Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectral Analysis of the Crab Pulsar and Nebula with the Fermi Large
  Area Telescope   The Crab Pulsar is a relatively young neutron star. The pulsar is the central
star in the Crab Nebula, a remnant of the supernova SN 1054, which was observed
on Earth in the year 1054. The Crab Pulsar has been extensively observed in the
gamma-ray energy band by the Large Area Telescope (LAT), the main instrument
onboard the Fermi Gamma-ray Space Telescope, during its first months of data
taking. The LAT data have been used to reconstruct the fluxes and the energy
spectra of the pulsed gamma-ray component and of the gamma-rays from the
nebula. The results on the pulsed component are in good agreement with the
previous measurement from EGRET, while the results on the nebula are consistent
with the observations from Earth based telescopes.

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The categories of this paper are: q-alg
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The categories of this paper are: mtrl-th
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The categories of this paper are: solv-int
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The categories of this paper are: funct-an
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The categories of this paper are: cond-mat
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The categories of this paper are: math-ph
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The categories of this paper are: adap-org
1
The categories of this paper are: cs
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The categories of this paper are: dg-ga
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The categories of this paper are: nucl-ex
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The categories of this paper are: gr-qc
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The categories of this paper are: nucl-th
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The categories of this paper are: alg-geom
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: physics