Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Chandra Observation of the Shell of Nova Persei 1901 (GK Persei):
  Detection of localized Non-thermal X-ray Emission from a Miniature Supernova
  Remnant   I present the data of the shell of classical Nova Persei (1901) obtained by
the Advanced CCD Imaging Spectrometer S3 detector on-board \cha Observatory.
The X-ray nebula is affected mostly by the complex interstellar medium around
the nova and has not developed a regular shell with bulk of emission coming
from the southwestern quadrant. The part of the bright zone that is co-spatial
with the brightest non-thermal radio emission region, is found to be a source
of non-thermal X-ray emission with a power law photon index of
2.3$^{+1.5}_{-0.9}$ and alpha=0.68^${+0.03}_{-0.15}$ at about a flux of
1.7x10^{-13} erg cm^{-2} s^{-1}. There are strong indications for nonlinear
diffusive shock acceleration occurring in the forward shock/transition zone
with an upper limit on the non-thermal X-ray flux of 1.0\times 10^{-14} erg
cm^{-2} s^{-1}.The total X-ray spectrum of has two components of emission. The
component dominant below 2 keV is most likely a non-equilibrium ionization
thermal plasma of kT_s=0.1-0.3 keV with an X-ray flux of 1.6x10^{-11} erg
cm^{-2} s^{-1}. There is also a higher temperature, kT_s=0.5-2.6 keV, embedded,
N_H=(4.0-22.0)x10^{22} cm^{-2}, emission component prominent above 2 keV. The
unabsorbed X-ray flux from this component is 1.5x10^{-10} erg cm^{-2} s^{-1}.
The X-ray emitting plasma is of solar composition except for enhancement in the
elemental abundances (mean abundances over the remnant)of Ne/Ne$_{\odot}$ and
N/N$_{\odot}$ in a range 13-21 and 1-5, respectively. A distinct emission line
of neon, He-like Ne IX, is detected which reveals a distribution of several
emission knots/blobs and shows a cone-like structure with wings extending
toward NW and SE at expansion velocities about 2600 km s^{-1} in the X-rays.

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The categories of this paper are: chem-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: physics
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The categories of this paper are: gr-qc
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: nucl-ex
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The categories of this paper are: q-alg
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The categories of this paper are: nlin
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The categories of this paper are: acc-phys
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The categories of this paper are: stat
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The categories of this paper are: q-bio
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The categories of this paper are: q-fin
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The categories of this paper are: hep-ex
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The categories of this paper are: alg-geom
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The categories of this paper are: quant-ph