Related papers: Cosmic Ray Backgrounds in an LBNE far detector on …
The physics results of high energy gamma-ray astronomy are reported, emphasizing recent achievements with ground-based detectors. This includes some of the instrumental developments and latest projects. The fundamental contribution of the…
The origin of cosmic rays is one of the major unresolved astrophysical questions. In particular, the highest energy cosmic rays observed possess macroscopic energies and their origin is likely to be associated with the most energetic…
The riddle of the origin of Cosmic Rays is open since one century. Recently we got the experimental proof of hadronic acceleration in Supernovae Remnants, however new questions rised and no final answer has been provided so far. Gamma ray…
This is a summary of a series of lectures on the current experimental and theoretical status of our understanding of origin and nature of cosmic radiation. Specific focus is put on ultra-high energy cosmic radiation above ~10^17 eV,…
I give a brief review of the observational properties of low-luminosity AGNs (LLAGNs). I outline some unresolved issues in the study of LLAGNs, emphasizing the uncertainties in the role of the truncated thin accretion disk, the dusty…
Dark Matter (DM) may be comprised of axion-like particles (ALPs) with couplings to photons and the standard model fermions. In this paper we study photon signals arising from cosmic ray (CR) electron scattering on background ALPs. For a…
The origin of cosmic rays with energies higher than 10$^{20}$ eV remains a mystery. Accelerating particles up to these energies is a challenge even for the most energetic astrophysical objects known. While the isotropy in arrival directions…
The properties of the cosmic microwave background radiation provide unique constraints on cosmological models, i.e. on the content, history, and evolution of the Universe. I discuss the latest measurements of the spectral and spatial…
We study gravitational lensing of the cosmic neutrino background. This signal is undetectable for the foreseeable future, but there is a rich trove of information available. At least some of the neutrinos from the early universe will be…
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…
Cosmic rays are energetic charged particles from extraterrestrial sources, with the highest energy events thought to come from extragalactic sources. Their arrival is infrequent, so detection requires instruments with large collecting…
After a century of observations, we still do not know the origin of cosmic rays. I will review the current state of cosmic ray observations at the highest energies, and their implications for proposed acceleration models and secondary…
Observation of Ultra High Energy Cosmic Rays (UHECR) -whose energy exceeds $10^20$eV- is still a puzzle for modern astrophysics. The transfer of more than 16 Joules to a microscopic particle can hardly be achieved, even in the most powerful…
The origin of high-energy cosmic rays, atomic nuclei that continuously impact Earth's atmosphere, has been a mystery for over a century. Due to deflection in interstellar magnetic fields, cosmic rays from the Milky Way arrive at Earth from…
Recent PAMELA and ATIC data seem to indicate an excess in positron cosmic rays above approximately 10 GeV which might be due to galactic Dark Matter particle annihilation. However the background of this signal suffers many uncertainties…
A critical review of the standard paradigm for the origin of Galactic cosmic rays is presented. Recent measurements of local and far-away cosmic rays reveal unexpected behaviours, which challenge the commonly accepted scenario. These recent…
Assuming that cosmic rays entering the Earth's atmosphere contain a small admixture of nuggets of strange quark matter in form of strangelets one can explain a number of apparently "strange" effects observed in different cosmic rays…
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 show that the flux of the high-energy cosmic ray positrons observed near Earth is that expected from the decay of mesons produced by the primary cosmic rays (CRs) in the local interstellar medium.
Although cosmic rays were discovered 90 years ago, we do not know how and where they are accelerated. There is compelling evidence that the highest energy cosmic rays are extra-galactic -- they cannot be contained by our galaxy's magnetic…