Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Search for anomalous features in gamma-ray blazar spectra corrected for
  the absorption on the extragalactic background light   We consider the ensemble of very-high-energy gamma-ray sources observed at
distances and energies where a significant absorption of gamma rays is expected
due to pair production on the extragalactic background light (EBL). Previous
studies indicated that spectra of these sources, upon correction for the
absorption, exhibit unusual spectral hardenings which happen precisely at the
energies where the correction becomes significant. Here, we address this
subject with the most recent clean sample of distant gamma-ray blazars, making
use of published results of imaging atmospheric Cerenkov telescopes and of the
Fermi-LAT Pass 8 data, supplemented by the newest absorption models and
individual measurements of sources' redshifts. We perform a search for spectral
breaks at energies corresponding to unit optical depth with respect to the
absorption on EBL. These energies are different for distant and nearby objects,
and consequently, such features may not be related to intrinsic properties of
the sources. While in some spectra such breaks are not seen, hardenings at
distance-dependent energies are present in many of them, though the overall
statistical significance of the effect is lower than reported in previous
studies. The dependence of the break strength on the redshift found earlier is
not confirmed in the new analysis.

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The categories of this paper are: atom-ph
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The categories of this paper are: q-fin
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The categories of this paper are: adap-org
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: nucl-th
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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: physics
5
The categories of this paper are: gr-qc
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The categories of this paper are: nucl-ex
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The categories of this paper are: chem-ph
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The categories of this paper are: alg-geom
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The categories of this paper are: hep-ex
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The categories of this paper are: hep-th
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The categories of this paper are: math