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REVIEW 3 major objections 4 minor 1 cited by

Neutrinos in IceCube and KM3NeT

T0 review · 3 major / 4 minor · reviewed 2026-08-10 · deepseek-v4-flash

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Pith's one-line read Stacked Seyfert galaxies show a 3-sigma neutrino excess, supporting them as high-energy neutrino sources.

desk verdict A useful conference-floor review with an abstract that overstates a pre-trial, self-cited stacking significance as 'independent evidence.' read the letter →

arxiv 2501.18076 v1 pith:4ZCMZJQ6 submitted 2025-01-30 astro-ph.HE hep-ex

Shiqi Yu This is my paper · ORCID
classification astro-ph.HEhep-ex
keywords high-energyneutrinosIceCubeKM3NeTSeyfertgalaxiesactivegalacticnucleineutrinooscillationsatmosphericstackinganalysis
verification ladder T0 review T1 audit T2 compute T3 formal

The pith

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

The reading

This review synthesizes recent IceCube and KM3NeT results to argue that X-ray-bright Seyfert galaxies are emerging as a genuine source class of high-energy neutrinos, not just one exceptional galaxy. The key new result it highlights is a stacking analysis of 13 Southern-Hemisphere Seyferts that finds a cumulative excess of 6.7 events over background, at 3.0 sigma significance. On the atmospheric side, the paper points to competitive measurements of neutrino oscillation parameters from DeepCore and ORCA, while KM3NeT's ARCA detector has recorded an ultra-high-energy event of several tens of PeV. If these claims hold, neutrino telescopes can use Seyfert galaxies to map cosmic-ray acceleration in active galactic nuclei.

What carries the argument

The carrying mechanism is the stacking search for neutrino point sources, in which each of 13 selected Southern-Sky sources is weighted by the number of signal events IceCube would expect if the source followed the disc-corona model, a model that derives each Seyfert's expected neutrino flux from its X-ray corona, and the weighted events are summed and tested against background. The background model also subtracts diffuse Milky Way neutrino emission, which is critical for sources near the Galactic Plane such as Circinus and Centaurus A. This weighting is what turns a set of individually sub-threshold sources into a combined 3.0 sigma signal.

What would settle it

Recompute the stacking of the same 13 sources using an $E^{-2}$ spectrum or an updated Galactic diffuse template; if the local significance falls below 3 $\sigma$, the excess depends on the disc-corona weights rather than on an intrinsic source population. Alternatively, a KM3NeT/ARCA stacking of the same sources with comparable exposure that finds no excess would challenge the claim.

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Extended reading notes

Core claim

The paper's central claim is that independent searches now point to a population of X-ray-bright Seyfert galaxies as high-energy neutrino emitters. Following IceCube's evidence for neutrino emission from NGC 1068, follow-up studies identify NGC 4151, NGC 3079, CGCG 420-015, and the Circinus Galaxy as candidate sources; a stacking analysis of 13 Southern-Hemisphere sources reports a combined 6.7-event excess at 3.0 sigma significance. The paper also reports KM3NeT's detection of an ultra-high-energy neutrino event at several tens of PeV arriving about 1 degree above the horizon, which it treats as a preview of Southern-Hemisphere capabilities. Its broader assertion is that IceCube and KM3NeT together provide complementary full-sky coverage that will turn candidate Seyfert sources into established cosmic-ray accelerators.

Load-bearing premise

The stacking claim rests on two assumptions: the model connecting each Seyfert's X-ray corona to its expected neutrino spectrum sets the right weights, and the background subtraction fully removes Milky Way neutrinos for sources near the Galactic Plane; if either fails, the 6.7-event excess is not a reliable source signal.

