An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory

Pierre Auger Collaboration

RECORD

An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory

Pierre Auger Collaboration

Astrophysics · Submitted 26 Jun 2006

abstract compiled · 2026-09-23 · no language-model review

The authors' main claim An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies greater than 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory.

how it is stated · asserted 1.00 read the record →

Comment (0) Read on arXiv ↗

Cite ▾

arXiv IDastro-ph/0606619 (version 2)

Pith ID6BY6AKZG, Pith's permanent record of this paper and its review

CitationPierre Auger Collaboration. "An upper limit to the photon fraction in cosmic rays above 10^19 eV from the Pierre Auger Observatory." arXiv:astro-ph/0606619 (2006). https://pith.science/paper/6BY6AKZG

Claim paper

The compiled record

The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Open the compiled record

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 3,637 input tokens, $0.0002 reported.

What the abstract itself states, as probabilities: claims first 0.93 · states limitation 0.40 · human participants 0.01 · controlled comparison 0.11 · randomized assignment 0.01 · states quantitative result 0.99 · compares with prior results 0.98 · mentions code or data availability 0.02.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; show every role.

An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies greater than 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favored.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#	sentence	role	the authors' own work	states the main conclusion	strength
s0	An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies greater than 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory.	result 1.00	0.97	0.96	asserted 1.00
s1	This is the first such limit on photons obtained by observing the fluorescence light profile of air showers.	contribution 0.83	0.89	0.06	asserted 1.00
s2	This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays.	interpretation 0.81	0.54	0.08	asserted 1.00
s3	Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favored.	result 0.56	0.93	0.09	asserted 0.55

What kind of paper the classifier reports this is: empirical study 1.00 · evidence from observation or experiment 0.97.

What was examined, and what was not

sources read

arXiv listing abstract v2

not examined

full text
figures and tables
references and citing sentences
relations to other papers

levels run

P abstract

not run

S sections
T body sentences
C citations
R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

The paper

Original abstract

An upper limit of 16% (at 95% c.l.) is derived for the photon fraction in cosmic rays with energies greater than 10^19 eV, based on observations of the depth of shower maximum performed with the hybrid detector of the Pierre Auger Observatory. This is the first such limit on photons obtained by observing the fluorescence light profile of air showers. This upper limit confirms and improves on previous results from the Haverah Park and AGASA surface arrays. Additional data recorded with the Auger surface detectors for a subset of the event sample, support the conclusion that a photon origin of the observed events is not favored.

Human review

How Pith checks papers → · Full audit of this paper →

References

Forward citations

Cited by 6 Pith papers

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

Vacuum Cherenkov radiation for nonminimal dimension-5 Lorentz violation
hep-ph 2025-08 conditional novelty 6.0 of 10

Isotropic dimension-5 Lorentz violation in fermions is constrained to below 1e-18 GeV^-1 (proton, m-type) and 3e-28 GeV^-1 (proton, a-type) by the absence of vacuum Cherenkov radiation in cosmic rays.
The Pierre Auger Observatory Upgrade - Preliminary Design Report
astro-ph.IM 2016-04 conditional novelty 6.0 of 10

A design report arguing that pairing a thin scintillator with each Auger water-Cherenkov detector yields shower-by-shower muon content, enabling mass-composition measurements up to the highest energies.
Theory and Phenomenology of Planckian Interacting Massive Particles as Dark Matter
hep-ph 2017-09 conditional novelty 5.0 of 10

Generalizing Planckian Interacting Dark Matter from scalars to fermions, vectors, and Kaluza-Klein gravitons leaves the relic abundance essentially unchanged, so a GUT-scale dark matter mass stays testable through fut...
Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory
astro-ph.HE 2016-12 accept novelty 5.0 of 10

Fitting Auger spectrum and Xmax data above the ankle favors low maximum rigidity near 5e18 V, an injection index near 1, and a helium-nitrogen-silicon composition, with model systematics larger than the statistical errors.
Measurement of the energy spectrum of cosmic rays above 10^18 eV using the Pierre Auger Observatory
astro-ph.HE 2010-02 conditional novelty 5.0 of 10

A combined hybrid and surface-detector measurement gives a cosmic ray spectrum with a break at 10^18.6 eV (index 3.26 below, 2.55 above) and a flux suppression at 10^19.6 eV significant at more than 20 sigma.

Show 1 more citing papers

Ultra-High-Energy Cosmic Rays
astro-ph.HE 2018-07 accept novelty 2.0 of 10

A review synthesizing UHECR data concludes that nearby starburst galaxies accelerating mixed heavy nuclei best explain the spectrum, the composition trend, and the intermediate-scale anisotropy.

How the literature uses it

13 arXiv papers cite this in 17 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 12 sentences without a confident label

Uses its data or values 4 papers

Here, we use another Auger event [ref] with a slightly higher energy, $E_prim=212 EeV=2.12 ×10^20 eV$.

New two-sided bound on the isotropic Lorentz-violating parameter of modified Maxwell theory · New indirect bounds on the isotropic LV parameter · 0.92
Particularly it is already possible to put upper limits on the fraction of photons on the $10%$ level at energies above $10^19$ eV using Auger hybrid observations [ref] , AGASA [ref] and Yakutsk [ref] data.

Lorentz Violation for Photons and Ultra-High Energy Cosmic Rays · Introduction · 0.88
The Auger collaboration set limits on the fraction of $γ$-rays at energies above 2, 3, 5, and 10$×$10$^18$ eV (2, 3, 5, and 10 EeV) ( [ref] ).

Ultrahigh Energy Cosmic Rays · Limits on the fraction of gamma-rays · 0.89

Discussion

Know something about this paper? Leave a comment, or highlight any passage above to comment on it.