092167

Shock waves are one of the most important phenomena to understand the growth ofgalaxy clusters and large-scale structures. In particular for accretion shocksdue to faint emission at the expected region no study has yet been performed onan individual object. Here we propose deep 228 ksec XMM-Newton and a Chandrasnapshot (25 ksec) observations of the bridge connecting the massive galaxyclusters Abell 399-Abell 401 to identify and characterize the nature of a shockonto the bridge which is potentially an accretion shock. To provide solidconfirmation and a better understanding of the possible shock structure theproposed observations together with our multi-wavelength (radio SZ) data aim todetermine the temperature and surface brightness profiles of the shock candidate. [truncated! Please see actual data for full text]