Editorial extensions

If this is right

  • X-ray-bright Seyfert galaxies join blazars and the Galactic plane as empirically supported sites of high-energy neutrino production.
  • The candidate source list expands from NGC 1068 to include NGC 4151, NGC 3079, CGCG 420-015, and the Circinus Galaxy, giving targeted multi-messenger follow-up targets.
  • Once KM3NeT/ARCA is fully deployed, its better Southern-Hemisphere sensitivity should allow independent confirmation or rejection of the 3.0 sigma stacking excess.
  • The reported ultra-high-energy KM3NeT event supports searches for multi-PeV neutrinos and motivates combined IceCube-KM3NeT all-sky analyses.
  • Atmospheric neutrino measurements from DeepCore and ORCA will feed global fits that may determine the neutrino mass ordering at 3 sigma.

Reading between the lines

Editorial extensions of the paper, not claims the author makes directly.

  • Beyond the paper: If the 3.0 sigma stacking signal is real and the disc-corona weighting is roughly right, the Seyfert neutrino luminosity function is likely dominated by the most X-ray-bright members, and the same population could explain part of the diffuse astrophysical neutrino flux.
  • Beyond the paper: The stacking result could be tested with KM3NeT data alone, since KM3NeT sees the Southern sky well; an independent stacking of the same 13 sources with similar weights would either confirm the excess or reveal that the IceCube result depends on Northern-hemisphere systematics.
  • Beyond the paper: A natural extension is to apply per-source Galactic diffuse background modeling to other source classes near the Galactic Plane, rather than subtracting a single global template.
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Editorial analysis

A structured set of objections, weighed in public.

Desk editor's note, referee report, and a circularity audit.

Referee Report

3 major / 4 minor

Summary. This manuscript is a short, conference-style review of recent IceCube and KM3NeT results. It summarizes atmospheric muon-neutrino flux measurements, neutrino oscillation analyses from DeepCore and ORCA, sterile-neutrino searches, and astrophysical-neutrino follow-ups of X-ray-bright Seyfert galaxies. Its central new claim is that a stacking analysis of 13 Southern-Hemisphere Seyferts, weighted by a disc-corona model, yields a cumulative excess of 6.7 events at 3.0 sigma, which the abstract describes as independent evidence for Seyferts as neutrino sources. The paper also reports a KM3NeT ultra-high-energy event of several tens of PeV and discusses the future potential of ARCA.

Significance. If the stacked 3.0 sigma signal were a properly trial-corrected, model-robust measurement, the paper would provide a useful cross-experiment synthesis and would strengthen the case that a subset of X-ray-bright Seyfert galaxies are high-energy neutrino emitters. The article is clearly organized and helpful in collecting atmospheric and oscillation results from both experiments, and it explicitly acknowledges important systematic limitations, such as KM3NeT energy-scale uncertainties and Monte Carlo modeling challenges. However, the headline astrophysical claim currently rests on an unpublished, author-owned analysis and on a pre-trial local p-value; as written, the paper does not substantiate the phrase 'independent evidence.' Because the claim is central to the abstract and summary, the manuscript needs substantial revision in presentation and evidentiary framing.

