Galactic cosmic rays above 10<sup>18</sup>eV

Wdowczyk, J.; Wolfendale, A. W.

doi:10.1088/0305-4616/10/10/015

Cited by 77 publications

(29 citation statements)

References 5 publications

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“…To examine correlations with the galactic plane, Wdowczyk and Wolfendale (1984) introduced a galactic plane enhancement parameter f E and claimed a positive value from data available at that time. The f E value is expressed as…”

Section: Comparison With the Spectrum In The Lower-energy Regionmentioning

confidence: 99%

Observations and implications of the ultrahigh-energy cosmic rays

2000

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The authors define ''ultrahigh-energy cosmic rays'' (UHECRs) as those cosmic rays with energies above 10 18 eV. It had been anticipated that there would be a cutoff in the energy spectrum of primary cosmic rays around 6ϫ10 19 eV induced by the interaction of the particles with the 2.7-K primordial photons. However, recent experimental data have established that particles exist with energies greatly exceeding this. It follows that the sources of such particles are probably nearby, on a cosmological scale. However, although the trajectories of such energetic particles through the galactic and intergalactic magnetic fields may be nearly rectilinear, no astronomical sources have as yet been identified. This is the enigma of the highest-energy cosmic rays. The paper reviews the history of research in this energy regime and critically assesses the observational results on the energy spectrum, arrival directions, and composition of the primary cosmic rays based on observations made by six experiments. The detection methods currently available are described. Special techniques have been developed as particles of 10 20 eV or higher occur at a rate of only about 1 per km 2 per century. Errors in measurement are given particular attention. The authors also review the theoretical predictions for a number of candidate sources of cosmic rays beyond the predicted cutoff. Finally, the four major projects planned to address the question of the origin of UHECRs are briefly described. CONTENTS

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Section: Comparison With the Spectrum In The Lower-energy Regionmentioning

confidence: 99%

Observations and implications of the ultrahigh-energy cosmic rays

2000

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“…Hadrons which escaped from the SNR can be partially captured by molecular clouds and also produce γ‐rays. In the calculations of the γ‐ray spectra for hadrons we apply the scaling break model for hadronic interactions (Wdowczyk & Wolfendale 1987) suitable for the considered energy range of hadrons.…”

Section: A Model For γ‐Ray Productionmentioning

confidence: 99%

γ-ray emission from PWNe interacting with molecular clouds

Bartko

Bednarek

2008

Monthly Notices RAS

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We consider a situation in which a pulsar is formed inside or close to a high‐density region of a molecular cloud. Right after birth, the pulsar was very active and accelerated hadrons and leptons to very high energies. Hadrons diffuse through the supernova remnant and some of them are trapped in the nearby cloud interacting with the matter. We extend a recent time‐dependent model for the γ radiation of pulsar wind nebulae (PWNe) to describe this more complicated astrophysical scenario. The typical calculations have been performed for two objects, IC 443 and W41, which have recently been discovered as sources of TeV γ‐rays. In this model the low‐energy TeV emission should be correlated with the birth place of the pulsar and the region of dense soft radiation rather than with its present position, provided that the injection rate of relativistic particles into the PWN has been much more efficient at early times. The high‐energy TeV emission should be correlated with the location of dense clouds which were able to capture high‐energy hadrons due to their strong magnetic fields.

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“…Combining anisotropy searches in α over a range of declinations could dilute the results, since significant but out of phase Rayleigh vectors from different declination bands can cancel each other out. Moreover, the analysis methods that consider distributions in one celestial coordinate, while integrating away the second, have proved to be potentially misleading [71]. An unambiguous interpretation of anisotropy data requires two ingredients: exposure to the full celestial sphere and analysis in terms of both celestial coordinates.…”

Section: Distribution Of Arrival Directionsmentioning

confidence: 99%

Astrophysical origins of ultrahigh energy cosmic rays

2004

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In the first part of this review we discuss the basic observational features at the end of the cosmic ray energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these particles. We then briefly discuss the status of the chemical composition and the distribution of arrival directions of cosmic rays. After that, we examine the energy losses during propagation, introducing the Greisen-Zaptsepin-Kuzmin (GZK) cutoff, and discuss the level of confidence with which each experiment have detected particles beyond the GZK energy limit. In the second part of the review, we discuss astrophysical environments able to accelerate particles up to such high energies, including active galactic nuclei, large scale galactic wind termination shocks, relativistic jets and hot-spots of Fanaroff-Riley radiogalaxies, pulsars, magnetars, quasar remnants, starbursts, colliding galaxies, and gamma ray burst fireballs. In the third part of the review we provide a brief summary of scenarios which try to explain the super-GZK events with the help of new physics beyond the standard model. In the last section, we give an overview on neutrino telescopes and existing limits on the energy spectrum and discuss some of the prospects for a new (multi-particle) astronomy. Finally, we outline how extraterrestrial neutrino fluxes can be used to probe new physics beyond the electroweak scale. Solicited Review Article Prepared for Reports on Progress in Physics 1 PREFACEReviewing cosmic ray physics is a risky business. Theoretical models continue to appear at an amazing rate, both in the astrophysical and more exotic domains. We warn the reader: we do not (nor we could) intend to make an homogeneous coverage of all the ideas of our fellow colleagues. Reading differently focused reviews on the issue (quoted here along the way) is, in our view, the best approach to such a wide topic of research.2 Contents

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Galactic cosmic rays above 10¹⁸eV

Cited by 77 publications

References 5 publications

Observations and implications of the ultrahigh-energy cosmic rays

Observations and implications of the ultrahigh-energy cosmic rays

γ-ray emission from PWNe interacting with molecular clouds

Astrophysical origins of ultrahigh energy cosmic rays

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Galactic cosmic rays above 1018eV

Cited by 77 publications

References 5 publications

Observations and implications of the ultrahigh-energy cosmic rays

Observations and implications of the ultrahigh-energy cosmic rays

γ-ray emission from PWNe interacting with molecular clouds

Astrophysical origins of ultrahigh energy cosmic rays

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Product

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Galactic cosmic rays above 10¹⁸eV