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arXiv · 1801.10203

Light rays and wave fronts in strong gravity

V. Karas·Y. Kojima·D. Kunneriath
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Abstract

Accretion onto black holes often proceeds via an accretion disk or a temporary disk-like pattern. Variability features observed in light curves as well as theoretical models of accretion flows suggest that accretion disks tend to be inhomogeneous -- variety of substructures (clumps) emerge within the flow. Rapid orbital motion of individual clumps then modulates the observed signal in X-rays. Furthermore, changes of spectral lines and polarization properties of the observed signal (or the absence of changes) constrain the models and reveal information about general relativity (GR) effects. In this write-up we summarize the basic equations that have been employed to study light propagation near black holes and to derive the radiation signal that can be expected at a detector within the framework of geometrical optics approximation.

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V. Karas, Y. Kojima, D. Kunneriath. 2018-01-30. Light rays and wave fronts in strong gravity. https://arxiv.org/abs/1801.10203

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