Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: ASCA X-Ray Spectroscopy of LMC Supernova Remnants and the Metal
  Abundances of the LMC   We present the results of X-ray spectroscopy of a flux-limited sample of
seven middle-aged supernova remnants (SNRs) in the Large Magellanic Cloud (LMC)
(N23, N49, N63A, DEM71, N132D, 0453-68.5, and N49B), using nonequilibrium
ionization Sedov-phase SNR models. All the remnants were well described by the
model, allowing us to derive accurate values for their ages, densities, initial
explosion energies, and metal abundances. Four SNRs are fully consistent with
the Sedov model and yield a mean value of the initial SN explosion energy of
(1.1+/-0.5)x10^51 erg. We show that it is likely that the other three remnants
exploded within preexisting cavities in the interstellar medium. The limits on
high energy X-ray emission (>3 keV) that we present indicate that these SNRs do
not contain very luminous pulsar-powered synchrotron nebulae. We find
statistical evidence for enrichment by supernova ejecta in the sense that
smaller remnants show a somewhat higher mean metallicity than the larger ones.
For DEM71, the remnant of a SN Ia, the derived Fe abundance is about a factor
of two larger than the other remnants in the sample. These things being said,
however, the derived abundances are in general dominated by swept-up
interstellar material and so we use the SNR sample to estimate the mean LMC
gas-phase abundances. We find that the astrophysically common elements from O
to Fe are less abundant than the solar values by factors of 2--4. Overall these
results are consistent with previous ones based on optical and UV data, but do
not show the anomalous overabundance of Mg and Si seen by others.

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The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ph
11
The categories of this paper are: hep-lat
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
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The categories of this paper are: funct-an
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The categories of this paper are: dg-ga
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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-ex
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The categories of this paper are: stat
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The categories of this paper are: nlin
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The categories of this paper are: hep-ex
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The categories of this paper are: cmp-lg