Variability time scales in active galaxies

Abstract

Black Holes\nActive galactic nuclei contain a supermassive black hole (SMBH) surrounded by an accretion disk. As disk material falls toward the SMBH, it heats up enough to emit optical light. Burke et al. investigated how such optical emission varies over time in a sample of 67 active galaxies (see the Perspective by Lira and Arevalo). They observed a characteristic variability in timing that scaled with the SMBH mass. The results elucidate the physical processes within accretion disks and provide a method to estimate SMBH mass from optical variability observations.\n\nScience , abg9933, this issue p. [789][1]; see also abk3451, p. [734][2]\n\n [1]: /lookup/doi/10.1126/science.abg9933\n [2]: /lookup/doi/10.1126/science.abk3451