April 13, 2024

Puzzling Periodicity of a Fast Radio Burst Probed by Two of the Biggest Radio Telescopes in the World

We report how the Westerbork dishes (left) detected a regular, brief Fast Radio Burst in the blue, high-frequency radio sky. The radio rainbow itself also goes from “bluer,” short-wavelength radio to “redder” long-wavelength radio. Fast Radio Bursts were never seen at long radio wavelengths before, fuelling theories that they were surrounded by dense electron mists. The group of astronomers has now studied a Fast Radio Burst at 2 radio wavelengths– one bluer, one much redder– at the very same time. We saw 2 days of bluer, radio bursts, followed by 3 days of redder radio bursts.

Integrating Westerbork and LOFAR
Both telescopes tape-recorded radio movies with thousands of frames per second. “Once we analyzed the data, and compared the two radio colors, we were extremely shocked,” states Pastor-Marazuela. We saw 2 days of bluer, radio bursts, followed by 3 days of redder radio bursts.
The Fast Radio Burst detections were the very first ever with LOFAR. Dr. Yogesh Maan from ASTRON initially laid eyes on the LOFAR bursts: “It was delighting to discover that Fast Radio Burst shine at such long wavelengths. “The truth that some Fast Radio Bursts live in tidy environments, relatively unobscured by any dense electron mist in the host galaxy, is extremely exciting,” states co-author Dr. Liam Connor (U. Amsterdam/ASTRON).
Magnetars
The LOFAR telescope and the Apertif system on Westerbork each are powerful in their own right, however the advancements were made possible due to the fact that the group straight connected the two, as if they were one. “We built a real-time device finding out system on Westerbork that informed LOFAR whenever a burst came in,” states principal private investigator Dr. Joeri van Leeuwen (ASTRON/U. Amsterdam), “But no simultaneous LOFAR bursts were seen. Initially, we believed a haze around the Fast Radio Bursts was obstructing all redder bursts– but surprisingly, as soon as the bluer bursts had stopped, redder bursts appeared after all. When we recognized simple binary wind models were ruled out, thats. Quick Radio Bursts are bare, and could be made by magnetars.”
Their magnetic fields are many times more powerful than the greatest magnet in any Earth lab. “It feels a lot like being a detective– our observations have substantially narrowed down which Fast Radio Burst designs can work.”
Reference: “Chromatic routine activity down to 120 megahertz in a quick radio burst” by Inés Pastor-Marazuela, Liam Connor, Joeri van Leeuwen, Yogesh Maan, Sander ter Veen, Anna Bilous, Leon Oostrum, Emily Petroff, Samayra Straal, Dany Vohl, Jisk Attema, Oliver M. Boersma, Eric Kooistra, Daniel van der Schuur, Alessio Sclocco, Roy Smits, Elizabeth A. K. Adams, Björn Adebahr, W. J. G. de Blok, Arthur H. W. M. Coolen, Sieds Damstra, Helga Dénes, Kelley M. Hess, Thijs van der Hulst, Boudewijn Hut, V. Marianna Ivashina, Alexander Kutkin, G. Marcel Loose, Danielle M. Lucero, Ágnes Mika, Vanessa A. Moss, Henk Mulder, Menno J. Norden, Tom Oosterloo, Emanuela Orrú, Mark Ruiter and Stefan J. Wijnholds, 25 August 2021, Nature.DOI: 10.1038/ s41586-021-03724-8.

We report how the Westerbork dishes (left) detected a regular, short Fast Radio Burst in the blue, high-frequency radio sky. Time passed, the stable background stars turned into trails. Only much later did the exact same source produce at a loss, low-frequency radio sky. The LOFAR telescope (right) now found these for the very first time. This chromatic behavior reveals the bursts are not regularly obstructed by binary-star winds. Credit: Joeri van Leeuwen
By linking 2 of the greatest radio telescopes in the world, astronomers have discovered that an easy binary wind can not cause the perplexing periodicity of a Fast Radio Burst. The radio detections also reveal that Fast Radio Bursts, some of the most energetic occasions in the Universe, are free from shrouding product.
Radio colors
Using “radio colors” caused the breakthrough. In optical light, colors are how the eye distinguishes each wavelength. Our rainbow goes from shorter-wavelength blue optical light, to longer-wavelength red optical light. Electro-magnetic radiation that the human eye can not see, because the wavelength is short or too long, is equally genuine. Astronomers call this “ultra-violet light” or “radio light.” The radio-light extends the rainbow beyond the red edge we see. The radio rainbow itself also goes from “bluer,” short-wavelength radio to “redder” long-wavelength radio. Radio wavelengths are a million times longer than the wavelengths of optical blue and red, but fundamentally they are just “colors”: radio colors.
Fast Radio Bursts were never ever seen at long radio wavelengths prior to, sustaining theories that they were surrounded by dense electron mists. We report the first-ever long wavelength radio detection, utilizing the LOFAR telescope (squares on the right); working in tandem with the Westerbork meals (left). We conclude there is, in fact, no mist around the Fast Radio Burst. That transparent and clear view is essential for cosmology. Credit: Joeri van Leeuwen
The group of astronomers has now studied a Fast Radio Burst at two radio wavelengths– one bluer, one much redder– at the exact same time. Quick Radio Bursts are some of the brightest flashes in the radio sky, but they produce outside of our human vision. They just last about 1/1000th of a second. The energy required to form Fast Radio Bursts must be exceedingly high. Still, their exact nature is unknown. Some Fast Radio Bursts repeat, and in the case of FRB 20180916B, that repeating is regular. This periodicity led to a series of models in which Fast Radio Bursts come from a set of stars orbiting each other. The binary orbit and excellent wind then produce the periodicity. “Strong stellar winds from the companion of the Fast Radio Burst source were expected to let most blue, short-wavelength radio light get away the system. But the redder long-wavelength radio needs to be obstructed more, or perhaps totally,” states Inés Pastor-Marazuela (University of Amsterdam and ASTRON), the first author of the publication.