Detailed simulations of Fermi-LAT constraints on UHECR production scenarios
Bibliographic record
Abstract
We have performed high-resolution simulations of the flux and spectrum of gammas detectable by Fermi-LAT, coming from UHECR-induced cascades, using the state-of-the-art (Gilmore) model of extragalactic background light, ELMAG to simulate the EM cascade (modified to work correctly for the Gilmore EBL) and CRPropa3 to simulate the production of EM secondaries from UHECR propagation. We examine the validity and limitations of the Liu et al. (2016) constraints, which found that we live in a local UHECR over-density. We also examine whether a model such as that of Unger, Farrar, and Anchordoqui (2015) -- which explains the full extragalactic CR spectrum and composition including the ankle, based on nuclear photodisintegration in the neighborhood surrounding the source -- satisfies the Fermi-LAT constraints, or requires Earth to be in an atypical position in the Universe as claimed by Liu et al. for pure proton primaries. We conclude that a mixed-composition scenario, like that of Unger, Farrar, and Anchordoqui, satisfies Fermi-LAT constraints evading any need for Earth to be in an atypical position in the Universe.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.001 | 0.004 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.001 | 0.001 |
| Bibliometrics | 0.001 | 0.001 |
| Science and technology studies | 0.001 | 0.001 |
| Scholarly communication | 0.001 | 0.001 |
| Open science | 0.002 | 0.001 |
| Research integrity | 0.002 | 0.002 |
| Insufficient payload (model declined to judge) | 0.005 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".