Solar flare observations with the Radio Neutrino Observatory Greenland (RNO-G)

Agarwal S, Aguilar JA, Ali S, Allison P, Betts M, Besson D, Bishop A, Botner O, Bouma S, Buitink S, Cataldo M, Clark BA, Coleman A, Couberly K, de Kockere S, de Vries KD, Deaconu C, DuVernois MA, Glaser C, Glüsenkamp T, Hallgren A, Hallmann S, Hanson JC, Hendricks B, Henrichs J, Heyer N, Hornhuber C, Hughes K, Karg T, Karle A, Kelley JL, Korntheuer M, Kowalski M, Kravchenko I, Krebs R, Lahmann R, Latif U, Laub P, Liu CH, Marsee MJ, Meyers Z, Mikhailova M, Monstein C, Mulrey K, Muzio M, Nelles A, Novikov A, Nozdrina A, Oberla E, Oeyen B, Punsuebsay N, Pyras LM, Ravn M, Ryckbosch D, Schlüter F, Scholten O, Seckel D, Seikh MF, Stoffels J, Terveer K, Toscano S, Tosi D, Van Den Broeck DJ, van Eijndhoven N, Vieregg AG, Vijai A, Welling C, Williams DR, Windischhofer P, Wissel S, Young R, Zink A (2025)

Publication Type: Journal article

Publication year: 2025

Journal

Book Volume: 164

Article Number: 103024

DOI: 10.1016/j.astropartphys.2024.103024

Abstract

The Radio Neutrino Observatory – Greenland (RNO-G) seeks discovery of ultra-high energy neutrinos from the cosmos through their interactions in ice. The science program extends beyond particle astrophysics to include radioglaciology and, as we show herein, solar observations, as well. Currently seven of 35 planned radio-receiver stations (24 antennas/station) are operational. These stations are sensitive to impulsive radio signals with frequencies between 80 and 700 MHz and feature a neutrino trigger threshold for recording data close to the thermal floor. RNO-G can also trigger on elevated signals from the Sun, resulting in nanosecond resolution time-domain flare data; such temporal resolution is significantly shorter than from most dedicated solar observatories. In addition to possible RNO-G solar flare polarization measurements, the Sun also represents an extremely useful above-surface calibration source. Using RNO-G data recorded during the summers of 2022 and 2023, we find signal excesses during solar flares reported by the solar-observing Callisto network and also in coincidence with ∼2/3 of the brightest excesses recorded by the SWAVES satellite. These observed flares are characterized by significant time-domain impulsivity. Using the known position of the Sun, the flare sample is used to calibrate the RNO-G absolute pointing on the radio signal arrival direction to sub-degree resolution. We thus establish the Sun as a regularly observed astronomical calibration source to provide the accurate absolute pointing required for neutrino astronomy.

Authors with CRIS profile

Involved external institutions

Vrije Universiteit Brussel (VUB) Belgium (BE) University of Kansas (KU) United States (USA) (US) Pennsylvania State University (Penn State) United States (USA) (US) Université libre de Bruxelles (ULB) / Free University of Brussels Belgium (BE) Ohio State University United States (USA) (US) University of Wisconsin - Madison United States (USA) (US) Uppsala University Sweden (SE) University of Maryland United States (USA) (US) Deutsches Elektronen-Synchrotron DESY Germany (DE) Università della Svizzera italiana (USI) Switzerland (CH) University of Nebraska-Lincoln United States (USA) (US) Radboud University Nijmegen Netherlands (NL) University of Delaware (UDEL) United States (USA) (US) Universiteit Gent (UGent) / Ghent University Belgium (BE) Whittier College United States (USA) (US) The University of Alabama United States (USA) (US)

How to cite

APA:

Agarwal, S., Aguilar, J.A., Ali, S., Allison, P., Betts, M., Besson, D.,... Zink, A. (2025). Solar flare observations with the Radio Neutrino Observatory Greenland (RNO-G). Astroparticle Physics, 164. https://doi.org/10.1016/j.astropartphys.2024.103024

MLA:

Agarwal, S., et al. "Solar flare observations with the Radio Neutrino Observatory Greenland (RNO-G)." Astroparticle Physics 164 (2025).

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