INVESTIGADORES
HANSEN Patricia Maria
artículos
Título:
Measurement of the cosmic-ray energy spectrum above 2.5 × 1018 eV using the Pierre Auger Observatory
Autor/es:
THE PIERRE AUGER COLLABORATION (P HANSEN PERTENECE A LA COLABORACIÓN AUGER)
Revista:
PHYSICAL REVIEW D - PARTICLE AND FILDS
Editorial:
American Physical Society.
Referencias:
Año: 2020 p. 1 - 27
ISSN:
0556-2821
Resumen:
We report a measurement of the energy spectrum of cosmic rays for energies above 2.5 × 1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature of the work is that the estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5 × 1019 eV. The principal conclusions are(1) The flattening of the spectrum near 5 × 1018 eV, the so-called ?ankle,? is confirmed.(2) The steepening of the spectrum at around 5 × 1019 eV is confirmed.(3) Anewfeature has been identified in the spectrum: in the region above the ankle the spectral index γ of the particle flux (∝ E−γ) changes from 2.51 0.03 ðstatÞ 0.05 ðsystÞ to 3.05 0.05 ðstatÞ 0.10 ðsystÞ before changing sharply to 5.1 0.3 ðstatÞ 0.1 ðsystÞ above 5 × 1019 eV.(4) No evidence for any dependence of the spectrum on declination has been found other than a mildexcess from the Southern Hemisphere that is consistent with the anisotropy observed above8 × 1018 eV.