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The newly discovered bursts come from repetitive sources, which means that they have been observed many times. Previously, only two repeated radio bursts had been observed. New observations suggest that repeated bursts are more common than previously thought.
"It was certainly on the table that [repeaters] were quite rare and you will not see many, "said Deborah Good, co-author of the study and PhD student. student at the University of British Columbia. "Having eight other sources is a good sign that it's not uncommon to have a repeater."
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We are excited to announce Astronomy new magazine Space and beyond subscription box – a quarterly adventure, organized with a collection on the theme of astronomy in each box. Learn more >>Fast radio bursts are flashes of electromagnetic energy that only last a few fractions of a second. Finding repeaters is useful to understand their nature. Currently, it is thought that fast radio bursts, which originate from outside the Milky Way, are caused by a type of compact object – a neutron star, a pulsar, or a black hole – but scientists do not know exactly which mechanism triggers them.
"Anything you propose as a model for fast radio bursts must explain why repeaters and point tasks are totally different objects, or must be able to easily explain the burst that occurs again and again," Good said.
Gusts were captured by the Canadian hydrogen intensity mapping experiment, or CHIME, a telescope located near Penticton, British Columbia, Canada. The experiment continually maps the sky into radio frequencies, observing every day the entire northern sky. Telescopes collect much more information than can be analyzed or even stored. As a result, automated computer algorithms continually analyze the data to search for interesting events.
The eight new events, reported in a new document submitted to the Letters from the Astrophysical Journal and published on the arXiv pre-print site, were seen in sightings from August 2018 to March 2019, while CHIME was just beginning its main science campaign.
After analyzing the data, scientists found a unique structure in the signal of some repeaters. During the burst, the frequency of the signal decreased slightly, as had been observed during the two previous repetitions. Why does this happen, and if it is something that is like repeating fast bursts of radio, is not yet clear.
"It may be that only repeaters have this structure, but it's not all repeaters that have this structure," Good said. "It's still an open question."
It is possible that a different source or mechanism is responsible for the drift signal in these repeaters, but it is still too early to say. Within the scientific community there is still a debate about whether single sources are distinct or whether they are simply repeaters that have not yet been repeated.
"We still do not have enough fast localized radio repeats to host galaxies and say something about [the leading] theories, but as we find more repeaters and identify their location in their host galaxies, we will begin to be able to distinguish different theories, "said Emily Petroff, astronomer at the Anton Pannekoek Institute of the University of Amsterdam. the new study.
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