The origin of cosmic rays holds still many mysteries hundred years after they
were first discovered. Supernova remnants have for long been the most likely
sources of Galactic cosmic rays. I discuss here some recent evidence that
suggests that supernova remnants can indeed efficiently accelerate cosmic rays.
For this conference devoted to the Astronomical Institute Utrecht I put the
emphasis on work that was done in my group, but placed in a broader context:
efficient cosmic-ray acceleration and the im- plications for cosmic-ray escape,
synchrotron radiation and the evidence for magnetic- field amplification,
potential X-ray synchrotron emission from cosmic-ray precursors, and I conclude
with the implications of cosmic-ray escape for a Type Ia remnant like Tycho and
a core-collapse remnant like Cas A.Comment: Proceedings of the Meeting "370 years of astronomy in Utrecht",
Noordwijkerhout, The Netherlands, April 2-5, 2012 (ASPCS Conference Series