The Hubble Space Telescope has captured the image of the first-ever predicted supernova explosion that offers a unique opportunity for astronomers to test how mass – especially that of mysterious dark matter – is distributed within a galaxy cluster.
Many stars end their lives with a with a bang, but only a few of these stellar explosions have been caught in the act.
When they are, spotting them successfully has been down to pure luck – until now.
On December 11, astronomers not only imaged a supernova in action, but saw it when and where they had predicted it would be.
The supernova, nicknamed Refsdal, has been spotted in the galaxy cluster MACS J1149.5+2223.
While the light from the cluster has taken about five billion years to reach us, the supernova itself exploded much earlier, nearly 10 billion years ago.
“While studying the supernova, we realised that the galaxy in which it exploded is already known to be a galaxy that is being lensed by the cluster,” explained Steve Rodney, study co-author from University of South Carolina in a Nasa statement.
“The supernova’s host galaxy appears to us in at least three distinct images caused by the warping mass of the galaxy cluster,” he noted.
These multiple images of the galaxy presented a rare opportunity.
As the matter in the cluster – both dark and visible – is distributed unevenly, the light creating each of these images takes a different path with a different length.
Therefore, the images of the host galaxy of the supernova are visible at different times.
“We used seven different models of the cluster to calculate when and where the supernova was going to appear in the future,” added Tommaso Treu, lead author from University of California-Los Angeles.
Astronomers are now eager to see what other surprises the ongoing Hubble Frontier Fields programme will bring to light.