Friday 16 September 2016
to 11:30 at
Alexandra Veledina (Nordita)
Accreting black hole binaries are among the most powerful sources in the Universe. They are factories transferring gravitational energy to radiation with an efficiency
exceeding that obtained in the thermonuclear reactions. Physical processes operating in these objects used to be studied through the X-ray vision as these are the wavelengths where most of the gravitational energy is liberated.
Because all the black hole binaries are far far away, their direct imaging is impossible, and they are studied through the spectroscopic and timing techniques. Black hole binaries demonstrate high amplitude of variability on a range of timescales from milliseconds to weeks. Properties of the shortest timescales are good tracers of system geometry and were initially used to prove that the central source of these objects is highly compact, much more compact than a typical star.
I will describe recent advances in the field of X-ray timing and show how they can be used to obtain physical parameters of accretion, such as the accretion disc viscosity.