major comments (3)
  1. [Abstract and Section 3 / Table 1] Table 1 labels the stacked-source p-value as pre-trial (plocal = 0.0013, 3.0 sigma), and the table caption states that all listed p-values are pre-trial. The abstract and Section 4 nevertheless describe this result as 'a cumulative neutrino signal at 3.0 sigma' and 'independent evidence.' A pre-trial local p-value does not account for the fact that 13 sources were searched, nor for the freedom in the stacking weights; the manuscript provides no post-trial p-value and no number of trials. Since the text itself quotes a post-trial significance of 2.9 sigma for NGC 4151, the distinction is known to the author and should be applied consistently to the stacking result.
  2. [Section 3, stacking analysis paragraph] The stacking significance depends on three ingredients that are not documented in the manuscript: the list of 13 sources and their selection criteria, the Galactic neutrino background model (cited as R. et al. 2023), and the disc-corona neutrino spectra from Kheirandish et al. (2021) used to weight each source. The text states only that each source was weighted by its expected IceCube signal under that model, with no quantitative treatment of how the 3.0 sigma changes under model or background uncertainties. Because Yu et al. (2024) is referenced without a journal, arXiv number, or version, the reader cannot verify the central result or assess the impact of the model assumptions on the claimed significance.
  3. [Section 3, KM3NeT ultra-high-energy event] The ultra-high-energy KM3NeT event is described as 'several tens of PeV,' arriving from approximately one degree above the horizon, and as occurring only once in a million detected events. No reconstructed energy, arrival-direction uncertainty, or local/post-trial significance is given, and no public KM3NeT reference is cited for the event. As presented, the reader cannot distinguish a robust astrophysical candidate from a background fluctuation; the claim should be accompanied by the public KM3NeT number and significance, or explicitly labeled as a preliminary event report.
minor comments (4)
  1. [Introduction] There is a typo in the Introduction: 'proprieties' should be 'properties.'
  2. [References] Several references are malformed or incomplete, including 'R., A., et al. 2023, Science' and 'R.A., et al. 2024,' which obscure the relevant collaborations, and the first reference in the list has no author names; these should be expanded to standard collaboration author lists.
  3. [Figure 6 caption] The figure legend uses the abbreviation 'w/o' without defining it in the caption; it should be written as 'without Centaurus A' or defined explicitly, and '5 DP' should be expanded to '5 sigma discovery potential.'
  4. [Table 1] For consistency, the table should state for every row whether the quoted p-value is pre-trial or post-trial, not only for the stacked sources row, especially since the text quotes a post-trial value for NGC 4151.

Circularity Check

0 steps flagged · score 0.0 of 10

No circular derivation; self-cited stacking result is a reported measurement, not an input-output reduction.

full rationale

This manuscript is a conference proceedings summary rather than a derivation, so most of the content is a literature report of external results (IceCube, KM3NeT, Super-K, ANTARES). The only self-referential element is the stacking result from Yu et al. (2024), which the abstract calls 'independent evidence.' That is a self-citation and the quoted significance is labeled in Table 1 as a pre-trial local p-value, but this is a statistical reporting limitation, not a circular reduction: the paper does not fit a parameter to the data and then rename it as a prediction. The disc-corona weights (Kheirandish et al. 2021) are fixed external model inputs; the stacking excess of 6.7 events is a data measurement, not an output that is equivalent to the weights by construction. The broader claim that X-ray-bright Seyferts may produce neutrinos is independently supported by the cited NGC 1068, NGC 4151, and Neronov et al. results, so the self-citation is not load-bearing for the paper's main conclusion. I therefore find no significant circularity.

Assumptions & free parameters 2 free parameters · 3 assumptions · 0 invented entities

The paper introduces no new equations or entities. Its central claims are a summary of prior experimental papers. The load-bearing inputs that the reader cannot verify from this preprint are the accuracy of cited measurements, the validity of the disc-corona model used to weight stacking sources, and the fidelity of the Galactic neutrino background subtraction. The model parameters behind the disc-corona weighting are counted as free parameters even though they were fitted elsewhere, because the quoted stacking significance is conditional on them.

free parameters (2)
  • Disc-corona model neutrino spectral parameters (Kheirandish et al. 2021) = Not stated in this review
    Used to weight sources in the 13-source stacking analysis (Section 3); the 3.0 sigma excess is conditional on these weights.
  • Galactic neutrino background model parameters = Not stated in this review
    The paper says advanced techniques account for Milky Way neutrinos, but no model parameters or validation are given.
assumptions (3)
  • domain assumption The external IceCube and KM3NeT measurements cited in Sections 2 and 3 are accurately reported.
    The review contains no raw data or original analysis, so its accuracy rests on trust in the cited collaboration papers.
  • domain assumption The disc-corona model (Kheirandish et al. 2021) adequately describes neutrino emission from X-ray-bright Seyfert galaxies.
    Used to compute expected signal counts and source weights in the stacking analysis; invoked in Section 3.
  • domain assumption The Galactic neutrino background model used in Yu et al. (2024) correctly handles Milky Way neutrinos near the Galactic Plane.
    The paper states this mitigation is critical for sources like Circinus and Centaurus A; Section 3.

