A combination of powerful radio telescopes and supercomputers has allowed scientists a peek at how stars and massive galaxies formed in the infancy of our Universe. And, the picture they got is of unimaginable forces clashing, and forging massive clumps of matter into familiar cosmic objects.
The researchers from Cambridge University studying a quasar 13 billion years ago found it spitting out cold gas at speeds up to 2000kms per second, and across distances of nearly 200,000 light years — much farther than has been observed before. Quasars are extremely luminous objects powered by super massive black holes with the mass of a billion suns.
The supercomputer simulations show that on its way out of the parent galaxy, there is just enough time for some of the hot gas to cool to temperatures low enough to be observable with radio telescopes. The results are presented in two separate papers published today (16 January) in the journals Monthly Notices of the Royal Astronomical Society and Astronomy & Astrophysics.
"It is the first time that we have seen outflowing cold gas moving at these large speeds at such large distances from the super massive black hole," said Claudia Cicone, a PhD student at Cambridge's Cavendish Laboratory and Kavli Institute for Cosmology, and lead author on the first of the two papers. ""It is very difficult to have matter with temperatures this low move as fast as we observed.""
How this cold gas — the raw material for star formation in galaxies — can be accelerated to such high speeds had remained a mystery. Detailed comparison of new observations and supercomputer simulations has only now allowed researchers to understand how this can happen: the gas is first heated to temperatures of tens of millions of degrees by the energy released by the super massive black hole powering the quasar. This enormous build-up of pressure accelerates the hot gas and pushes it to the outskirts of the galaxy.
Quasars are amongst the most luminous objects in the Universe, and the most distant quasars are so far away that they allow us to peer back billions of years in time. They are powered by super massive black holes at the centre of galaxies, surrounded by a rapidly spinning disk-like region of gas. As the black hole pulls in matter from its surroundings, huge amounts of energy are released.
Cicone's observations allowed the second team of researchers specialising in supercomputer simulations to develop a detailed theoretical model of the outflowing gas around a bright quasar.
"We found that while gas is launched out of the quasar at very high temperatures, there is enough time for some of it to cool through radiative cooling - similar to how the Earth cools down on a cloudless night," said Tiago Costa, a PhD student at the Institute of Astronomy and the Kavli Institute for Cosmology, and lead author on the second paper. "The amazing thing is that in this distant galaxy in the young Universe the conditions are just right for enough of the fast moving hot gas to cool to the low temperatures that Claudia and her team have found."
http://timesofindia.indiatimes.com/followceleb.cms?alias=supercomputers,Quasar,powerful radio telescopes,Cambridge University,Black holes
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