Uncovering the engines of engine-driven supernovae

Magnetars have gained favour as the engines of extreme supernova (SN)explosions, but direct observational evidence is lacking. A uniquecharacteristic of a magnetar engine is nonthermal Xray emission a few yearsafter the explosion. This has so far eluded unambiguous detection due to theextremely high absorption by the ejecta itself before it expands sufficiently,and the rapid decay of the magnetar luminosity. To balance this tradeoff, wepropose to observe a small sample of SNe at intermediate epochs when the ejectaare expected to become transparent to soft Xrays. This allows us to detect orconstrain the properties of the magnetar and shed light onto the engines ofthese extreme SNe. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]