After upgrading the network of radio telescopes in Westerbork, the Netherlands, astronomers have found five new fast radio bursts. Telescope images, much sharper than before, revealed that multiple bursts had pierced our neighboring Triangle galaxy. This allowed astronomers to determine for the first time the maximum number of otherwise invisible atoms in this galaxy.

Fast radio bursts, or FRBs, are among the brightest explosions in the universe. Bursts primarily emit radio waves. The lightning is so powerful that radio telescopes can detect it even over four billion (!) light-years away. This continuous visibility over such vast distances means that the gusts contain immense amounts of energy. When extinguished, a single FRB contains ten trillion (ten million times a million) times the annual energy consumption of the entire world population.

This gigantic generation of energy makes FRBs very interesting. Many astronomers believe they are emitted by neutron stars. The density and intensity of the magnetic field of these extremely compact stars are unique in the universe. By studying lightning, astronomers aim to better understand the fundamental properties of the matter that makes up the universe. But the study of these flashes is difficult. No one knows where in the sky the next burst will explode. And an FRB only lasts a millisecond: if you blink, you’ll miss it.

Powered by new receivers and a new supercomputer (the Apertif Radio Transient System, ARTS), Westerbork has now discovered five new FRBs. He also spotted them immediately, says lead researcher Joeri van Leeuwen (ASTRON): “We now have an instrument with both a very wide field of view and very sharp vision. And all this live. It’s new and exciting.

Previously, radio telescopes such as Westerbork detected FRBs as with the compound eyes of a fly. Flies can see in all directions, but blurry. Upgrading Westerbork is like crossing the eyes of a fly with those of an eagle. The ARTS supercomputer continuously combines images from twelve Westerbork dishes to create a sharp image over a massive field of view. “You can’t just buy the complex electronics you need for this,” says system architect Eric Kooistra (ASTRON). “We designed most of the system ourselves, with a great team. This resulted in a state-of-the-art machine, one of the most powerful in the world.

Skewed galaxies

Astronomers want to understand how and why FRBs get so bright. But the flashes are also interesting because on their way to Earth they pierce other galaxies. Electrons from these galaxies, normally mostly invisible, distort lightning. Tracking down invisible electrons and the atoms that accompany them is important because most of the matter in the universe is dark and we still know little about it. Previously, radio telescopes could only indicate approximately where an FRB was occurring. The ARTS supercomputer now allows Westerbork to pinpoint the exact location of an FRB very precisely. Van Leeuwen: “We demonstrated that three of the FRBs we discovered had skewered our neighbor, the Triangle Galaxy! We were thus able to count for the first time how many invisible electrons this galaxy contains at most. A fantastic result.

Reference: “The Apertif Radio Transient System (ARTS): design, commissioning, data release and detection of the first five fast radio bursts” by Joeri van Leeuwen, Eric Kooistra, Leon Oostrum, Liam Connor, Jonathan E. Hargreaves, Yogesh Maan, Inés Pastor-Marazuela, Emily Petroff, Daniel van der Schuur, Alessio Sclocco, Samayra M. Straal, Dany Vohl, Stefan J. Wijnholds, Elizabeth AK Adams, Björn Adebahr, Jisk Attema, Cees Bassa, Jeanette E. Bast, Anna Bilous, Willem JG de Blok, Oliver M. Boersma, Wim A. van Cappellen, Arthur HWM Coolen, Sieds Damstra, Helga Dénes, Ger NJ van Diepen, David W. Gardenier, Yan G. Grange, André W. Gunst, Kelley M Hess, Hanno Holties, Thijs van der Hulst, Boudewijn Hut, Alexander Kutkin, G. Marcel Loose, Danielle M. Lucero, Ágnes Mika, Klim Mikhailov, Raffaella Morganti, Vanessa A. Moss, Henk Mulder, Menno J. Norden, Tom A Oosterloo, Emaneula Orrú, Zsolt Paragi, Jan-Pieter R. de Reijer, Arno P. Schoenmakers, Klaas JC Stuurwold, Sander ter Veen, Yu-Yang Wang, Alwin W. Zanting and Jacob ZiemkeApril 12, 2023 , Astronomy & Astrophysics.
DOI: 10.1051/0004-6361/202244107