down versions of the supermassive black holes that power active galactic nuclei. However, if the physics of accretion is universal, it should also be possible to extend this scaling to other types of accreting systems, irrespective of accretor mass, size, or type. We examine new observations, obtained with Kepler/K2 and ULTRACAM, regarding accreting white dwarfs and young stellar objects. Every object in the sample displays the same linear correlation between the brightness of the source and its amplitude of variability (rms-flux relation) and obeys the same quantitative scaling relation as stellar-mass black holes and active galactic nuclei. We also show that the most important parameter in this scaling relation is the physical size of the accreting object. This establishes the universality of accretion physics from proto-stars still in the star-forming process to the supermassive black holes at the centers of galaxies.

Description
Copyright © 2015, The Authors. This is an open-access article distributed under the terms of the Creative Commons Attribution license, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Keywords
Accretion, Black Holes, White Dwarfs, Young-Stellar Objects, Timing, Variability, Unification
Citation
Scaringi, S., Maccarone, T. J., Körding, E., Knigge, C., Vaughan, S., Marsh, T. R., Aranzana, E., Dhillon, V. S., & Barros, S. C. C. (2015). Accretion-induced variability links young stellar objects, white dwarfs, and black holes. Science Advances, 1(9), e1500686. https://doi.org/10.1126/sciadv.1500686
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