# A Search for Technosignatures Around 11,680 Stars with the Green Bank Telescope at 1.15-1.73 GHz

**Authors:** Jean-Luc Margot, Megan G. Li, Pavlo Pinchuk, Nathan Myhrvold, Lea E. Alcantara, Megan T. Andrakin, Jeth Arunseangroj, Damien S. Baclet, Madison H. Belk, Zerxes R. Bhadha, Nicholas W. Brandis, Robert E. Carey, Harrison P. Cassar, Sai S. Chava, Calvin Chen, James Chen, Kellen T. Cheng, Alessia Cimbri, Benjamin Cloutier, Jordan A. Combitsis  
**arXiv:** [2308.02712](https://arxiv.org/abs/2308.02712)  
**Date:** 2023-08-04  
**Summary page:** https://www.summarizepaper.com/en/arxiv-id/2308.02712v1/

## Key points

- Conducted search for narrowband radio signals using the L-band receiver of the Green Bank Telescope
- Observed 62 TESS Objects of Interest, capturing radio emissions from approximately 11,860 stars and planetary systems
- Detected signals were confirmed to be of anthropogenic origin, ruling out extraterrestrial technosignatures
- UCLA SETI pipeline demonstrated high signal recovery rate (94.0% excluding RFI, 98.7% overall)
- Another pipeline utilizing incoherent sums of consecutive spectra achieved a significantly lower recovery rate (approximately 6%)
- Developed an improved Drake Figure of Merit for SETI search volume calculations to account for pipeline efficiency and frequency drift rate coverage
- High probability (94.0-98.7%) that less than ~0.014% of stars earlier than M8 within a distance of 100 parsecs host detectable transmitters with EIRP greater than 10^12 watts
- UCLA SETI pipeline natively detects signals previously detected using AI techniques by Ma et al in 2023
- Contributes to ongoing efforts in searching for extraterrestrial intelligence and highlights importance of pipeline efficiency in SETI research

## Summary

In this study, the authors conducted a search for narrowband radio signals using the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. The observations were carried out over four observing sessions from 2020 to 2023 and pointed towards 62 TESS Objects of Interest, resulting in the capture of radio emissions from approximately 11,860 stars and planetary systems within the telescope's ~9 arcminute beam. All detections were carefully examined through an automated rejection process and subsequent visual inspection which confirmed that all detected signals were of anthropogenic origin, ruling out any potential extraterrestrial technosignatures. Additionally, the authors assessed the efficiency of radio SETI pipelines by conducting a signal injection and recovery analysis. The UCLA SETI pipeline demonstrated a high recovery rate, successfully recovering 94.0% of injected signals across the usable frequency range of the receiver when excluding regions with dense radio frequency interference (RFI), this recovery rate increased to 98.7%. In contrast, another pipeline that utilized incoherent sums of consecutive spectra only achieved a recovery rate of approximately 6%, which is significantly lower. The efficiency of SETI pipelines has implications for various calculations related to SETI search volumes and upper bounds on the number of transmitting civilizations; thus to account for pipeline efficiency and frequency drift rate coverage, the authors developed an improved Drake Figure of Merit for SETI search volume calculations. Based on their observations and analysis it was determined that there is a high probability (94.0-98.7%) that less than ~0.014% of stars earlier than M8 within a distance of 100 parsecs host detectable transmitters with an equivalent isotropic radiated power (EIRP) greater than 10^12 watts; furthermore it was found that the UCLA SETI pipeline natively detects signals previously detected using artificial intelligence (AI) techniques by Ma et al in 2023. Overall this study contributes to ongoing efforts in searching for extraterrestrial intelligence and highlights importance in pipeline efficiency in SETI research; providing valuable insights into detectability technosignatures as well as informing future studies aiming to expand our understanding potential technological civilizations beyond Earth.