Observations of Supernovae during and after Shock Breakout

Supernovae (SNe) are some of the most energetic explosion since the birth of the universe. Over the past few years, space-based observatories have allowed detailed studies of these energetic events in previously unexplored wavelength regimes. NASA's \textit{Swift} observatory is particularly suited to probe the early emission of SNe due to its fast response, flexible scheduling capabilities, and large wavelength band coverage, ranging from the optical, UV, and X-ray to the Gamma-ray bands. By studying the outgoing SN shocks with material in its surroundings, the explosion physics and nature of progenitor stars can be studied. Furthermore, monitoring the X-ray emission of SNe with space-based X-ray observatories is being used to map the density structure in SN environments out to large radii from the sites of the explosions ($>$10$^{20}$ cm, 10,000 times larger than our solar system), the transition of a SN into an old supernova remnant can be studied, and the mass-loss rates of the progenitor stars can be probed over significant timescales ($>$10$^{4}$ years) in the stellar wind history. In combination, these observations give unprecedented insights into the nature of energetic explosions and their environments. During this talk, I will present highlights from recent observations, among them the first observation of a SN \textit{during} the actual explosion with \textit{Swift}.