Using the Hubble Space Telescope, astronomers were able to capture images of the first ever predicted explosion of a supernova.
The exploded star dubbed Refsdal supernova, which was named after Norwegian astronomer Sjur Refsdal, and can be found in the galaxy cluster MACS J1149.5+2223. Its reappearance was calculated based on different models of the galaxy cluster.
Successfully spotting stellar explosions in action is often attributed to pure luck, and there are only a few instances when these explosions have been caught. The event marks the first time that astronomers managed to image a supernova in action as well as see the explosion when and where they predicted this to occur.
Scientists first found four separate images of the supernova in an arrangement called Einstein Cross within MACS J1149.5+2223 in November 2014. The cosmic optical illusion is due to the mass of galaxy within the cluster that warps and magnifies the light from the distant explosion of a star, a process called gravitational lensing.
The effect of gravitational lensing is similar to that of a glass lens that bends light and distorts the image of the object lying behind, resulting in the galaxy producing four separate images of the supernova.
Steve Rodney, from the University of South Carolina, said that the multiple images of the galaxy provided a rare opportunity for astronomers since the images of the supernova's host galaxy can be spotted at different times.
Other lensed galaxies within the galaxy cluster along with the Einstein Cross event discovery, allowed scientists to make an accurate prediction when and where the supernova would again appear.
Calculations have revealed that the supernova has already appeared earlier in a third image of a host galaxy albeit the event was not observed by any telescope.
"We used seven different models of the cluster to calculate when and where the supernova was going to appear in the future," said Tommaso Treu, from the University of California. He added that all of these seven models had approximately the same time frame prediction for when the new image of the supernova would again appear.
Since October this year, Hubble, a collaboration of NASA and the European Space Agency, has been periodically looking at MACS J1149.5+2223 with the hope of observing the unique rerun of the distant explosion that occurred nearly 10 billion years ago. Finally on Dec. 11, the supernova made its predicted reappearance.