Ultra-High Energy Cosmic Rays: Papers 1996-99

Item Title Authors Source Publ. Yr. Abstract Preprint#/Link
1 A model of the primary cosmic ray spectra Adams-JH-Jr; Lee-J Radiation-Measurements. vol.26, no.3; May 1996; p.467-70 1996 The authors have collected published experimental measurements of the Galactic cosmic ray spectra of the primary elements, H, He, C, O, Ne, Mg, Si and Fe in the energy range from 45 MeV/nucleon to 1 TeV/nucleon in the years 1963-1987. They have fit these data with a solution to the spherically symmetric diffusion equation using boundary spectra which are a solution of the cosmic ray propagation equation in the leaky-box model. In the present work, they show how the energy spectra of these elements at 1 AU are represented by this model.  
2 A NEW EXPERIMENTAL SETUP TO STUDY UHE COSMIC RAY BASED ON MEASUREMENT OF ARRIVAL TIME SPREAD OF SECONDARY PARTICLES FROM EAS T. Bezboruah, K. Boruah, P.K. Boruah (Gauhati U.) Nucl. Instrum. Meth. A410, 206-212 (1998) 1998   ??
3 A new technique for the observation of EeV and ZeV cosmic rays Kieda-DB Astroparticle-Physics. vol.4, no.2; Dec. 1995; p.133-50 1995 Describes a new technique for the detection of EeV (10/sup 18/ eV) and ZeV (10/sup 21/ eV) cosmic rays in the atmosphere. The technique uses the fact that the Cerenkov light emitted by atmospheric extensive showers generated by primaries in this energy range is brighter than the fluctuations in the ambient light of the night sky, even with a full Moon present. The Cerenkov light is also brighter than fluctuations in the twilight sky, and can even be of similar size as fluctuations in direct sunlight. For the highest energy cosmic rays (E>1 ZeV), this may allow optical detection with on-time efficiency limited only by the weather. The energy, angular, and X/sub max/ resolution of the technique is examined as a function of the background day and night sky conditions. Using a "shadowing" method for determining the direction of the original cosmic ray primary, angular resolution between 0.3 degrees to approximately=3 degrees is possible, depending upon the zenith angle and energy of the primary, and the amou  
4 About the most energetic cosmic rays Cocconi-G Astroparticle-Physics. vol.4, no.3; Feb. 1996; p.281-3 1996 Consequences of the observed anisotropy of energetic cosmic rays are discussed. The author considers arrival directions, energies, origins, high energy proton propagation.  
5 Acceleration and Interaction of Ultra High Energy Cosmic Rays R.J. Protheroe Chapter in "Topics in cosmic-ray astrophysics" 1998   astro-ph/9812055
6 Acceleration of UHE Cosmic Ray Particles at Relativistic Jets in Extragalactic Radio Sources M. Ostrowski (Jagellonian U.) Submitted to Astron.Astrophys 1998   astro-ph/9803299
7 Angle-Time-Energy Images of Ultra-High Energy Cosmic Ray Sources Guenter Sigl (Univ. of Chicago) To appear in Proceedings of the Workshop on "Observing Giant Cosmic Ray Air Showers for > 10**(20) eV Particles from Space", Univ. of Maryland, Nov 13-15, 1997. 1997   astro-ph/9712144
8 Anisotropy of Ultra High Energy Cosmic Rays in the Dark Matter Halo Model V.Berezinsky, A.Mikhailov Phys.Lett. B449 (1999) 237-239 1998   astro-ph/9810277
9 Arrival directions of the most energetic cosmic rays Stanev-T; Biermann-PL; Lloyd-Evans-J; Rachen-JP; Watson-AA Physical-Review-Letters. vol.75, no.17; 23 Oct. 1995; p.3056-9 1995 Examines the arrival directions of the most energetic cosmic rays (E>2*10/sup 19/ eV) detected by several air shower experiments. The authors find that data taken by different air shower arrays show positive correlations, indicating a nonuniform arrival direction distribution. The authors also find that the events with energy >4*10/sup 19/ eV exhibit a correlation with the general direction of the supergalactic plane, where a large number of potential sources are located. If confirmed by data from other experiments the results would support models for the extragalactic origin of the highest energy cosmic rays.  
10 Arrival directions of the southern highest energy cosmic rays Kewley-LJ; Clay-RW; Dawson-BR Astroparticle-Physics. vol.5, no.1; June 1996; p.69-74 1996 The authors have examined the arrival directions of the highest energy cosmic rays recorded by the southern hemisphere SUGAR air shower array to determine whether there exists in the south a preference for directions along the supergalactic plane as suggested by northern data. The authors have not found such an effect.  
