The First High Frequency Technosignature Search Survey with the Sardinia Radio Telescope

TL;DR

This paper reports the first high-frequency technosignature search using the Sardinia Radio Telescope at 6 and 18 GHz, setting new constraints on extraterrestrial radio emissions and emphasizing the advantages of higher frequency observations.

Contribution

It introduces the first survey at 18 GHz for technosignatures and provides comprehensive high-frequency data, expanding the search beyond traditional 1.4 GHz studies.

Findings

No definitive extraterrestrial signals detected.

Set new upper limits on radio emissions from ~500,000 stars.

Highlighted the benefits of high-frequency searches for clearer spectral landscapes.

Abstract

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 $5\times 10^{5}$ stars, establishing an isotropic radiated power limit of $1.8\times 10^{19} W$. 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.