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Cite this review

Pith. "Pith review of Neutrinos in IceCube and KM3NeT." pith.science (2026). https://pith.science/paper/4ZCMZJQ6

@misc{pith2026250118076,
  author       = {Pith},
  title        = {Pith review of: Neutrinos in IceCube and KM3NeT},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/4ZCMZJQ6}},
  note         = {Machine review of arXiv:2501.18076}
}
abstract

Neutrino observatories such as IceCube, Cubic Kilometre Neutrino Telescope (KM3NeT), and Super-Kamiokande cover a broad energy range that enables the study of both atmospheric neutrinos and astrophysical neutrinos. IceCube and KM3NeT focus on a similar energy range, from a few GeV to PeV, and have conducted competitive work on the atmospheric neutrino flux, three-flavor oscillation parameter measurements, searches beyond the Standard Model, and investigations of cosmic-ray accelerators using high-energy astrophysical neutrinos. Recent IceCube findings of evidence of neutrino signals from NGC~1068 have triggered a series of follow-up studies. These studies provide evidence that a subset of Seyfert galaxies may produce high-energy neutrinos. The emerging candidates are NGC~4151, NGC~3079, CGCG~420-015, and Circinus Galaxy. Furthermore, a stacking analysis of 13 selected sources in the Southern Hemisphere reported a cumulative neutrino signal at 3.0\,$\sigma$, offering independent evidence that some X-ray-bright Seyfert galaxies could be potential high-energy neutrino sources. KM3NeT, still under construction, continues to accumulate data that will support future studies of astrophysical neutrino sources. However, with its currently deployed detection units, it has detected an ultra-high-energy event of several tens of PeV originating from approximately 1 degree above the horizon. This contribution highlights and summarizes recent findings from IceCube and KM3NeT in both neutrino physics and astrophysics.

Figures

Figures reproduced from arXiv: 2501.18076 by the authors.

Figure 1
Figure 1. Atmospheric muon neutrino flux measurement using data taken with ORCA6 data (black) compared with the measurements from Super-Kamiokande (orange, Richard et al. (2016)) and ANTARES (green, Adri´an-Mart´ınez et al. (2013)). baselines and energies, as illustrated in the 2D oscillo￾gram in [PITH_FULL_IMAGE:figures/full_fig_p002_1.png] view at source ↗
Figure 2
Figure 2. The muon neutrino survival probability (color), assuming normal ordering of neutrino masses, is plotted as a function of true cos(θzenith) versus true energy. Sketched arrows and shaded regions indicate the visibility of DeepCore (yellow), IceCube-Upgrade and KM3NeT-ORCA (teal), and long-baseline accelerator-based experiments (green). in the 2D oscillogram provide strong constraints on the measurement of ∆m2 32. KM3… view at source ↗
Figure 4
Figure 4. [PITH_FULL_IMAGE:figures/full_fig_p003_4.png] view at source ↗
Figures from the paper (4 more)
Figure 3
Figure 3. Figure 3: Allowed regions at 90% CL for the oscilla￾tion parameters sin2 θ23 and ∆m2 31 are shown for KM3NeT (black, Joao et al. (2024)) in both NO and IO, and for IceCube (dotted, IceCube Collaboration (2024)) in NO only, compared to results from other experiments. Plot is from…
Figure 5
Figure 5. Figure 5: Contour of the 90% CL limit of mea￾surements from ORCA (black), DeepCore (green, Abbasi et al. (2024a)), IceCube TeV study (teal, Abbasi et al. (2024b)), ANTARES (pink, Albert et al. (2019)), and Super￾Kamiokande (orange, Abe et al. (2015)). using updated sub-100 GeV s…
Figure 6
Figure 6. Figure 6: Expected energy spectrum of each source (gray) from the disc-corona model, with the top 4 sources high￾lighted in color. The total stacking flux (excluding Centau￾rus A) at the best-fit is shown as a solid black curve, with 1 σ errors indicated by the gray shaded band,…
Figure 7
Figure 7. Figure 7: Comparison of the observed limits on the flux for the ARCA6-21 point source analysis assuming E−2 spectrum of full sky, with ANTARES (15-year, Alves & Collaboration (2023)) and IceCube (10-year, Aartsen et al. (2020)) sensi￾tivities. is expected to offer better sensiti…

