Drift Rates of Narrowband Signals in Long-term SETI Observations for Exoplanets

Li, Jian-Kang; Zhao, Hai-Chen; Tao, Zhen-Zhao; Zhang, Tong-Jie; Sun, Xiaohui

doi:10.3847/1538-4357/ac90bd

Cited by 11 publications

(13 citation statements)

References 59 publications

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“…According to Tao et al (2022), the value of MDR depends on the observed frequency band because the drift rate is proportional to the transmitted frequency of the signal. For FAST L-band, we set the MDR to 4 Hz s −1 , which is large enough to search for signals transmitted from a typical planet in a habitable zone (Li et al 2022;Tao et al 2022). TurboSETI outputs the best-fit frequency, drift rate, and S/N of the hits to a .dat file.…”

Section: Discussionmentioning

confidence: 99%

Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST

Luan

Tao

Zhao

et al. 2023

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The search for extraterrestrial intelligence (SETI) is to search for technosignatures associated with extraterrestrial life, such as engineered radio signals. In this paper, we apply the multibeam coincidence matching (MBCM) strategy, and propose a new search mode based on the MBCM which we call the MBCM blind search mode. In our recent targeted SETI research, 33 exoplanet systems are observed by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). With this blind search mode, we search for narrowband drifting signals across 1.05–1.45 GHz in two orthogonal linear polarization directions separately. There are two special signals, one of which can only be detected by the blind search mode while the other can be found by both blind and targeted search modes. This result reveals huge advantages of the new blind search mode. However, we eliminate the possibility of the special signals being ETI signals based on much evidence, such as the polarization, drift, frequency, and beam coverage characteristics. Our observations achieve an unprecedented sensitivity and our work provides a deeper understanding to the polarization analysis of extraterrestrial signals.

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Section: Discussionmentioning

confidence: 99%

Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST

Luan

Tao

Zhao

et al. 2023

Self Cite

View full text Add to dashboard Cite

show abstract

“…According to Tao et al (2022), the value of MDR depends on the observed frequency band because the drift rate is proportional to transmitted frequency of the signal. For FAST L-band, we set the MDR to 4 Hz/s, which is large enough to search for signals transmitted from a typical planet in habitable zone (Li et al 2022;Tao et al 2022). TurboSETI outputs the best fit frequency, drift rate, and S/N of the hits to a DAT file.…”

Section: Discussionmentioning

confidence: 99%

Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST

Luan¹,

Tao²,

Zhao³

et al. 2023

Preprint

View full text Add to dashboard Cite

The search for extraterrestrial intelligence (SETI) is to search for technosignatures associated with extraterrestrial life, such as engineered radio signals. In this paper, we apply the multibeam coincidence matching (MBCM) strategy, and propose a new search mode based on the MBCM which we call MBCM blind search mode. In our recent targeted SETI research, 33 exoplanet systems are observed by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). With this blind search mode, we search for narrowband drifting signals across 1.05 − 1.45 GHz in two orthogonal linear polarization directions separately. There are two special signals, one of which can only be detected by the blind search mode while the other can be found by both blind and targeted search modes. This result reveals huge advantages of the new blind search mode. However, we eliminate the possibility of the special signals being ETI signals based on much evidence, such as the polarization, drift, frequency and beam coverage characteristics. Our observations achieve an unprecedented sensitivity and our work provides a deeper understanding to the polarization analysis of extraterrestrial signals.

show abstract

“…However, this process relies on a fully representative library of simulated ETI signals, including more possible patterns of birdies. For example, the pattern may be different for different brightness, drift rate (e.g., Li et al 2022), and relative position to the beams. Some interesting candidates may be missed (removed with RFI) because there is no kind of birdie that could guide our parameter selection.…”

Section: Discussionmentioning

confidence: 99%

A Search for Extraterrestrial Technosignatures in Archival FAST Survey Data Using a New Procedure

Wang,

Tao,

Zhang

et al. 2023

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The search for extraterrestrial intelligence (SETI) commensal surveys aim to scan the sky to find possible technosignatures from an extraterrestrial intelligence (ETI). The mitigation of radio frequency interference (RFI) is an important step, especially for the most sensitive Five-hundred-meter Aperture Spherical radio Telescope (FAST), which can detect more weak RFI. In this paper, we propose several new techniques for RFI mitigation and use our procedure to search for ETI signals from the archival data of FAST’s first SETI commensal survey. We detect the persistent narrowband RFI by setting a threshold of the signals’ sky separation and detect the drifting RFI (and potentially other types of RFI) using the Hough transform. We also use the clustering algorithms to remove more RFI and select candidates. The results of our procedure are compared to the earlier work on the same FAST data. We find that our methods, though relatively simpler in computation, remove more RFI (99.9912% compared to 99.9063% in the earlier work) but preserve the simulated ETI signals, except for those (5.1%) severely affected by the RFI. We also report more interesting candidate signals, about a dozen of which are new candidates that were not previously reported. In addition, we find that the proposed Hough transform method, with suitable parameters, also has the potential to remove the broadband RFI. We conclude that our methods can effectively remove the vast majority of the RFI while preserving and finding the candidate signals that we are interested in.

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Drift Rates of Narrowband Signals in Long-term SETI Observations for Exoplanets

Cited by 11 publications

References 59 publications

Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST

Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST

Multibeam Blind Search of Targeted SETI Observations toward 33 Exoplanet Systems with FAST

A Search for Extraterrestrial Technosignatures in Archival FAST Survey Data Using a New Procedure

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