| Issue |
A&A
Volume 419, Number 1, May III 2004
|
|
|---|---|---|
| Page(s) | 71 - 87 | |
| Section | Extragalactic astronomy | |
| DOI | https://doi.org/10.1051/0004-6361:20040071 | |
| Published online | 23 April 2004 | |
AGN and starburst radio activity in the A3558 cluster complex*
1
INAF – Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy
2
Istituto di Radioastronomia del CNR, via Gobetti 101, 40129, Bologna, Italy
3
Dipartimento di Astronomia, Università di Bologna, via Ranzani 1, 40127, Bologna, Italy
Corresponding author: T. Venturi, tventuri@ira.cnr.it
Received:
10
June
2003
Accepted:
2
February
2004
We present Very Large Array (VLA) 1.4 GHz (21 cm)
observations of the region between the centres of A3558 and A3562, in the major
cluster 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,
is consistent with the “universal” RLF for early-type galaxies.
This result suggests that the deficit in radio galaxies found in our
previous work over the whole A3558 chain is entirely due to the
cluster A3558.
A population of faint radio
galaxies (log 
(W Hz-1) 
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.
Key words: radio continuum: galaxies / galaxies: clusters: general / galaxies: clusters: individual: A3558, A3562, SC 1329-313, SC 1327-312
© ESO, 2004
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