The quest for radio signals from technologically-advanced extraterrestrial intelligence has traditionally concentrated on the vicinity of 1.4 GHz. In this paper, we extend the search to unprecedented territories, detailing our extensive observations at 6 GHz and initiating the first-ever survey at 18 GHz with the Sardinia Radio Telescope (SRT). Our strategy entailed rigorous observation sessions, totaling 36 hours, directed towards the Galactic Center and 72 selected TESS targets-making this the most comprehensive high-frequency technosignature search to date. Our narrowband signal search found no definitive evidence of drifting signals that could suggest an extraterrestrial origin from the surveyed regions. Nevertheless, our efforts have enabled us to set new constraints on the presence of radio emissions from approximately 5×105 stars, establishing an isotropic radiated power limit of 1.8×1019W. We also provide a comparative analysis of the 'hits' recorded across both frequencies to highlight the significance of pursuing technosignature searches at higher frequencies, where the spectral landscape is less congested and more conducive to detection.
@article{arxiv.2410.09288,
title = {The First High Frequency Technosignature Search Survey with the Sardinia Radio Telescope},
author = {Lorenzo Manunza and Alice Vendrame and Luca Pizzuto and Monica Mulas and Karen I. Perez and Vishal Gajjar and Andrea Melis and Maura Pilia and Delphine Perrodin and Giambattista Aresu and Marta Burgay and Alessandro Cabras and Giuseppe Carboni and Silvia Casu and Tiziana Coiana and Alessandro Corongiu and Steve Croft and Elise Egron and Owen A. Johnson and Adelaide Ladu and Matt Lebofsky and Francesca Loi and David MacMahon and Emilio Molinari and Matteo Murgia and Alberto Pellizzoni and Tonino Pisanu and Antonio Poddighe and Erika Rea and Andrew Siemion and Paolo Soletta and Matteo Trudu and Valentina Vacca},
journal= {arXiv preprint arXiv:2410.09288},
year = {2025}
}