Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The gamma-ray source AGL J2241+4454 as the possible counterpart of MWC
  656   The AGILE satellite discovered the transient source AGL J2241+4454 in 2010
which triggered the study of the associated field allowing for the discovery of
the first Be/black hole binary system: MWC 656. This binary was suggested to be
the counterpart of AGL J2241+4454, but this is still not a firm association. In
this work we explore the archival AGILE and Fermi/LAT data in order to find
more transient events originating in the field of AGL J2241+4454 and address
the possibility to link them to the accretion/ejection processes of MWC 656. We
found a total of 9 other transient events with AGILE compatible with the
position of AGL J2241+4454, besides the one from 2010. We folded this events
with the period of the binary system and we did not find significant results
that allow us to associate the gamma-ray activity to any particular orbital
phase. By stacking the 10 transient events we obtained a spectrum that extends
between 100 MeV and 1 GeV, and we fitted it with a power law with photon index
{\Gamma} = 2.3 +/- 0.2. We searched into the Fermi /LAT data in order to
complement the gamma-ray information provided by AGILE but no significant
results arose. In order to investigate this apparent contradiction between the
two gamma-ray telescopes, we studied the exposure of the field of AGL
J2241+4454 in both instruments finding significant differences. In particular,
AGILE exposed for longer time and at lower off-axis angle distance the field of
AGL J2241+4454. This fact, together with the energy dependent sensitivity of
both instruments, and the soft spectrum found in the stacking analysis, might
explain why AGILE observed the transient events not seen by Fermi/LAT.

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The categories of this paper are: acc-phys
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The categories of this paper are: atom-ph
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The categories of this paper are: mtrl-th
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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: hep-th
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The categories of this paper are: dg-ga
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The categories of this paper are: gr-qc
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The categories of this paper are: funct-an
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The categories of this paper are: adap-org
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The categories of this paper are: math
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The categories of this paper are: chem-ph
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The categories of this paper are: nucl-th
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The categories of this paper are: bayes-an
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The categories of this paper are: cmp-lg
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The categories of this paper are: quant-ph