Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Active Galactic Nuclei: present observations and prospects   INTEGRAL has made a very significant contribution to our understanding of the
physics of AGN. We illustrate this progress by looking at the considerations
that were made at the time of the selection of the INTEGRAL mission and
discussing some observations and results obtained in the intervening time.
  It is seen that while a number of results pertaining to the variability of
AGN have been obtained, the potential of the INTEGRAL data in short timescale
variability domain is still largely under exploited. The characteristic
variability timescale of AGN, and X-ray binaries, can be understood in the
frame of the cascade of shocks model and more generally depends solely on the
Compton cooling properties of a hot electron plasma located at a distance
proportional to the mass of the object from a soft photon source.
  Although INTEGRAL is not a focusing instrument, it is possible to resolve a
small but significant fraction of the diffuse extragalactic background at
energies higher than 10\,keV.

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The categories of this paper are: math
5
The categories of this paper are: gr-qc
11
The categories of this paper are: hep-lat
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The categories of this paper are: nucl-th
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The categories of this paper are: patt-sol
36
The categories of this paper are: cmp-lg
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The categories of this paper are: q-bio
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The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
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The categories of this paper are: chao-dyn
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The categories of this paper are: solv-int
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The categories of this paper are: econ
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The categories of this paper are: chem-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: adap-org
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The categories of this paper are: alg-geom