![]() The bursts fell into two types: ones with high brightness and others with low brightness. During some episodes, there was about one every 30 seconds. The bursts turned out to be much more intensive than expected. So, they decided to spare about an hour every day to monitor it. When the team performed test observations during the telescope’s commissioning phase, they noticed that FRB 121102 was in a frenzy of activity, frequently emitting bright pulses. Thanks to the unprecedented sensitivity of FAST, it can catch less energetic pulses that other telescopes cannot, says Di Li, the paper’s lead author and FAST’s chief scientist. FAST did more than one thousand, which is amazing,” Petroff says. “With a repeating source, other telescopes usually get somewhere between two and a hundred pulses. Prior to FAST’s mother lode of new events, scientists using other radio telescopes had reported nearly 350 FRBs from this source, which is nestled in a galaxy where lots of young stars are taking shape. FRB 121102 is the best studied such source so far. Statistics drawn from the ever-expanding catalog of detections have now revealed that about 20 percent of FRBs happen more than once, and these repeating sources allow astronomers to make more detailed follow-up observations. It was not until 2016 that observers detected the first repeating source, named FRB 121102. For a time-before FAST and other FRB-hunting telescopes began operations, anyway-the running joke among theorists was that FRB theories outnumbered the known FRB events themselves. Explanations for FRBs have ranged from enormous magnetic eruptions upon spinning neutron stars to the emissions from star-hopping alien spaceships. Early on, researchers had little clue what the bursts could be, and scrambled to come up with ideas. ![]() The first FRBs struck astrophysicists like thunderbolts out of a clear blue sky no theory had predicted their existence. “Such in-depth analyses of individual sources will be a top priority in FRB research in the near future.” A Bevy of Bursts “The study is very thorough, with a level of details and sensitivity we’ve never had before,” says astrophysicist Emily Petroff from the University of Amsterdam in the Netherlands and McGill University in Canada, who is not involved in the research. Besides dramatically boosting the total number of known FRB events, the observations also revealed a very wide range of brightnesses among the recorded events, offering new clues about the astrophysical nature of their mysterious source. According to their paper published in Nature today, between August and October 2019 the Five-Hundred-Meter Aperture Spherical Radio Telescope (FAST) in southwestern China recorded a total of 1,652 such brief and bright outbursts from a single repeating FRB source in a dwarf galaxy three billion light years away. Now, using the world’s largest single-dish radio telescope, an international team has reported the largest set of FRB events ever detected in history. ![]() First discovered in 2007, FRBs have challenged and tantalized scientists seeking to uncover their obscure origins and to use them as unique tools for probing the depths of intergalactic space. They pop up all across the sky multiple times a day, but most appear to be one-off events and are thus hard to catch. Coming from deep space, these outbursts can flash and fade in a matter of milliseconds, yet in each instance can release as much energy as the sun does in a year. Fast radio bursts, or FRBs, are one of the greatest mysteries of our universe. ![]()
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