[astro-ph.IM] 3I/ATLAS is the third confirmed interstellar object passing through the Solar System.
In this work, we conduct narrowband radio technosignature search toward 3I/ATLAS using the Five-hundred-meter Aperture Spherical Telescope (FAST) L-band multibeam receiver from October 2025 to January 2026 on 4 separate dates (i.e. Mars closest, perihelion, Earth closest and a post-Earth-closest epoch, respectively).
We carry out frequency-drifting signal searching with signal-to-noise ratio (SNR) over 10 within 1.05-1.45 GHz via bliss pipeline. These signal hits are grouped into event by beam, frequency and drift rate matching, the events are then filtered by cluster analysis and drift rate cut-off.
We also characterized the events by their significance in SNR, structure tensor as well as principal component analysis (PCA). No credible narrowband radio technosignature are detected from 3I/ATLAS after visual inspections. The null results place constraints on the presence of transmitters above 2.862×10−3 W.
We further introduce a Bayesian inference framework to assess the occurrence probability of hypothetical transmitters while accounting for uncertainty in their characteristic transmitter power through physically motivated priors.
Jian-Kang Li, Zhen-Zhao Tao, Tong-Jie Zhang
Comments: 29 pages, 16 figures, 7 tables. Accepted for publication in The Astronomical Journal
Subjects: Instrumentation and Methods for Astrophysics (astro-ph.IM)
Cite as: arXiv:2603.19023 [astro-ph.IM] (or arXiv:2603.19023v2 [astro-ph.IM] for this version)
https://doi.org/10.48550/arXiv.2603.19023
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Submission history
From: Jiankang Li
[v1] Thu, 19 Mar 2026 15:24:06 UTC (29,187 KB)
[v2] Thu, 25 Jun 2026 17:18:52 UTC (30,742 KB)
https://arxiv.org/abs/2603.19023
Astrobiology, SETI,
