Extending the Breakthrough Listen nearby star survey to other stellar objects in the field using Gaia DR2

  • Bart Wlodarczyk-Sroka

Student thesis: Master of Science by Research


Following the work of Wlodarczyk-Sroka, Garrett & Siemion (2020), the source sample recently observed by the Breakthrough Listen Initiative (Enriquez et al. 2017; Price et al. 2020) is extended, by probing Gaia DR2 to include additional stars residing within the > 10% sensitivity response range of the GBT and Parkes radio telescope target fields. With parallax and position data from Gaia, these stars have distance estimates published in extensions of the Gaia DR2 catalogue (Bailer-Jones et al. 2018). Extending the EIRP calculations of Price et al. (2020) to a much larger sample of stellar objects (increased from 1327 sources to 965469) results in substantially better Continuous Waveform Transmitter Rate Figures of Merit (CWTFM) than previous analyses, producing the tightest limits achieved to date on the prevalence of nearby high duty cycle extraterrestrial transmitters. Gaia data for sources in the extended sample is also used to place new constraints on the prevalence of such transmitters by stellar type and spectral class. The results suggest ~ 5.3*10^13 W) and ~ 1.3*10^15 W). The extended sample includes sources as distant as 10 kpc, although caution should be exercised when considering results beyond a few hundred pc, as detection of narrow-band signals from such distances may be affected by interstellar scintillation. The results also suggest targeted analyses of SETI radio data can benefit from considering the fact that in addition to the target at the field centre, many other cosmic objects reside within the primary beam response of a parabolic radio telescope. These include foreground and background Galactic stars, but also extragalactic systems. With distances to these objects calculated from Gaia data or otherwise, these additional sources can be used to place improved limits on the prevalence of extraterrestrial transmitters, and to extend the analysis to a wide range of cosmic objects.
Date of Award1 Aug 2021
Original languageEnglish
Awarding Institution
  • The University of Manchester
SupervisorPaddy Leahy (Supervisor) & Michael Garrett (Supervisor)


  • SETI
  • Breakthrough Listen
  • Gaia

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