From: LARRY KLAES (ljk4_at_msn.com)
Date: Tue Oct 02 2007 - 06:46:22 PDT
http://www.dailygalaxy.com/my_weblog/2007/10/mysterious-radi.html
October 01, 2007
Mysterious Radio Burst from Magellanic Cloud Stuns & Baffles Astronomers
In a fascinating finding, reminiscent of the extraterrestrial Tycho Monolith
blast on the Moon in Arthur C. Clarke's 2001 A Space Odyssey, astronomers
using Australia's Parkes telescope have detected a huge burst of radio
energy from the distant universe that could open up a new field in
astrophysics.
The research team, led by Assistant Professor Duncan Lorimer of West
Virginia University, reports its discovery today in the online journal
Science Express. The intense, single, short-lived blast of radio waves
likely occurred some 3 billion light-years from Earth, and it may signal a
cosmic crash of two neutron stars, the death throes of a black hole—or
something else.
"This is something that's completely unprecedented," said Duncan Lorimer, an
astrophysicist at West Virginia University in Morgantown and the National
Radio Astronomy Observatory who led the discovery-making team. He noted that
radio-emitting pulsars send out similar emissions, but repeat them every few
hours.
"Normally the kind of cosmic activity we're looking for at this distance
would be very faint but this was so bright that it saturated the equipment,"
said Professor Matthew Bailes of Swinburne University in Melbourne.
The burst was so bright that at the time it was first recorded it was
dismissed as man-made radio interference. It put out a huge amount of power
(10exp33 Joules), equivalent to a large (2000MW) power station running for
two billion billion years.
"The burst may have been produced by an exotic event such as the collision
of two neutron stars or be the last gasp of a black hole as it evaporates
completely," Professor Lorimer said. The burst lasted just five
milliseconds.
"We're confused and excited, but it could open up a whole new research
field," Lorimer told SPACE.com of the 5-millisecond blip on the cosmic radar
screen. "If we really go after these things, we expect to find out that a
couple hundred of them occur each day."
If the bursts are as frequent as Lorimer's team thinks, and they indicate
the death of black holes or two super-dense neutron stars violently smacking
together, a step toward closure of the universe's great mystery of gravity
may soon come.
The dramatic cosmic events are predicted to let loose gravity waves that
Einstein's theory of relativity predicts, but the phenomenon has never been
directly observed. LIGO—the Laser Interferometer Gravitational Wave
Observatory based in both Louisiana and Washington state—has been searching
for such waves since it went online in 2002.
The previously undetected radio burst was found in data from a 2001 radio
survey of the Small Magellanic Cloud, a nearby dwarf galaxy. Based on its
location, however, Lorimer said the burst almost certainly did not come from
the galaxy.
Lorimer said the emission's offset location and wide dispersion made it
"completely inconsistent" with that of a nearby object, whether in our own
galaxy or the Small Magellanic Cloud. "We've looked at it for about 90
hours, and it definitely seems to be a singular event," he said.
Astronomers originally created the 480-hour-long observation over 20 days to
look for repetitive radio emissions from pulsars, which are thought to be
fast-rotating neutron stars, but the event remained hidden in the data
because no one had set out to find single bursts.
Lorimer cautioned that it's impossible to say for certain what the radio
burst might indicate at this point, as it is the only one that has been
detected so far.
"We're keeping very open minds about this thing," Lorimer said, adding that
their uncertainty stems from the inability to pinpoint it to a galaxy or
other celestial object that could reveal some clues to its identity.
So far, the search has left the researchers empty-handed, but it may be an
issue of sensitivity. Lorimer emphasized that the records are several years
old and few radio observatories have the sensitivity to detect such short
bursts.
"Based on the area we looked at, we think this type of burst may occur at a
rate of a couple hundred each day," Lorimer said. He thinks that whole-sky
surveys using next-generation radio observatories would be needed to detect
most of them.
Although they've found only one burst, the astronomers can estimate how
often they occur. "We'd expect to see a few bursts over the whole sky every
day," said Dr John Reynolds, Officer in Charge at CSIRO's Parkes
Observatory.
"A new telescope being built in Western Australia will be ideal for finding
more of these rare, transient events.
"The Australian SKA Pathfinder, which is going to be built by 2012, will
have a very wide field of view--be able to see a very large piece of
sky--which is exactly what you want for this kind of work," he said.
Posted by Casey Kazan. Adapted from a CSIRO release
Story links:
http://www.space.com/scienceastronomy/070927_new_astronomy.html
http://www.theregister.co.uk/2007/09/28/super_radio_burst/
http://www.physorg.com/news110194718.html
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