Nov 13, 2013 |
Black hole jets pack a powerful punch
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(Nanowerk News) Black-hole jets recycle matter and energy into space and can affect when and where a galaxy forms stars.
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"Jets from supermassive black holes help determine a galaxy's fate — how it evolves," said CSIRO’s Dr Tasso Tzioumis, a member of the research team.
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"So we want to understand better the impact jets have on their environment."
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The work, led by Dr María Díaz Trigo of the European Southern Observatory, is published in the journal Nature today ("Baryons in the relativistic jets of the stellar-mass black-hole candidate 4U 1630-47").
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Visualisation of a black-hole system like 4U1630-47: a stellar-mass black hole being "fed" by a companion star. (Image: NASA / CXC / M. Weiss)
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Astronomers have known for decades that black-hole jets contain electrons, which are low-mass particles.
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But using the European Space Agency's XMM-Newton space telescope and CSIRO's Compact Array radio telescope in northwest NSW, the research team found the first evidence of heavy atoms — iron and nickel — in the jets from a 'typical' black hole known as 4U1630-47.
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An iron atom is about 100,000 times more massive than an electron. When a massive particle is moving it carries more energy than a lighter particle moving at the same speed.
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"Heavy atoms have been seen in jets from one other system, SS433, but that’s a very unusual system, an oddball, whereas this system is quite typical, much more likely to represent black holes in general," Dr Tzioumis said.
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While 4U1630-47 is a small black hole, a few times the mass of the Sun, the physics of black holes "is scalable", he said, meaning that the finding would apply to larger black holes.
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The discovery suggests that jets are powered by the black hole's accretion disk — a belt of hot gas swirling around the black hole — and not by the spin of the black hole itself, which would be more likely to produce jets containing only light particles.
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The jets from 4U1630-47 are travelling fast, at two-thirds the speed of light.
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When such fast-moving jets containing heavy particles smash into matter in space, they could generate gamma rays and neutrinos, which might be detectable with current and future telescopes.
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