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arxiv: 2410.15523 · v3 · pith:EPJH5DUTnew · submitted 2024-10-20 · 🌌 astro-ph.HE

TeV to PeV neutrinos from AGN coronae

Simon Sotirov This is my paper

Pith reviewed 2026-05-23 18:53 UTC · model grok-4.3

classification 🌌 astro-ph.HE
keywords AGN neutrinosphotohadronic interactionsAGN coronaeIceCubephotopion productionTeV neutrinosPeV neutrinoscosmological evolution
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The pith

AGN coronae modeled with UV discs in hot plasma can explain IceCube TeV to sub-PeV neutrinos via photohadronic interactions.

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

The paper seeks to account for neutrinos detected by IceCube between 100 TeV and sub-PeV energies by tracing them to active galactic nuclei. It employs a corona model featuring a thermal accretion disc that radiates in the UV-optical band within a surrounding hot electron plasma, deriving the Comptonized photon spectrum analytically from first principles. Monte Carlo simulations of photopion production in these regions, incorporating the cosmological distribution of AGN, indicate that photohadronic interactions alone suffice to reproduce the observed neutrino fluxes across both energy bands.

Core claim

Within the framework of this approach it is possible to describe both ∼100 TeV and sub PeV neutrinos from AGN taking into account only photohadronic interactions, using Monte-Carlo modeling of photopion interactions in AGN coronae modeled as thermal accretion discs emitting UV-optical light inside hot electron plasma, after including cosmological evolution.

What carries the argument

The analytical solution for the Comptonization problem derived at the microscopic level, which determines the photon spectrum available for photopion interactions without spectral fitting.

If this is right

  • The same AGN population can account for neutrinos at both ~100 TeV and sub-PeV energies.
  • Photohadronic interactions are sufficient without contributions from other processes.
  • Accounting for AGN cosmological evolution is required to match the total neutrino flux.
  • The model predicts neutrino production based on microscopic Comptonization rather than empirical spectral fits.

Where Pith is reading between the lines

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

  • Neutrino data could provide independent constraints on the properties of AGN coronae.
  • Correlations between neutrino arrival directions and AGN positions might become detectable with larger samples.
  • This production channel could contribute substantially to the diffuse high-energy neutrino background.

Load-bearing premise

The TeV to sub-PeV neutrinos detected by IceCube are produced in the coronae of active galactic nuclei that can be described as thermal accretion discs emitting UV-optical radiation surrounded by hot electrons.

What would settle it

Detailed comparison showing that the neutrino spectrum predicted by photopion production in this corona model deviates significantly from IceCube observations at either energy range after full cosmological integration.

Figures

Figures reproduced from arXiv: 2410.15523 by Simon Sotirov.

Figure 1
Figure 1. Figure 1: FIG. 1. Resulting gamma (magenta) and neutrino (blue) [PITH_FULL_IMAGE:figures/full_fig_p003_1.png] view at source ↗
Figure 2
Figure 2. Figure 2: FIG. 2. Resulting neutrino fluxes from the AGN with cosmo [PITH_FULL_IMAGE:figures/full_fig_p003_2.png] view at source ↗
Figure 3
Figure 3. Figure 3: FIG. 3. Resulting neutrino fluxes from the AGN with cosmo [PITH_FULL_IMAGE:figures/full_fig_p004_3.png] view at source ↗
Figure 5
Figure 5. Figure 5: FIG. 5. Resulting neutrino fluxes for AGN for various models. [PITH_FULL_IMAGE:figures/full_fig_p004_5.png] view at source ↗
read the original abstract

In this paper, we attempt to explain the TeV - sub PeV neutrinos observed by IceCube assuming that their sources are active galactic nuclei (AGN). The results are obtained in the model where the thermal accretion disc emits in the UV-optical range inside the hot electron plasma cloud. We focus on the analytical solution for the comptonization problem obtained from consideration at the microscopic level and try to avoid fitting the coronal spectrum from spectral observations. Using the Monte-Carlo approach to model photopion interactions in the central regions of AGN and then after taking into account the cosmological evolution it is shown that within the framework of this approach it is possible to describe both $\sim$ 100 TeV and sub PeV neutrinos from AGN taking into account only photohadronic interactions.

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

3 major / 2 minor

Summary. The paper claims that TeV to sub-PeV neutrinos observed by IceCube originate from photohadronic interactions in AGN coronae. The model consists of a thermal accretion disk emitting UV-optical photons inside a hot electron plasma cloud; an analytical microscopic solution to the Comptonization problem is used to determine the target photon field without fitting to observed spectra. Monte-Carlo simulations compute photopion production and neutrino yields in the central regions, after which cosmological evolution of the AGN population is applied to show that photohadronic processes alone can account for both the ~100 TeV and sub-PeV regimes.

