Scientists observe a superluminous supernova that appears to have exploded twice
http://phys.org/news/2016-07-scientists-superluminous-supernova.html
In recent years, a new type of supernova has been discovered, about which very little is yet known, and which are brighter and longer-lasting.
Astronomers call them superluminous supernovae (SLSN). Although only about a dozen of them are known, an international group of researchers has
used the Gran Telescopio CANARIAS (GTC) to observe a superluminous supernova almost from the moment it occurred. The research has revealed
surprising behaviour, because this supernova showed an initial increase in brightness that later declined for a few days, and then increased
again much more strongly. The scientists have combined from the GTC with other observations in order to try to explain the origin of the phenomenon.
PIC: This graph shows the evolution of the apparent brigntness of the new supernova it is shown according to data collected by the Dark Energy Survey.
It can be seen how an initial increase in brightness occurs which is then reduced for several days. Subsequently, the brightness increases again during
the main sequence of the supernova. Credit: Mathew Smith.
