Perhaps one of the most exciting of the mysterious astronomical phenomena could be fast radio bursts, or FRBs. Located in the radio band of the electromagnetic spectrum, these strange flashes of light come from outer space and appear randomly.
Their sources are thought to be likely black holes, neutron stars or even aliens, and they persist for less than a millisecond to a few seconds before disappearing without trace.
Now researchers have announced that they have detected five new FRBs, thanks to an update to the Westerbork Synthesis Radio Telescope in the Netherlands. Three of these FRBs traveled through space as they approached Earth, piercing past our spiral galaxy (galaxy) neighbor, the Triangle Galaxy (also known as Triangulum Galaxy or Messier 33), about 2.73 million light-years away.
New FRBs were detected in 2019, but they were detailed in a paper recently published by an international team led by Joeri van Leeuwen at the University of Amsterdam. “Fast radio bursts (FRBs) must be powered by unique energetic emission mechanisms,” the paper says.
What is FRB and why does it occur?
FRBs are radio waves, so they are not visible to the human eye, but they are not uncommon. Although they come from all over the sky, they have managed to baffle researchers for years as little understood why and how they arise and spread.
It may be possible for them to be emitted by neutron stars. However, some scientists have also suggested that they may be artificial signals created by intelligent beings. In 2017, a team at the Harvard-Smithsonian Center for Astrophysics said they could come from distant alien transmitters powering interstellar probes. Professor Avi Loeb from the Institute said it was worth considering that there might be an artificial source of these signals at the time.
A single FRB explosion contains 10 trillion times the annual energy consumption of the entire world population. These flares are so powerful that radio telescopes can detect them more than four billion light-years away. However, FRBs are difficult to study, as it is not possible to know where the next eruption will occur in the sky. Also, although there have been instances found in the past year that lasted three seconds, 1,000 times longer than average, each of these bursts typically only lasted a millisecond. For this reason, experts rely on land-based telescopes deployed around the world to detect these transient radio waves at any time.
Radio telescope array at WesterborkAstronomers have updated the radio telescope array at Westerbork with a new supercomputer called the Apertif Radio Transient System (ARTS). Built on the site of the former Nazi isolation camp in WWII, Westerbork contains 14 bowls, each 25 meters in diameter. The ARTS supercomputer now continuously combines images from 12 Westerbork dish antennas to create a sharp picture over a huge field of view.
In the past, radio telescopes could only approximate where an FRB occurred, but ARTS now allows experts to accurately pinpoint an FRB’s exact location.
FRBs are known to pierce other galaxies on their way to Earth, and the normally mostly invisible electrons in these galaxies disrupt the flares.
The researchers found that as five FRBs traveled through space, three of them “finely pierced” the halo of the Triangulum galaxy, also known as M33. Then they encountered the halo of the much larger Andromeda galaxy (M31) close to M33, and finally the halo and disk of our own Milky Way.
From the sharp new images, astronomers were for the first time able to estimate the maximum number of invisible atoms in Triangulum. The team now wants to learn more about how and why FRBs got so bright and their mysterious origins.
The study was published in the journal Astronomy & Astrophysics.
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