Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Intensity and polarization of radiation reflected from accretion disc   We consider the reflection of non-polarized radiation from the point-like
sources above the accretion discs both the optically thick and optically thin.
We investigate the dependence of the polarization of reflected radiation on the
aperture angle of incident radiation. The aperture angle is determined by the
radius of accretion disc and the height of the source above the disc. For
optically thick accretion discs we show that, if the aperture angle is smaller
70 grad, then the wave electric field oscillations of reflected radiation are
parallel to the accretion disc plane. For aperture angle greater than 70 grad
the electric field oscillations are parallel to the plane "normal to accretion
disc - the line of sight". The latter also holds for reflection from the
optically thin accretion disc independent of the aperture angle value.

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The categories of this paper are: comp-gas
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The categories of this paper are: mtrl-th
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: econ
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The categories of this paper are: solv-int
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The categories of this paper are: dg-ga
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The categories of this paper are: q-fin
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-ex
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: math
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-th