While a significant fraction of silicate dust in stellar winds has a crystalline structure, in the interstellar medium nearly all of it is amorphous. One possible explanation for this observation is the amorphization of crystalline silicates by relatively ‘‘low’’ energy, heavy-ion cosmic rays. Here we present the results of multiple laboratory experiments showing that single-crystal synthetic f...

The apparent lack of suitable astrophysical sources for the observed highest energy cosmic rays within approximately 20 Mpc is the "Greisen-Zatsepin-Kuzmin (GZK) paradox." We constrain representative models of the extragalactic magnetic field structure by Faraday rotation measurements; limits are at the microG level rather than the nG level usually assumed. In such fields, even the highest ener...

Contribution of nearby pulsars to the cosmic rays observed at Earth has been studied. It is found that the experimental bound on amplitude of cosmic ray anisotropy may produce significant constraint on the efficiency of converting pulsar rotational energy to emitted particles kinetic energy. Cosmic ray fluxes from two well known nearby gamma ray pulsars, namely the Vela and Geminga pulsars, are...

Cosmic ray astronomy attempts to identify and study the sources of ultrahigh energy cosmic rays. It is unique in its reliance on charged particles as the information carriers. While no discrete source of ultrahigh energy cosmic rays has been identified so far, a new generation of detectors is acquiring the huge exposure that is needed at the highest energies, where deflection by magnetic fields...

We present a convolution-based algorithm for finding cosmic rays in single well-sampled astronomical images. The spatial filter used is the point spread function (approximated by a Gaussian) minus a scaled delta function, and cosmic rays are identified by thresholding the filtered image. This filter searches for features with significant power at spatial frequencies too high for legitimate obje...

The H(3)(+) molecular ion has been used by Oka and collaborators to trace the rate of ionization by cosmic rays in the interstellar medium. More energetic cosmic rays also produce diffuse γ-radiation. Now that several supernova remnants (SNRs) have been identified as γ-ray sources, it is possible to use spectroscopy of molecular ions to search for enhanced ionization rates that would pinpoint t...

High energy γ-rays from individual giant molecular clouds contain unique information about the hidden sites of acceleration of galactic cosmic rays, and provide a feasible method for study of propagation of cosmic rays in the Galactic Disk on scales ≤ 100 pc. I discuss the spectral features of π-decay γ-radiation from clouds/targets located in proximity of relatively young proton accelerators, ...

Statistical arguments show that the volumeand time-averaged kinetic power of GRBs and fireball transients (FTs) into an L galaxy like the Milky Way is at the level of 10 ergs s. This number, though with wide uncertainties related to the internal or external shock efficiency, is sufficient to power hadronic cosmic rays observed locally. The release of energy by the high-mass progenitor stars of ...

The Parker instability, which has been considered as a process governing the structure of the interstellar medium, is induced by the buoyancy of magnetic field and cosmic rays. In previous studies, while the magnetic field has been fully incorporated in the context of isothermal magnetohydrodynamics, cosmic rays have been normally treated with the simplifying assumption of infinite diffusion al...

This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz’min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is...