Diffusive shock acceleration induced by a cluster mergerquestionMark

We have discovered an extraordinarily long, narrow steep spectrum radio relic inthe galaxy cluster CIZA J2242.8+5301. The relic has a remarkable radio spectralindex gradient perpendicular to its long axis and polarization points to amagnetic field parallel to it. Here we propose deep Xray observations to (i)confirm the presence of a shock front at the position of the radio relic, (ii)determine the shock physical conditions, (iii) characterize the dynamical stateof the cluster, and (iv) map the temperature distribution. These observationswill (i) provide conclusive evidence for the existence of diffusive shockacceleration and, (ii) constrain scenarios connecting the properties of shockfronts, particle acceleration mechanisms, and the occurrence of radio relics. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]