THE most powerful quasar yet discovered in our cosmic neighbourhood is confounding astronomers by spewing out huge amounts of matter at up to 10 per cent of the speed of light.
Quasars are mighty X-ray sources thought to be powered by supermassive black holes, which are supposed to attract, not expel material. The discovery may change our understanding of these mysterious objects.
The gravity near black holes is so strong that even light cannot escape, and they cannot be seen directly. But we can see the material spiralling into their centres, as well as the powerful X-ray jets produced at right angles to the spiral disc.
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Paul O鈥橞rien of the University of Leicester and his colleagues used the European Space Agency鈥檚 XMM-Newton X-Ray Telescope and UV data from the Hubble Space Telescope to study a quasar called PDS456, which at 800 million light years away is relatively nearby. At the National Astronomy Meeting in Dublin last week, O鈥橞rien鈥檚 team reported that in addition to huge amounts of radiation, the quasar is spewing out at least the mass of our Sun every year. 鈥淲e didn鈥檛 expect to find this material coming out and we are puzzled by it,鈥� he says. 鈥淚t is a very large amount of material and we don鈥檛 know where it goes.鈥� One theory is that PDS456 has recently drawn in so much material it cannot swallow it all, causing the black hole to somehow 鈥渃hoke鈥� and expel some of the matter back outwards.
The phenomenon might be quite common among quasars. O鈥橞rien and his colleagues have already observed a second quasar expelling material and another team, using NASA鈥檚 Chandra X-Ray telescope, has just reported two similar bodies. 鈥淧erhaps this sort of thing is more common than we imagined and we are only seeing them now because of the incredible power of new X-ray observatories,鈥� says O鈥橞rien. He says the team now plans to look at more quasars to see if they are behaving in the same way. 鈥淚f they do then we have a brand new problem to solve.鈥�
