Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: AGN and starburst radio activity in the A3558 cluster complex   In this paper we present Very Large Array (VLA) 1.4 GHz (21 cm) observations
of the region between the centres of A3558 and A3562, in the majorcluster
merger complex of the Shapley Concentration. Our final catalogue includes a
total of 174 radio sources above the flux density limit of 0.25 mJy b$^{-1}$.
By cross-correlation with optical and spectroscopic catalogues we found 33
optical counterparts belonging to the Shapley Concentration. We investigated
the effects of cluster merger on the radio emission properties of the galaxy
population by means of the radio source counts and the radio luminosity
functions (RLF). We found that the radio source counts are consistent with the
field source counts.The RLF of elliptical and S0 galaxies in the region
surveyed here, is consistent with the ``universal'' RLF for early--type
galaxies.This result suggests that the deficit in radio galaxies found in
ourprevious works over the whole A3558 chain, is entirely due to the cluster
A3558. A population of faint radio galaxies (logP$_{1.4 GHz}$(W Hz$^{-1}$)
\ltsim 22) is also found.Half of these objects are also blue, suggesting that
starburst is the main mechanism driving the radio emission. Finally, we
detected 14 spiral radio galaxies, whose ratio between radio and optical
emission is similar to those found in galaxies located in rich and dynamically
evolved clusters. Our results are briefly discussed in the light of the age and
stage of the merger in the A3558 cluster complex.

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The categories of this paper are: atom-ph
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The categories of this paper are: eess
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The categories of this paper are: cs
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The categories of this paper are: acc-phys
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The categories of this paper are: cmp-lg
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The categories of this paper are: patt-sol
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The categories of this paper are: solv-int
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The categories of this paper are: supr-con
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: comp-gas
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The categories of this paper are: math-ph
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The categories of this paper are: hep-th
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The categories of this paper are: physics
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The categories of this paper are: ao-sci
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The categories of this paper are: quant-ph