Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A New Dual-Component Photoionization Model for the Narrow Emission-Line
  Regions in Active Galactic Nuclei   Having found that type 1 Seyfert nuclei have excess [FeVII]6087 emission with
respect to type 2s, Murayama & Taniguchi have proposed that the high-ionization
nuclear emission-line region (HINER) traced by the [FeVII]6087 emission resides
in the inner wall of dusty tori. The covering factor of the torus is usually
large (e.g., ~ 0.9). Further, electron density in the tori (e.g., ~ 10^7-10^8
cm-3) is considered to be higher significantly than that (e.g., ~ 10^3-10^4
cm^-3) in the narrow-line region (NLR). Therefore it is expected that the torus
emission contributes to the majority of the higher-ionization emission lines.
Taking this HINER component into account, we have constructed new
dual-component (i.e., a typical NLR with a HINER torus) photoionization models.
Comparison of our model with the observations show that that if the torus
emission contributes ~ 10 % of the NLR emission, our dual-component model can
explain the observed high [FeVII]6087/[OIII]5007 intensity ratios of the
Seyfert 1s without invoking any unusual assumptions (e.g., the overabundance of
iron).

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The categories of this paper are: plasm-ph
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The categories of this paper are: eess
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The categories of this paper are: dg-ga
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The categories of this paper are: atom-ph
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The categories of this paper are: econ
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The categories of this paper are: hep-ph
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The categories of this paper are: nucl-ex
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The categories of this paper are: cond-mat
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The categories of this paper are: nlin
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The categories of this paper are: cmp-lg
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The categories of this paper are: gr-qc
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The categories of this paper are: math
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The categories of this paper are: physics
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The categories of this paper are: funct-an
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The categories of this paper are: ao-sci
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The categories of this paper are: solv-int