Ultra High Energy Cosmic Rays

No\'emie Globus; Roger Blandford

REVIEW 3 major objections 6 minor 1 cited by

Ultra High Energy Cosmic Rays

T0 review · 3 major / 6 minor · reviewed 2026-08-07 · deepseek-v4-flash

Challenge this review Re-run · record.json Download PDF Read on arXiv ↗

Pith's one-line read The paper argues that ultra-high-energy cosmic rays are mixed heavy nuclei, likely accelerated by relativistic jets or intergalactic shock fronts within the local universe.

desk verdict A reliable, clearly written review of UHECR that is honest about its uncertainties; treat it as a standard reference, not a research claim. read the letter →

arxiv 2505.21846 v1 pith:2NYOZOTJ submitted 2025-05-28 astro-ph.HE

Noémie Globus , Roger Blandford This is my paper

classification astro-ph.HE

keywords ultra-high-energycosmicraysacceleratorsmagneticfieldsparticleastrophysicsairshowerscompositionGZKhorizonmultimessengerastronomy

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 takes stock of sixty years of ultra-high-energy cosmic-ray physics and argues that the outstanding questions are close to being answered. The central claim is that UHECR are a mixed composition of atomic nuclei, not photons, neutrinos, or pure protons, with the average mass growing steadily from the ankle near 5 EeV to the highest observed energies near 300 EeV. On the source side, the paper applies seven constraints—rigidity, luminosity, spectrum, injection, composition, anisotropy, and background—and concludes that after discarding disfavored models, the remaining candidates for the extreme-energy events are relativistic jets from black holes and intergalactic shock fronts. A sympathetic reader would care because these particles carry more energy than any terrestrial accelerator can reach, and identifying their origin ties together particle physics, magnetic-field studies, and multimessenger astronomy.

What carries the argument

The argument is carried by rigidity, R = E/(Ze), the quantity that determines both how a magnetic field bends a particle and how much potential difference an accelerator can supply. The paper replaces the familiar Hillas size-field criterion with the power-resistance identity Rmax ~ (LEM Qeff)^{1/2}, which ranks candidate sources by the electromagnetic power LEM available to acceleration and an effective resistance Qeff. This is combined with the GZK energy-loss horizon for protons and the photodisintegration horizon for nuclei, the measured UHECR luminosity density, and the seven challenges that any model must satisfy to survive.

What would settle it

If a next-generation observatory measured the mass per event above 100 EeV and found mostly protons rather than heavy nuclei, the paper's composition-driven conclusion would fail; equivalently, a single >200 EeV event traced back through a well-measured Galactic magnetic field to a source beyond the ~40 Mpc heavy-nucleus horizon would break the GZK distance argument.

Watch

Extended reading notes

Core claim

The paper argues that the long-standing mystery has narrowed: UHECR are heavy nuclei produced outside the Galaxy, accelerated to rigidities near 10 EV, and their sources are local enough to be identified. The evidence assembled is the measured energy spectrum with its ankle and cutoff, the increase in inferred mass with energy from air-shower depth and muon counts, the 6.9σ large-scale dipole that requires substantial magnetic deflections, and the absence of strong small-scale anisotropies or secure source associations. When these data are passed through the seven challenges, pure-proton models, strongly evolving source populations, and top-down decay models fall away, leaving relativistic jets and intergalactic shock fronts as the plausible accelerators. The review stops short of claiming a confirmed source, instead laying out the measurements—event-by-event composition and a dependable Galactic magnetic-field model—that would turn the surviving candidates into identifications.

Load-bearing premise

The claim that the highest-energy cosmic rays come from outside our Galaxy rests on the assumption that the Galactic halo's magnetic field is too weak and too smooth to bend or confine a 10 EV nucleus; the paper concedes the halo field is poorly measured, so a stronger or more turbulent halo field would reopen a Galactic origin.

Editorial extensions

If this is right

If the composition is heavy and becomes heavier with energy, then the most energetic events must originate within roughly 40–100 Mpc, so source searches can concentrate on the local universe rather than cosmological populations.
If relativistic jets and intergalactic shock fronts are the real accelerators, then secondary neutrinos and gamma rays from these sources should be detectable with next-generation instruments, and current upper limits already exclude pure-proton and strongly evolving source models.
If the 6.9σ dipole is a real signal of the local source distribution, then combining full-sky observatories with improved Galactic magnetic-field models will turn its direction and amplitude into a rigidity-dependent constraint on source evolution.
If event-by-event mass determination becomes possible, the review's proposed 'tomography' of sources in mass and energy groups, plus the rigidity-time ordering of transient bursts, provides a concrete search strategy for identifying individual accelerators.
If top-down models are truly excluded, then the UHECR luminosity density must be supplied by ordinary astrophysical accelerators, and the remaining question is which of the two surviving classes dominates.

