Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the origin of X-ray dips in Her X-1   A strong X-ray illumination of the optical star atmosphere in Her X-1,
asymmetric because of a partial shadowing by the tilted twisted accretion disk
around central neutron star, leads to the formation of matter flows coming out
of the orbital plane and crossing the line of sight before entering the disk.
We suggest that the absorption of X-ray emission by this flow leads to the
formation of pre-eclipse and anomalous dips of type I. These dips are observed
during several orbits after turn-on both in the main-on and short-on state.
Almost coherent action of tidal torques and matter streams enhances the disk
wobbling which causes the disk edge to shield the X-ray source after the
turn-on. Anomalous dips of type II and post-eclipse recovery appear due to this
process only on the first orbit after turn-on.

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The categories of this paper are: hep-th
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The categories of this paper are: econ
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The categories of this paper are: eess
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The categories of this paper are: hep-lat
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The categories of this paper are: chem-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: supr-con
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The categories of this paper are: nlin
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The categories of this paper are: quant-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: math
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The categories of this paper are: stat
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The categories of this paper are: gr-qc
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The categories of this paper are: q-alg