Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The XMM-Newton view of the radio-quiet neutron star 1E 1207.4-5209   We have observed the radio-quiet X-ray pulsar 1E 1207.4-5209 with the high
throughput EPIC cameras onboard XMM-Newton. The spectrum of this peculiar
source is characterized by two broad absorption features which present
significant substructures and show a clear phase-dependence. We believe that
these features represent a strong evidence for the presence of a magnetized
atmosphere containing heavy elements.

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The categories of this paper are: quant-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: acc-phys
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The categories of this paper are: hep-lat
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The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
34
The categories of this paper are: chem-ph
31
The categories of this paper are: ao-sci
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The categories of this paper are: nlin
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The categories of this paper are: adap-org
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The categories of this paper are: funct-an
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The categories of this paper are: hep-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-th
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The categories of this paper are: nucl-ex