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The Origin of Galactic Cosmic Rays as Revealed by their Composition
- Source :
- POS-Proceedings of Science, 37th International Cosmic Ray Conference, 37th International Cosmic Ray Conference, Jul 2021, Berlin, Germany. pp.153, ⟨10.22323/1.395.0153⟩, Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2021, 508 (1), pp.1321-1345. ⟨10.1093/mnras/stab2533⟩, Monthly Notices of the Royal Astronomical Society, 2021, 508 (1), pp.1321-1345. ⟨10.1093/mnras/stab2533⟩
- Publication Year :
- 2021
-
Abstract
- Galactic cosmic-rays (GCRs) are thought to be accelerated in strong shocks induced by massive star winds and supernova explosions sweeping across the interstellar medium. But the phase of the interstellar medium from which the CRs are extracted has remained elusive until now. Here, we study in detail the GCR source composition deduced from recent measurements by the AMS-02, Voyager 1 and SuperTIGER experiments to obtain information on the composition, ionisation state and dust content of the GCR source reservoirs. We show that the volatile elements of the CR material are mainly accelerated from a plasma of temperature higher than $\sim 2$ MK, which is typical of the hot medium found in galactic superbubbles energised by the activity of massive star winds and supernova explosions. Another GCR component, which is responsible for the overabundance of $^{22}$Ne, most likely arises from acceleration of massive star winds in their termination shocks. From the CR-related $\gamma$-ray luminosity of the Milky Way, we estimate that the ion acceleration efficiency in both supernova shocks and wind termination shocks is of the order of $10^{-5}$. The GCR source composition also shows evidence for a preferential acceleration of refractory elements contained in interstellar dust. We suggest that the GCR refractories are also produced in superbubbles, from shock acceleration and subsequent sputtering of dust grains continuously incorporated into the hot plasma through thermal evaporation of embedded molecular clouds. Our model explains well the measured abundances of all primary and mostly primary CRs from H to Zr, including the overabundance of $^{22}$Ne.<br />Comment: 24 pages, 18 figures, submitted to MNRAS. Version 2: as accepted for publication
- Subjects :
- stars: abundances
Milky Way
Astrophysics::High Energy Astrophysical Phenomena
FOS: Physical sciences
Cosmic ray
Astrophysics
Astrophysics::Cosmology and Extragalactic Astrophysics
01 natural sciences
ISM: abundances
Luminosity
cosmic rays
0103 physical sciences
Astrophysics::Solar and Stellar Astrophysics
010303 astronomy & astrophysics
Astrophysics::Galaxy Astrophysics
Cosmic dust
High Energy Astrophysical Phenomena (astro-ph.HE)
supernova remnants
[PHYS]Physics [physics]
Physics
010308 nuclear & particles physics
Molecular cloud
Astronomy and Astrophysics
Plasma
Interstellar medium
Supernova
13. Climate action
Space and Planetary Science
[SDU]Sciences of the Universe [physics]
Astrophysics::Earth and Planetary Astrophysics
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Astrophysics - High Energy Astrophysical Phenomena
Subjects
Details
- Language :
- English
- ISSN :
- 00358711 and 13652966
- Database :
- OpenAIRE
- Journal :
- POS-Proceedings of Science, 37th International Cosmic Ray Conference, 37th International Cosmic Ray Conference, Jul 2021, Berlin, Germany. pp.153, ⟨10.22323/1.395.0153⟩, Monthly Notices of the Royal Astronomical Society, Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP): Policy P-Oxford Open Option A, 2021, 508 (1), pp.1321-1345. ⟨10.1093/mnras/stab2533⟩, Monthly Notices of the Royal Astronomical Society, 2021, 508 (1), pp.1321-1345. ⟨10.1093/mnras/stab2533⟩
- Accession number :
- edsair.doi.dedup.....2ecfc75136b55f7616401d545dc7379b