Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Long term spectral variability in the soft gamma ray repeater SGR
  1900+14   We present a systematic analysis of all the BeppoSAX data of SGR 1900+14. The
observations spanning five years show that the source was brighter than usual
on two occasions: ~20 days after the August 1998 giant flare and during the
10^5 sec long X-ray afterglow following the April 2001 intermediate flare. In
the latter case, we explore the possibility of describing the observed short
term softening only with a change of the temperature of a blackbody-like
component. In the only BeppoSAX observation performed before the giant flare,
the spectrum of the SGR 1900+14 persistent emission was significantly harder
and possibly detected also above 10 keV with the PDS instrument. In the last
BeppoSAX observation (April 2002) the flux was ~25 % lower than the historical
level, suggesting that the source was entering a quiescent period.

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The categories of this paper are: q-fin
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The categories of this paper are: hep-lat
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The categories of this paper are: q-bio
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The categories of this paper are: quant-ph
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ex
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The categories of this paper are: econ
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The categories of this paper are: nlin
7
The categories of this paper are: hep-th
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The categories of this paper are: plasm-ph
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The categories of this paper are: adap-org
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The categories of this paper are: atom-ph
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The categories of this paper are: supr-con
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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: chem-ph