******************************************************
   PR #   110
   Scientific objectives:Tycho is a young type 1 supernova remnant which
   shows a nearly circular shellstructure with a radius of 4 arcmin. The
   scientific goal is to measurespatial distributions of heavy elements (
   Mg, Si, S, Ar, Ca, Fe, and Ni ) andplasma parameters (nt, kT, and EI).
   These parameters are crucial to study thedynamical and chemical
   structure of Tycho, which also provide strongconstrains on theoretical
   models of type 1 supernova explosion. Calibration objective:X-ray
   spectrum contains various strong emission lines, which are useful
   tocalibrate the energy scale of the SIS and the GIS.
 ******************************************************