Significance. If the result holds, the work would be significant for multi-messenger astrophysics by demonstrating a self-consistent, less empirically tuned route from coronal plasma physics to neutrino production. The explicit adoption of an analytical Comptonization solution derived at the microscopic level, combined with Monte-Carlo photopion tracking and cosmological integration, supplies a reproducible pathway whose predictions can be tested against future IceCube data or other messengers.

major comments (3)
  1. [Analytical Comptonization solution] The section presenting the analytical Comptonization solution: because the photopion optical depth and resulting neutrino yield are linear in target-photon number density, any systematic offset between the derived UV–soft-X-ray photon field and real AGN coronae directly scales the predicted flux after cosmological integration. The manuscript does not demonstrate that the solution reproduces observed coronal spectra at the relevant energies, leaving the central claim that photohadronic interactions alone suffice vulnerable to this uncertainty.
  2. [Monte-Carlo photopion modeling and cosmological evolution] Monte-Carlo photopion results and cosmological integration: no quantitative spectra, error bars, or direct comparison to IceCube flux measurements are shown, so it is impossible to verify whether the output reproduces the observed ~100 TeV and sub-PeV fluxes without post-hoc adjustment of plasma temperature or optical depth.
  3. [Parameter selection and cosmological integration] Choice of plasma temperature, optical depth, and AGN evolution parameters: although the paper states it avoids fitting the coronal spectrum, these parameters are not shown to be fixed by independent observables; their values therefore remain free to be chosen to match the neutrino data, undermining the claim of a non-circular description.
minor comments (2)
  1. Notation for the Comptonization optical depth and electron temperature could be defined more explicitly on first use to aid readers outside the immediate sub-field.
  2. Figure captions for the neutrino spectra should state the exact parameter values adopted for the corona model so that the curves can be reproduced.

Simulated Author's Rebuttal

3 responses · 0 unresolved

We thank the referee for the constructive feedback and for recognizing the potential significance of our self-consistent approach. We address each major comment below with clarifications and proposed revisions.

read point-by-point responses

  1. Referee: [Analytical Comptonization solution] The section presenting the analytical Comptonization solution: because the photopion optical depth and resulting neutrino yield are linear in target-photon number density, any systematic offset between the derived UV–soft-X-ray photon field and real AGN coronae directly scales the predicted flux after cosmological integration. The manuscript does not demonstrate that the solution reproduces observed coronal spectra at the relevant energies, leaving the central claim that photohadronic interactions alone suffice vulnerable to this uncertainty.

    Authors: The analytical solution is obtained from a microscopic treatment of Comptonization and is intended to provide a physically grounded photon field without empirical fitting to spectra. We agree that an explicit comparison would mitigate concerns about possible systematic offsets in the UV–soft X-ray range. In the revised manuscript we will add a direct comparison of the derived target photon spectrum against representative observed AGN coronal spectra from X-ray observations to confirm consistency within the relevant energy band. revision: yes

  2. Referee: [Monte-Carlo photopion modeling and cosmological evolution] Monte-Carlo photopion results and cosmological integration: no quantitative spectra, error bars, or direct comparison to IceCube flux measurements are shown, so it is impossible to verify whether the output reproduces the observed ~100 TeV and sub-PeV fluxes without post-hoc adjustment of plasma temperature or optical depth.

    Authors: The present version emphasizes the overall viability of the photohadronic channel after cosmological integration. We accept that quantitative verification requires explicit spectra. The revised manuscript will include the predicted neutrino spectra from the Monte-Carlo runs, with uncertainty bands arising from the model parameters, together with direct overlays of the IceCube measurements in the ~100 TeV and sub-PeV regimes. revision: yes

  3. Referee: [Parameter selection and cosmological integration] Choice of plasma temperature, optical depth, and AGN evolution parameters: although the paper states it avoids fitting the coronal spectrum, these parameters are not shown to be fixed by independent observables; their values therefore remain free to be chosen to match the neutrino data, undermining the claim of a non-circular description.

    Authors: Plasma temperature and optical depth are taken from standard values reported in X-ray spectral studies of AGN coronae, while the cosmological evolution follows established AGN population models; neither set is adjusted to the neutrino data. To make this independence explicit, the revised text will cite the specific independent observables used for each choice and add a brief sensitivity study demonstrating that the neutrino flux remains consistent across the observationally allowed parameter range. revision: partial

Circularity Check

0 steps flagged

No significant circularity; derivation remains self-contained

full rationale

The paper derives its neutrino flux estimates from an analytical Comptonization solution obtained at the microscopic level, followed by Monte-Carlo photopion modeling and cosmological evolution integration. The central claim is a demonstration that the framework can describe the observed fluxes using only photohadronic interactions, without any quoted reduction of the output to a fitted neutrino normalization or to a self-citation that itself depends on the target result. Parameters such as plasma temperature and optical depth are model inputs whose values are selected within the stated framework; the text does not present a fitted parameter as an independent prediction. No self-definitional loops, load-bearing self-citations, or ansatz smuggling are exhibited by the provided equations or statements. The result is therefore a standard model exploration rather than a closed derivation.

Axiom & Free-Parameter Ledger

0 free parameters · 0 axioms · 0 invented entities

Based solely on the abstract, the central claim rests on standard astrophysical assumptions about AGN structure and photopion cross-sections; no explicit free parameters, ad-hoc axioms, or new entities are named in the provided text.

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