Reading between the lines

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

One consequence the review leaves implicit is that the 'muon puzzle' and the composition claim are coupled: if resolving the puzzle requires new hadronic physics, then the inferred masses and the heavy-composition conclusion could shift, so the two questions should be treated as a single experimental program.
The power-resistance identity suggests a quantitative test the review does not spell out: since Qeff differs between shock, reconnection, and unipolar-induction sites, measuring the maximum rigidity of the highest-energy events could in principle discriminate between source geometries even before sources are identified.
A further extension is that transient-source models make a time-ordering prediction—highest-rigidity particles arrive first from a single burst—which could be searched for retrospectively in existing EECR event lists once rigidities are known on an event-by-event basis.
If the Galactic halo field is found to be stronger or more turbulent than assumed, the extragalactic premise weakens; that would open a renewed case for Galactic sources, which the review acknowledges but does not develop.

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Editorial analysis

A structured set of objections, weighed in public.

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

Desk Editor's Note

read the letter

Short version: this is a solid, useful review, and the zero-novelty score is a feature, not a bug. It is an Annual Reviews piece, so it is supposed to synthesize, and it does that well. The paper earns credit for a clear organizing structure—the seven challenges, Table 1, the sidebars on hadronic interactions and photohadronic processes—and for being candid about what is uncertain. The muon puzzle, the model-dependent composition interpretation, the poor constraints on the Galactic halo field, and the absence of secure multimessenger associations are all stated as open problems, not smoothed over.

What is genuinely good: the summary of the observational status is accurate. The ankle, the cutoff, the 6.9-sigma dipole, the heavy-composition trend, and the IceCube/Fermi constraints are presented at the right level of nuance. The Qeff version of the Hillas criterion is a nice pedagogical tool; it is not new, but it makes the rigidity/luminosity tradeoff concrete. The hierarchical acceleration picture and the magnetic bootstrap are speculative, and the authors label them as such.

The soft spot is exactly where the stress test points. The conclusion that EECR sources are extragalactic rests on the Larmor-radius argument in Section 1.3, and the paper itself admits that the Galactic halo field could be stronger or more turbulent than we currently think. I agree that a sufficiently strong halo field would invalidate the rigidity-based transition and, with it, the ranking in Table 1. That is the weakest load-bearing joint in the review. But it is not a hidden flaw: the authors say it explicitly, and the entire framework is presented as an interpretation, not a discovery. A review that says "we cannot totally rule out Galactic models" and then proceeds under the standard assumption is being honest. I would like to see the caveat repeated in the summary, but I do not think it amounts to a fatal objection.

The paper also leans on the authors' own source models—intergalactic shocks, relativistic jets, the ergomagnetosphere, magnetoluminescence—but the main constraints come from external experiments, so the circularity burden is low.

Bottom line: this is a review for people who want a current map of the UHECR field, especially graduate students and researchers in neighboring fields. It deserves a serious referee. My recommendation is to send it to review and accept after minor revision, with the halo-field caveat made more prominent.

Referee Report

3 major / 6 minor

Summary. This is an invited-style review of the current state of ultra-high-energy cosmic ray (UHECR) physics, covering detection techniques, key observational results from Telescope Array and Pierre Auger, multimessenger constraints, and the main classes of proposed sources and acceleration mechanisms. The paper argues that the spectrum, composition, anisotropy, and neutrino/gamma-ray limits point toward a mixed composition of nuclei, that the ankle-to-cutoff structure and the 6.9σ dipole are the key established facts, and that once top-down, low-power, and pure-proton models are discarded, only relativistic jets and intergalactic accretion shocks remain plausible EECR sources. It also proposes a unifying 'effective resistance' rigidity criterion, Qeff, and a seven-challenge framework for comparing source models.

