This research was supported by the European Research Council (ERC) under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 617199 ('ALERT'); by Vici research programme 'ARGO' with project number 639.043.815, financed by the Dutch Research Council (NWO); by the Netherlands eScience Center under the project 'AA-ALERT' (027.015.G09, grant ASDI.15.406); by the Netherlands Research School for Astronomy, NOVA, under 'NOVA-NW3', and 'NOVA5-NW3-10.3.5.14'; and through CORTEX (NWA.1160.18.316), under the research programme NWA-ORC, financed by NWO. Instrumentation development was supported by NWO (grant 614.061.613 'ARTS') and NOVA ('NOVA4-ARTS'). PI of aforementioned grants is JvL. EP acknowledges funding from an NWO Veni Fellowship. The contributions of SMS were supported by NASA grant NNX17AL74G issued through the NNH16ZDA001N Astrophysics Data Analysis Program (ADAP). EAKA is supported by the WISE research programme, which is financed by NWO. BA acknowledges funding from the German Science Foundation DFG, within the Collaborative Research Center SFB1491 "Cosmic Interacting Matters - From Source to Signal". KMH acknowledges financial support from the State Agency for Research of the Spanish Ministry of Science, Innovation and Universities through the "Center of Excellence Severo Ochoa" awarded to the Instituto de Astrofisica de Andalucia (SEV-2017-0709), from the coordination of the participation in SKA-SPAIN, funded by the Ministry of Science and Innovation (MCIN). KMH and TvdH acknowledge funding from the ERC under the European Union's Seventh Framework Programme (FP/2007-2013)/ERC Grant Agreement No. 291531 ('HIStoryNU'). RM acknowledges support from the same programme under ERC Advanced Grant RADIOLIFE-320745. This work makes use of data from the Apertif system installed at the Westerbork Synthesis Radio Telescope owned by ASTRON. ASTRON, the Netherlands Institute for Radio Astronomy, is an institute of NWO.

Fast radio bursts (FRBs) must be powered by uniquely energetic emission mechanisms. This requirement has eliminated a number of possible source types, but several remain. Identifying the physical nature of FRB emitters arguably requires good localisation of more detections, as well as broad-band studies enabled by real-time alerting. In this paper, we present the Apertif Radio Transient System (ARTS), a supercomputing radio-telescope instrument that performs real-time FRB detection and localisation on the Westerbork Synthesis Radio Telescope (WSRT) interferometer. It reaches coherent-addition sensitivity over the entire field of the view of the primary-dish beam. After commissioning results verified that the system performed as planned, we initiated the Apertif FRB survey (ALERT). Over the first 5 weeks we observed at design sensitivity in 2019, we detected five new FRBs, and interferometrically localised each of them to 0.4–10 sq. arcmin. All detections are broad band, very narrow, of the order of 1 ms in duration, and unscattered. Dispersion measures are generally high. Only through the very high time and frequency resolution of ARTS are these hard-to-find FRBs detected, producing an unbiased view of the intrinsic population properties. Most localisation regions are small enough to rule out the presence of associated persistent radio sources. Three FRBs cut through the halos of M31 and M33. We demonstrate that Apertif can localise one-off FRBs with an accuracy that maps magneto-ionic material along well-defined lines of sight. The rate of one every ~7 days ensures a considerable number of new sources are detected for such a study. The combination of the detection rate and localisation accuracy exemplified by the first five ARTS FRBs thus marks a new phase in which a growing number of bursts can be used to probe our Universe. © The Authors 2023.

van Leeuwen et al.--Full list of authors: van Leeuwen, Joeri; Kooistra, Eric; Oostrum, Leon; Connor, Liam; Hargreaves, Jonathan E.; Maan, Yogesh; Pastor-Marazuela, Ines; Petroff, Emily; van der Schuur, Daniel; Sclocco, Alessio; Straal, Samayra M.; Vohl, Dany; Wijnholds, Stefan J.; Adams, Elizabeth A. K.; Adebahr, Bjoern; Attema, Jisk; Bassa, Cees; Bast, Jeanette E.; Bilous, Anna; de Blok, Willem J. G.; Boersma, Oliver M.; van Cappellen, Wim A.; Coolen, Arthur H. W. M.; Damstra, Sieds; Denes, Helga; van Diepen, Ger N. J.; Gardenier, David W.; Grange, Yan G.; Gunst, Andre W.; Hess, Kelley M.; Holties, Hanno; van der Hulst, Thijs; Hut, Boudewijn; Kutkin, Alexander; Loose, G. Marcel; Lucero, Danielle M.; Mika, Agnes; Mikhailov, Klim; Morganti, Raffaella; Moss, Vanessa A.; Mulder, Henk; Norden, Menno J.; Oosterloo, Tom A.; Orru, Emaneula; Paragi, Zsolt; de Reijer, Jan-Pieter R.; Schoenmakers, Arno P.; Stuurwold, Klaas J. C.; ter Veen, Sander; Wang, Yu-Yang; Zanting, Alwin W.; Ziemke, Jacob

With funding from the Spanish government through the "Severo Ochoa Centre of Excellence" accreditation (SEV-2017-0709).

Peer reviewed