{"record":{"author":{"account_ref":null,"orcid":null},"builds_on":[],"content_schema":"pubphys.content.revision/1","content_sha256":"124a242c2f0a2b5ba70f8fc9d1133a9024b6bab33c2c249edbacd10bfafe5625","created":"2026-10-15T23:43:22Z","files":[],"origin":{"assisted_by":[],"kind":"seed"},"parents":["a6a796561663976f3ddf558ae535abc711ec941b5c6dd67689033d9388daf318","ce59fb6cd812fc05906d0c60a71c75ea22bc686bcf38e7c3ef7010834d98ee7b"],"salt":"a4368e81cb1300799e1dd85cbcde9fc471832b0e0e9d2b794dfa91fd72cae325","schema":"pubphys.record/2","site":"pubphys.com","target":null,"type":"revision"},"content":{"answer_type":"value","assisted_by":[],"external_id":"astro.cosmic-ray-origins.galactic-extragalactic-transition","kind":"well-posed","literature_status":"contested","n":"2","parents":[],"plain":"Below some energy cosmic rays come from our own galaxy and above it from other galaxies; whether the handover happens near $10^{17}\\,\\mathrm{eV}$ or near $5 \\times 10^{18}\\,\\mathrm{eV}$ (the ankle, where the spectrum flattens) is unsettled.","posed_since":"","precise":"Determine the energy at which the extragalactic flux exceeds the Galactic flux, using the iron knee near $8 \\times 10^{16}\\,\\mathrm{eV}$, the second knee near $10^{17}\\text{ to }3 \\times 10^{17}\\,\\mathrm{eV}$, the ankle near $5 \\times 10^{18}\\,\\mathrm{eV}$, the energy dependence of the mean shower depth $X_{\\max}$ and its spread (lightest composition near $2 \\times 10^{18}\\,\\mathrm{eV}$), and the change of the dipole direction from near the Galactic center below $10^{18}\\,\\mathrm{eV}$ to away from it above $8 \\times 10^{18}\\,\\mathrm{eV}$. Answer: the transition energy and the Galactic component spectrum, including whether a second Galactic population beyond the knee sources is required.","problem_ref":"a6a796561663976f3ddf558ae535abc711ec941b5c6dd67689033d9388daf318","references":"","settled_by":"Mass-resolved spectra and anisotropies from $10^{16} \\text{ to } 10^{19}\\,\\mathrm{eV}$ with overlapping detectors, fit by a two-population model with propagation.","status_note":"","title":"At what energy do extragalactic cosmic rays take over from Galactic ones?","topic_ref":null},"attested":{"attestation":{"batch":null,"client_id":null,"id_token_sha256":null,"kind":"platform"},"record_hash":"8a4a0f392b9b8378c31430b3418dca0b6d228b24045497484a3a64331716b335","schema":"pubphys.attested/1"},"envelope":{"attested_hash":"023df7780d515794e340225a45dda79a84cb1a646a565a13de66e80096e3e112","platform_signature":{"key_id":"c6afc19b31429869751f06879c75cd64ea92654423d15b44be775bf1310a60da","sig":"QVEC9VYCPKbBvqzEaJU7-jPr4PaHv297t2HaDw7UAS-Ocu-NATrC0UIAe_z5PE-f0oe5r1m_AdzD_iSRnGICCw"},"schema":"pubphys.envelope/1"},"record_hash":"8a4a0f392b9b8378c31430b3418dca0b6d228b24045497484a3a64331716b335","leaf_index":2332}