A team of international astronomers has pinpointed the precise position of one of the most mysterious phenomena in the cosmos: a fast radio burst (FRB). As the name suggests, fast radio bursts are short-lived, but powerful, pulses of radio waves from space that last for only fractions of a second.
First discovery and speculation of source
The first FRB was discovered in 2007, in archived data from the Parkes Radio Telescope in Australia. Astronomers were searching for new examples of magnetized neutron stars called pulsars, but found a new phenomenon — a radio burst from 2001. Since then, 18 FRBs have been found.
Astronomers believed these flashes were coming from incredibly powerful sources. Some thought they were coming from cataclysmic events in the deep universe, such as a hypernova or a supermassive black hole ejecting material. Others argued that fast radio bursts originated from pulsars surrounded by galactic dust or intense magnetic events in our own Milky Way galaxy.
The problem was that these blasts of radio light were also infinitesimally brief, lasting only a few milliseconds — which made them extremely difficult to locate, especially given that radio telescopes can only look at a small patch of sky at a time.
Astronomers pinpoint source as small dwarf glaxy
After years of painstaking observations, astronomers finally pinpointed the origin of an FRB. Named FRB 121102, it was first discovered by scientists at the massive Arecibo Observatory in Puerto Rico.
After watching FRB 121102 for 83 hours over six months, the astronomers picked up nine bursts from the same spot. Together, those flashes of light allowed them to pinpoint the location — and then use the Gemini North telescope in Hawaii to study its source. The source turned out to be a dwarf galaxy some 3 billion light years away that holds about a hundredth of our Milky Way’s mass.
“The host galaxy for this FRB appears to be a very humble and unassuming dwarf galaxy, which is less than 1 percent of the mass or our Milky Way galaxy.
“That’s surprising. One would generally expect most FRBs to come from large galaxies which have the largest numbers of stars and neutron stars — remnants of massive stars.”
Since this is the only known repeating burst, it’s possible it could represent a completely different phenomenon to other FRBs. Further research will be needed to clarify the nature of the flashes, and to determine whether all FRBs are caused by the same phenomenon or have different causes.
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