The Search for Extraterrestrial Intelligence aims to find evidence of technosignatures, which can point toward the possible existence of technologically advanced extraterrestrial life. Radio signals similar to those engineered on Earth may be transmitted by other civilizations, motivating technosignature searches across the entire radio spectrum. In this endeavor, the low-frequency radio band has remained largely unexplored; with prior radio searches primarily above 1 GHz. In this survey at 110-190 MHz, observations of 1,631,198 targets from TESS and Gaia are reported. Observations took place simultaneously with two international stations (noninterferometric) of the Low Frequency Array in Ireland and Sweden. We can reject the presence of any Doppler drifting narrowband transmissions in the barycentric frame of reference, with equivalent isotropic radiated power of 10 17 W, for 0.4 million (or 1.3 million) stellar systems at 110 (or 190) MHz. This work demonstrates the effectiveness of using multisite simultaneous observations for rejecting anthropogenic signals in the search for technosignatures.
@article{arxiv.2310.15704,
title = {A Simultaneous Dual-site Technosignature Search Using International LOFAR Stations},
author = {Owen A. Johnson and Vishal Gajjar and Evan F. Keane and David J. McKenna and Charles Giese and Ben McKeon and Tobia D. Carozzi and Cloe Alcaria and Aoife Brennan and Bryan Brzycki and Steve Croft and Jamie Drew and Richard Elkins and Peter T. Gallagher and Ruth Kelly and Matt Lebofsky and Dave H. E. MacMahon and Joseph McCauley and Imke de Pater and Shauna Rose Raeside and Andrew P. V. Siemion and S. Pete Worden},
journal= {arXiv preprint arXiv:2310.15704},
year = {2023}
}