An Opportunistic Search for ExtraTerrestrial Intelligence (SETI) with the Murchison Widefield Array

Abstract

A spectral line image cube generated from 115 minutes of MWA data that covers a field of view of 400 sq. deg. around the Galactic Centre is used to perform the first Search for ExtraTerrestrial Intelligence (SETI) with the Murchison Widefield Array. Our work constitutes the first modern SETI experiment at low radio frequencies, here between 103 and 133 MHz, paving the way for large-scale searches with the MWA and, in the future, the low frequency Square Kilometre Array. Limits of a few hundred mJy/beam for narrow band emission (10 kHz) are derived from our data, across our 400 sq. deg. field of view. Within this field, 45 exoplanets in 38 planetary systems are known. We extract spectra at the locations of these systems from our image cube, to place limits on the presence of narrow line emission from these systems. We then derive minimum isotropic transmitter powers for these exoplanets; a small handful of the closest objects (10s of pc) yield our best limits of order $10^{14}$ W (Equivalent Isotropic Radiated Power: EIRP). These limits lie above the highest power directional transmitters near these frequencies currently operational on Earth. A SETI experiment with the MWA covering the full accessible sky and its full frequency range would require approximately one month of observing time. The MWA frequency range, its Southern Hemisphere location on an extraordinarily radio quiet site, its very large field of view, and its high sensitivity make it a unique facility for SETI.

Accepted to ApJ Letters

References in corpus (6)

• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• The low-frequency environment of the Murchison Widefield Array: radio-frequency interference analysis and mitigation
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• Science with the Murchison Widefield Array: Phase I Results and Phase II Opportunities
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• Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST
• A 4-8 GHz Galactic Center Search for Periodic Technosignatures
• A Search for Technosignatures toward the Galactic Centre at 150 MHz
• Strategies for Maximizing Detection Rate in Radio SETI
• Intermittent Signals and Planetary Days in SETI
• A Simultaneous Dual-site Technosignature Search Using International LOFAR Stations
• An Extragalactic Widefield Search for Technosignatures with the Murchison Widefield Array