Dark Energy Survey Spots Rare and Exotic Superluminous Supernova

Astronomers have made some new and surprising discoveries in the first images taken by the Dark Energy Survey (DES). They've spotted rare, superluminous supernova that erupted in a galaxy located 7.8 billion light years away.

Supernovae are very bright, and can shine anywhere from one hundred million to a few billion times more brightly than the sun for weeks at a time. These stellar explosions can be found all across the universe. Yet superluminous supernovae are a relatively recently discovery, and have only been recognized as a distinct class of objects in the past five years. These particular cosmic explosions are 10 to 50 times brighter at their peak than the brightest regular supernovae.

In this case, the superluminious supernova spotted is called DES13S2cmm. It easily outshines most galaxies and could even be seen in collected data about six months after it first appeared.

"Fewer than 40 such supernovae have ever been found and I never expected to find one in the first DES images!" said Andreas Papadopoulos, one of the researchers, in a news release. "As they are rare, each new discovery brings the potential for great understanding-or more surprises."

DES13S2cmm is unusual even among superluminous supernovae. The rate that it's fading away over time is much slower than others in its category. This "light curve," in particular, gives researchers information about the mechanisms that cause the explosion in the first place, and the composition of the ejected materials.

"Its unusual, slow decline was not apparent at first," said Mark Sullivan, one of the researchers. "But as more data came in and the supernova stopped getting fainter, we would look at the light curve and ask ourselves, 'what is this?'"

The scientists have actually attempted to explain the supernova as the result of the decay of the radioactive isotope Nickel-56. But to match the peak brightness, the supernova would have needed to produce more than three times the mass of our sun of the element. This doesn't seem likely, considering current data.

Currently, the scientists plan to hunt for more superluminous supernovae as DES begins its second season in August. They hope to find more of them in order to learn a little bit more about them, and the mechanisms that cause these massive and super-luminous explosions.