Conducting High Frequency Radio SETI using ALMA

arXiv (Cornell University)

Abstract

The Atacama Millimeter/Submillimeter Array (ALMA) remains unparalleled in sensitivity at radio frequencies above 35 GHz. In this paper, we explore ALMA's potential for narrowband technosignature detection, considering factors such as the interferometer's undistorted field of view, signal dilution due to significant drift rates at high frequencies and the possibility of spectral confusion. We present the first technosignature survey using archival ALMA data in Band 3, focusing on two spectral windows centred on 90.642 GHz and 93.151 GHz. Our survey places new limits at these frequencies on the prevalence of extraterrestrial transmitters for 28 galactic stars, selected from the Gaia DR3 catalogue. We employ a stellar 'bycatch' method to sample these objects within the undistorted field of view of four ALMA calibrators. For the closest star in our sample, we find no evidence of transmitters with EIRP_min > 7 x 10^17 W. To the best of our knowledge, this represents the first technosignature search conducted using ALMA data.

Authors 3

1. M. A. Garrett Aachen Leiden Observatory

   Leiden University · University of Manchester · Leiden Observatory

   Affiliation as printed

   Jodrell Bank Centre for Astrophysics, University of Manchester

   Leiden Observatory, Leiden University

2. Kelvin Wandia

   University of Manchester

   Affiliation as printed

   Jodrell Bank Centre for Astrophysics, University of Manchester

3. Andrew P. V. Siemion

   University of Manchester · University of California, Berkeley · University of Oxford · University of Malta · Search for Extraterrestrial Intelligence

   Affiliation as printed

   Jodrell Bank Centre for Astrophysics, University of Manchester

   Astrophysics Sub-Department, Department of Physics, University of Oxford

   SETI Institute

   Berkeley SETI Research Centre, University of California

   University of Malta