G354.4+0.0: the youngest Galactic supernova remnantquestionMark

Although the supernova rate in the Milky Way is thought to be 3 per century,only two supernova remnants younger than 400 yr are known, Cas A and G1.9+0.4.Both these sources are Xray synchrotron emitters, and in both these sourcesfreshly synthesized, radioactive Ti44 has been detected. This year a new,small (1.6 arcmin) shelltype supernova remnant was discovered, G354.4+0.0,which is a good candidate to be the youngest supernova remnant in the Galaxy. Wepropose to observe G354.4+0.0 both with XMMNewton, for detailed imagingspectroscopy, and with NuStar for characterizing the potential synchrotronemission and search for line emission caused by the decay of Ti44 at 68 keV and78 keV. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]