Tomas Pechacek

In 2014, Tomas has moved to University of Crete to work with Iossif Papadakis.

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Tomas Pechacek is postdoctoral researcher. He is interested in stochastic variability of X-ray sources and calculates, in full generality, power spectra profiles corresponding to orbiting hot spots in accretion discs.

Radiation from accreting black holes varies on different timescales. In X-rays, the observed light-curve is a complicated noisy curve that can be represented by a broad-band power spectrum. 'Hot spots' on the accretion disc have been identified as a possible contributor to this variability. Various schemes have been proposed in which spots are mutually interconnected in some way, however, the origin of variability has not yet been fully understood. In my current research project I study statistical properties of model light-curves, constructed as a sum of contributions from many sources that are orbiting above an underlying accretion disc. The expected power spectral profiles are generated by employing different avalanching mechanisms, within the framework of the theory of point processes.