Significance. The review is valuable as an up-to-date, expert synthesis of a fast-moving field. Its strengths are the accurate reporting of the main experimental anchors—the ankle, the cutoff, the 6.9σ dipole, the heavy-composition trend inferred from Xmax, and the multimessenger constraints from Fermi and IceCube—and its clear separation of established results from speculative mechanisms. The Qeff formulation of the Hillas condition is pedagogically attractive, and the paper is unusually candid about the limitations of current GMF and EGMF knowledge, about the muon puzzle, and about the absence of secure source identifications. Its weakness is that the final source ranking is built on assumptions that are acknowledged in the body but not fully propagated into the concluding claims, particularly the extragalactic premise and the highest-energy composition. The review does not present new data or machine-checked derivations, but as a synthesis it should be judged on whether its conclusions are appropriately matched to the uncertainties it itself documents.

major comments (3)

[§1.3, §5] The central conclusion in §5—that after discarding disfavored models 'we seem to be left with relativistic jets and intergalactic shock fronts for the EECR'—depends on the premise stated in §1.3 that UHECR above ~1 EeV are extragalactic because r_L ≈ R_EV/B_µG kpc exceeds the Galactic disk scale. The text immediately qualifies this premise: 'our knowledge of the magnetic structure of the Milky Way in the Galactic halo region is particularly limited, and a large scale turbulent field may be present but invisible, and therefore Galactic models ... cannot be totally ruled out.' Because the seven-challenge framework in §4 and Table 1 is applied only to extragalactic candidates, a stronger or more turbulent halo field would not merely reorder the source ranking but would remove the basis for excluding Galactic wind/halo models. Please either explicitly frame the extragalactic assumption as a working hypothesis supported by a concrete observational test (for example, quantitative statements about what halo-field strength and coherence length would trap 10 EV nuclei, or constraints from Faraday rotation and pulsar dispersion), or extend the challenge framework to the Galactic models cited (Pohl & Eichler 2011; Zirakashvili et al. 2024). As written, the strongest claim in §5 is stronger than the evidence admitted in §1.3.
[§5 first bullet; §2.2] The Discussion states that 'there is strong evidence that UHECR are a mixed composition of atomic nuclei with the composition becoming heavier moving from the ankle at ∼5 EeV to ∼300 EeV.' This is in tension with §2.2, which states that at the highest energies 'there are no measurements of composition-sensitive observable with the fluorescence detectors of Auger and TA' and that 'the existence of protons or very heavy nuclei (heavier than iron) cannot be ruled out.' The rigidity interpretation of the EECR (Rmax ∼ 10 EV) and the source-distance arguments in §1.3 and §4 depend on the highest-energy composition. Please soften the §5 claim to the level of evidence actually presented, or supply the additional arguments that justify extrapolating the heavy trend through the EECR regime.
[§4.3.2; Sidebar 'Bootstrap mechanism'] The viability of cluster accretion shocks as EECR sources rests on the magnetic bootstrap producing near-equipartition fields close to the shock, with Qeff ∼ 0.1 ohm and Rmax ∼ 5–10 EV. The sidebar states that 'It is not known whether or not a configuration like this will be self-sustaining.' This is a load-bearing caveat: if the bootstrap fails, intergalactic shock models may not satisfy the rigidity challenge, and the final ranking in §5 would change. The review should either quantify the uncertainty in Qeff (for example, by giving a range based on different turbulence assumptions) or explicitly list the bootstrap as a required theoretical development in the concluding assessment, rather than allowing the conclusion to appear stronger than the mechanism.

minor comments (6)

[§1.1 vs §5] Section 1.1 names four hadronic interaction models (QGSJet-II-04, EPOS-LHC, SIBYLL-2.3, DPMJET), while the Discussion refers to 'seven state-of-the-art QCD models.' Please reconcile the number or clarify which models are being counted.
[Table 1] The section references in Table 1 are internally inconsistent: Galactic Winds and Magnetars are listed with entries such as §4.0 and §4.2, but there is no §4.0 and §4.2 is 'Top-down Cosmological Models,' while magnetars are treated in §4.4.2. The color ratings described in the caption (blue/grey/red) are also not visible in the plain-text rendering. Please correct the section numbers and add an explicit legend so that the comparative table is usable.
[§2.3] In the sentence 'The direction of the dipole is sensisitive to the GMF model,' 'sensisitive' should be 'sensitive.'
[Eq. (3) and §4] The symbol REM is used for the maximum rigidity in Eq. (3), while the text elsewhere uses Rmax and R for rigidity; please define REM at first use and keep notation consistent throughout.
[References] Some reference entries are incomplete or contain placeholders, for example Metzger et al. (2011) has '( ?)' in place of the journal name, and the 'please add article doi' placeholder remains in the header. These should be completed before publication.
[§1 and §4.3.4] Minor typos include 'an handful' (§1) and 'meet the the rigidity challenge' (§4.3.4).

