Extensive air shower

Studies of the composition of the highest energy cosmic rays with the Pierre Auger Observatory, including examination of hadronic physics effects on the structure of extensive air showers. Submissions to the 31st ICRC, Lodz, Poland (July 2009).

The simultaneous observation of the electromagnetic and TeV muon components of extensive air showers by the EAS-TOP and MACRO detectors, respectively, is described for a period of 100 days in 1990. The two detectors and their combined resolutions are briefly reviewed and muon multiplicity distributions for various detector configurations are presented. A first analysis of the physical parameters Nmu and

Frequency distributions of local muon densities in high-energy extensive air showers (EAS) are presented as signature of the primary cosmic ray energy spectrum in the knee region. Together with the gross shower variables like shower core position, angle of incidence, and the ...

The normalization constant of the lateral distribution function (LDF) of an extensive air shower is a monotonous (almost linear) increasing function of the energy of the primary. Therefore, the interpolated signal at some fixed distance from the core can be calibrated to estimate the energy of the shower. There is, somehow surprisingly, a reconstructed optimal distance, r_{opt}, at which the effects on the inferred signal, S(r_{opt}), of the uncertainties on true core location, LDF functional form and shower-to-shower fluctuations are minimized. We calculate the value of r_{opt} as a function of surface detector separation, energy and zenith angle and we demonstrate the advantage of using the r_{opt} value of each individual shower instead of a same fixed distance for every shower, specially in dealing with events with saturated stations. The effects on the determined spectrum are also shown.

The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection ...

The energy spectrum of cosmic rays above 2: 5 1018 eV, derived from 20 000 events recorded at the Pierre Auger Observatory, is described. The spectral index of the particle flux, J/Eÿ, at energies between 4 1018 eV and 4 1019 eV is 2: 69 0: 02 stat 0: 06 syst, steepening to 4: 2 0: 4 stat 0: 06 syst at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

The cosmic ray interaction event generator Sibyll is widely used in extensive air shower simulations for cosmic ray and neutrino experiments. Charmed particle production has been added to the Monte Carlo with a phenomenological, non-perturbative model that properly accounts for charm production in the forward direction. As prompt decays of charm can become a significant background for neutrino detection, proper simulation of charmed particles is very important. We compare charmed meson and baryon production to accelerator data.

Energy is among the characteristics of Ultra High Energy Cosmic Rays (E > 5 ×1019 eV ) which could be estimated experimentally based on simulations. This paper attempts to estimate the energy of an UHECR proton by applying a Monte Carlo simulation code. A number of extensive air showers, vertical and inclined, are simulated to derive the lateral distribution functions of the shower particles. The scenario of simulations is adapted to the P. Auger Observatory site.

Abstract: We will present the multi-wavelength modeling of the supernova remnant Cassiopeia A’s shell based on radio, X-rays, and GeV-TeV gamma rays. Our aim is to estimate the location of TeV gamma rays with the help of spectral analysis of X-rays from different regions of the shell, because Chandra X-ray observations have a far better angular resolution than the gamma-ray measurements. Our analysis shows X-ray flux levels from various regions of the remnant to be different. We find that leptonic model is unable to explain the GeV and TeV data, simultaneously. So, we invoke a hadronic model as an additional component to explain the GeV and TeV data.

A recently published article in Science 1 by the Pierre Auger Laboratory, has helped pinpoint the source of ultrahigh energy cosmic rays, which are the most energetic particles known in the universe. The sources found indicate support for the “active galactic nuclei” theory, which is that the ultra-high energy (UHE) cosmic rays come from super massive black holes found at the centers of galaxies. The Pierre Auger Observatory 2 records the extensive air showers through an array of 1,600 particle detectors placed 1.5 km apart in a grid spread across 3000 square kilometers. In light of this latest development the author wishes to discuss extensive air showers.

We have studied Extensive Air Showers (EAS) with two small arraysof 1 m2 scintillation detectors inTehran, 1200 m above sea level.The distribution of air showersin zenith and azimuth angles has been studied and a cosnTdistribution with n = 7.2±0.2 was obtained for zenith angledistribution. An asymmetry has been observed in the azimuthaldistribution of EAS of cosmic rays because of magnetic

The air fluorescence detector of the Pierre Auger Observatory is designed to perform calorimetric measurements of extensive air showers created by cosmic rays of above 1018eV. To correct these measurements for the effects introduced by atmospheric fluctuations, the Observatory contains a group of monitoring instruments to record atmospheric conditions across the detector site, an area exceeding 3000km2. The atmospheric data are used extensively in the reconstruction of air showers, and are ...