Hubble captures first-ever predicted exploding star

[n2doc]

This image composite shows the search for the supernova, nicknamed Refsdal, using the NASA/ESA Hubble Space Telescope. The image to the left shows a part of the the deep field observation of the galaxy cluster MACS J1149.5+2223 from the Frontier Fields program. The circle indicates the predicted position of the newest appearance of the supernova. To the lower right the Einstein cross event from late 2014 is visible. The image on the top right shows observations by Hubble from October 2015, taken at the beginning of observation program to detect the newest appearance of the supernova. The image on the lower right shows the discovery of the Refsdal Supernova on Dec. 11, 2015, as predicted by several different models.

The NASA/ESA Hubble Space Telescope has captured the image of the first-ever predicted supernova explosion. The reappearance of the Refsdal supernova was calculated from different models of the galaxy cluster whose immense gravity is warping the supernova's light.

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 11 December 2015 astronomers not only imaged a supernova in action, but saw it when and where they had predicted it would be.

The supernova, nicknamed Refsdal [1], 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 [2].

Refsdal's story began in November 2014 when scientists spotted four separate images of the supernova in a rare arrangement known as an Einstein Cross around a galaxy within MACS J1149.5+2223 (heic1505 -- http://www.spacetelescope.org/news/heic1505/) [3]. The cosmic optical illusion was due to the mass of a single galaxy within the cluster warping and magnifying the light from the distant stellar explosion in a process known as gravitational lensing [4].

"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," explains Steve Rodney, co-author, from the University of South Carolina. "The supernova's host galaxy appears to us in at least three distinct images caused by the warping mass of the galaxy cluster."

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http://www.sciencedaily.com/releases/2015/12/151216135824.htm

[eppur_se_muova]

1. Ummmm ... sounds like all they 'predicted' was the difference of the light paths.

Perhaps one should say "modeled" rather than "predicted", since they already knew the explosion had occurred. It was just a question of when the light would arrive by the fourth pathway (if I'm reading the article correctly), which required modeling the approximate mass distribution of the lensing cluster from the three images already in hand.

[gvstn]

2. Fascinating, thank you!