Bursting the bubble\: evolved AGN feedback in a galaxy group

We propose a 42 ks observation of the galaxy group Nest 200047. LOFAR imageswith unprecedented sensitivity at low radio frequencies revealed a surprisinglycomplex filamentary structure related to the AGN feedback in this system,extending more than 200 kpc in radius. We interpret this unique morphology asbeing due to an old AGN bubble that is in the process of breaking up as it isbuoyantly rising out of the group and interacting with the surrounding medium.To our knowledge, this is the most advanced stage of bubble evolution observedto date. The proposed exposure will allow us to quantify the morphology of theXray cavities associated with the largescale radio lobes and perform adetailed analysis of the substructure and thermodynamical properties of this spectacular system. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]