The Mysterious, Ordered Variability

of Black Hole X-ray Binaries

Omer Blaes

UCSB Physics

 

Accretion flows onto black holes are complex, chaotic whirlpools of plasma full of magnetohydrodynamical turbulence.  It is therefore not surprising that these flows exhibit broadband variability on all sorts of time scales.  What is surprising, however, is that there is order in all this chaos.  The accretion flow appears to be "quantized" into three well-defined spectral/variability states, and in one of these states there is quasi-periodic variability occurring at stable frequencies:  there is some sort of clock in the flow that knows about the properties of the black hole spacetime.