SETI & Technosignatures

The Breakthrough Listen Search for Intelligent Life: Technosignature Search of 97 Nearby Galaxies

By Keith Cowing
Status Report
December 8, 2023
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The Breakthrough Listen Search for Intelligent Life: Technosignature Search of 97 Nearby Galaxies
Sky map of galaxy targets. The colored squares indicate whether the full source is covered by the GBT beam at all four bands (see Table 1), three bands, two, one, or none. The blue dots are galaxy targets in the southern hemisphere that are part of the Parkes Observatory sample for observation by Murriyang and are not discussed further here. At least one cadence was taken per source per band (Appendix A). All “on” pointings in a given cadence were aimed at the center of the target galaxy. — astro-ph.IM

The Breakthrough Listen search for intelligent life is, to date, the most extensive technosignature search of nearby celestial objects.

We present a radio technosignature search of the centers of 97 nearby galaxies, observed by Breakthrough Listen at the Robert C. Byrd Green Bank Telescope. We performed a narrowband Doppler drift search using the turboSETI pipeline with a minimum signal-to-noise parameter threshold of 10, across a drift rate range of ± 4 Hz\ s−1, with a spectral resolution of 3 Hz and a time resolution of ∼ 18.25 s.

We removed radio frequency interference by using an on-source/off-source cadence pattern of six observations and discarding signals with Doppler drift rates of 0.

We assess factors affecting the sensitivity of the Breakthrough Listen data reduction and search pipeline using signal injection and recovery techniques and apply new methods for the investigation of the RFI environment.

We present results in four frequency bands covering 1 — 11 GHz, and place constraints on the presence of transmitters with equivalent isotropic radiated power on the order of 1026 W, corresponding to the theoretical power consumption of Kardashev Type II civilizations.

Carmen Choza, Daniel Bautista, Steve Croft, Bryan Brzycki, Andrew Siemion, Krishnakumar Bhattaram, Daniel Czech, Imke de Pater, Vishal Gajjar, Howard Isaacson, Kevin Lacker, Brian Lacki, Matthew Lebofsky, David H. E. MacMahon, Danny Price, Sarah Schoultz, Sofia Sheikh, Savin Shynu Varghese, Lawrence Morgan, Jamie Drew, S. Pete Worden

Comments: 25 pages, 22 figures
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM); Astrophysics of Galaxies (astro-ph.GA)
Cite as: arXiv:2312.03943 [astro-ph.IM] (or arXiv:2312.03943v1 [astro-ph.IM] for this version)
Journal reference: AJ 167 10 (2024)
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Submission history
From: Carmen Choza
[v1] Wed, 6 Dec 2023 22:52:01 UTC (13,678 KB)
Astrobiology, SETI,

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