Related papers: Ultrahigh energy cosmic rays from dark matter anni…
A spectre is haunting physics---the spectre of non-thermal processes. Manifesting itself in astroparticle physics, all classical disciplines of physics and astronomy have entered into a holy alliance to exorcise this spectre: While…
The origin and composition of ultra-high energy cosmic rays (UHECRs) remain a mystery. The common lore is that UHECRs are deflected from their primary directions by the Galactic and extragalactic magnetic fields. Here we describe an…
We briefly review sources of cosmic rays, their composition and spectra as well as their propagation in the galactic and extragalactic magnetic fields, both regular and fluctuating. A special attention is paid to the recent results of the…
The origin of ultra-high-energy cosmic rays (UHECRs) is one of the most intriguing problems of modern cosmic ray physics. We briefly review the main astrophysical models of their origin and the forthcoming orbital experiments TUS and…
There is strong evidence about the existence of unknown dark matter in the Universe. Many different theories about this dark matter exist, but most probably it is made of a new kind of fundamental particle that has to be massive, stable,…
The existence of cosmic ray particles up to the ultra-high energy limit (> 10^20 eV) is now beyond any doubt. The detection of cosmic particles with such energies imposes a challenge for the comprehension of their sources and nature. On one…
Bright gamma-ray flares observed from sources far beyond our Galaxy are best explained if enormous amounts of energy are liberated by black holes. The highest-energy particles in nature--the ultra-high energy cosmic rays--cannot be confined…
In this chapter I give an overview of shock acceleration, including a discussion of the maximum energies possible and the shape of the spectrum near cut-off, interactions of high energy cosmic rays with, and propagation through, the…
We provide a detailed formulation for calculating the angular power spectrum of the cosmic background photons arising from the dark matter decay or annihilation in a comprehensive manner. We pay particular attention to the case of dark…
We propose a new mechanism for explaining the very long lifetime of superheavy dark matter X, which is proposed as a source of the ultra high-energy cosmic rays above the GZK cutoff (5 \times 10^{19} eV). The singlet X particle couples to…
The origin of the cosmic gamma-ray background at 1-20 MeV remains a mystery. We show that gamma-ray emission accompanying annihilation of 20 MeV dark matter particles explains most of the observed signal. Our model satisfies all of the…
It is shown that Eddington-like accretion event in the Galactic center several million years ago and particle acceleration at accompanying shocks and jets could explain the observed cosmic ray spectrum at energies above 1 PeV. Cosmic ray…
The understanding of the nature of ultra-high-energy cosmic rays is one of the most intriguing open questions for current and future observatories. These particles are expected to be accelerated in extragalactic sources. Because of their…
The current status of the theory of particle acceleration at relativistic shocks is presented, and a few possible scenarios for ultra-high-energy cosmic ray production at such shocks are briefly discussed.
The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe…
The origin of highest energy cosmic rays (UHECR) is yet unknown. In order to understand their propagation we determine the probability that an ultrahigh energy (above 5\cdot 10^{19} eV) proton created at a distance r with energy E arrives…
We briefly review the main channels of gamma ray and neutrino production due to the propagation of ultra high energy cosmic rays. We show how the observations of these secondary radiations are of paramount importance in tagging mass…
We argue that the superheavy gravitinos that we had previously proposed as candidates for Dark Matter can offer a possible explanation for the ultra-high energy cosmic ray (UHECR) events observed at the Pierre Auger Observatory, via…
The extra-dimensional origin of dark matter is a fascinating and nowadays often discussed possibility. Here, we present the gamma-ray signatures that are expected from the self-annihilation of Kaluza-Klein dark matter particles. For…
We propose an explanation for the recently reported ultra-high-energy neutrino signal at KM3NeT, which shows no clear association with known astrophysical sources. While decaying dark matter in the Galactic Center is a natural candidate,…