Published in

American Astronomical Society, Astronomical Journal, 6(165), p. 255, 2023

DOI: 10.3847/1538-3881/acccf0

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A 4–8 GHz Galactic Center Search for Periodic Technosignatures

This paper is made freely available by the publisher.
This paper is made freely available by the publisher.

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Preprint: archiving forbidden
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Postprint: archiving forbidden
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Published version: archiving allowed
Data provided by SHERPA/RoMEO

Abstract

Abstract Radio searches for extraterrestrial intelligence have mainly targeted the discovery of narrowband continuous-wave beacons and artificially dispersed broadband bursts. Periodic pulse trains, in comparison to the above technosignature morphologies, offer an energetically efficient means of interstellar transmission. A rotating beacon at the Galactic Center (GC), in particular, would be highly advantageous for galaxy-wide communications. Here, we present blipss, a CPU-based open-source software that uses a fast folding algorithm (FFA) to uncover channel-wide periodic signals in radio dynamic spectra. Running blipss on 4.5 hr of 4–8 GHz data gathered with the Robert C. Byrd Green Bank Telescope, we searched the central 6 ′ of our galaxy for kHz-wide signals with periods between 11 and 100 s and duty cycles (δ) between 10% and 50%. Our searches, to our knowledge, constitute the first FFA exploration for periodic alien technosignatures. We report a nondetection of channel-wide periodic signals in our data. Thus, we constrain the abundance of 4–8 GHz extraterrestrial transmitters of kHz-wide periodic pulsed signals to fewer than one in about 600,000 stars at the GC above a 7σ equivalent isotropic radiated power of ≈2 × 1018 W at δ ≃ 10%. From an astrophysics standpoint, blipss, with its utilization of a per-channel FFA, can enable the discovery of signals with exotic radio frequency sweeps departing from the standard cold plasma dispersion law.