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SkyMapper Protected Science Project

Exploring Supernovae through light echoes

Wolfgang Kerzendorf (ESO), Armin Rest (STScI)

Supernovae are the brilliant explosive death throes of stars. They are one of the most energetic events in the Universe and thus are excellent laboratories to explore high energy physics. Furthermore, a subclass of these objects - namely Type Ia supernovae - can be calibrated to serve as cosmic distance probes, enabling the discovery of the accelerated expansion of the Universe. Transient surveys, targeting extragalactic supernovae, supply a wealth of information about the early phase (to a maximum of a couple years post-explosion), while close-by Galactic supernovae are studied hundreds of years post-explosion through their remnants, but in much greater detail than is possible for their extragalactic counterparts. Linking the studies of remnants and early-time observations is essential to combine the unique information about supernovae coming from each of these disparate measurements. Light echoes are the most direct way of connecting a remnant to its early-time spectra which can then be used for classification. This technique has successfully been applied to a handful of supernovae, most notably classifying Tycho's supernova as Type Ia and Cas A as Type IIb.
We will use Skymapper to survey large areas of the southern sky in order to detect light echo systems associated with historical supernovae (including Kepler (SN 1604), SN 1006, RCW86, Crab Nebula, and W49B). Once detected we will obtain follow-up spectra using 8-m class telescopes and hope that in some favourable cases we will not only provide a classification spectrum, but also a three dimensional view of the event by observing different light echoes.