ASASSN-15lh

hypernova

ASASSN-15lh is a supernova detected on 14 June 2015. It is the most luminous supernova ever detected.[1] At its brightest it was 50 times brighter than the whole Milky Way.[2][3]

"The exploding star was first observed back in June last year but is still radiating vast amounts of energy.
At its peak, the event was 200 times more powerful than a typical supernova, making it shine with 570 billion times the brightness of our Sun.
Researchers think the explosion and ongoing activity have been boosted by a very dense, highly magnetised, remnant object called a magnetar.
This object, created as the supernova got going, is probably no bigger than a major city, such as London, and is likely spinning at a fantastic rate - perhaps a thousand times a second".[1]

The supernova is some 3.8 billion light-years from Earth. It was found by the All Sky Automated Survey for SuperNovae (ASAS-SN).[1]

References