Strange News And The UneXplained!

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Mysterious radio waves emitted from nearby galaxy

Posted by 3citynewswire on 04/15/2010

Something in there is producing an unusually radio signal

There is something strange in the cosmic neighbourhood. An unknown object in the nearby galaxy M82 has started sending out radio waves, and the emission does not look like anything seen anywhere in the universe before.

“We don’t know what it is,” says co-discoverer Tom Muxlow of Jodrell Bank Centre for Astrophysics near Macclesfield, UK. The thing appeared in May last year, while Muxlow and his colleagues were monitoring an unrelated stellar explosion in M82 using the MERLIN network of radio telescopes in the UK. A bright spot of radio emission emerged over only a few days, quite rapidly in astronomical terms. Since then it has done very little except baffle astrophysicists.

It certainly does not fit the pattern of radio emissions from supernovae: they usually get brighter over a few weeks and then fade away over months, with the spectrum of the radiation changing all the while. The new source has hardly changed in brightness over the course of a year, and its spectrum is steady.
Warp speed

Yet it does seem to be moving – and fast: its apparent sideways velocity is four times the speed of light. Such apparent “superluminal” motion has been seen before in high-speed jets of material squirted out by some black holes. The stuff in these jets is moving towards us at a slight angle and travelling at a fair fraction of the speed of light, and the effects of relativity produce a kind of optical illusion that makes the motion appear superluminal.

Could the object be a black hole? It is not quite in the middle of M82, where astronomers would expect to find the kind of supermassive central black hole that most other galaxies have. Which leaves the possibility that it could be a smaller-scale “microquasar”. A microquasar is formed after a very massive star explodes, leaving behind a black hole around 10 to 20 times the mass of the sun, which then starts feeding on gas from a surviving companion star. Microquasars do emit radio waves – but none seen in our galaxy is as bright as the new source in M82. Microquasars also produce plenty of X-rays, whereas no X-rays have been seen from the mystery object. “So that’s not right either”, Muxlow said.

His best guess is still that the radio source is some kind of dense object accreting surrounding material, perhaps a large black hole or a black hole in an unusual environment. Perhaps the phenomenon also happens occasionally in our galaxy, but is more common in M82 because it is a “starburst” galaxy – a cosmic cauldron where massive stars are forming and exploding at a much higher rate than in the Milky Way, creating a lot of new black holes.

Muxlow will report the discovery at the Royal Astronomical Society National Astronomy Meeting in Glasgow, UK,

Radio image of M82 made with the MERLIN and VLA telescopes. The resolution of the main image (the size of a pixel) is 100 milliarcseconds, the diameter of a 1 pence coin when viewed at a distance of 40 km. Insets show MERLIN images from April 25th and May 3rd 2009 demonstrating the sudden appearance of the mystery object. The resolution of these inset images is 40 mas. All images are at a frequency of 5 GHz. Credit: T.W.B. Muxlow, University of Manchester.

A paper on the discovery has been submitted to the Monthly Notices of the Royal Astronomical Society

(Submitted on 4 Mar 2010) Brief Report below from Rob Beswick. [Jodrell Bank Centre for Astrophysics, Manchester]

A faint new radio source has been detected in the nuclear region of the starburst galaxy M82 using MERLIN radio observations designed to monitor the flux density evolution of the recent bright supernova SN2008iz. This new source was initially identified in observations made between 1-5th May 2009 but had not been present in observations made one week earlier, or in any previous observations of M82. In this paper we report the discovery of this new source and monitoring of its evolution over its first 9 months of existence. The true nature of this new source remains unclear, and we discuss whether this source may be an unusual and faint supernova, a supermassive blackhole associated with the nucleus of M82, or intriguingly the first detection of radio emission from an extragalactic microquasar.

Below is a video tour of M82 Galaxy

Source: Jodrell Bank Centre for Astrophysics


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