The most sensitive SETI observation by multi-beam coincidence matching strategy towards exoplanet systems

Abstract

`Are we alone?' The Search for Extra-Terrestrial Intelligence (SETI) aims to answer this profound question. Apart from examining environments in our solar system and detecting biosignatures in exoplanet atmospheres, SETI is another main approach to search for life beyond Earth by detecting technosignatures indicative of extra-terrestrial intelligence (ETI), such as engineering radio signals. Massive efforts have been made by SETI scientists using radio telescopes around the world. Though some candidate signals were detected, none of them has been confirmed as an ETI technosignature so far. Most targeted SETI observations performed in recent years use on-off strategy to distinguish signals transmitted from celestial bodies from radio frequency interference (RFI) generated near the ground. Here we report a SETI campaign employing another SETI observation strategy, multi-beam coincidence matching (MBCM), at the Five-hundred-meter Aperture Spherical radio Telescope (FAST) towards 33 currently discovered planetary systems, searching for narrow band drifting signals at a band of $1.05-1.45$ GHz. Our observations achieve an unprecedented sensitivity with a minimum Equivalent Isotropic Radiated Power (EIRP) of $1.5 \times 10^{9} ~\text{W}$. We process the data of two orthogonal polarization separately, aiming to discriminate instrumental RFI signals. A particular signal at 1140.604 MHz from the observation towards Kepler-438 passes our initial selection criteria. Although we have not yet determined the exact cause of this signal, its polarization characteristic suggests that it is most likely to be attributed to RFI. In spite of this, our work verifies that compared to single-beam on-off strategy, MBCM greatly improves both time efficiency and radio frequency interference (RFI) identification effectiveness of targeted SETI observations.

UAP Research in Germany: Single Case Studies, Data Management, Understanding of “Strangeness”

“…Zwar machen die Radiowellen-SETI-Projekte inzwischen große Fortschritte (Enriquez et al, 2017;Franz et al, 2022;Gajjar et al, 2021;Garrett & Siemion, 2023;Harp et al, 2016Harp et al, , 2019Ma, P. X., 2023Price et al, 2020;Sheikh et al, 2020;Suresh et al, 2023;Tao et al, 2022;Wlodarczyk-Sroka et al, 2020;Zhang et al, 2020). Doch um mit der gegenwärtigen Empfindlichkeit (10 -26 Watt pro Quadratmeter in einem 1-Hertz-Kanal) beispielsweise Signale von einem 200 Lichtjahre fernen Planeten zu empfangen, müsste der potenziell detektierbare Sender eine Leistung von 10 13 bis 10 15 Watt haben.…”

Drift Rates of Narrow-band Signals in Long-term SETI Observations for Exoplanets

“…Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the largest single aperture radio telescope in the world (Li & Pan 2016) which covers 57% of the celestial sphere. As the most sensitive radio telescope in the world (Jiang et al 2020;Wang et al 2021a), FAST has carried out its first SETI observation by drift-scan survey (Zhang et al 2020) and the first targeted SETI observation (Tao et al 2022). Since FAST has its unique advantages of large sky coverage and high sensitivity, we use FAST as an example of receivers on the Earth in the following calculations.…”