Related papers: Correlating Fermi gamma-ray sources with ultra-hig…
Very recently, the Pierre Auger Collaboration reported a $4.5\sigma$ correlation between the arrival directions of the highest energy cosmic rays and nearby starburst galaxies. The cosmic rays producing the anisotropy signal have been…
We predict the arrival distribution of UHECRs above $4 \times 10^{19}$ eV with the event number expected by future experiments in the next few years. We perform event simulations with the source model which is adopted in our recent study…
gamma-ray bursts (GRBs) are likely sources of ultra-high energy, >10^{19} eV, protons and high energy, >1 TeV, neutrinos. Large volume detectors of ultra high energy cosmic rays (UHECRs) and high energy neutrinos, which are already…
We use the recent measurement of the isotropic $\gamma$-ray background (IGRB) by Fermi LAT and analysis of the contribution of unresolved point $\gamma$-ray sources to IGRB to build constraints on the models of ultra-high cosmic rays…
The origin, propagation, and mechanisms of acceleration of the ultra-high energy cosmic rays (UHECRs) are not yet well understood. Aiming for a better interpretation of the available experimental data, these data have to be confronted with…
The origin of ultra-high-energy cosmic rays (UHECRs) remains a fundamental question in astroparticle physics. While localized 3 $\sigma$ correlations with active galactic nuclei and starburst galaxies have been reported using…
The angular clustering of 5 Ultrahigh Energy Cosmic Rays (UHECRs) in the combined published AGASA-HiRes data has a probability of ~ 2 10^-3 of occurring by chance. A first analysis of the implications of the event energies and angular…
The nature of ultrahigh-energy cosmic rays (UHECRs) at energies >10^20 eV remains a mystery. They are likely to be of extragalactic origin, but should be absorbed within ~50 Mpc through interactions with the cosmic microwave background. As…
We propose a new way to detect individual bright Ultra-High Energy Cosmic Ray (UHECR) sources above background if the Galactic Magnetic Field (GMF) gives the main contribution to UHECR deflections. This method can be directly applied to…
The physics of Ultra High Energy Cosmic Rays will be reviewed, discussing the latest experimental results and theoretical models aiming at explaining the observations in terms of spectra, mass composition and possible sources. It will be…
Ultra High Cosmic Rays (UHECR) should be tracing their sources, making a new astronomy. Their events counting are finally growing, by Auger experiment, into cosmic sky. Their map should follow the mass distribution in a narrow cosmic volume…
Extensive simulations of the ultra-high energy cosmic ray (UHECR) propagation in the Galactic magnetic field (GMF) have been performed, and the results are presented. The use of different available models of the large-scale GMF and/or…
Detecting neutrinos and photons is crucial to identifying the sources of ultrahigh-energy cosmic rays (UHECRs), especially for transient sources. We focus on ultrahigh-energy gamma-ray emission from transient sources such as gamma-ray…
Several explanations for the existence of Ultra High Energy Cosmic Rays (UHECR) invoke the idea that they originate from the decay of massive particles created in the reheating following inflation. It has been suggested that the decay…
The wealth of data collected in the last few years thanks to the Pierre Auger Observatory and recently to the Telescope Array made the problem of the origin of ultra high energy cosmic rays a genuinely experimental/observational one. The…
We have used recently published data from the Pierre Auger Observatory and the Telescope Array Project to conclude some inferences concerning the origin and composition of ultra high-energy cosmic rays (UHECR). We advocate for model the…
Very-high energy (GeV-TeV) gamma rays in the universe suggest the presence of an accelerator in the source. Neutrinos and gamma rays are intriguing astrophysical messengers. Multi-messenger particle emission produced by interactions of…
It has been speculated earlier that Gamma Ray Bursts are sources of ultrahigh energy cosmic rays. Recently, the search for high energy photons from Gamma Ray Bursts by Milagro group has put limits on the isotropic luminosity of these…
The statistical distribution of energies among particles responsible for long Gamma Ray Burst (GRB) emission is analyzed in light of recent results of the Fermi Observatory. The allsky flux, $F_{\gamma}$, recorded by the Gamma Ray Burst…
The energetics of electromagnetic acceleration of ultra-high-energy cosmic rays (UHECRs) is constrained both by confinement of a particle within an acceleration site and by radiative energy losses of the particle in the confining magnetic…