A ~1-hour X-ray periodicity in an active galaxy RE J1034+396

Understand

Active galactic nuclei and quasars are thought to be scaled up versions of Galactic black hole binaries, powered by accretion onto supermassive black holes with masses of 10^6-10^9 M_Sun, as opposed to the ~10 M_Sun in binaries.

• One example of the similarities between these two types of systems is the characteristic rapid X-ray variability seen from the accretion flow.
• The power spectrum of this variability in black hole binaries consists of a broad, band-limited noise with multiple quasi-periodic oscillations superimposed, where power is concentrated over a narrow range of frequencies.
• Although the broad noise component has been observed in many active galactic nuclei, there are no significant detections of quasi-periodic oscillations.