Origin of a non-repeating fast radio burst pinpointed

An article published in the journal “Science” reports the localization of the point of origin of a non-repeating fast radio burst. A team of researchers led by Keith Bannister of CSIRO (Australia’s Commonwealth Science and Industrial Research Organization) discovered the fast radio burst cataloged as FRB 180924 with the ASKAP radio telescope and then proceeded using the Keck, Gemini South and VLT telescopes to pinpoint its origin in a galaxy about 3.6 billion light years away. Before this result, only the origin of a repeating fast radio burst was pinpointed.

Fast radio bursts were detected for the first time in 2007 by analyzing archive data collected in 2001 and are still a mystery because such powerful radio emissions require an estimated energy that’s about what the Sun emitted in 80 years despite their duration of a few milliseconds.

On September 24, 2018, the fast radio burst later cataloged as FRB 180924 was identified using the ASKAP (Australian Square Kilometer Array Pathfinder) radio telescope, one of the precursors of SKA, the next generation radio telescope, which has already practically doubled the known number of these events. The 36 ASKAP antennas work as a single instrument, however the electromagnetic waves of the fast radio burst take a slightly different time to reach the different antennas even if the differences are less than a billionth of a second. These are incredibly short times but enough to identify the galaxy from which FRB 180924 originated, classified as DES J214425.25-405400.81.

Nicolas Tejos, one of the authors of this research, explained that ASKAP gave them the two-dimensional position in the sky of the fast radio burst FRB 180924 but using the Keck, Gemini South and VLT (Very Large Telescope) telescopes it was possible to determine the distance and other characteristics by observing the galaxy in which it originated completing the localization in three dimensions. In essence, the three optical telescopes made it possible to identify the area within the galaxy in which FRB 180924 originated, which turned out to be in its periphery. The identification of these phenomena and the analysis of the electromagnetic waves detected could provide us with what Tejos called a cosmic tomography to create a three-dimensional map of the location of baryonic matter, the common one, among the galaxies.

The image (Courtesy CSIRO/Dr Andrew Howells. All rights reserved) shows an artistic representation of the ASKAP radio telescope that identifies a fast radio burst with follow-up observations with the Keck, Gemini South and VLT telescopes of the galaxy in which it originated.

Andrea Possenti of the Italian National Institute of Astrophysics in Cagliari, not part of the team that carried out this research, commented noting that in the case of gamma-ray bursts it took 25 years from the first recognized event to identify the origin of one of them, for fast radio bursts it took 12 years. About this identification, he pointed out that it confirms the hypothesis that there are at least two classes of fast radio bursts: repeating and non-repeating. Various researches, including one published in May 2019 in the journal “Astronomy & Astrophysics”, indicate that the repeating ones originate in magnetar-type neutron stars while the non-repeating ones could be generated by catastrophic phenomena that can’t be repeated because the object associated to them gets destroyed in the event.

In essence, research on fast radio bursts isn’t just a scientific curiosity but is connected to a number of cosmological problems concerning various phenomena and the composition of the universe. The ASKAP radio telescope showed in a short time to be extremely useful and the situation will improve even more when the SKA radio telescope will be completed and its activity will begin.

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