A narrow-band search for extraterrestrial intelligence (seti) using the interstellar contact channel hypothesis

Abstract

We report a search for narrow spectral line emission from 176 targets (including 166 stars and seven globular clusters) at the hypothesized 'interstellar communications channel' frequency of 4.462336275 GHz ( = jt times the neutral hydrogen line at 1.42 GHz) using the Parkes Radio telescope. The frequency was Doppler corrected for the solar barycentre, target barycentre and cosmic microwave background (CMB) reference frames. If a 'Galactic club' of extraterrestrial civilizations exists, then our null results, down to a 3a limit of 2 Jy (6 Jy in CMB frame), set an upper limit of 10s yr on the lifetime of such civilizations.