Remember the spectacle of
that gigantic
telescope unveiled in a mountain-ringed valley in China just a few
years ago? Well, the Five-hundred-meter
Aperture Spherical Radio Telescope (FAST) has now picked up a
mysterious space signal known as a fast radio burst.
Fast radio bursts or
FRBs are brief but powerful pulses of energy from distant parts of the cosmos.
The first one was spotted in 2007, and we're finding
more of them all the time. While astronomers have recently made some
exciting progress in tracing FRBs, we just don't know exactly what
these signals are, or how they originate. They might be caused by black holes or neutron stars called magnetars, perhaps.
What's exciting about the
detection by FAST is that this fast radio burst is a repeater. The burst is
officially known as FRB 121102: first picked up in 2012 at the Arecibo
Observatory in Puerto Rico, it's appeared several
times since. Researchers note that the signal has travelled around 3
billion light-years across the Universe to reach us.
FAST latched on to FRB
121102 on August 30, before recording dozens of later pulses (on one particular
day, September 3, more than 20 pulses were detected). So, this looks like a
particularly persistent FRB. The 19-beam receiver on FAST is especially
sensitive to radio signals, covering the 1.05-1.45 GHz frequency range, and
that makes it perfect for keeping an eye on FRB 121102.
The more observations we can
make of these FRBs, the better our chances of being able to work out exactly
what they are. One idea is that FRBs are produced upon disintegration of the
crusts of certain types of neutron stars. Another hypothesis posits that
different FRBs actually have
different causes, which may explain why FRB 121102 repeats and others don't
appear to do so. We are at least getting
better at pinpointing where these mysterious bursts of electromagnetic
radiation come from.
Now we can add the data
gathered by FAST to our growing database of knowledge on these most intriguing
of space phenomena. The team at the telescope has already been able to
eliminate aircraft and satellite interference from their measurements.
“I just think it is so amazing that nature produces something like that,” physicist Ziggy Pleunis of McGill University told ScienceAlert, after helping to detail eight new FRBs in a paper published last month. “Also, I think that there is some very important information in that structure that we just have to figure out how to encode and it has been a lot of fun to try to figure out what exactly that is.”
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