Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Optical depth for VHE gamma-rays from distant sources from a generic EBL
  density   Very-high-energy (VHE; E>100GeV) gamma-rays from distant sources suffer
attenuation through pair-production with low energy photons from the diffuse
extragalactic photon fields in the ultraviolet (UV) to far-infrared (FIR)
(commonly referred to as Extragalactic Background Light; EBL). When modeling
the intrinsic spectra of the VHE gamma-ray sources it is crucial to correctly
account for the attenuation. Unfortunately, direct measurements of the EBL are
difficult and the knowledge about the EBL over certain wavelength ranges is
poor. To calculate the EBL attenuation usually predictions from theoretical
models are used. Recently, the limits on the EBL from direct and indirect
methods have narrowed down the possible EBL range and many of the previous
models are in conflict with these limits. We propose a new generic EBL density
(not a complete model), which is in compliance with the new EBL limits. EBL
evolution with redshift is included in the calculation in a very simple but
effective ad-hoc way. Properties of this generic EBL are discussed.

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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: physics
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The categories of this paper are: math-ph
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The categories of this paper are: supr-con
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The categories of this paper are: acc-phys
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The categories of this paper are: eess
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The categories of this paper are: quant-ph
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The categories of this paper are: solv-int
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The categories of this paper are: hep-lat
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The categories of this paper are: dg-ga
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The categories of this paper are: cond-mat
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The categories of this paper are: chao-dyn
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The categories of this paper are: atom-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: nlin