Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A receding torus model for the Iwasawa-Taniguchi effect for
  Compton-thick AGN   Recently, Boorman et al. (2018) reported on the discovery of the
Iwasawa-Taniguchi (I-T) effect (a.k.a. X-ray Baldwin effect) for Compton-thick
AGN. They measured a decrease of the 6.4 keV iron line equivalent width with
the 12mu luminosity, assumed as a proxy for the intrinsic X-ray luminosity,
which in Compton-thick AGN is not directly observable. One of the most popular
explanations of the classic I-T effect is the so-called receding torus model,
i.e. the decrease of the covering factor of the molecular `torus' with X-ray
luminosity. In this paper we show that an I-T effect for Compton-thick AGN is
indeed expected in the receding torus model, assuming that the torus is
funnelling the primary X-ray luminosity which is then scattered in a `hot
mirror'. We found that the observed relation is well reproduced provided that
the typical column density of the `hot mirror' is about 7.5x10^{22} cm^{-2}.

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The categories of this paper are: supr-con
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: solv-int
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The categories of this paper are: eess
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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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: ao-sci
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The categories of this paper are: q-alg