Supernova remnants across the electromagnetic spectrum

Supernova remnants (SNRs) are the products of some of the most energetic explosions in the universe: supernovae. The supernovae launch stellar material into the ambient medium with speeds up to 20,000 km/s, thereby creating shock waves, which heat and sweep up the interstellar medium in shells that expand for thousands up to 100,000 yrs. On top of that, these shocks are efficiently accelerating electrons, protons and other ions to very high energies. These energetic particles are known as cosmic rays, and SNRs are thought to be the dominant source of them in the Milky Way.
In this thesis we report studies of several aspects of SNR physics across the electromagnetic spectrum. In the first scientific Chapter we investigate 6 SNR candidates using radio and X-ray data. We confirm the nature of one of the candidates and follow it up with a dedicated X-ray observation in Chapter 3. In Chapter 4 we perform a molecular line study of clouds in the direction of an unusually shaped SNR whereas Chapter 5 is dedicated to a broadband spatial study of cosmic ray produced synchrotron emission in SNR Cassiopeia A. Finally, in Chapter 6 I present an exploratory study of a candidate historical SNR for which we detect an optical emission for the first time.