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Properties of Iron Primary Cosmic Rays: Results from the Alpha Magnetic Spectrometer
M Aguilar1, L Ali Cavasonza2, M S Allen3
1Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas (CIEMAT), 28040 Madrid, Spain.
Physical Review Letters
|February 12, 2021
Summary
Primary iron (Fe) cosmic rays exhibit new properties. Above 80.5 GV, their flux rigidity dependence matches Helium, Carbon, and Oxygen, indicating they belong to the same cosmic ray class.
Area of Science:
- Astrophysics
- Cosmic Ray Physics
Background:
- Cosmic rays are high-energy particles originating from outer space.
- Understanding the composition and behavior of cosmic rays is crucial for astrophysics.
Purpose of the Study:
- To investigate the properties of primary iron (Fe) cosmic rays.
- To compare the rigidity dependence of iron cosmic rays with other elements.
Main Methods:
- Analysis of 0.62×10^6 iron nuclei data collected by the Alpha Magnetic Spectrometer (AMS) on the International Space Station.
- Examining the flux of cosmic rays in the rigidity range of 2.65 GV to 3.0 TV.
Main Results:
- Above 80.5 GV, the rigidity dependence of the iron cosmic ray flux is identical to that of Helium (He), Carbon (C), and Oxygen (O) fluxes.
- The iron to oxygen (Fe/O) flux ratio was found to be constant at 0.155±0.006.
- This indicates that iron, helium, carbon, and oxygen cosmic rays belong to the same primary class.
Conclusions:
- Iron cosmic rays share properties with lighter elements like Helium, Carbon, and Oxygen.
- This grouping is distinct from the class that includes Neon, Magnesium, and Silicon.
- The findings reveal unexpected similarities in the origin or propagation of different cosmic ray species.
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