The interaction of post-explosion supernova ejecta with the surrounding circumstellar
medium creates emissions across the electromagnetic spectrum. Since the circumstellar
medium is created by the mass lost from the progenitor star, it carries tell-tale
signatures of the progenitor. Consequently, observations and modeling of radiation
produced by the interaction in various types of supernovae have provided valuable
insights into their progenitors. Detailed studies have shown that the interaction
in supernovae begins and sustains over various timescales and lengthscales, with differing
mass-loss rates in distinct sub-classes. This reveals diverse progenitor histories
for these stellar explosions. This review paper summarizes various supernova subtypes,
linking them to stellar death pathways, and presents an updated supernova classification
diagram. We then present a multi-wavelength study of circumstellar interaction in
different supernova classes. We also present unpublished X-ray as well as radio observations
of a type IIn supernova, SN 2010jl, which allow us to extend its circumstellar interaction
studies to about 7 years post-explosion. The new data indicates that the extreme mass-loss
rate (similar to 0.1 M circle dot yr-1) in SN 2010jl, reported by Chandra et al. commenced
within the last 300 years before the explosion. We summarize the current status of
the field and argue that via detailed studies of the circumstellar interaction, a.k.a.
"Time Machine" technique, one of the big mysteries of stellar evolution, i.e., mapping
supernovae progenitors to their explosive outcomes can be solved.
