Discovery of optical echoes from supernova 1987A: new probes of the Large Magellanic Cloud

Coronagraphic observations of SN 1987A have revealed the first light echo or transient reflection nebula due to light from an SN. Two echoes from dust 400 and 980 lt-yr in front of SN 1987A were discovered on March 4.05, 1988 (UT). These phenomena can be exploited to probe the physics of the dust, the structure of the interstellar medium, the unobserved initial hours of SN 1987A, and the relation between gasdynamics and star formation in an active portion of the LMC. The results show that the dust scatters consistent with Rayleigh's law, that at least some of the light echo is reflected from the N157C superbubble nebula, and that future reobservation of the time evolution of the UV light pulse associated with the shock outbreak through the progenitor star's surface may be difficult to reoslve. 16 references.