X-Ray Studies of Supernova Remnants: A Different View of Supernova
  Explosions
  The unprecedented spatial and spectral resolutions of Chandra have
revolutionized our view of the X-ray emission from supernova remnants. The
excellent data sets accumulated on young, ejecta dominated objects like Cas A
or Tycho present a unique opportunity to study at the same time the chemical
and physical structure of the explosion debris and the characteristics of the
circumstellar medium sculpted by the progenitor before the explosion. Supernova
remnants can thus put strong constraints on fundamental aspects of both
supernova explosion physics and stellar evolution scenarios for supernova
progenitors. This view of the supernova phenomenon is completely independent
of, and complementary to, the study of distant extragalactic supernovae at
optical wavelengths. The calibration of these two techniques has recently
become possible thanks to the detection and spectroscopic follow-up of
supernova light echoes. In this paper, I will review the most relevant results
on supernova remnants obtained during the first decade of Chandra, and the
impact that these results have had on open issues in supernova research.
