An international group of astronomers – led by scientists from the University of Southampton (USA) – has observed the most distant supernova ever detected, which occurred 10.5 billion years ago when the universe was still very young, just a quarter of its size. current age. The cataclysmic explosion has been dubbed DES16C2nm and its discovery has been published in The Astrophysical Journal.
The event is classified as a superluminous supernova, the brightest and rarest of all known supernova types . DES16C2nm is at least 10 times brighter than the standard supernova, and the researchers believe it was caused by falling material onto the densest object in the universe – a rapidly spinning neutron star that forms in the explosion of a massive star.
“It is exciting to be part of the research that has uncovered the oldest known supernova. DES16C2nm is extremely distant, extremely bright and extremely rare – not the type of object you stumble upon every day as an astronomer,” explains Mathew Smith, Leader. from work. “As well as being a very exciting discovery in its own right, DES16C2nm’s extreme distance gives us a unique insight into the nature of superluminous supernovae.”
Thanks to Dark Energy Survey
The researchers used the light from the stellar explosion to understand what kinds of elements were produced in these events and the temperatures at which they occurred. They hope to better characterize this type of supernova, which has only been known for just 15 years.
Specifically, DES16C2nm was detected thanks to the Dark Energy Survey (DES), an international collaboration that maps the position of several hundred million galaxies in three-dimensional space to understand the properties of dark energy, which is believed to be responsible. of the accelerated expansion of the universe.
More than 400 researchers from more than 25 institutions participate in DES who, from 2013 to the end of 2018, will work with this data.
What is already the oldest known supernova was first detected in August 2016, and its distance and extreme brightness were confirmed in October of that year using three of the most powerful telescopes in the world: the Very Large Telescope (VLT) and the Magallanes, both located in Chile, and the Keck, in Hawaii.
“We didn’t think about those supernovae when we started DES more than a decade ago. Such discoveries show the importance of empirical science – sometimes you just have to go out and look for something surprising,” adds study co-author Bob Nichol.
The survey covers an area of the sky that measures 5,000 square degrees , an area equivalent to 25,000 times the full Moon in the sky in five different optical filters to obtain detailed information about each galaxy. Thanks to this discovery, the team will now search for more of these events in the survey.
“Finding more distant events, determining the variety and total number of these events, is the next step,” commented Mark Sullivan, also a co-author of the work.
More than 400 researchers from more than 25 institutions are involved in the Dark Energy Survey, which began in 2013 and will conclude later this year.
Reference: M. Smith et al. Studying the Ultraviolet Spectrum of the First Spectroscopically Confirmed Supernova at Redshift Two, The Astrophysical Journal (2018). DOI: 10.3847 / 1538-4357 / aaa126
Image credit: Mat Smith and DES collaboration