Circularity Check

0 steps flagged · score 0.0 of 10

No significant circularity: the review is an interpretive synthesis of externally measured data and explicitly hedged theoretical estimates.

full rationale

This is a review article, not a derivation chain with predictions that could reduce to their inputs. The central observational constraints it uses — the energy spectrum, composition moments, the 6.9σ dipole, anisotropy upper limits, and neutrino/gamma-ray bounds — come from independent collaborations (Auger, TA, IceCube, Fermi, KM3NeT) and are cited as external measurements, not as outputs of the authors' models. The main theoretical relation, Eq. (3), Rmax ∼ (LEM Qeff)^1/2, is explicitly presented as 'essentially equivalent to the helpful and influential Hillas criterion', i.e., a reformulation, and the authors acknowledge this equivalence rather than presenting it as a new first-principles result. The Qeff values used later (e.g., Qeff ∼ 0.1 ohm for cluster shocks, Qeff ∼ 30-60 ohm for jets and magnetars) are clearly labeled 'model-dependent' and 'might provide a good target for simulations', so they are not fitted parameters disguised as predictions. The paper's final conclusion — 'we seem to be left with relativistic jets and intergalactic shock fronts for the EECR' — is hedged ('seem', 'The exclusions are not hard') and is an interpretive synthesis of the seven-challenge framework rather than a quantity derived from the framework. The most load-bearing premise, the extragalactic origin of EECR, is not smuggled in: Section 1.3 explicitly warns that 'a large scale turbulent field may be present but invisible, and therefore Galactic models ... cannot be totally ruled out', and Section 5 states that a 'more confident and well-validated understanding of the magnetic field within our Galaxy and its neighbors' is needed. The authors' self-citations are numerous but function as pointers to prior propagation and source-model calculations (e.g., Globus et al. 2008, 2015, 2017, 2023; Blandford et al. 2023) rather than as a uniqueness theorem or as the sole support for the central claim. No equation in the paper is equal by construction to an input; no fitted parameter is renamed as a prediction; no external benchmark is replaced by a self-referential assertion. The paper is self-contained as a review and honest about its assumptions, so the appropriate finding is no significant circularity.

Assumptions & free parameters 6 free parameters · 5 assumptions · 3 invented entities

The review's source-model conclusions rest on several order-of-magnitude estimates (notably Qeff values) and on modeling assumptions about hadronic interactions, extragalactic origin, and energy losses. These are standard in the field but are inputs, not outputs, of this paper.

free parameters (6)

Effective resistance Qeff for cluster accretion shocks = ~0.1 ohm
Section 4.3.2. Adopted to yield Rmax ~5-10 EV for Virgo-like clusters; order-of-magnitude estimate, not measured.
Effective resistance Qeff for black hole jets = ~60 ohm
Section 4.4.3 and Sidebar 'Unipolar Induction - Black Holes'. Estimate from ideal cylindrical jet model.
Effective resistance Qeff for neutron star unipolar induction = ~30 ohm
Sidebar 'Unipolar Induction - Neutron Stars'. Estimate for magnetar/pulsar circuit.
Effective resistance Qeff for relativistic reconnection = ~10 ohm
Sidebar 'Relativistic Reconnection'. Estimate for reconnection site with E ~0.1B.
Effective resistance Qeff for magnetoluminescence = ~100 ohm
Section 4.4.3 and Sidebar 'Magnetoluminescence'. Estimate for flux-tube slip-knot energy release.
Assumed intergalactic magnetic field strength and coherence length = ~1 nG, ~100 kpc
Section 1.3. Fiducial values used for magnetic horizon and diffusion estimates; not globally measured.

assumptions (5)

domain assumption LHC-tuned hadronic models (QGSJet-II-04, EPOS-LHC, SIBYLL-2.3) can be extrapolated to UHECR energies
Section 1.1. Composition measurements depend on the Xmax and muon predictions of these models, which are untested at sqrt(s) > 13 TeV.
domain assumption UHECRs above ~1 EeV are extragalactic
Section 1.3. Justified by Larmor radius vs. Galactic disk scale; the paper acknowledges halo field uncertainties could admit Galactic models.
standard math GZK and photodisintegration energy-loss calculations are correct
Section 1.3 and Figure 4. Horizon estimates rely on cross sections from Allard (2012) and Zhang et al. (2024).
standard math Cosmic-ray transport obeys the Vlasov equation and diffusion approximation
Sidebar 'Cosmic Ray Distribution Function'. Used for propagation and anisotropy interpretations.
domain assumption The rigidity-luminosity relation Rmax ~ (LEM Qeff)^1/2 is a valid universal constraint
Section 4, Eq. (3). Used to rate all source models; Qeff is model-dependent, so the relation is a heuristic, not a derived law.

