The space object is different from other radio bursts in recent years, according to a new study.
Fast radio bursts or FRBs are bursts of radio waves in space lasting milliseconds. Individual radio bursts are broadcast once and do not recur. But repetitive fast bursts are known to send short, vigorous radio waves several times.
Astronomers have been able to trace some radio bursts back to their home galaxies, but have not yet determined the true cause of the impulses. Learning more about the origins of these bright, intense radio emissions can help scientists understand what causes them.
Astronomers discovered an object called FRB 190520 when it released a burst of radio waves on May 20, 2019. Researchers used a five-hundred-meter aperture or FAST spherical radio telescope in China, and discovered the telescope explosion in November 2019. When subsequent observations, astronomers they noticed something unusual: the object emitted frequent, recurring bursts of radio waves.
In 2020, the team used a very large array of Karl G. Jansky, or VLA of the National Telescope Science Foundation, to pinpoint the origin of the explosion before directing it with the Subaru Telescope in Hawaii. Subaru’s observations in visible light showed that the explosion came from the edge of a distant dwarf galaxy.
A study describing the findings was published in the journal Nature on Wednesday.
Two of a kind
VLA observations also revealed that the celestial object constantly emits weaker radio waves between repeated bursts. This is very similar to only one other well-known repetitive fast radio: FRB 121102, discovered in 2016.
The initial discovery and subsequent tracking of FRB 121102 back to its starting point in a small dwarf galaxy more than 3 billion light-years away was a breakthrough in astronomy. This was the first time astronomers have learned about the distance and environment of these mysterious objects.
“Now we actually have to explain this double mystery and why the FRB and permanent radio sources sometimes come together,” said study co-author Casey Lowe, a radio astronomy scientist at the California Institute of Technology. “Is it common when FRBs are young? Or maybe the object that makes the outbursts is a massive black hole that is cluttering up a neighboring star? Theorists have much more detail to work on now, and the scope of the explanation is shrinking.
It is now known that less than 5% of the hundreds of identified rapid radio outbreaks occur, and only a few are regularly active.
But FRB 190520 is the only one that is constantly active, which means it has never “switched off” since it was discovered, said study author Di Li, chief scientist at the radio department of China’s National Astronomical Observatories and FAST Operations Center. Meanwhile, FRB 121102, “the first known repeater, could be shut down for months,” Lee said.
New questions
Recent discoveries raise more questions because astronomers are now wondering if there could be two types of rapid radio bursts.
“Are those that recur often different from those that don’t? What about constant radio broadcasting – is it common?” said in a statement co-author of the study Kshitij Aggarwal, who participated in the study as a doctoral student at the University of West Virginia.
It is possible that there are different mechanisms that cause radio bursts, or that what produces them behaves differently during different stages of evolution.
Scientists have previously suggested that rapid radio bursts are caused by dense debris left after a supernova called a neutron star or neutron stars with incredibly strong magnetic fields called magnetars.
FRB 190520 is considered a possible “newborn” object because it is located in a dense environment, Lo said. This medium can be caused by material released by the supernova, which led to the formation of a neutron star. As this material dissipates over time, the outbreaks of FRB 190520 may decrease with age.
In the future, Lee wants to detect more rapid radio bursts.
“A consistent picture of the origins and evolution of the FRB is likely to emerge in just a few years,” Lee said.
Lo is excited about the consequences of having a new class of radio sources.
“For decades, astronomers thought there were basically two types of radio sources we could see in other galaxies: the accumulation of supermassive black holes and star-forming activity,” Lo said. “Now we say that it can no longer be either / or categorization! There is a new child in the city and we must take this into account when studying the populations of radio sources in the universe. “
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