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arxiv: 2512.18142 · v2 · pith:JFNHSJJOnew · submitted 2025-12-19 · 🌌 astro-ph.EP · astro-ph.IM· physics.pop-ph

A Search for Radio Technosignatures from Interstellar Object 3I/ATLAS with the Allen Telescope Array

Sofia Z. Sheikh , Valeria Garcia Lopez , Isabel Gerrard , James R. A. Davenport , Wael Farah , Blayne Griffin , Steve Croft , Luigi F. Cruz
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Imke de Pater Ben Jacobson-Bell Mark Masters Karen I. Perez Alexander W. Pollak Carol Shumaker Andrew Siemion
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Pith reviewed 2026-05-22 12:40 UTC · model grok-4.3

classification 🌌 astro-ph.EP astro-ph.IMphysics.pop-ph
keywords interstellar objecttechnosignatureSETIradio search3I/ATLASAllen Telescope Arraynon-detectionnarrowband signal
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The pith

No radio technosignatures detected from interstellar object 3I/ATLAS, establishing power upper limits of 10-110 W.

A machine-rendered reading of the paper's core claim, the machinery that carries it, and where it could break.

The paper describes a radio search for artificial signals from the newly discovered interstellar object 3I/ATLAS during its approach to the solar system. Observers used the Allen Telescope Array across 1-9 GHz for 7.25 hours and applied the bliss pipeline to sift through nearly 74 million narrowband detections. After removing radio frequency interference by frequency and drift rate and applying localization checks, 211 candidates remained for visual review. None survived as credible technosignatures. The resulting non-detection yields an upper limit of 10-110 W on the effective isotropic radiated power of any such signals within the surveyed parameters.

Core claim

The survey detected no signals from 3I/ATLAS that warranted follow-up after Doppler drift correction and successive filtering stages for interference and beam localization. This absence of detections directly constrains any radio technosignatures to an effective isotropic radiated power no greater than 10-110 W across the 1-9 GHz band and the drift rates examined.

What carries the argument

The bliss pipeline, which applies Doppler drift correction, blanks hits by frequency and drift rate to suppress interference, then uses NBeamAnalysis localization followed by visual inspection of the surviving candidates.

If this is right

  • Any radio-emitting technology associated with 3I/ATLAS must lie below the 10-110 W effective isotropic radiated power threshold in the 1-9 GHz range.
  • The filtering sequence reduced 74 million raw hits to 211 candidates suitable for manual review.
  • The same observational and analysis approach can be applied to future interstellar objects for comparable sensitivity.
  • Non-detections of this kind limit the parameter space for narrowband radio probes sent between stellar systems.

Where Pith is reading between the lines

These are editorial extensions of the paper, not claims the author makes directly.

  • Repeating the search at other frequencies or with longer integration times would further tighten the power limits.
  • Combining these radio constraints with optical or infrared observations of 3I/ATLAS could test for non-radio artifact signatures.
  • The upper limits provide a quantitative benchmark for modeling the detectability of low-power interstellar probes in the solar system.

Load-bearing premise

Any technosignature would appear as a narrowband signal whose frequency drift could be corrected and that would survive the frequency, drift-rate, and NBeamAnalysis filters if it originated from the object.

What would settle it

A narrowband signal that remains after all blanking steps, localizes to the position of 3I/ATLAS in multiple beams, and persists across multiple observations.

Figures

Figures reproduced from arXiv: 2512.18142 by Alexander W. Pollak, Andrew Siemion, Ben Jacobson-Bell, Blayne Griffin, Carol Shumaker, Imke de Pater, Isabel Gerrard, James R. A. Davenport, Karen I. Perez, Luigi F. Cruz, Mark Masters, Sofia Z. Sheikh, Steve Croft, Valeria Garcia Lopez, Wael Farah.

Figure 1
Figure 1. Figure 1: The radial acceleration of 3I/ATLAS over the 9 days containing our observations (blue line). Observation times are highlighted in yellow. This allows us to determine the expected drift rates for potential signals coming from 3I/ATLAS. We then converted the acceleration to a drift rate using the following equation from (Sheikh et al. 2019): ν˙ = dv dt × νobs c (1) where ˙ν is the drift rate in Hz/s, νobs is… view at source ↗
Figure 2
Figure 2. Figure 2: Frequency distribution of the ∼ 74 million hits obtained in this survey. The top, middle, and bottom panels correspond to the “low” (1000–3688 MHz), “mid” (3688–6376 MHz), and “high” (6376–9064 MHz) frequency ranges, respectively. All y-axes are scaled to the same limits. Hits are shown in blue, blanking ranges are shown with yellow bars, the hits after blanking within the ranges are shown in brown, and th… view at source ↗
Figure 3
Figure 3. Figure 3: The distribution of the ∼ 74 million hits from this survey across drift rate. Note the peak of hits around 0 Hz/s (expected because most RFI transmitters are in the same reference frame as the telescope, i.e., on the ground). After the drift rate cut, the count of hits is much more even across the restricted drift rate range. Note that the sawtooth pattern seen across drift rate is a known artifact in the … view at source ↗
Figure 4
Figure 4. Figure 4: The distribution of the ∼ 74 million hits from this survey across SNR. As expected, there are significantly more weak hits than strong ones, and there is no significant trend in SNR when filters are applied to frequency and drift rate [PITH_FULL_IMAGE:figures/full_fig_p008_4.png] view at source ↗
Figure 5
Figure 5. Figure 5: An output waterfall plot from NBeamAnalysis for a signal which was ranked in the top 211 events. The on-beam (pointed at 3I/ATLAS) is shown in the left subplot, while the off-beam is shown in the right subplot. Each subplot is a normalized waterfall plot with frequency on the horizontal axis, time on the vertical axis, and intensity (scaled to the on-beam plot from 0–1) indicated by the color bar. This hit… view at source ↗
Figure 6
Figure 6. Figure 6: An output waterfall plot from NBeamAnalysis from an observation with 0 signals above the 5.29 SNR ratio threshold. This signal had a non-blanked frequency, a drift rate in the allowable range, and does appear to be truly narrowband (i.e., technological). However, the signal has a similar SNR in both the on-beam and the off-beam, indicating a local interferer in the allocation allotted to fixed-satellite se… view at source ↗
read the original abstract

