Open AccessPreliminary indirect measurement of cosmic-ray proton spectrum using Earth’s γ-ray data from Fermi Large Area Telescope
Author(s) -
Patomporn Payoungkhamdee
Publication year - 2021
Publication title -
journal of physics. conference series
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.21
H-Index - 85
eISSN - 1742-6596
pISSN - 1742-6588
DOI - 10.1088/1742-6596/1719/1/012016
Subject(s) - cosmic ray , physics , fermi gamma ray space telescope , proton , spectral index , telescope , astrophysics , rigidity (electromagnetism) , spitzer space telescope , ultra high energy cosmic ray , spectral line , nuclear physics , astronomy , quantum mechanics
Cosmic rays (CRs) are high-energy particles, mostly protons, propagating in space. The rigidity (momentum per charge) spectrum of CRs is well described by a power law for which the spectral index is approximately 2.8 around 30 - 1000 GV. Recent measurements by PAMELA and AMS-02 indicate an abrupt change of the CR proton spectral index at about 340 GV. When CRs interact with the Earth’s upper atmosphere, γ rays can be produced and detected by space-based detectors. Here we use the Earth’s γ -ray data collected by the Fermi Large Area Telescope along with a proton-air interaction model to indirectly determine the CR proton spectral index and compare against observations by other instruments.