Related papers: ARGO-YBJ: Status and Highlights
Since their first observation in 1962, the existence of Ultra High Energy Cosmic Rays (UHECR) remains a mystery in modern astrophysics. Those cosmic rays, with energies well above 50 EeV ($50\times 10^{18}$eV), can hardly be accelerated,…
This paper presents the highlights from the recent measurements of the energy spectrum, mass composition, and arrival directions of the ultra-high energy ($> 10^{17}$ eV = 0.1 EeV) cosmic rays (UHECR) by the Pierre Auger Observatory. The…
A survey of Galactic gamma-ray sources at a median energy of ~20 TeV has been performed using the Milagro Gamma Ray Observatory. Eight candidate sources of TeV emission are detected with pre-trials significance $>4.5\sigma$ in the region of…
The Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope provides both direct and indirect measurements of Galactic cosmic rays (CR). The LAT high-statistics observations of the 7 GeV - 1 TeV electron plus positron spectrum and…
We review the basic ideas on the origin of cosmic rays with energy in excess of $\sim 10^{19}$ eV, in the light of the most recent observational findings. The limited statistics of events detected by the two largest experiments currently…
We introduce a static toy model of the cosmic ray (CR) universe in which cosmic ray propagation is taken to be diffusive and cosmic ray sources are distributed randomly with a density the same as that of local L* galaxies, $5 \times…
In 2008 the blazar Markarian 421 entered a very active phase and was one of the brightest sources in the sky at TeV energies, showing frequent flaring episodes. Using the data of ARGO-YBJ, a full coverage air shower detector located at…
We study the propagation of ultra-high-energy cosmic rays (UHECR) in the Galaxy, concentrating on the energy range below the ankle in the spectrum at 4 EeV. A Monte-Carlo method, based on analytical solutions to the time-dependent diffusion…
The Tibet experiment, operating at Yangbajing (4,300 m above sea level), is the lowest energy air shower array and the new high density array constructed in 1996 has sensitivity to $\gamma$-ray air showers at energies as low as 3 TeV. With…
In this paper some recent results from the Pierre Auger Collaboration are presented. These are the measurement of the energy spectrum of cosmic rays over a wide range of energies ($10^{17.5}$ to above $10^{20}$ eV), studies of the…
It has recently been shown that the highest energy cosmic rays (CRs) may originate in the same cosmological objects producing $\gamma$-ray bursts. This model requires the presence of intergalactic magnetic fields (IGMF) to delay the arrival…
In this review we discuss the important progress made in recent years towards understanding the experimental data on cosmic rays with energies $\agt 10^{19}$ eV. We begin with a brief survey of the available data, including a description of…
Recent measurements of cosmic ray electrons and positrons by PAMELA, ATIC, Fermi and HESS have revealed interesting excesses and features in the GeV-TeV range. Many possible explanations have been suggested, invoking one or more nearby…
Cosmic-ray (CR) sources temporarily enhance the relativistic particle density in their vicinity over the background distribution accumulated from the Galaxy-wide past injection activity and propagation. If individual sources are close…
The Tibet AS$\gamma$ and LHAASO collaborations recently reported the observation of a $\gamma$-ray diffuse emission with energy up to the PeV from the Galactic plane. We discuss the relevance of non-uniform cosmic-ray transport scenarios…
The origin of Galactic cosmic rays (GCRs) remains a mystery after more than one century of their discovery. The diffusive propagation of charged particles in the turbulent Galactic magnetic field makes us unable to trace back to their…
This paper summarizes the status and the recent measurements from the Pierre Auger Observatory. The energy spectrum is described and its features discussed. We report searches for anisotropy of cosmic ray arrival directions on large scales…
Simulations of the cosmic-ray (CR) anisotropy down to TeV energies are presented, using turbulence parameters consistent with those inferred from observations of the interstellar medium. We compute the angular power spectra $C_{\ell}$ of…
The High-Altitude Water Cherenkov (HAWC) Observatory, located 4100 m above sea level near Sierra Negra (19$^\circ$ N) in Mexico, is sensitive to gamma rays and cosmic rays at TeV energies. The arrival direction distribution of cosmic rays…
The Energetic Gamma-Ray Experiment Telescope (EGRET) experiment onboard the Compton Gamma-Ray Observatory (CGRO) has provided the most precise measurements of the gamma-ray sky to date. The EGRET measurements of the diffuse emission across…