Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ASCA Observations of the Ionized Gas in the Seyfert Galaxy NGC 3783   We present the results from ASCA observations of NGC 3783 carried out during
1993 and 1996. Variability is observed both between the two epochs and within
the individual observations, the latter due to a non-stationary process.
  We find the spectra at both epochs to contain features due to absorption by
ionized material, predominantly due to Ovii and Oviii. We find the opacity for
such material to decrease by a factor approx 2 in the approx 0.7--1.0 keV band
between the epochs while the photoionizing flux increases by approx25%. By
comparison with detailed photoionization models we show this behaviour is
inconsistent with that expected from a single-zone of photoionized gas. A
deficit in the data compared to such models, consistent with excess absorption
by Oviii, supports the suggestion that the material consists of two or more
zones.
  Significant Fe K-shell emission is also observed during both epochs. We show
this emission is dominated by the asymmetric line profile expected from the
innermost regions of the accretion flow. We find no evidence that the Fe
emission varied in either shape or equivalent width between the two epochs.

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The categories of this paper are: econ
11
The categories of this paper are: hep-lat
1
The categories of this paper are: cs
22
The categories of this paper are: chao-dyn
9
The categories of this paper are: nlin
36
The categories of this paper are: cmp-lg
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
27
The categories of this paper are: comp-gas
21
The categories of this paper are: adap-org
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
8
The categories of this paper are: hep-ex
34
The categories of this paper are: chem-ph