DR. ATISH KAMBLE

The rapidly expanding supernova shock wave races ahead of the radioactive ejecta and emits synchrotron radiation predominantly in radio waves. The radio emission naturally carries the stamp of the environment that has been sculpted by the progenitor through winds, eruptions, binary interactions etc. The supernova shock wave that is ploughing through this environment thus traces the final centuries in the life of the progenitor that are otherwise inaccessible to observations or current theories. Our detailed investigation of radio SNe sprang surprises in the progenitors' life history. The speaker will start with the intriguing class of supernovae, known as Type IIb, with particular emphasis on their radio properties. He will argue that their progenitors display a broader range of properties, such as radius and mass-loss rate, than what is implied by their typical and possibly inadequate classification as Type IIb. He will then discuss SN progenitors with denser environments and its implications for interaction powered SNe such as Type IIn and Super Luminous SNe. In such interaction powered SNe, proton-proton collisions may lead to the production of secondary electrons from pion decays. He will show that this is an observable effect. Detection of these secondary electrons could be valuable in understanding cosmic ray acceleration.