Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New Insights into SNR Evolution Revealed by the Discovery of Recombining
  Plasmas   We report the discovery of recombining plasmas in three supernova remnants
(SNRs) with the Suzaku X-ray astronomy satellite. During SNR's evolution, the
expanding supernova ejecta and the ambient matter are compressed and heated by
the reverse and forward shocks to form an X-ray emitting hot plasma. Since
ionization proceeds slowly compared to shock heating, most young or middle-aged
SNRs have ionizing (underionized) plasmas. Owing to high sensitivity of Suzaku,
however, we have detected radiative recombination continua (RRCs) from the SNRs
IC 443, W49B, and G359.1-0.5. The presence of the strong RRC is the definitive
evidence that the plasma is recombining (overionized). As a possible origin of
the overionization, an interaction between the ejecta and dense circumstellar
matter is proposed; the highly ionized gas was made at the initial phase of the
SNR evolution in dense regions, and subsequent rapid adiabatic expansion caused
sudden cooling of the electrons. The analysis on the full X-ray band spectrum
of IC 443, which is newly presented in this paper, provides a consistent
picture with this scenario. We also comment on the implications from the fact
that all the SNRs having recombining plasmas are correlated with the
mixed-morphology class.

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The categories of this paper are: hep-ph
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The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
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The categories of this paper are: q-fin
4
The categories of this paper are: cond-mat
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph
22
The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
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The categories of this paper are: hep-lat
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The categories of this paper are: hep-ex
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The categories of this paper are: physics
27
The categories of this paper are: comp-gas
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The categories of this paper are: nlin
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The categories of this paper are: q-bio