News

Durham University joins NASA mission to determine source of the cosmic X-ray background

(13 June 2012)

A revolutionary NASA-led mission to determine the source of X-rays radiating from the cosmos and improve our understanding of the growth of black holes is due to be launched into orbit on board a satellite today (June 13th), with major input from Durham University experts.

The $170 million NuSTAR observatory satellite, sensitive to the detection of high-energy X-ray photons, will include an investigation into the origin of the X-ray background as one of its key scientific missions.

Professor David Alexander, from Durham University’s Department of Physics, is co-ordinating the deepest component of the X-ray background project.

Professor Alexander said: “The X-ray background is made up of X-rays that reach the Earth from all directions within the cosmos. Despite being first discovered 50 years ago in 1962, astronomers are still not entirely sure what produces this cosmic X-ray ‘noise’, with possible candidates ranging from growing black holes to yet undiscovered ‘exotic’ objects.”

The key technological advance that will allow NuSTAR to resolve this decades’ long mystery are its mirrors, which have a special coating that will allow us to accurately focus high-energy X-ray photons from space for the first time.

Dr James Mullaney, a researcher at Durham University working with Professor Alexander, offered a simple analogy to explain the improvement that NuSTAR will provide. He said: “It is as though we were previously trying to read a book without our glasses. You can see that there is text but can’t make out the individual letters. Currently we can only make out 2 per cent of this ‘cosmic text’. With NuSTAR, we will be able to make out the majority of the story, dramatically improving our understanding of black-hole growth and the history of the high-energy Universe.”

Amongst its many aims, NuSTAR will also study the remnants of supernovae, stars that have explored within our galaxy, and galaxy clusters. Galaxy clusters are some of the largest structures in the known Universe and are believed to be held together by dark matter – a mysterious substance thought to account for 85 per cent of the matter in the Universe.

NuSTAR is scheduled to launch no earlier than 8:30 a.m. PDT (4:30 p.m. BST) on June 13th from Kwajalein Atoll in the Marshall Islands. The spacecraft will lift off on an Orbital Sciences Pegasus XL launch vehicle, released from an aircraft flying south of Kwajalein. The satellite, orbiting the Earth at an altitude of approximately 550 kilometres, will initially be packaged up tightly. Approximately one week after the launch, a 10-metre mast will deploy, allowing NuSTAR to achieve its unique X-ray focusing capabilities.