Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Highly ionized Fe K emission lines from the LINER galaxy M 81   We present spectral and timing results from a long (130 ks) XMM-NEWTON EPIC
observation of the nucleus of the Seyfert/LINER galaxy M 81. During the
observation the X-ray flux varied by 20%, but there was no significant change
in spectral shape. The 2-10 keV spectrum is well described by a power law
continuum and three narrow Fe K emission lines at 6.4, 6.7 and 6.96 keV. The
three emission lines have equivalent widths of 39, 47, and 37 eV respectively.
The ratios of the three lines are thus more similar to those observed from the
Galactic Centre region than to those typically observed from Seyfert galaxies.
The high ionization lines most likely originate either from photoionized gas
within 0.1 pc of the nucleus of M 81, or from a non-thermal distribution of
cosmic-ray electrons interacting with the 0.2-0.6 keV thermal plasma which is
found in the bulge of M 81.

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The categories of this paper are: econ
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The categories of this paper are: quant-ph
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The categories of this paper are: acc-phys
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The categories of this paper are: cs
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The categories of this paper are: gr-qc
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The categories of this paper are: hep-ex
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The categories of this paper are: eess
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The categories of this paper are: solv-int
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The categories of this paper are: nlin
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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: math-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: stat