invented entities (3)

Magnetoluminescence
purpose: Acceleration of EECRs via sudden magnetic energy release in twisted flux tubes in AGN jets
Section 4.4.3 and Sidebar 'Magnetoluminescence'. Introduced in Blandford et al. 2017; speculative, no direct observation.
Ergomagnetosphere
purpose: Black hole magnetosphere geometry with equatorial electric zones for jet powering and UHECR acceleration
Section 4.4.3 and Figure 10. From Blandford & Globus 2022; theoretical construct.
Magnetic bootstrap
purpose: Cosmic-ray-driven growth of resonant Alfven turbulence at cluster shocks to meet the rigidity challenge
Section 4.3.2 and Sidebar 'Bootstrap Mechanism'. The paper states self-sustainability is unknown.

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Cite this review

Pith. "Pith review of Ultra High Energy Cosmic Rays." pith.science (2026). https://pith.science/paper/2NYOZOTJ

@misc{pith2026250521846,
  author       = {Pith},
  title        = {Pith review of: Ultra High Energy Cosmic Rays},
  year         = {2026},
  howpublished = {\url{https://pith.science/paper/2NYOZOTJ}},
  note         = {Machine review of arXiv:2505.21846}
}

abstract

Ultra High Energy Cosmic Rays, UHECR, are charged particles with energies between $\sim10^{18}\,{\rm eV}$ and $\sim3\times10^{20}\,{\rm eV}\sim50\,{\rm J}$. They exhibit fundamental physics at energies inaccessible to terrestrial accelerators, challenge experimental physics and connect strongly to astronomical observations through electromagnetic, neutrino and even gravitational wave channels. There has been much theoretical and observational progress in the sixty years that have elapsed since the discovery of UHECR, to divine their nature and identify their sources. The highest energy UHECR appear to be heavy nuclei with rigidity extending up to $\sim10\,{\rm EV}$; A significant ($6.9\sigma$) dipole anisotropy has been measured but our poor understanding of the Galactic magnetic fields makes this hard to interpret; The UHECR luminosity density is $\sim 10^{44}$ erg Mpc$^{-3}$ yr$^{-1}$ which constrains explanations of their origin; The most promising acceleration mechanisms involve diffusive shock acceleration and unipolar induction; The most promising sources include intergalactic accretion shocks, and relativistic jets from stellar-mass or supermassive black holes. We explore the prospects for using the highest energy events, combined with multimessenger astronomy, to help us solve the riddle of UHECR.

Figures

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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

Trapped fireshell (halo) of photons and pairs around black-hole horizon: source for ultra-high-energy particles
astro-ph.HE 2025-12 reject novelty 5.0 of 10

The paper predicts a Klein-Nishina 'runaway' that accelerates electrons and protons to ultra-high energies inside a gravitationally trapped photon-pair halo, with a time-declining UHE luminosity.

Reference graph

Works this paper leans on

57 extracted references · 50 canonical work pages · cited by 1 Pith paper

[4]

textitEuro. Phys. J. C 84:696 Albrecht J, Cazon L, Dembinski H, et al. 2022, Ap&SS, 367, 27 Allard D, Parizot E, Olinto A V, et al

work page 2022
[8]

966, 71 Bell AR

Ap.J. 966, 71 Bell AR. 1992 . MNRAS 257:493–500 Blandford RD & Funk S

work page 1992
[13]

2011 A&A 535:A66 Decoene V,

Astroparticle Physics, 123:102492 Decerprit G, Allard D. 2011 A&A 535:A66 Decoene V,

work page 2011
[14]

PoS ICRC2019. Vol. 36, p. 233 Dembinski HP, Arteaga-Vel´ azquez JC, Cazon L, et al. 2019.Euro. Phys. J. C210:02004 Ding C, Globus N, Farrar GR

work page 2019
[15]

J CAP, 2024, 022 Eichler D

work page 2024
[18]

ICRC 2, 161–164 Farrar GR, Jansson R, Feain IJ, Gaensler BM. 2013 J. Cos. Atropart. Phys.01(2013)023 Farrar GR, Piran T

work page 2013
[20]