11 Can Ultra High Energy Cosmic Rays be Evidence for New Particle Physics? Glennys R. Farrar Invited talk at the Workshop on "Observing the Highest Energy Particles (> 10^{20} eV) from Space", College Park, MD, Nov. 13-15 1997 1998   astro-ph/9801020
12 Correlation between Compact Radio Quasars and Ultra-High Energy Cosmic Rays Glennys R. Farrar (Rutgers Univ.), Peter L. Biermann (Max Planck Institute for Radio Astronomy, Bonn) Phys.Rev.Lett. 81 (1998) 3579-3582 1998   astro-ph/9806242
13 Cosmic ray astrophysics (history and general review) Ginzburg-VI Physics-Uspekhi. vol.39, no.2; Feb. 1996; p.155-68. Translated from: Uspekhi-Fizicheskii-Nauk. vol.166, no.2; Feb. 1996; p.169-83 1996 The history of the discovery and investigation of cosmic rays prior to the advent of the cosmic ray astrophysics is presented. Some data about cosmic rays near the Earth and in the Universe are given. The main part of cosmic rays observed near the Earth is generated in our Galaxy by supernova explosions. The most important problem yet to be solved in cosmic ray astrophysics is the origin of cosmic rays of superhigh energy.  
14 Cosmic rays from primordial black holes and constraints on the early universe Carr-BJ; MacGibbon-JH Physics-Reports. vol.307, no.1-4; Dec. 1998; p.141-54 1998 The constraints on the number of evaporating primordial black holes imposed by observations of the cosmological gamma-ray background do not exclude their making a significant contribution to the Galactic flux of cosmic ray photons, electrons, positrons and antiprotons. Even if this contribution is small, cosmic ray data place important limits on the number of evaporating black holes and thereby on models of the early Universe. Evaporating black holes are unlikely to be detectable in their final explosive phase unless new physics is invoked at the QCD phase transition.  
15 Cosmic rays: the most energetic particles in the universe Cronin-JW Reviews-of-Modern-Physics. vol.71, no.2; Feb. 1999; p.S165-72 1999 Cosmic rays are an ever present aspect of nature. The birth of the field of elementary-particle physics can be traced to studies of cosmic rays. Now advances in technology and new instrumentation are changing the nature of cosmic-ray research. New forms of astronomy are being created. Ground-based instruments, spawned by cosmic-ray techniques, permit the observation of astrophysical objects emitting radiation in very-high-energy gamma rays, (>or=100 GeV), high-energy neutrinos (>or=1 TeV), and the most energetic particles found in the cosmic radiation (>or=5*10/sup 19/ eV). At these energies the galactic and intergalactic magnetic fields deflect the cosmic-ray protons by only a few degrees. The interaction of these cosmic rays with the cosmic background radiation limits the possible sources to redshifts far less than unity. The origin of these highest-energy cosmic rays is not understood. The present status of knowledge of these cosmic rays and the prospects for solving the mystery concerning their origin are  
16 Cosmic Strings - Dead Again? Mark Hindmarsh (Sussex) talk given at Cosmo 97, Ambleside, England, Sept 97 1998   hep-ph/9806469
17 Cosmological origin for cosmic rays above 10/sup 19/ eV Waxman-E Astrophysical-Journal,-Letters. vol.452, no.1, pt.2; 10 Oct. 1995; p.L1-4 1995 The cosmic-ray spectrum at 10/sup 19/-10/sup 20/ eV, reported by the Fly's Eye and the AGASA experiments, is shown to be consistent with a cosmological distribution of sources of protons, with a power-law generation spectrum dlnN/dlnE=-2.3+or-0.5 and energy production rate of 4.5+or-1.5*10/sup 44/ ergs Mpc/sup -3/ yr/sup -1/. The two events measured above 10/sup 20/ eV are not inconsistent with this model. Verifying the existence of a "blackbody cutoff", observed with low significance, would require approximately 30 observation years with existing experiments, but only approximately 1 year with the proposed approximately 5000 km/sup 2/ detectors. For a cosmological source distribution, no anisotropy is expected in the angular distribution of events with energies up to approximately 5*10/sup 19/ eV.  