In 2025 July, the third-ever interstellar object, 3I/ATLAS, was discovered on its ingress into the Solar System. Similar to the NASA Voyager missions sent in 1977, science probes by extraterrestrial life ("artifact technosignatures") could be sent to explore other stellar systems like our own. In this campaign, we used the SETI Institute's Allen Telescope Array to observe 3I/ATLAS from 1-9 GHz. We detected nearly 74 million narrowband hits in 7.25\,hr of data using the newly-developed search pipeline bliss. We then blanked hits by frequency and drift rate to mitigate radio frequency interference in our dataset, narrowing the dataset down to ~2 million hits. These hits were further filtered by the localization code NBeamAnalysis, and the remaining 211 hits were visually inspected in the time-frequency domain. We did not find any signals worthy of additional follow-up. Accounting for the Doppler drift correction and given the non-detection, we are able to set an effective isotropic radiated power upper limit of 10-110 W on radio technosignatures from 3I/ATLAS across the frequency and drift rate ranges covered by our survey.

Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, simulated authors' rebuttal, and a circularity audit. Tearing a paper down is the easy half of reading it; the pith above is the substance, this is the friction.

Referee Report

2 major / 2 minor

Summary. The paper reports a radio technosignature search for the interstellar object 3I/ATLAS using the Allen Telescope Array over 1-9 GHz for 7.25 hours. The bliss pipeline detected ~74 million narrowband hits, which were filtered by frequency and drift rate to mitigate RFI (~2 million remaining), then localized via NBeamAnalysis to 211 candidates that were visually inspected, yielding no detections. From this non-detection, after accounting for Doppler drift correction, the authors derive an EIRP upper limit of 10-110 W across the surveyed frequency and drift-rate ranges.

Significance. If robust, the non-detection and derived upper limit provide useful constraints on possible radio emissions from an interstellar object, extending SETI searches to a novel target class. The application of the newly developed bliss pipeline and NBeamAnalysis localization adds methodological value for future surveys, though the overall impact is tempered by the standard nature of the null result in the absence of detailed completeness metrics.

major comments (2)
  1. [Methods and Results (bliss pipeline and NBeamAnalysis description)] Methods/Results section describing the bliss pipeline and filtering steps: The central EIRP upper limit claim (10-110 W) is load-bearing on the assumption that any genuine technosignature would appear as a narrowband, drift-correctable signal that survives the frequency/drift-rate blanking and NBeamAnalysis localization filters. The manuscript provides no quantitative completeness estimate or injection-recovery tests for signals outside the searched drift-rate range, with mismatched beam modeling, or in blanked frequency channels; this directly affects whether the non-detection applies to the full parameter space claimed.
  2. [Upper limit calculation (near end of Results or Discussion)] Discussion or upper-limit derivation paragraph: The translation from non-detection to the specific 10-110 W EIRP range lacks an explicit sensitivity calculation or error budget that incorporates the 7.25 hr integration time, exact system temperature, and frequency-dependent factors; without this, it is unclear how the range is obtained or whether it is conservative across the full 1-9 GHz band.
minor comments (2)
  1. [Methods] Specify the exact drift-rate search range (in Hz/s) and the precise frequency resolution used in the bliss pipeline for reproducibility.
  2. [Introduction] Add a brief comparison to prior technosignature searches of interstellar objects (e.g., 1I/'Oumuamua or 2I/Borisov) to contextualize the target choice and limits.

Simulated Author's Rebuttal

2 responses · 0 unresolved

We thank the referee for their careful and constructive review of our manuscript. Their comments highlight important aspects of our search methodology and upper-limit derivation that we have clarified in the revision.

read point-by-point responses

  1. Referee: Methods/Results section describing the bliss pipeline and filtering steps: The central EIRP upper limit claim (10-110 W) is load-bearing on the assumption that any genuine technosignature would appear as a narrowband, drift-correctable signal that survives the frequency/drift-rate blanking and NBeamAnalysis localization filters. The manuscript provides no quantitative completeness estimate or injection-recovery tests for signals outside the searched drift-rate range, with mismatched beam modeling, or in blanked frequency channels; this directly affects whether the non-detection applies to the full parameter space claimed.

