Similarly to other cluster of galaxies previously classified as cooling flow systems, the Chandra observation of MKW 3s reveals that this object has a complex X-ray structure hosting both a X-ray cavity and a X-ray filament. Unlike the other clusters, however, the temperature map of the core of MKW 3s shows the presence of extended regions of gas heated above the radially averaged gas temperature at any radius. As the cluster does not show evidences for ongoing major mergers Mazzotta et al. suggest a connection between the heated gas and the activity of the central AGN. Nevertheless, due to the lack of high quality radio maps, this interpretation was controversial. In this paper we present the results of two new radio observations of MKW 3s at 1.28 GHz and 604 MHz obtained at the GMRT. Together with the Chandra observation and a separate VLA observation at 327 MHz from Young, we show unequivocal evidences for a close connection between the heated gas region and the AGN activity and we briefly summarize possible implications.

• PASQUALE MAZZOTTA(Dipartimento di Fisica, Universita di Roma Tor Vergata, via della Ricerca Scientifica/Harvard-Smithsonian Center for Astrophysics)
• GIANFRANCO BRUNETTI(Istituto di Radioastronomia del CNR)
• SIMONA GIACINTUCCI(INAF - Osservatorio Astronomico di Bologna, via Ranzani)
• TIZIANA VENTURI(Istituto di Radioastronomia del CNR)
• SANDRO BARDELLI(INAF - Osservatorio Astronomico di Bologna, via Ranzani)