Low-Energy Break in the Spectrum of Galactic Cosmic Rays - Archive ouverte HAL
Article Dans Une Revue Physical Review Letters Année : 2012

Low-Energy Break in the Spectrum of Galactic Cosmic Rays

Résumé

Measurements of the low-energy spectrum of Galactic cosmic rays (GCRs) by detectors on or near Earth are affected by solar modulation. To overcome this difficulty, we consider nearby molecular clouds as GCR detectors outside the Solar System. Using γ-ray observations of the clouds by the Fermi telescope, we derive the spectrum of GCRs in the clouds from the observed γ-ray emission spectrum. We find that the GCR spectrum has a low-energy break with the spectral slope hardening by ΔΓ=1.1±0.3 at an energy of E=9±3GeV. Detection of a low-energy break enables a measurement of GCR energy density in the interstellar space U=0.9±0.3eV/cm3.

Dates et versions

hal-00713442 , version 1 (01-07-2012)

Identifiants

Citer

A. Neronov, D.V. Semikoz, A.M. Taylor. Low-Energy Break in the Spectrum of Galactic Cosmic Rays. Physical Review Letters, 2012, 108, pp.051105. ⟨10.1103/PHYSREVLETT.108.051105⟩. ⟨hal-00713442⟩
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