[1] The indirect radiative forcing of atmospheric aerosols is sensitive to particle size and concentration, which are influenced significantly by nucleation processes. Via its role in aerosol formation, cosmic ray may affect the cloud condensation nuclei abundance and hence the global cloud properties and climate. Systematic variations in ionization rates due to the modulation of cosmic ray rad...

The Perseus galaxy cluster was observed by the MAGIC Cherenkov telescope for a total effective time of 24.4 hours during November and December 2008. No significant γ-ray excess was detected. The resulting upper limits on the γ-ray emission above 100 GeV are 4.63 and 6.55 × 10−12cm−2 s−1 for spectral indices of −1.5 and −2.2, respectively. The obtained limits constrain the emission produced by c...

The Monte Carlo program FLUKA was used to calculate the number of muons reaching detection level in events initiated by primary cosmic gamma ray interactions in the atmosphere. The calculation was motivated by the desire to gauge the sensitivity of arrays like that of Project GRAND to primary gamma cosmic rays while measuring single muons at detection level. Because direct gamma pair production...

We review the evidence for cosmic ray acceleration in the superbubble/hot phase of the interstellar medium, and discuss the implications for the composition of cosmic rays and the structure and evolution of the interstellar medium (ISM). We show that the bulk of the galactic supernovae, their expanding remnants, together with their metal-rich grain and gas ejecta, and their cosmic ray accelerat...

A fixed-point measurement of cosmic-ray intensity has being continued at Chiba, near Tokyo in Japan to obtain the time-sequential data. High efficiency neutron rem counter and Multi-sphere neutron Spectrometer (Bonner Sphere: BS) were used for the measurement of cosmic-ray neutron components and for the evaluation of the cosmic-ray ionizing components, NaI(Tl) scintillation spectrometer was emp...

The total cosmic-ray luminosity of the Galaxy is an important constraint on models of cosmic-ray generation. The diffuse high energy γ-ray and radio-synchrotron emissions of the Milky Way are used to derive this luminosity. The result is almost two orders of magnitude larger than the standard estimate, based on the observed isotopic abundances of cosmic ray nuclides. We discuss the plausible in...

We show that recent γ-ray observations of the Small Magellanic Cloud with EGRET rule out a universal cosmic ray flux only at energies below ≈ 10 GeV, while the observed diffuse X-ray and γ-ray background radiations have already ruled out, by more than three orders of magnitude, a universal extragalactic cosmic ray flux identical to that observed in the local solar neighborhood at energies below...

The isotropic component of the γ-ray flux between 100MeV and 100EeV (10 eV) contains important information about the origin of highest energy cosmic rays and the extragalactic magnetic field (EGMF). Using numerical simulations of extragalactic cosmic and γ-ray propagation we show that an average fraction of ≃ 10% γ-rays in the total cosmic ray flux around 10EeV would imply both a non-accelerati...

Evidence for the possible existence of a strong flux of low-energy (< 10 MeV) cosmic ray electrons in the Galaxy has been recently established by GINGA, OSSE and COMPTEL observations of the diffuse galactic gamma ray continuum emission down to photon energies below 50 keV. We explain the implied presence of many low-energy cosmic ray electrons with the existence of interstellar in-situ reaccele...

Cosmic ray causes hazards to microelectronic circuits. Presence of charged particles in the atmosphere was first noticed by Coloumb in 1785. But cosmic ray was discovered by Victor Hess in 1912. However new era of particle physics was started with the invention of neutron monitor in 1948 by John A. Simpson. New information regarding the energy spectrum, anisotropy, latitudinal, longitudinal and...