Light Echoes of Transients and Variables in the Local Universe

摘要: Astronomical light echoes, the time-dependent scattered by dust in vicinity of varying objects, have been recognized for over a century. Initially, their utility was thought to be confined mapping out three-dimensional distribution interstellar dust. Recently, discovery spectroscopically useful echoes around centuries-old supernovae Milky Way and Large Magellanic Cloud has opened up new scientific opportunities exploit echoes. In this review, we describe history local Universe cover many developments both observation interpretation from them. Among other benefits, highlight our ability classify outbursting objects spectroscopically, view them multiple perspectives, obtain spectroscopic time series outburst, establish accurate distances source event. We also broader range variable with properties that may better understood light-echo observations. Finally, discuss prospects techniques not yet realized practice.