The world's most powerful X-ray telescope has reached its final orbit around the Earth and is pointed at the edge of the universe, ready to reveal some of the secrets of the cosmos.
Launched last month, the European Space Agency's £689 million X-ray Multi-Mirror (XMM) telescope, which will explore previously unexamined areas of the universe, is the largest scientific spacecraft yet developed in Europe. "It is the flagship European X-ray astronomy mission," stated Dr Luke Drury, head of astrophysics at the Dublin Institute of Advanced Studies.
Its movements in space are being controlled by software developed by an Irish company, CAPTEC, based in Malahide, Co Dublin. Its software ensures the telescope is pointing where astronomers want it to point, and helps to keep the satellite safe.
CAPTEC's software makes sure the XMM does not directly face the sun which could ruin the telescope. "This is critical software," said Mr Fred Kennedy, managing director of CAPTEC. "If it did not work properly, the satellite would be lost." The XMM was launched on December 10th aboard an Ariane 5 launcher. The satellite's instruments are being checked and there have been no problems, according to an ESA spokeswoman. The first pictures will arrive in March, after which the instruments will be calibrated, leaving XMM ready for routine use by June.
The satellite uses X-ray astronomy, a relatively new branch of astrophysics that studies the Xray light emitted by stars and other objects. It will record dramatic events such as when a star is being swallowed by a black hole, or a dying star explodes as a supernova. All X-ray astronomy is carried out in space because Xrays from distant stars cannot penetrate the Earth's atmosphere. The XMM satellite collects these X-ray emissions using its three large and sensitive mirrors, which have a total area the size of a tennis court. Dr Lorraine Hanlon of the Department of Experimental Physics in UCD uses the analogy of a bucket to describe the telescope's sensitivity.
"Think of a bucket collecting raindrops. A larger bucket can collect more raindrops," she said. Raindrops in the XMM satellite's case are photons, single "droplets" of X-ray light. The more photons collected, the more information there is about the object that emitted the light.
As the State is a member of the European Space Agency, astronomers and astrophysicists from Irish research institutions can apply for viewing time through XMM. Prof Brian McBreen and Dr Hanlon from UCD have submitted a proposal and they expect to have their chance sometime next year.
As well as gathering more Xrays, instruments on the XMM can also distinguish the "colour" of the X-rays being viewed. The incoming X-rays are reflected into a spectrograph which acts as a kind of prism, splitting the light into its various colours with each of these indicating the presence of a specific element. This reveals the chemical composition of the object or the gas that emitted the X-ray light.
This information can help astronomers studying parts of the universe where galaxies are formed, as well as giving them further information about the origins of the universe - and of humankind. "After all, we're all made from cosmic dust. It would be nice to know where we came from," said Dr Hanlon.
XMM will be of particular benefit for astronomers studying celestial phenomena that occur when a star dies. These include black holes, which exert such a massive gravitational pull that photons cannot escape, and neutron stars, where a star has collapsed in on itself leaving a super dense object comparable to the sun collapsing into a lump the size of Dublin. These are both extremely hot objects, ones that can be found using X-ray astronomy.
XMM will be useful for examining how matter behaves in conditions of high temperature and pressure, conditions that cannot be replicated on earth, said Dr Paul Callanan, Department of Physics, UCC. Examining celestial phenomena such as black holes and neutron stars using XMM may help prove theories about the physics of the universe.