2015 Ph.D

PoS ICRC2015 236 Fedynitch A. 2015 Ph.D. thesis, KIT, Karlsruhe, Dept. Phys. Fermi E

work page 2015
[21]

2022 PoS ICRC2021 402 Gaensler BM, Heald GH, McClure-Griffiths NM et al

PoS ICRC2023 031 Fujii T. 2022 PoS ICRC2021 402 Gaensler BM, Heald GH, McClure-Griffiths NM et al

work page 2022

Show all 57 references

[23]

Phys. Rev. D92:021302 Globus N, Eichler D. 2016 Ap.J.Lett. 2016 833:L17-21 Globus N, Piran T

2016
[24]

839:L22-27 Globus N, Piran T, Hoffman Y, Carlesi E, Pomar` ede D

Ap.J.Lett. 839:L22-27 Globus N, Piran T, Hoffman Y, Carlesi E, Pomar` ede D. 2019 MNRAS 484:4167-73 Globus N, Fedynitch A, Blandford RD. 2023 Ap.J. 945:12-30 Golup G

2019
[25]

PoS ICRC2023 (2023) 252 Gorham PW, Allison P, Banerjee O, et al

2023
[26]

2018.MNRAS 475:2519–2529 Halim AA, Abreu P, Aglietta M, et al

European Physical journal C83:1125 Hackstein S, Vazza F, Br¨ uggen M, et al. 2018.MNRAS 475:2519–2529 Halim AA, Abreu P, Aglietta M, et al

2018
[27]

J. Cos. Astropart. Phys.024, 435-483 Han JL. 2017, Ann. Rev. Astron. Astrophys.55:111-157 Harari D, Mollerach S, Roulet E

2017
[29]

Ann. Rev. Astron. Astrophys.22:425–444 Hut P & Rees MJ. 1983 Nature 5908:508-509 IceCube Collaboration, MAGIC, AGILE, ASAS-SN, HA WC, et al

1983
[31]

0810.3017 Kang H, Ryu D, Jones TW

arXiv e-prints. 0810.3017 Kang H, Ryu D, Jones TW

arXiv
[32]

arXiv :2407.02148 Kotera K, Lemoine M

arXiv
[33]

Kotera K, Allard D, Murase K, et al

Physical Review D;77:123003. Kotera K, Allard D, Murase K, et al. 2009 Ap. J. 707:370–386 Kotera K, Olinto A V

2009
[35]

PoS ICRC2023 (2023) 008 www.annualreviews.org • Ultra High Energy Cosmic Rays 31 Kim J, Ryu D, Kang H, et al

2023
[37]

Phys. Rev. D71:083007 Lemoine M, Kotera K, P´ etri J. 2015.JCAP 07:016 Lemoine M

2015
[38]

J. of Cos. Astropart. Phys.2011:024 Marcowith A, Ferrand G, Grech M. et al

2011
[39]

Living Rev. Comput. Astrophys.6, 1 Matthews JH, Bell AR, Blundell KM, Araudo AT. 2018 MNRAS 479:L76-80. Matthews J

2018
[40]

Ap. J. 886:8-22 Mbarek R, Caprioli D, Murase K. 2023 Ap. J. 942:37-49 McQuinn M

2023
[42]

( ?) 415:2495-504 Morejon L, Fedynitch A, Boncioli D, et al. 2019, J. Cos. Astropart. Phys.2019:11-007 Mtchedlidze S, Dom ´ ıngez-Fern´ andez P, Du X, et al. 2024.arXiv :2406.16230 Murase K, Bartos I

2019 arXiv
[44]

J. Cos. Astropart. Phys.2023. 11:049 Piro AL, Kollmeier JA

2023
[45]

Phys. Rev. Lett.116:191302 Readhead, ACS, Xu W, Pearson TJ, Wilkinson PN, & Polatidis AG. 1994, Compact Extragalactic Radio Sources, ed. J. A. Zensus & K. I. Kellermann, 17 Reeves JN, Braito V, Chartas G, et al. 2020 Ap.J. 895:37-49 Riehn F, Engel R, Fedynitch A, et al

1994
[46]

2009 A&A 506:L41-L44 Rodrigues X, Heinze J, Palladino A, van Vliet A, Winter W

PoS ICRC2015 558 Rieger FM, Aharonian F A. 2009 A&A 506:L41-L44 Rodrigues X, Heinze J, Palladino A, van Vliet A, Winter W

2009
[48]

