Related papers: CRAFT (Cosmic Ray Acceleration From Turbulence) in…
Ultra-high energy cosmic ray protons accelerated in astrophysical objects produce secondary electromagnetic cascades during propagation in the cosmic microwave and infrared backgrounds. We show that such cascades can contribute between ~1%…
Clusters of galaxies are believed to be capable to accelerate protons at accretion shocks to energies exceeding 10^18 eV. At these energies, the losses caused by interactions of cosmic rays with photons of the Cosmic Microwave Background…
Context: Since a few years, signatures of supernova remnants associated with molecular clouds have been detected in gamma rays. Whether these gamma rays are generated by cosmic ray electrons or by cosmic ray protons is usually not known.…
Observations of large-scale radio emissions prove the existence of shock accelerated cosmic-ray electrons in galaxy clusters, while the lack of detected $\gamma$-rays limits the acceleration of cosmic-ray protons in galaxy clusters. This…
We present the first simulations evolving resolved spectra of cosmic rays (CRs) from MeV-TeV energies (including electrons, positrons, (anti)protons, and heavier nuclei), in live kinetic-MHD galaxy simulations with star formation and…
Laboratory experiments to explore plasma conditions and stimulated particle acceleration can illuminate aspects of the cosmic particle acceleration process. Here we discuss the cosmic-ray candidate source object variety, and what has been…
Cosmic rays in star-forming galaxies are a dominant source of both diffuse $\gamma$-ray emission and ionisation in gas too deeply shielded for photons to penetrate. Though the cosmic rays responsible for $\gamma$-rays and ionisation are of…
Clusters of galaxies are storage rooms of cosmic rays. They confine the hadronic component of cosmic rays over cosmological time scales due to diffusion, and the electron component due to energy losses. Hadronic cosmic rays can be…
Cosmic-ray scattering on magnetic turbulence leads to spatial diffusive propagation; if the scattering medium is moving, this will inevitably also cause changes in the momentum of the particles, so-called diffusive reacceleration. This can…
The Earth is bombarded by ultra-relativistic particles, known as cosmic rays (CRs). CRs with energies up to a few PeV (=10$^{15}$ eV), the knee in the particle spectrum, are believed to have a Galactic origin. One or more factories of PeV…
Relativistic jets are believed to be born magnetically dominated. Very and ultra-high energy cosmic rays can be efficiently accelerated by magnetic reconnection in these sources. We here demonstrate this directly, with no extrapolations to…
We report the analysis of the Fermi-Large Area Telescope data from six nearby giant molecular clouds (MCs) belonging to the Gould Belt and the Aquila Rift regions. The high statistical {\gamma}-ray spectra above 3 GeV well described by…
In the cosmological blast-wave model for gamma ray bursts (GRBs), high energy (> 10 GeV) gamma-rays are produced either through Compton scattering of soft photons by ultrarelativistic electrons, or as a consequence of the acceleration of…
We study interactions of cosmological relics, $X$, of mass $m$ and electric charge $qe$ in the galaxy, including thermalization with the interstellar medium, diffusion through inhomogeneous magnetic fields and Fermi acceleration by…
We attempt to explain the non-thermal emission arising from galaxy clusters as a result of the re-acceleration of electrons by compressible turbulence induced by cluster mergers. In our model intracluster medium (ICM) is represented by a…
The extragalactic sources of ultra-high-energy (E > 4x10^19 eV) cosmic rays that make a small contribution to the flux of particles recorded by ground-based arrays are discussed. We show that cosmic rays from such sources can produce a…
We study the propagation of mildly-relativistic cosmic rays (CRs) in multiphase interstellar medium environments with conditions typical of nearby disk galaxies. We employ the techniques developed in Armillotta+21 to post-process three…
Gamma-ray bursts (GRBs) are widely suggested as potential sources of ultrahigh-energy cosmic rays (UHECRs). The kinetic energy of the jets dissipates, leading to the production of an enormous amount of $\gamma$-ray photons and possibly also…
In galaxy clusters, the intracluster medium (ICM) is expected to host a diffuse, long-lived, and invisible population of "fossil" cosmic-ray electrons (CRe) with 1-100 MeV energies. These CRe, if re-accelerated by 100x in energy, can…
The interstellar molecular clouds are the site of star formation and also the target for the cosmic ray protons to produce \gamma-rays via the hadronic process. The interstellar atomic gas is enveloping the molecular clouds and may also be…