An international team of astronomers, including Professor Bob Nichol from the University of Portsmouth, UK, has confirmed the discovery of the most distant supernova ever detected – a huge cosmic explosion that took place 10.5 billion years ago, or three-quarters the age of the Universe itself.
The most distant supernova ever detected, named DES16C2nm, was detected by the Dark Energy Survey (DES), an international collaboration to map several hundred million galaxies in order to find out more about dark energy – the mysterious force believed to be causing the accelerated expansion of the Universe.
In a new study published in the Astrophysical Journal, the team explain that the light from the event had taken 10.5 billion years to reach Earth, making it the oldest and most distant supernova ever discovered.
What is a supernova?
- A supernova is the explosion of a massive star that ejects most of its mass at the end of its life cycle;
- DES16C2nm is classified as a superluminous supernova (SLSN), the brightest and rarest class of supernovae, and was first discovered ten years ago; and
- It is thought to have been caused by material falling onto the densest object in the Universe – a rapidly rotating neutron star newly formed in the explosion of a massive star.
Nichol, Professor of Astrophysics and Director of the Institute of Cosmology and Gravitation, commented: “Such supernovae were not thought of when we started DES over a decade ago. Such discoveries show the importance of empirical science; sometimes you just have to go out and look up to find something amazing.”
Dr Mathew Smith, of the University of Southampton, said: “It’s thrilling to be part of the survey that has discovered the oldest known supernova. DES16C2nm is extremely distant, extremely bright, and extremely rare – not the sort of thing you stumble across every day as an astronomer.
“As well as being a very exciting discovery in its own right, the extreme distance of DES16C2nm gives us a unique insight into the nature of SLSN.”
More than 400 scientists from over 25 institutions worldwide are involved in the DES, a five-year project when it began.
Over five years (2013-2018), the DES collaboration is using 525 nights of observation to carry out a deep, wide-area survey to record information from 300 million galaxies that are billions of light-years from Earth.
The survey is imaging 5,000 square degrees of the southern sky in five optical filters to obtain detailed information about each galaxy. A fraction of the survey time is used to observe smaller patches of sky roughly once a week to discover and study thousands of supernovae and other astrophysical transients.