Related papers: Cosmic Rays: The Second Knee and Beyond
We show that the simplest assumptions for the dynamics of particle production allow us to understand the fluxes of hadrons and photons at mountain altitudes as well as the structure of individual events. The analysis requires a heavy…
Cosmic ray (CR) knees (spectral steepenings) encode information on CR accelerator populations. We seek population features that imprint onto knee observables in a manner that is robust enough to be discernible even in the presence of…
We have published the energy spectrum of ultra-high energy cosmic rays (UHECRs) for E > 10^18.2 eV from our first 5-year observation with the surface detectors of Telescope Array. We found two breaking points in the power-law spectrum, a…
We review open questions and prospects for progress in ultrahigh-energy cosmic ray (UHECR) research, based on a series of discussions that took place during the `The High-Energy Universe: Gamma-Ray, Neutrino, and Cosmic-ray Astronomy' MIAPP…
Recent accurate measurements of cosmic-ray (CR) protons and nuclei by ATIC-2, CREAM, and PAMELA reveal: a) unexpected spectral hardening in the spectra of CR species above a few hundred GeV per nucleon, b) a harder spectrum of He compared…
We perform a fit to measurements of the cosmic ray spectrum and of the depth of shower maximum in the energy range between $10^{15}$~eV and $10^{18}$~eV. We consider a Galactic component that is a mixture of five representative nuclear…
The baryonic mass composition of ultrahigh energy ($\gtrsim 10^{18}$ eV) cosmic rays (UHECRs) at injection accompanied by their interactions on universal photon backgrounds during propagation directly governs the UHECR flux on the Earth.…
Ultra high energy cosmic rays (UHECR) pose a problem either for particle physics or for astrophysics (or for both) by the unexpectedly high number of cosmic ray showers observed with energy above about 5x10^{19}eV, the…
We investigate the implications of the current data regarding large scale anisotropies, and examine to what extent they can be used to constrain the origin of UHECRs and the astrophysical parameters of the source scenarios. We discuss the…
Analysis of cosmic ray surface data collected with the IceTop array of Cherenkov detectors at the South Pole provides an accurate measurement of the cosmic ray spectrum and its features in the "knee" region up to energies of about 1 EeV.…
The arrival directions of ultrahigh energy cosmic rays (UHECRs) may show anisotropies on all scales, from just above the experimental angular resolution up to medium scales and dipole anisotropies. We find that a global comparison of the…
We have developed a model that explains cosmic rays with energies E between \~0.3 PeV and the energy of the second knee at E_2 ~ 3*10^{17} eV as originating from a recent Galactic gamma-ray burst (GRB) that occurred ~1 Myr ago within 1 kpc…
Combined recent data from cosmic-ray detectors and gamma-ray detectors have produced some surprising insights regarding the sources of ultrahigh-energy cosmic rays (UHECRs), magnetic fields inside and outside the Milky Way, and the…
Several kinds of measurements are combined in an attempt to obtain a consistent estimate of the spectrum and composition of the primary cosmic radiation through the knee region. Assuming that the knee is a signal of the high-energy end of a…
We briefly summarize our study on anisotropy of Ultra-High Energy Cosmic-Rays (UHECRs), in which we define a statistics that measures the correlation between UHECRs and Large Scale Structure (LSS). We also comment here on recently published…
The lack of a high energy cutoff in the cosmic ray spectrum together with an apparently isotropic distribution of arrival directions for the highest energy events have strongly constrained most models proposed for the generation of these…
The knee of cosmic ray spectra reflects the maximum energy accelerated by galactic cosmic ray sources or the limit to the ability of galaxy to bind cosmic rays. The measuring of individual energy spectra is a crucial tool to ascertain the…
I further test the theory that the Cosmic Background Radiation (CBR) is made of photons with a weak U(1) component. Tipler (2005) has previously argued that the consistency of the Standard Model (SM) with the Second Law of Thermodynamics…
The paper investigates the overall and detailed features of cosmic ray (CR) spectra in the knee region using the scenario of nuclei-photon interactions around the acceleration sources. Young supernova remnants can be the physical realities…
The Ultra High Energy Cosmic Ray (UHECR), by UHE neutrino-relic neutrino--Z showering in Hot Dark Halos (HDM), shows an energy spectra, an anisotropy following the relic neutrino masses and clustering in dark halo. The lighter are the relic…