scholarly journals ASTROPARTICLE THEORY: SOME NEW INSIGHTS INTO HIGH ENERGY COSMIC RAYS

2004 ◽  
Vol 19 (07) ◽  
pp. 1133-1141 ◽  
Author(s):  
E. ROULET
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Diffusion Equations ◽  
New Developments ◽  
Diffusive Behavior ◽  
High Energy Cosmic Rays ◽  
Transport Diffusion ◽  
Neutrino Fluxes ◽  
Observed Behavior

Some new developments obtained in the last few years concerning the propagation of high energy cosmic rays are discussed. In particular, it is shown how the inclusion of drift effects in the transport diffusion equations leads naturally to an explanation for the knee, for the second knee and for the observed behavior of the composition and anisotropies between the knee and the ankle. It is shown that the trend towards a heavier composition above the knee has significant impact on the predicted neutrino fluxes above 1014 eV. The effects of magnetic lensing on the cosmic rays with energies above the ankle are also discussed, analyzing the main features of the different regimes that appear between the diffusive behavior that takes place at lower energies and the regime of small deflections present at the highest ones.

scholarly journals Planck Neutrinos as Ultra High Energy Cosmic Rays

2020 ◽  
Vol 29 (1) ◽  
pp. 40-46
Author(s):  
Dmitri L. Khokhlov
Keyword(s):  
Black Holes ◽  
Cosmic Rays ◽  
Standard Model ◽  
Active Galactic Nuclei ◽  
Planck Scale ◽  
Galactic Nuclei ◽  
High Energy ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
The Standard Model

AbstractThe studied conjecture is that ultra high energy cosmic rays (UHECRs) are hypothetical Planck neutrinos arising in the decay of the protons falling onto the gravastar. The proton is assumed to decay at the Planck scale into positron and four Planck neutrinos. The supermassive black holes inside active galactic nuclei, while interpreted as gravastars, are considered as UHECR sources. The scattering of the Planck neutrinos by the proton at the Planck scale is considered. The Planck neutrinos contribution to the CR events may explain the CR spectrum from 5 × 1018 eV to 1020 eV. The muon number in the Planck neutrinos-initiated shower is estimated to be larger by a factor of 3/2 in comparison with the standard model that is consistent with the observational data.

scholarly journals Starburst galaxies strike back: a multi-messenger analysis with Fermi-LAT and IceCube data

2021 ◽  
Vol 503 (3) ◽  
pp. 4032-4049
Author(s):  
Antonio Ambrosone ◽  
Marco Chianese ◽  
Damiano F G Fiorillo ◽  
Antonio Marinelli ◽  
Gennaro Miele ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Gamma Ray ◽  
Neutrino Flux ◽  
Data Interpretation ◽  
Realistic Model ◽  
High Energy ◽  
Starburst Galaxies ◽  
Neutrino Factory ◽  
High Energy Cosmic Rays ◽  
Astrophysical Objects

ABSTRACT Starburst galaxies, which are known as ‘reservoirs’ of high-energy cosmic-rays, can represent an important high-energy neutrino ‘factory’ contributing to the diffuse neutrino flux observed by IceCube. In this paper, we revisit the constraints affecting the neutrino and gamma-ray hadronuclear emissions from this class of astrophysical objects. In particular, we go beyond the standard prototype-based approach leading to a simple power-law neutrino flux, and investigate a more realistic model based on a data-driven blending of spectral indexes, thereby capturing the observed changes in the properties of individual emitters. We then perform a multi-messenger analysis considering the extragalactic gamma-ray background (EGB) measured by Fermi-LAT and different IceCube data samples: the 7.5-yr high-energy starting events (HESE) and the 6-yr high-energy cascade data. Along with starburst galaxies, we take into account the contributions from blazars and radio galaxies as well as the secondary gamma-rays from electromagnetic cascades. Remarkably, we find that, differently from the highly-constrained prototype scenario, the spectral index blending allows starburst galaxies to account for up to $40{{\ \rm per\ cent}}$ of the HESE events at $95.4{{\ \rm per\ cent}}$ CL, while satisfying the limit on the non-blazar EGB component. Moreover, values of $\mathcal {O}(100\, \mathrm{PeV})$ for the maximal energy of accelerated cosmic-rays by supernovae remnants inside the starburst are disfavoured in our scenario. In broad terms, our analysis points out that a better modelling of astrophysical sources could alleviate the tension between neutrino and gamma-ray data interpretation.

Propagation of cosmic rays and their secondaries in the intracluster medium

2020 ◽  
Vol 15 (S359) ◽  
pp. 178-179
Author(s):  
Saqib Hussain ◽  
Rafael Alves Batista ◽  
Elisabete Maria de Gouveia Dal Pino ◽  
Klaus Dolag
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Intergalactic Medium ◽  
Three Dimensional ◽  
High Energy ◽  
Intracluster Medium ◽  
High Energy Cosmic Rays ◽  
Test Particles

AbstractWe present results of the propagation of high-energy cosmic rays (CRs) and their secondaries in the intracluster medium (ICM). To this end, we employ three-dimensional cosmological magnetohydrodynamical simulations of the turbulent intergalactic medium to explore the propagation of CRs with energies between 1014 and 1019 eV. We study the interaction of test particles with this environment considering all relevant electromagnetic, photohadronic, photonuclear, and hadronuclear processes. Finally, we discuss the consequences of the confinement of high-energy CRs in clusters for the production of gamma rays and neutrinos.

ENERGY ORDERING EFFECTS IN THE ARRIVAL DIRECTIONS OF ULTRA-HIGH ENERGY COSMIC RAYS MEASURED BY THE PIERRE AUGER OBSERVATORY

2011 ◽  
Vol 20 (supp02) ◽  
pp. 50-56
Author(s):  
◽  
PETER SCHIFFER
Keyword(s):  
Cosmic Rays ◽  
Magnetic Fields ◽  
Charged Particles ◽  
High Energy ◽  
Pierre Auger Observatory ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Ordering Effects ◽  
Arrival Directions

The Pierre Auger Observatory is the world's largest experiment for the measurement of ultra-high energy cosmic rays (UHECRs). These UHECRs are assumed to be to be charged particles, and thus are deflected in cosmic magnetic fields. Recent results of the Pierre Auger Observatory addressing the complex of energy ordering of the UHECRs arrival directions are reviewed in this contribution. So far no significant energy ordering has been observed.

scholarly journals High energy cosmic ray interactions and UHECR composition problem

2019 ◽  
Vol 210 ◽  
pp. 02001
Author(s):  
Sergey Ostapchenko
Keyword(s):  
Experimental Data ◽  
Monte Carlo ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Hadronic Interactions ◽  
High Energy Cosmic Rays ◽  
Cosmic Ray Interactions ◽  
Composition Problem

The differences between contemporary Monte Carlo generators of high energy hadronic interactions are discussed and their impact on the interpretation of experimental data on ultra-high energy cosmic rays (UHECRs) is studied. Key directions for further model improvements are outlined. The prospect for a coherent interpretation of the data in terms of the UHECR composition is investigated.

Energy spectrum and mass composition of high-energy cosmic rays

2003 ◽  
Vol 66 (7) ◽  
pp. 1145-1206 ◽  
Author(s):  
Andreas Haungs ◽  
Heinigerd Rebel ◽  
Markus Roth
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
High Energy ◽  
Mass Composition ◽  
High Energy Cosmic Rays
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