A Search for Technosignatures Around 11,680 Stars with the Green Bank Telescope at 1.15-1.73 GHz
Margot, Jean-Luc; Lynch, Ryan S.; Chen, James; Yamaguchi, Natsuko; Davis, Kyle W.; Li, Zhuofu (Chester); Li, Megan G.; Pinchuk, Pavlo; Myhrvold, Nathan; Lesyna, Larry; Alcantara, Lea E.; Andrakin, Megan T.; Arunseangroj, Jeth; Baclet, Damien S.; Belk, Madison H.; Bhadha, Zerxes R.; Brandis, Nicholas W.; Carey, Robert E.; Cassar, Harrison P.; Chava, Sai S.; Chen, Calvin; Cheng, Kellen T.; Cimbri, Alessia; Cloutier, Benjamin; Combitsis, Jordan A.; Couvrette, Kelly L.; Coy, Brandon P.; Delcayre, Antoine F.; Du, Michelle R.; Feil, Sarah E.; Fu, Danning; Gilmore, Travis J.; Grahill-Bland, Emery; Iglesias, Laura M.; Juneau, Zoe; Karapetian, Anthony G.; Karfakis, George; Lambert, Christopher T.; Lazbin, Eric A.; Li, Jian H.; Liskij, Nicholas M.; Lopilato, Anthony V.; Lu, Darren J.; Ma, Detao; Mathur, Vedant; Minasyan, Mary H.; Muller, Maxwell K.; Nasielski, Mark T.; Nguyen, Janice T.; Nicholson, Lorraine M.; Niemoeller, Samantha; Ohri, Divij; Padhye, Atharva U.; Penmetcha, Supreethi V.; Prakash, Yugantar; Qi, Xinyi (Cindy); Rindt, Liam; Sahu, Vedant; Scally, Joshua A.; Scott, Zefyr; Seddon, Trevor J.; Shohet, Lara-Lynn V.; Sinha, Anchal; Sinigiani, Anthony E.; Song, Jiuxu; Stice, Spencer M.; Tabucol, Nadine M.; Uplisashvili, Andria; Vanga, Krishna; Vazquez, Amaury G.; Vetushko, George; Villa, Valeria; Vincent, Maria; Waasdorp, Ian J.; Wagaman, Ian B.; Wang, Amanda; Wight, Jade C.; Wong, Ella; Zhang, Zijin; Zhao, Junyang
United States
Abstract
We conducted a search for narrowband radio signals over four observing sessions in 2020-2023 with the L-band receiver (1.15-1.73 GHz) of the 100 m diameter Green Bank Telescope. We pointed the telescope in the directions of 62 TESS Objects of Interest, capturing radio emissions from a total of ~11,680 stars and planetary systems in the ~9' beam of the telescope. All detections were either automatically rejected or visually inspected and confirmed to be of anthropogenic nature. We also quantified the end-to-end efficiency of radio SETI pipelines with a signal injection and recovery analysis. The UCLA SETI pipeline recovers 94.0% of the injected signals over the usable frequency range of the receiver and 98.7% of the injections when regions of dense radio frequency interference are excluded. In another pipeline that uses incoherent sums of 51 consecutive spectra, the recovery rate is ~15 times smaller at ~6%. The pipeline efficiency affects calculations of transmitter prevalence and SETI search volume. Accordingly, we developed an improved Drake figure of merit and a formalism to place upper limits on transmitter prevalence that take the pipeline efficiency and transmitter duty cycle into account. Based on our observations, we can state at the 95% confidence level that fewer than 6.6% of stars within 100 pc host a transmitter that is continuously transmitting a narrowband signal with an equivalent isotropic radiated power (EIRP) > 1013 W. For stars within 20,000 ly, the fraction of stars with detectable transmitters (EIRP > 5 × 1016 W) is at most 3 × 10-4. Finally, we showed that the UCLA SETI pipeline natively detects the signals detected with AI techniques by Ma et al.