Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Soft X-ray spectroscopy of Compton-thick Seyfert 2 galaxies with
  BeppoSAX   We present a X-ray spectroscopic study of the bright Compton-thick Seyfert 2s
NGC1068 and the Circinus Galaxy, performed with BeppoSAX. Matt et al. (1997 and
1998) interpreted the spectrum above 4 keV as the superposition of Compton
reflection and warm plasma scattering of the nuclear radiation. When this
continuum is extrapolated downwards to 0.1 keV, further components arise. The
NGC1068 spectrum is rich in emission lines, mainly due to K-alpha transitions
of He-like elements from oxygen to iron, plus a K-alpha fluorescent line from
neutral iron. If the ionized lines originate in the warm scatterer, its thermal
and ionization structure must be complex. From the continuum and line
properties, we estimate a column density, of the warm scatterer less than a few
10^21 atoms/cm/cm. In the Circinus Galaxy, the absence of highly ionized iron
is consistent with a scattering medium with ionization parameter U<5 and
density about a few times 10^22 atoms/cm/cm. In both cases the neutral iron
line is most naturally explained as fluorescence in the medium responsible for
the Compton reflection continuum. In NGC1068 an optically thin plasma emission
with kT~500 eV and strongly sub-solar metallicity is required, while such a
component is only marginal in the Circinus Galaxy. We tentatively identify this
component as emission of diffuse hot gas in the nuclear starbursts. Possible
causes for the metal depletion are discussed.

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The categories of this paper are: q-fin
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The categories of this paper are: stat
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The categories of this paper are: plasm-ph
1
The categories of this paper are: cs
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The categories of this paper are: math-ph
2
The categories of this paper are: math
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-ph
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The categories of this paper are: funct-an
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The categories of this paper are: bayes-an
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The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
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The categories of this paper are: mtrl-th