Extension of the Cosmic-Ray Energy Spectrum beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff

Takeda, M.; Hayashida, N.; Honda, K.; Inoue, N.; Kadota, K.; Kakimoto, F.; Kamata, K.; Kawaguchi, S.; Kawasaki, Y.; Kawasumi, N.; Kitamura, Hisashi; Kusano, Eiji; Matsubara, Y.; Murakami, Kazuaki; Nagano, M.; Nishikawa, D.; Ohoka, H.; Sakaki, N.; Sasaki, Misao; Shinozaki, K.; Souma, N.; Teshima, M.; Torii, R.; Tsushima, I.; Uchihori, Y.; Yamamoto, T.; Yoshida, Shigeru; Yoshii, H.

doi:10.1103/physrevlett.81.1163

Cited by 593 publications

(262 citation statements)

References 32 publications

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“…If CRs originate in the Galactic halo, the absence of the "Greisen-Zatsepin cutoff" -that is otherwise made quite puzzling by the lack of extragalactic source candidates near the direction of individual UHE-CRs [65] -is readily understood. At a distance of typically 20 kpc no significant absorption of UHE protons in the 3 K • background radiation is expected.…”

Section: Can Second-order Acceleration In the Plasmoids Reach Ultra-hmentioning

confidence: 99%

A possible universal origin of hadronic cosmic rays from ultrarelativistic ejecta of bipolar supernovae

Plaga¹

2002

New Astronomy

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Based on the "cannonball model" for gamma-ray bursts of Dar and De Rújula it is proposed that masses of baryonic plasma ("cannonballs"), ejected in bipolar supernova explosions in our Galaxy are the sources of hadronic Galactic cosmic rays (CRs) at all energies. The propagation of the cannonballs in the Galactic disk and halo is studied. Two mechanisms for the acceleration of the observed CRs are proposed. The first is based on ultrarelativistic shocks in the interstellar medium and could accelerate the bulk of CRs up to the "knee" energy of 4 × 10 15 eV. The second operates with second-order Fermi acceleration within the cannonball. If the total initial energy of the ejected plasmoids in a SN explosion is 10 53 ergs or higher this second mechanism may explain the CR spectrum above the knee up to the highest observed energies. It is shown that together with plausible assumptions about CR propagation in the Galactic confinement volume the observed spectral indices of the CR spectrum can be theoretically understood to first order. The model allows a natural understanding of various basic CR observations like the absence of the Greisen-Zatsepin cutoff, the anisotropy of arrival directions as function of energy and the small Galactocentric gradient of the CR density.

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Section: Can Second-order Acceleration In the Plasmoids Reach Ultra-hmentioning

confidence: 99%

A possible universal origin of hadronic cosmic rays from ultrarelativistic ejecta of bipolar supernovae

Plaga¹

2002

New Astronomy

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“…If cosmic-rays originate from cosmological distances, their flux at the highest energies (E 6 × 10 19 eV) should be suppressed due to interactions with the cosmological background photons, creating a feature in the spectrum called the "GZK cutoff" [13,14]. The fact that the AGASA experiment did not observe such a feature [15] led Ref. [11] to develop a model of acceleration of ultrahigh energy iron nuclei in young strongly magnetized Galactic neutron star winds.…”

Section: Introductionmentioning

confidence: 99%

Ultrahigh energy cosmic ray acceleration in newly born magnetars and their associated gravitational wave signatures

Kotera

2011

Phys. Rev. D

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Newly born magnetars are good candidate sources of ultrahigh energy cosmic rays. These objects can in principle easily accelerate particles to the highest energies required to satisfy the ultrahigh energy cosmic ray scenario (E ∼ 10 20−21 eV), thanks to their important rotational and magnetic energy reservoirs. Their acceleration mechanism, based on unipolar induction, predicts however a hard particle injection that does not fit the observed ultrahigh energy cosmic ray spectrum. Here we show that an adequate distribution of initial voltages among magnetar winds can be found to soften the spectrum. We discuss the effect of these distributions for the stochastic gravitational wave background signature produced by magnetars. The magnetar population characteristics needed to fit the ultrahigh energy cosmic ray spectrum could lead in most optimistic cases to gravitational wave background signals enhanced of up to four orders of magnitudes in the range of frequency 1 − 100 Hz, compared to the standard predictions. These signals could reach the sensitivities of future detectors such as DECIGO or BBO.

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“…Actually, according to an empirical scaling law proposed by Makishima (1999b), the maximum particle energy attainable in an acceleration site is roughly given by E max = v × B × L, where v is the typical internal velocity of the system, B is again the magnetic field, and L is the system size. Substituting v = 7 × 10 5 m s −1 , B = 1 nT, and L = 1 Mpc, we obtain E max ∼ 10 19 eV, which is close to the energy of the highest-energy cosmic rays (Takeda et al, 1998).…”

Section: Particle Accelerationmentioning

confidence: 99%

Magnetic reconnection in large-scale cosmic plasmas

Makishima

2014

Earth Planet Sp

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X-ray emitting hot plasmas of a temperature 2-12 keV, associated with galaxy clusters, constitute the most dominant form of baryons in the universe. The plasma is thought to be magnetized at least to 0.1-1 nT, although the β value is relatively high at 10-100. The plasma is confined by gravity of each cluster in a stable manner, but the member galaxies are moving through it with an approximately transonic speed. Therefore, the plasma must be in a magnetohydrodynamically turbulent condition, where frequent magnetic reconnection is expected to take place. Mainly based on observations with the ASCA X-ray Observatory, evidence for such magnetic reconnection is accumulating.

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Extension of the Cosmic-Ray Energy Spectrum beyond the Predicted Greisen-Zatsepin-Kuz'min Cutoff

Cited by 593 publications

References 32 publications

A possible universal origin of hadronic cosmic rays from ultrarelativistic ejecta of bipolar supernovae

A possible universal origin of hadronic cosmic rays from ultrarelativistic ejecta of bipolar supernovae

Ultrahigh energy cosmic ray acceleration in newly born magnetars and their associated gravitational wave signatures

Magnetic reconnection in large-scale cosmic plasmas

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