TY - JOUR
T1 - Origin and impacts of the first cosmic rays
AU - Ohira, Yutaka
AU - Murase, Kohta
N1 - Funding Information:
We thank Tom Abel, Katusaki Asano, Takashi Hosokawa, Fumio Takahara, and Ryo Yamazaki for useful comments. This work is supported by Japan society for the promotion of science (JSPS) KAKENHI Grant No. JP16K17702 (Y. O.), JP19H01893 (Y. O.) and Alfred P. Sloan Foundation and National Science Foundation (NSF) Grant No. PHY-1620777 (K. M.). Y. O. is supported by Ministry of Education, Culture, Sports, Science and Technology (MEXT/JSPS) Leading Initiative for Excellent Young Researchers.
Publisher Copyright:
© 2019 American Physical Society.
PY - 2019/9/17
Y1 - 2019/9/17
N2 - Nonthermal phenomena are ubiquitous in the Universe, and cosmic rays (CRs) play various roles in different environments. When, where, and how are CRs first generated since the big bang? We argue that blast waves from the first cosmic explosions at z∼20 lead to Weibel mediated nonrelativistic shocks and CRs can be generated by the diffusive shock acceleration mechanism. We show that protons are accelerated at least up to sub-GeV energies, and the fast velocity component of supernova ejecta is likely to allow CRs to achieve a few GeV in energy. We discuss other possible accelerators of the first CRs, including accretion shocks due to the cosmological structure formation. These CRs can play various roles in the early Universe, such as the ionization and heating of gas, the generation of magnetic fields, and feedbacks on the galaxy formation.
AB - Nonthermal phenomena are ubiquitous in the Universe, and cosmic rays (CRs) play various roles in different environments. When, where, and how are CRs first generated since the big bang? We argue that blast waves from the first cosmic explosions at z∼20 lead to Weibel mediated nonrelativistic shocks and CRs can be generated by the diffusive shock acceleration mechanism. We show that protons are accelerated at least up to sub-GeV energies, and the fast velocity component of supernova ejecta is likely to allow CRs to achieve a few GeV in energy. We discuss other possible accelerators of the first CRs, including accretion shocks due to the cosmological structure formation. These CRs can play various roles in the early Universe, such as the ionization and heating of gas, the generation of magnetic fields, and feedbacks on the galaxy formation.
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U2 - 10.1103/PhysRevD.100.061301
DO - 10.1103/PhysRevD.100.061301
M3 - Article
AN - SCOPUS:85073030511
VL - 100
JO - Physical Review D
JF - Physical Review D
SN - 2470-0010
IS - 6
M1 - 061301
ER -