CALET data of the cosmic-ray carbon and oxygen spectra is open to public: spectral hardening is observed

CALET (a) carbon and (b) oxygen flux (multiplied E2.7) and (c) ratio of carbon to oxygen fluxes, as a function of kinetic energy. Also plotted are the other direct measurements.

CALET, launched to the International Space Station in August 2015, is a calorimeter to measure cosmic rays and has been accumulating scientific data for over five years. CALET measured the spectra of the cosmic-ray carbon and oxygen from 10 GeV/n to 2.2 TeV/n, and the spectra indicate the hardening around 200 GeV/n. The tables of the spectra measured by CALET are open to public via DARTS on March 2, 2021. The spectral hardening was also reported in the proton spectrum as well as in heavy nuclei spectra, compelled a revision of the standard paradigm of galactic cosmic-rays based on the acceleration in the supernovae remnant and propagation in the galactic magnetic fields, and prompted an intense theoretical activity to interpret these unexpected spectral features.
This result was published from Physical Review Letter on December 18, 2020.


(Mar. 2021)

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Last Modified: 29 March 2021