“Something like this has never been seen before.”
Astronomers working on the CHIME telescope recorded a powerful radio burst from a magnetar in the Milky Way. The peculiarity of this discovery is not only that the burst coincided with a period of increased activity of the magnetar, but also in that it resembles mysterious fast radio bursts. If the discovery is confirmed, then the magnetar will become the source of fast radio bursts closest to Earth, according to The Astronomer’s Telegram .
Fast radio bursts (Fast Radio Burst, FRB) – is short (up to several milliseconds), but the strong radio pulses. Their discovery was accidental and occurred in 2007, and it soon became clear that they could be of extraterrestrial nature. To date, about a hundred such bursts have been recorded that are associated with neutron stars , blitz , the decay of axion mini-clusters, extraterrestrial civilizations and other phenomena.
In 2018, it was possible to determine that fast repeating radio bursts from the source of FRB 121102 could occur in a magnetized medium near a rotating pulsar. Then the source of an individual fast radio burst was first determined , a second similar discovery soon followed , and then eight more sources of repeating FRB were discovered at once. All discoveries are united by the fact that all sources of fast radio bursts are extragalactic in nature. The source of FRB closest to us is in a large spiral galaxy with a redshift of z = 0.0337; recently, it was possible to detect the periodicity for the first time in fast radio bursts from it.
On April 27, 2020, the SGR 1935 + 2154 magnetar associated with the supernova remnant SNR G57.2 + 0.8 in the Milky Way, located 30 thousand light-years from us in the constellation Lisichka, experienced a burst of activity in the x-ray range. It was previously believed that this magnetar is a source of soft gamma-ray bursts. He became the target of observations for the Swift space telescope , the AGILE observatory , the NICER telescope mounted on the ISS, the INTEGRAL observatory, and other telescopes.
Initially, his behavior was typical for such objects, but on April 28, the Canadian CHIME telescope reported the registration of a powerful radio burst from the magnetar, which had two peak components five milliseconds long, separated by thirty milliseconds. The radio flux at frequencies of 400-800 megahertz amounted to several kilojans per millisecond.
An analysis of the CHIME archival data from the beginning of work at the end of 2018 did not reveal any similar events related to this magnetar in the past. If this magnetar were in another galaxy, then for the earth observer the signal would look like a fast radio burst. However, scientists have yet to analyze all the data for the similarity of the flash spectrum from SGR 1935 + 2154 with the spectra of extragalactic fast radio bursts.
An Indian group of scientists working on the GMRT telescope (Giant Metrowave Radio telescope) published a preprint in August 2019 reporting the discovery of a kind of “copy” of fast radio bursts from the J1810- magnetar 197 in our galaxy. Giant radio pulses were also observed from the pulsar in the Crab nebula, however, their generation mechanisms are still different from those that generate fast radio bursts. The situation is similar with SGR 1935 + 2154, where a phenomenon that looks similar to fast radio bursts can be very different from it in physical mechanism.