Nearby galaxy emitting mysterious radio waves: Scientists

Last Updated: Thursday, April 15, 2010 - 19:37

New York: An unknown object in the nearby
galaxy -- M82 -- is sending out radio waves, an incident which
has never happened in the universe before.

Researchers at the Jodrell Bank Centre for Astrophysics
near Macclesfield in UK, who have traced the radio waves said
that”they don`t know what it is".

The team, which presented the discovery at the Royal
Astronomical Society National Astronomy Meeting in Glasgow
today, said the thing appeared in May last year while they
were monitoring an unrelated stellar explosion in M82.

"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," lead
researcher Tom Muxlow was quoted as saying by New Scientist.

"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".

They added, the new source has hardly changed in
brightness over the course of a year, and its spectrum is
steady.

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", said the researchers who used the MERLIN
network of radio telescopes in the UK for the discovery.

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.

PTI



First Published: Thursday, April 15, 2010 - 19:37

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