Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Fourth Catalog of Active Galactic Nuclei Detected by the Fermi Large
  Area Telescope -- Data Release 2   An incremental version (4LAC-DR2) of the fourth catalog of active galactic
nuclei (AGNs) detected by the Fermi-LAT is presented. This version is
associated with the second release of the 4FGL general catalog (based on 10
years of data), where the spectral parameters, spectral energy distributions,
yearly light curves, and associations have been updated for all sources. The
new reported AGNs include two radio galaxies and 283 blazars. We briefly
describe the properties of the new sample and outline changes affecting the
previously published sample. Note: Users of this incremental release are
requested to cite the original 4LAC paper (Ajello M. et al., 2020, ApJ, 892,
105).

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The categories of this paper are: patt-sol
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The categories of this paper are: dg-ga
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The categories of this paper are: solv-int
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The categories of this paper are: acc-phys
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The categories of this paper are: chao-dyn
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The categories of this paper are: math
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: q-alg
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The categories of this paper are: ao-sci
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The categories of this paper are: cond-mat
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The categories of this paper are: hep-ph
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: quant-ph