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Forward citations

Cited by 1 Pith paper

Reviewed papers in the Pith corpus that reference this work. Sorted by Pith novelty score. Full citation record

  1. On the Blueprint of Active Galaxies Producing Neutrinos

    astro-ph.HE 2026-07 conditional novelty 4.0 of 10

    Neutrinos from active galaxies are produced in compact X-ray-bright coronae within about ten Schwarzschild radii of the black hole, and such sources may supply the diffuse neutrino flux.

Reference graph

Works this paper leans on

31 extracted references · 24 canonical work pages · cited by 1 Pith paper

  1. [1]

    2022, Progress in Particle and Nuclear Physics, 123, 103927

    work page 2022

  2. [2]

    2019, Physical Review D, 99

    Aartsen, M., et al. 2019, Physical Review D, 99

    work page 2019

  3. [3]

    G., Ackermann, M., Adams, J., et al

    Aartsen, M. G., Ackermann, M., Adams, J., et al. 2020, Phys. Rev. Lett., 124, 051103 6 T able 1.Summary of the most significant sources from IceCube searches and the stacking result using the disc-corona model (Kheirandish et al. 2021). The table lists the best-fit number of signals (ˆns), spectral index (ˆγ), pre-trial p-value (plocal), best-fit flux (ϕ1...

    work page 2024

  4. [4]

    G., Abbasi, R., Abdou, Y., et al

    Aartsen, M. G., Abbasi, R., Abdou, Y., et al. 2013, Physical Review Letters, 111, doi:10.1103/physrevlett.111.021103

    doi:10.1103/physrevlett.111.021103 2013

  5. [5]

    G., et al

    Aartsen, M. G., et al. 2017, The European Physical Journal C, 77

    work page 2017

  6. [6]

    2009, Physical Review D, 79

    Abbasi, R., Abdou, Y., Ackermann, M., et al. 2009, Physical Review D, 79

    work page 2009

  7. [7]

    2022, Science, 378, 538–543

    Abbasi, R., et al. 2022, Science, 378, 538–543

    work page 2022

  8. [8]

    2024c, Preprint, submitted to Astrophys

    Abbasi, R., et al. 2024c, Preprint, submitted to Astrophys. J., arXiv:2406.07601

    arXiv

Show all 31 references
  1. [9]

    2015, Phys

    Abe, K., et al. 2015, Phys. Rev. D, 91, 052019

    2015

  2. [10]

    A., et al

    Abi, B., Acciarri, R., Acero, M. A., et al. 2020, , , arXiv:2002.02967

    2020

  3. [11]

    2006, Astroparticle Physics, 26, 282–300 Adri´ an-Mart ´ ınez, S., et al

    Achterberg, A., Ackermann, M., Adams, J., et al. 2006, Astroparticle Physics, 26, 282–300 Adri´ an-Mart ´ ınez, S., et al. 2013, Eur. Phys. J. C, 73, 2606

    2006

  4. [12]

    2018, Physical Review Letters, 120

    Agafonova, N., Alexandrov, A., Anokhina, A., et al. 2018, Physical Review Letters, 120

    2018

  5. [13]

