086222

The Ophiuchus cluster exhibits a curious concave gas discontinuity near its core. It was discovered by Werner et al comma who considered a possibility of it being a boundary of an AGN-inflated bubble comma but discounted it because it required too powerful an outburst. Using very low-frequency openPar70-240 MHzclosePar data from MWA-GLEAM and GMRT comma we found that it is in fact a giant bubble filled with diffuse radio emission with an extremely steep spectrum. It appears to be a fossil of the most powerful AGN outbursts seen in any cluster - with the central AGN being a negligible radio source at present. We propose to survey this sector of the cluster to map the X-ray cavity comma look for signs of cluster-scale sloshing possibly triggered by this powerful event openParhinted at by ROSATclosePar comma and clarify the merger details.