    Authors: We agree that the manuscript benefits from greater transparency on search completeness. The bliss pipeline targets narrowband signals with linear frequency drifts within the range corresponding to the expected Doppler motion of 3I/ATLAS, and NBeamAnalysis requires localization consistent with the target position. We have revised the Methods section to explicitly state the searched drift-rate range, the rationale for frequency blanking (to excise persistent RFI), and the beam-model assumptions used in NBeamAnalysis. We have also added a short paragraph summarizing limited injection-recovery tests performed during pipeline validation, which confirm high recovery rates for signals inside the searched parameter space. The revised text now states that the reported EIRP upper limit applies strictly to the covered frequency and drift-rate ranges; signals outside these ranges are not constrained by this observation. revision: partial

  2. Referee: Discussion or upper-limit derivation paragraph: The translation from non-detection to the specific 10-110 W EIRP range lacks an explicit sensitivity calculation or error budget that incorporates the 7.25 hr integration time, exact system temperature, and frequency-dependent factors; without this, it is unclear how the range is obtained or whether it is conservative across the full 1-9 GHz band.

    Authors: We appreciate this observation. The 10–110 W range originates from the frequency-dependent sensitivity of the Allen Telescope Array across 1–9 GHz, driven by variations in system temperature and aperture efficiency. We have inserted a new subsection in the Results section that presents the explicit sensitivity calculation based on the radiometer equation, using the 7.25-hour on-source integration time, measured T_sys values per frequency band, and the distance to 3I/ATLAS at the epoch of observation. A brief error budget is now included, propagating uncertainties in T_sys, integration time, and distance; this shows that the quoted range remains conservative across the band. revision: yes

Circularity Check

0 steps flagged

Non-detection upper limit follows directly from sensitivity and null result

full rationale

The paper describes a standard radio SETI observation of 3I/ATLAS using the Allen Telescope Array across 1-9 GHz. Data were processed with the bliss pipeline to detect narrowband hits, followed by frequency/drift-rate blanking for RFI mitigation, NBeamAnalysis localization, and visual inspection, yielding no candidates. The reported 10-110 W EIRP upper limit is computed from the instrument noise floor, integration time, distance to the object, and the absence of surviving signals after these steps, with explicit accounting for the searched Doppler drift range. No parameter is fitted to a data subset and then re-used as a prediction, no uniqueness theorem is imported via self-citation, and no ansatz or known result is renamed as a new derivation. The chain is therefore self-contained and does not reduce to its inputs by construction.

Axiom & Free-Parameter Ledger

0 free parameters · 1 axioms · 0 invented entities

The central claim rests on standard radio-astronomy assumptions about the expected form of artificial signals rather than new postulates or fitted parameters.

axioms (1)
  • domain assumption Any radio technosignature would be narrowband and exhibit a Doppler drift rate correctable within the searched parameter space.
    This assumption justifies the initial hit detection in bliss and the subsequent blanking by frequency and drift rate.

pith-pipeline@v0.9.0 · 5823 in / 1408 out tokens · 51710 ms · 2026-05-22T12:40:01.667301+00:00 · methodology

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Works this paper leans on

3 extracted references · 3 canonical work pages

  1. [1]

    1959, Nature, 184, 844, doi: 10.1038/184844a0

    Alarcon, M. R., Serra-Ricart, M., Licandro, J., et al. 2025, The Astronomer’s Telegram, 17264, 1 Alvarez-Candal, A., Rizos, J., Lara, L., et al. 2025, arXiv preprint arXiv:2507.07312 Bannister, M., Bhandare, A., Dybczynski, P., et al. 2019, Nature astronomy Belyakov, M., Bolin, B. T., Fremling, C., & Graham, M. 2025, The Astronomer’s Telegram, 17276, 1 Bo...

    work page doi:10.1038/184844a0 2025

  2. [2]

    J., Smirnov, O

    https://www.astronomerstelegram.org/?read=17473 Pisano, D. J., Smirnov, O. M., Ivchenko, M., et al. 2025, The Astronomer’s Telegram, 17499,

    work page 2025

  3. [3]

    in prep, ”Instrumentation Upgrades to the Allen Telescope Array” Polstorff, W

    https://www.astronomerstelegram.org/?read=17499 Pollak, A., et al. in prep, ”Instrumentation Upgrades to the Allen Telescope Array” Polstorff, W. K. 1965, Dynamics of a rotating cylindrical space station, Tech. rep., NASA Rahatgaonkar, R., Carvajal, J. P., Puzia, T. H., et al. 2025, arXiv e-prints, arXiv:2508.18382 Rogers, B., Lintott, C. J., Croft, S., S...

    work page doi:10.3847/1538-3881/ad1f5a 1965