Light echoes from ancient supernovae in the Large Magellanic Cloud

Catch up with KeplerWe may soon be able to see the slight seen by Tycho and Kepler, but 400 years later. In 1940 Fritz Zwicky, the man who coined the term ‘supernova’ for massive star explosions, suggested that it should be possible to see echo light from historical supernovae centuries after the event. Data from the SuperMACHO survey, which is monitoring the millions of stars in the Large Magellanic Cloud for the brightening associated with gravitational microlensing, show that Zwicky was spot on. Echoes have now been traced back to three positions where young supernova remnants appear, and ages have been estimated for two of them, at 610 and 410 years. This discovery opens up the prospect of finding echoes from the supernovae in our own Galaxy that were observed by Tycho and Kepler. Light from the echoes can be observed spectroscopically to determine what type of supernova exploded.