Three new fast radio bursts detected by the Westerbork Telescope have been shown to have penetrated the halo of our neighboring Triangular Galaxy. The invisible electrons in that galaxy distort the FRBs. From new, sharp vivid images, astronomers can estimate the maximum number of unseen atoms in the Triangulum Galaxy for the first time. Credit: ASTRON/Futselaar/van Leeuwen
After updating the array of the radio telescope in Westerbork, the Netherlands, astronomers have found five new fast radio bursts. Telescope images, sharper than previously possible, showed that several bursts had pierced our neighboring triangular galaxy. This allowed astronomers to determine for the first time the maximum number of unseen atoms in this galaxy.
Fast radio bursts, FRBs, are among the brightest explosions in the universe. The bursts are mainly emitted by radio waves. The flashes are so strong that radio telescopes can detect them even from a distance of more than four billion (!) Light years. This continuous visibility across such vast distances means that the jets contain huge amounts of energy. When it explodes, a single FRB contains ten trillion (ten million times a million) times the annual energy consumption of the entire global population.
This massive power generation makes FRBs very exciting. Many astronomers believe that they are emitted by neutron stars. The intensity and strength of the magnetic field of these very young stars is unique in the universe. By examining the flashes, astronomers aim to better understand the fundamental properties of the matter that makes up the universe. But studying these flashes is difficult. No one knows where the next batch will explode in the sky. And the FRB only lasts a split second: 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 identified it immediately, too, said principal investigator Joeri van Leeuwen (ASTRON): “We now have an instrument with a very wide field of view and very sharp vision. And it’s all live. This is new and exciting.”
Previously, radio telescopes such as Westerborks detected FRBs as did the compound eyes of a fly. Flies can see in all directions, but it is not visible. Upgrading Westerbork is like crossing the eyes of a fly with the eye of an eagle. The ARTS supercomputer continuously combines images from twelve Westerbork dishes to create a sharp image over an enormous field of view. “One can’t afford to buy the complex electronics you need for this,” says system engineer Erik Koestra (ASTRON). “We designed most of the system ourselves, with a great team. This resulted in an advanced machine, one of the most powerful in the world.”
galactic aberration
Astronomers want to understand how and why FRBs get so bright. But the flashes are also interesting because on their way to Earth they pass through other galaxies. The electrons in those galaxies, usually invisible, distort the flashes. Tracking invisible electrons and their companion atoms is important because most of the matter in the universe is dark and we still know so little about it. Previously, radio telescopes could roughly indicate where the FRB was occurring. The ARTS supercomputer now allows Westerbork to pinpoint the exact location of the FRB with pinpoint accuracy. Van Leeuwen: “We have shown that three of the FRBs we have detected have distorted our Triangulum galaxy! Thus for the first time we have been able to calculate the number of invisible electrons that the galaxy contains at most. A remarkable result.”
Reference: “The Apertif Radio Transient System (ARTS): Design, Commissioning, Data Release, and Detection of the First Five Speed Radio Streams” by Joeri van Leeuwen, Eric Kooistra, Leon Oostrum, Liam Connor, Jonathan E. Hargreaves, Yogesh Maan, Ines Pastor-Marazuela Emily Petrov, Daniel van der Schoor, Alessio Skloko, Samira M. Block, William JGD, Oliver M Boersma, WM A. Van Capelen, Arthur H.W.M. Colin, Sedis Damstra, Helga Dens, Geer NG Van Diepen, David W. Gardiner, Jan Grange, Andre W. Jonst, Kelly M. Hess, Hanno Holtes, Theis van der Hulst, Baudouin Hutt, Alexander Kotkin, J. Marcel Luce, Daniel M. Lucero, Ognes Mika, Klim Mikhailov, Raffaella Morgante, Vanessa A. Moss, Henk Mulder, Minno 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 Ziemke12 April 2023 And Astronomy and astrophysics.
DOI: 10.1051/0004-6361/202244107
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