Related papers: Physics of cosmological cascades and observable pr…
We discuss theoretical issues and experimental data that brought the ultra high energy cosmic rays in the list of Nature's greatest puzzles. After many years of research we still do not know how astrophysical acceleration processes can…
We discuss the problem of the absorption of very high-energy gamma-rays by pair production interactions with extragalactic photons which originate from stellar emission in the near IR-UV and reradiation of starlight in the mid- and far-IR.…
Cosmic rays are charged energetic particles that permeate the interstellar medium. Their sizeable energy share and penetration power makes them essential players in the dynamical and chemical processes that rule Galactic evolution, such as…
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…
In Monte Carlo simulations with a local update algorithm, the auto-correlation with respect to the topological charge tends to become very long. In the extreme case one can only perform reliable measurements within fixed sectors. We…
The origin of the highest energy cosmic rays is still unknown. The discovery of their sources will reveal the workings of the most energetic astrophysical accelerators in the universe. Current observations show a spectrum consistent with an…
This paper presents a systematic literature review focusing on the application of machine learning techniques for deriving observational constraints in cosmology. The goal is to evaluate and synthesize existing research to identify…
The development of techniques whereby gamma rays of energy 100 GeV and above can be studied from the ground, using indirect, but sensitive, techniques has opened up a new area of high energy photon astronomy. The most exciting result that…
Electromagnetic cascades are initiated by TeV gamma rays propagating through the intergalactic medium (IGM), and they can be used to constrain the weak intergalactic magnetic field (IGMF) in cosmic voids. Primary TeV photons produce…
In the last years there has been a growing interest in the understanding a vast variety of scale invariant and critical phenomena occurring in nature. Experiments and observations indeed suggest that many physical systems develop…
Cosmic ray particles with energies in excess of 10**(20) eV have been detected. The sources as well as the physical mechanism(s) responsible for endowing cosmic ray particles with such enormous energies are unknown. This report gives a…
The origin and nature of ultrahigh energy cosmic rays with energies above $10^{20}\,$eV is a puzzle for the physics and astrophysics of cosmic rays which is still unresolved. In this paper, I report on an extensive study on the propagation…
Nearby sources of cosmic rays up to a ZeV(=10^21 eV) could be observed with a multi-messenger approach including secondary gamma-rays and neutrinos. If cosmic rays above ~10^18 eV are produced in magnetized environments such as galaxy…
Blazars are expected to produce both gamma rays and cosmic rays. Therefore, observed high-energy gamma rays from distant blazars may contain a significant contribution from secondary gamma rays produced along the line of sight by the…
We describe the results of a hybrid matrix--Monte Carlo calculation of cascading of UHE cosmic rays and $\gamma$-rays through the cosmic background radiation fields over cosmological distances. We calculate the $\gamma$-ray and neutrino…
Dark matter annihilation and other processes may precipitate a flux of diffuse ultra-high energy $\gamma$-rays. These $\gamma$-rays may be observable in present day experiments which observe diffuse fluxes at the GeV scale. Yet the universe…
Cosmic structures at large scales represent the earliest and most extended form of matter condensation. In this lecture we review the application of the methods and concepts of modern statistical physics to these structures. This leads to a…
On-going measurements of the cosmic radiation (nuclear, electronic, and gamma-ray) are shedding new light on cosmic-ray physics. A comprehensive picture of these data relies on an accurate determination of the transport and source…
Peculiar velocities are the motions of galaxies due to the gravitational influence of large-scale structure, and thus are an important cosmological probe of the underlying matter density field. In recent years the number of surveys designed…
In supersymmetric theories, cosmic strings produced in the early Universe often have a width of TeV scale, while the tension is much larger. In a scaling regime, an infinite cosmic string releases significant fraction of its energy in the…