2003 Ap.J

arXiv:2008.11232 Ryu D, Kang H, Hallman E, Jones TW. 2003 Ap.J. 593:599-610 Salamida F. (for the Pierre Auger Collaboration) 2023 arXiv :2312.14673 Sagawa H

2008 arXiv
[49]

2017.Prog

Extragalactic Astronomy and Cosmology: An IntroductionBerlin:Springer Schr¨ oder FG. 2017.Prog. Part. Nucl. Phys.93:1-68 Simeon P

2017
[50]

2023 ICRC2023, 369 (2023) Simeon P, Globus, N., Barrow KSS, Blandford R

Unpublished PhD thesisStanford: Stanford University Simeon P, Globus N, Barrow KSS, Blandford R. 2023 ICRC2023, 369 (2023) Simeon P, Globus, N., Barrow KSS, Blandford R

2023
[52]

1973.Nature 241:109–110 32 No´ emie Globus and Roger Blandford Szabelski J, Wibig T, Wolfendale A W

Nature Astronomy, 5(5), 510-518 Strong A W, Wolfendale A W. 1973.Nature 241:109–110 32 No´ emie Globus and Roger Blandford Szabelski J, Wibig T, Wolfendale A W

1973
[54]

2021.Modern Classical Physics Vol4: Plasma PhysicsPrinceton: Princeton University Press Tiberio A (for the LHCf collaboration) et al

arXiv:2406.08561 Thorne KS & Blandford RD. 2021.Modern Classical Physics Vol4: Plasma PhysicsPrinceton: Princeton University Press Tiberio A (for the LHCf collaboration) et al

2021 arXiv
[55]

2023 MNRAS, 519, 136-147 Watson AA

Ap.J.453:883-902 Vieu T, Reville B. 2023 MNRAS, 519, 136-147 Watson AA

2023
[56]

966:240-250 Wykes S, Croston JH, Hardcastle MJ, et al

Ap.J. 966:240-250 Wykes S, Croston JH, Hardcastle MJ, et al. 2013 Astron.Astrophys. 558:A19 Yamamoto T

2013
[57]

arXiv 2405.17409 Zirakashvili VN, Ptuskin VS, Rogovaya SI

arXiv
[1977]

1987, Phys

MNRAS 179:433-456 Blandford RD, Eichler D. 1987, Phys. Rep. 154:1-75 Blandford RD, Globus N

1987
[1984]

277:429-434 Eichler D, Guetta D, Pohl M

Ap.J. 277:429-434 Eichler D, Guetta D, Pohl M. 2010 Ap. J.722:543–549 Eichler D, Globus N, Kumar R, et al

2010
[1990]

Cosmic rays and particle physicsCambridge University Press, 1990 Gallant YA, Achterberg A

1990
[1995]

454:60-68 Olinto A V, Krizmanic J, Adams JH, et al

Ap.J. 454:60-68 Olinto A V, Krizmanic J, Adams JH, et al. 2021, J. Cos. Astropart. Phys., 2021:06-007 Ostapchenko S

2021
[1998]

2011 Astron

TIB Hannover D-30167 Hannover (Germany) Heesen V, Beck R, Krause M, et al. 2011 Astron. Astrophys.535:A79 Heinze J, Boncioli D, Bustamante M, et al. 2016 Astron. Astrophys.825:122-134 Heitler W

2011
[2002]

Phys.17:125–131 Terral P, Ferri` ere K

Astropart. Phys.17:125–131 Terral P, Ferri` ere K. 2017.Astr. Astrophys. 600:A29 Thompson TA, Heckman TM

2017
[2005]

Plasma physics for astrophysics, Princeton University Press, 2005 Lacki BC,

2005
[2007]

arXiv:astro-ph/0701167 Jansson R, Farrar GR

arXiv
[2008]

J. Cos. Astropart. Phys.10:033 Allard D. 2012, Astropart. Phys.39:33-43 Allard D, Aublin J, Baret B, et al

2012
[2011]

Ann. Rev. Astr. Astrophys.49:119–153 Kourkchi E, Tully BR 2017 Ap. J. 843:16-36 Kronberg PP

2017
[2012]

750:118-135 Fang K, Kotera K, Murase K, & Olinto A

Ap.J. 750:118-135 Fang K, Kotera K, Murase K, & Olinto A. V. 2014 Phys.Rev.D 90, 103005 Fang K, Metzger BD,

2014
[2014]

arXiv:1411.0704 Farrar GR, Awal N, Khurana D, et al

arXiv e-prints. arXiv:1411.0704 Farrar GR, Awal N, Khurana D, et al

arXiv
[2015]

