Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: THE UNUSUAL X-RAY AND OPTICAL PROPERTIES OF THE ULTRASOFT AGN ZWICKY
  159.034 (RE J 1237+264)   Zwicky 159.034, one of the Seyfert galaxies identified with EUV sources
detected during the ROSAT Wide Field Camera (WFC) all-sky survey, has unusual
properties. The ROSAT Position Sensitive Proportional Counter (PSPC) 0.1--2.5
keV X-ray spectrum, obtained simultaneously with the WFC survey, appears
extremely steep. Subsequent deeper pointed observations with ROSAT revealed
that its 0.1--2.5 keV count rate had decreased by an extremely large amount (a
factor of about 70). This is comparable to the variability amplitude seen in
another ultrasoft Seyfert, E1615+061. There appears to be about 10 times as
much flux in the soft component as in any expected hard tail suggesting that,
in the absence of partial covering of the hard flux, the soft flux cannot arise
via reprocessing of the hard tail. Its peculiar optical spectrum has permitted
lines with widths about 1200--1500 km s^{-1}, and forbidden lines are weak or
absent. Its optical spectrum shows evidence for variability, and might be used
to study the role reprocessed X-rays play in the formation of optical lines.

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The categories of this paper are: stat
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The categories of this paper are: cs
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The categories of this paper are: hep-ph
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The categories of this paper are: q-alg
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The categories of this paper are: math
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The categories of this paper are: eess
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The categories of this paper are: cmp-lg
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The categories of this paper are: cond-mat
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The categories of this paper are: physics
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The categories of this paper are: nucl-th
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The categories of this paper are: solv-int
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The categories of this paper are: hep-ex
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The categories of this paper are: adap-org
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The categories of this paper are: hep-lat
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The categories of this paper are: chao-dyn
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The categories of this paper are: alg-geom