    R., Allen, R

    Ahmad, Q. R., Allen, R. C., Andersen, T. C., et al. 2001, Phys. Rev. Lett., 87, 071301

    2001

  6. [14]

    2024, The European Physical Journal C, 84, 885

    Aiello, S., Albert, A., et al. 2024, The European Physical Journal C, 84, 885

    2024

  7. [15]

    2019, JHEP, 06, 113

    Albert, A., et al. 2019, JHEP, 06, 113

    2019

  8. [16]

    Alves, S., & Collaboration, T. A. 2023, in ICRC2023 (Proceedings of Science), 1128

    2023

  9. [17]

    2024, EXPLORING TAU NEUTRINO APPEARANCE MEASUREMENTS IN KM3NeT/ORCA, ,

    Chiara, L., et al. 2024, EXPLORING TAU NEUTRINO APPEARANCE MEASUREMENTS IN KM3NeT/ORCA, ,

    2024

  10. [18]

    1998, Phys

    Fukuda, Y., Hayakawa, T., Ichihara, E., et al. 1998, Phys. Rev. Lett., 81, 1562

    1998

  11. [19]

    Z., & Parke, S

    Funchal, R. Z., & Parke, S. 2024, The near term race for the Neutrino Mass Ordering, ,

    2024

  12. [20]

    2023, PoS, ICRC2023, 1080 IceCube Collaboration

    Huang, T.-Q., Cao, Z., Chen, M., et al. 2023, PoS, ICRC2023, 1080 IceCube Collaboration. 2024, arXiv:2405.02163

    2023 arXiv

  13. [21]

    2024, Latest results from KM3NeT, ,

    Joao, C., et al. 2024, Latest results from KM3NeT, ,

    2024

  14. [22]

    Kheirandish, A., Murase, K., & Kimura, S. S. 2021, Astrophys. J., 922, 45 KM3NeT Collaboration. 2024, JHEP, arXiv:2408.07015

    2021 arXiv

  15. [23]

    2018, Physical Review D, 98

    Li, Z., Abe, K., Bronner, C., et al. 2018, Physical Review D, 98

    2018

  16. [24]

    2024, First measurement of light sterile neutrino mixing parameters with KM3NeT/ORCA, ,

    Louis, B.-S., et al. 2024, First measurement of light sterile neutrino mixing parameters with KM3NeT/ORCA, ,

    2024

  17. [25]

    2023, in , 1018

    Muller, R., Heijboer, A., & van Eeden, T. 2023, in , 1018

    2023

  18. [26]

    Neronov, A., Savchenko, D., & Semikoz, D. V. 2024, Phys. Rev. Lett., 132, 101002 R., A., et al. 2023, Science, 380, 1338–1343 R.A., et al. 2024, Search for neutrino emission from hard X-ray AGN with IceCube, , , arXiv:2406.06684

    2024

  19. [27]

    2016, Physical Review D, 94

    Richard, E., Okumura, K., Abe, K., et al. 2016, Physical Review D, 94

    2016

  20. [28]

    2023, PoS, ICRC2023, 1093

    Markou, C. 2023, PoS, ICRC2023, 1093

    2023

  21. [29]

    P., Niederhausen, H., Sclafani, S., et al

    Twagirayezu, J. P., Niederhausen, H., Sclafani, S., et al. 2023, PoS, ICRC2023, 1175

    2023

  22. [30]

    P., Hu, F., Tian, W., et al

    Ye, Z. P., Hu, F., Tian, W., et al. 2024, A multi-cubic-kilometre neutrino telescope in the western Pacific Ocean, , , arXiv:2207.04519

    2024

  23. [31]

    2024, IceCube Search for High Energy Neutrino Emission from X-ray Bright Seyfert Galaxies, ,

    Yu, S., et al. 2024, IceCube Search for High Energy Neutrino Emission from X-ray Bright Seyfert Galaxies, ,

    2024

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