SPACE
Michael Irving
August 20th, 2019
The CHIME radio
telescope has picked up eight new repeating fast radio bursts (Credit: CHIME)
Since the first fast radio bursts
were discovered in 2007 in old data, dozens
of signals have been detected. Most are one-off events, but in 2015 a burst
was found coming from a location where another burst had been detected in 2012.
Since then this source, known as FRB 121102, has given off well over a hundred
signals, sometimes lying dormant for months, sometimes flashing dozens
of times in the space of a few hours.
For years FRB 121102 was the only
known repeater, but back in January this year a second was
discovered, followed by a third in June. And now, it looks like the ranks are
swelling with a ridiculous bumper crop of eight new repeating sources.
The incredible discovery comes
courtesy of a team of astronomers led by McGill University, using the Canadian
Hydrogen Intensity Mapping Experiment (CHIME)
radio telescope. The astronomers observed two bursts from six of the sources,
while another gave off three bursts. But one in particular really stole the
show, giving off 10 bursts within four months of observations.
One of the main mysteries of FRBs
is how closely related repeating and non-repeating signals are, and whether they
come from the same types of objects or environments. The discovery of eight new
repeaters gives astronomers a much wider toolset to work with, to help solve
this problem.
Comparing the new signals to
previously-known ones, the team noticed a few similarities and differences. The
dispersion measures – which is how "stretched" the signal becomes as it travels
across the cosmos – appear to be roughly within the same range for both types of
FRB sources. That said, bursts from repeaters tend to last longer than those
from non-repeaters. And finally, some of the new signals were also found to give
off weaker sub-bursts after the main show.
Altogether, the team concludes
that the phenomena may be coming from different sources, or at least similar
sources under different conditions. After all, FRB 121102 signals have been
found to be extremely
twisted, meaning the source object may be very close to a black hole, nebula
or supernova remnant. Not all repeaters may live in these extreme conditions,
which could change their signals.
With more and more telescopes
pointing skyward, the mystery of fast radio bursts feels like one that may be
solved in the relatively near future.
The research has been submitted
to the Astrophysical
Journal Letters for potential publication.
Source: New Atlas URL:
https://newatlas.com/eight-new-repeating-fast-radio-bursts/61137/arXiv
(PDF)