Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Searching for Axion-Like Particles with the Blazar Observations of MAGIC
  and Fermi-LAT   We explore the axion-like particle (ALP)-photon oscillation effect in the
$\gamma$-ray spectra of the blazars Markarian 421 (Mrk 421) and PG 1553+113,
which are measured by the Major Atmospheric Gamma Imaging Cherenkov Telescopes
(MAGIC) and Fermi Large Area Telescope (Fermi-LAT) with high precision. We
investigate the constraints on the ALP parameter space using the Mrk 421 and PG
1553+113 observations of 15 and 5 phases, respectively. We find that the
combined analysis with all the 15 phases improves the limits from the Mrk 421
observations. The combined limit set by the Mrk 421 observations has excluded
the ALP parameter region with the ALP-photon coupling of $g_{a\gamma} \gtrsim 2
\times 10^{-11} \, \rm GeV^{-1}$ for the ALP mass of $\sim 8\times 10^{-9}\,
{\rm eV} \lesssim m_a \lesssim 2\times 10^{-7}\rm \, eV$ at 95% $\rm C.L.$ We
also find that the ALP hypothesis can slightly improve the fit to the PG
1553+113 results in some parameter regions, and do not set the limit in this
case.

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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: nlin
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The categories of this paper are: comp-gas
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: supr-con
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The categories of this paper are: math-ph
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The categories of this paper are: cond-mat
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The categories of this paper are: mtrl-th
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The categories of this paper are: physics
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The categories of this paper are: bayes-an
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The categories of this paper are: econ
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The categories of this paper are: math
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The categories of this paper are: q-bio
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The categories of this paper are: alg-geom