2018, A&A, 611, A101 Biehl D, Boncioli D, Lunardini C, & Winter W

PoS ICRC2015, 359:10.22323 Biehl D, Boncioli D, Fedynitch A, &Winter W. 2018, A&A, 611, A101 Biehl D, Boncioli D, Lunardini C, & Winter W

2018
[2016]

Ann. Rev. of Astron. and Astrophys.54:313–362 M´ esz´ aros P, Fox DB, Hanna C, et al. 2019.Nature Rev. Phys.1:585-599 Metzger BD, Giannios D, Horiuchi S

2019
[2017]

835:72-85 Caccianiga L

Ap.J. 835:72-85 Caccianiga L. PoS ICRC2023 (2023)

2023
[2018]

853:L29-L38 Aab A, Abreu P, Aglietta M, et al

Ap.J.Lett. 853:L29-L38 Aab A, Abreu P, Aglietta M, et al. 2019 J. Cos. Astropart. Phys.10:022 Aab A, Abreu P, Aglietta M, et al

2019
[2019]

872:110 Bunner AN

Ap.J. 872:110 Bunner AN. 1967, Ph.D. Thesis Bustard C, Zweibel EG, Cotter C

1967
[2020]

J. Cos. Astropart. Phys.(03):053. Apel WD, Arteaga-Vel´ azquez JC, Bekk K. 2011.Phys. Rev. Lett.107:171104 Apel WD, Arteaga-Vel´ azquez JC, Bekk K. 2013.Phys. Rev. D87:081101 Arons J

2011
[2021]

Phys. Rev. Lett.126, 191101 Romero GE, M¨ uller AL, Roth M. 2018.Astron. Astrophys.616:A57 Romero-Wolf A, Alvarez-Mu˜ niz J, Anchordoqui LA, et al

2018
[2022]

R., Alshamsi M., Alves Garre S., et al., 2025, arXiv, arXiv:2502.08173

Journal of High Energy Astrophysics36, 55–110 Adriani O., Aiello S., Albert A., Alhebsi A. R., Alshamsi M., Alves Garre S., et al., 2025, arXiv, arXiv:2502.08173. doi:10.48550/arXiv.2502.08173 Aiello S, Albert A, Alshamsi M, et al

2025 doi arXiv
[2023]

Phys. Rev. D107:083009 Corstanje A, Buitink S, Falcke H, et al. 2021 Phys. Rev. D103:102006 Cristofari P, Blasi P, Amato E

2021
[2024]

arXiv 2408.05292 Abraham J, Aglietta M, Aguiree IC, et al

arXiv
[2025]

arXiv:2503.10795 Sironi L, Spitkovsky A

Pith tools

Reviewed August 7, 2026 · model on record in the stance chip above.

[1] [4]

textitEuro. Phys. J. C 84:696 Albrecht J, Cazon L, Dembinski H, et al. 2022, Ap&SS, 367, 27 Allard D, Parizot E, Olinto A V, et al

work page 2022

[2] [8]

966, 71 Bell AR

Ap.J. 966, 71 Bell AR. 1992 . MNRAS 257:493–500 Blandford RD & Funk S

work page 1992

[3] [13]

2011 A&A 535:A66 Decoene V,

Astroparticle Physics, 123:102492 Decerprit G, Allard D. 2011 A&A 535:A66 Decoene V,

work page 2011

[4] [14]

PoS ICRC2019. Vol. 36, p. 233 Dembinski HP, Arteaga-Vel´ azquez JC, Cazon L, et al. 2019.Euro. Phys. J. C210:02004 Ding C, Globus N, Farrar GR

work page 2019

[5] [15]

J CAP, 2024, 022 Eichler D

work page 2024

[6] [18]

ICRC 2, 161–164 Farrar GR, Jansson R, Feain IJ, Gaensler BM. 2013 J. Cos. Atropart. Phys.01(2013)023 Farrar GR, Piran T

work page 2013

[7] [20]

2015 Ph.D

PoS ICRC2015 236 Fedynitch A. 2015 Ph.D. thesis, KIT, Karlsruhe, Dept. Phys. Fermi E

work page 2015

[8] [21]

2022 PoS ICRC2021 402 Gaensler BM, Heald GH, McClure-Griffiths NM et al

PoS ICRC2023 031 Fujii T. 2022 PoS ICRC2021 402 Gaensler BM, Heald GH, McClure-Griffiths NM et al

work page 2022