Summary
Acta Astronautica paper (Manunza et al. 2025; arXiv:2410.09288, journal ref 2025AcAau.233..155M) reporting the first high-frequency radio technosignature survey conducted with the Sardinia Radio Telescope (SRT), a 64-m single dish in Italy. The team observed at 6 GHz and 18 GHz — the 18 GHz survey being the first SETI search ever attempted at that frequency — over 36 total observation hours directed at the Galactic Center and 72 selected TESS targets. The narrowband search for drifting signals returned a null result: no evidence of extraterrestrial-origin signals. The survey nonetheless set new constraints on radio emissions from roughly 5×10⁵ stars and established an isotropic radiated power (EIRP) limit of 1.8×10¹⁹ W. The authors argue for pushing technosignature searches to higher frequencies, where the spectral landscape is less congested. The author list is heavily Breakthrough Listen-affiliated, including vishal-gajjar, steve-croft, Andrew Siemion, Matt Lebofsky, and David MacMahon.
Key Claims
- First-ever radio technosignature survey at 18 GHz, and the most comprehensive high-frequency (6 GHz + 18 GHz) search to date (Manunza et al.).
- 36 hours of SRT observation toward the Galactic Center and 72 TESS targets; null result — no drifting narrowband signals of extraterrestrial origin (Manunza et al.).
- New constraints set on radio emissions from ~5×10⁵ stars (Manunza et al.).
- Isotropic radiated power (EIRP) detection limit of 1.8×10¹⁹ W established (Manunza et al.).
- Higher frequencies offer a less congested spectral environment, motivating future high-frequency surveys (Manunza et al.).
Notable Quotes
“Our narrowband signal search found no definitive evidence of drifting signals that could suggest an extraterrestrial origin from the surveyed regions.” — Manunza et al.
Key figures: 6 GHz + 18 GHz; 36 hrs; Galactic Center + 72 TESS targets; ~5×10⁵ stars constrained; EIRP limit 1.8×10¹⁹ W.