18 Cryptons: a stringy form of decaying superheavy dark matter, as a source of the ultra high energy cosmic rays D.V. Nanopoulos Talk given at the R. Arnowitt Fest: A Symposium on Supersymmetry and Gravitation, College Station, TX 5-7 April 1998. 1998   hep-ph/9809546
19 Dark matter halos and the anisotropy of ultra-high energy cosmic rays Gustavo Medina Tanco (Inst.Astron.e Geof.-USP-Brasil), Alan A. Watson (Univ.of Leeds-UK) Astroparticle Physics (accepted for publication) 1999   astro-ph/9903182
20 Deflection of ultra high energy cosmic rays by the galactic magnetic field: from the sources to the detector Gustavo A. Medina Tanco (IAG/RGO), Elisabete M. de Gouveia Dal Pino (IAG), Jorge E. Horvath (IAG) ?? 1997   astro-ph/9707041
21 Differences between gamma-ray and hadronic showers Hillas-AM Space-Science-Reviews. vol.75, no.1-2; Jan. 1996; p.17-30 1996 Cosmic gamma-ray sources may be sought if high-energy gamma-rays may be detected without confusion from the very intense isotropic background of hadronic cosmic rays. Ground-based methods are needed at energies above tens of GeV, using air showers, and at energies below tens of TeV, the detection of muons in showers is not the most efficient way to reject hadronic showers. The shape and orientation of Cerenkov images can reject far more than 99% of the background. The way in which Cerenkov radiation is distributed in showers is discussed, and the possibilities of using image shape, distribution of light on the ground, time profile, spectrum and polarization of the light are briefly discussed. Imaging alone appears to be the most powerful. Simulations suggest that the UV content of the light should not be a useful diagnostic.  
22 Exotic massive hadrons and ultra-high energy cosmic rays Ivone F.M.Albuquerque, Glennys R.Farrar, Edward W.Kolb Phys.Rev. D59 (1999) 015021 1998   hep-ph/9805288
23 Galactic Anisotropy as Signature of ``Top-Down'' Mechanisms of Ultra-High Energy Cosmic Rays S. L. Dubovsky, P. G. Tinyakov JETP Lett. 68 (1998) 107-111 1998   hep-ph/9802382
24 Gamma-ray bursters as sources of cosmic rays Milgrom-M; Usov-V Astroparticle-Physics. vol.4, no.4; April 1996; p.365-9 1996 From the little that is know of the physical conditions in gamma -ray bursters, it seems that they are potentially effective in the acceleration of high-energy cosmic rays (CRs), especially if the bursters are at cosmological distances. The authors find that, with the observed statistics and fluxes of gamma -ray bursts, cosmological bursters may be an important source of cosmic rays in two regions of the observed spectrum: (1) At the very-high-energy end (E>10/sup 19/ eV), where CRs must be of extragalactic origin. (2) Around and above the spectral feature that has been described as a bump and/or a knee, which occurs around 10/sup 15/ eV. The occasional bursters that occur inside the Galaxy-about once in a few hundred thousand years if burst emission is isotropic; more often, if it is beamed-could maintain the density of galactic cosmic rays at the observed level in this range. These two energy ranges might correspond to two typical CR energy scales characteristic of bursters: one pertinent to CR acceler  
25 Gamma-Ray Bursts, Ultra High Energy Cosmic Rays, and Cosmic Gamma-Ray Background Tomonori Totani Accepted by Astroparticle Physics 1998   astro-ph/9810207
26 GeV Photons from Ultra High Energy Cosmic Rays accelerated in Gamma Ray Bursts Mario Vietri Phys.Rev.Lett. 78 (1997) 4328-4331 1997   astro-ph/9705061
27 Highlights on very and ultra high energy cosmic ray physics Battistoni-G Nuclear-Physics-B,-Proceedings-Supplements. vol.48; May 1996; p.434-40 1996 A short selection out of the most interesting problems in high energy cosmic ray physics is presented, together with some recent experimental results.  
28 Limits on models of the ultrahigh energy cosmic rays based on topological defects Protheroe-RJ; Stanev-T Physical-Review-Letters. vol.77, no.18; 28 Oct. 1996; p.3708-11 1996 Using the propagation of ultrahigh energy nucleons, photons, and electrons in the universal radiation backgrounds, the authors obtain limits on the luminosity of topological defect scenarios for the origin of the highest energy cosmic rays. The limits are set as a function of the mass of the X particles emitted by the cosmic strings or other defects, the cosmological evolution of the topological defects, and the strength of the extragalactic magnetic fields. The existing data on the cosmic ray spectrum and on the isotropic 100 MeV gamma-ray background limit significantly the parameter space in which topological defects can generate the flux of the highest energy cosmic rays, and rule out models with the standard X-particle mass of 10/sup 16/ GeV and higher.  
29 Magnetic monopoles as the highest energy cosmic ray primaries Kephart-TW; Weiler-TJ Astroparticle-Physics. vol.4, no.3; Feb. 1996; p.271-9 1996 The authors suggest that the highest energy >or approximately=10/sup 20/ eV cosmic ray primaries may be relativistic magnetic monopoles. Motivations for this hypothesis are that conventional primaries are problematic, while monopoles are naturally accelerated to E~10/sup 20/ eV by Galactic magnetic fields. By matching the cosmic monopole production mechanism to the observed highest energy cosmic ray flux the authors estimate the monopole mass to be <or approximately=10/sup 10/ GeV.  
30 Magnetized local supercluster and the origin of the highest energy cosmic rays Blasi-P; Olinto-AV Physical-Review-D. vol.59, no.2; 15 Jan. 1999; p.023001/1-7 1999 A sufficiently magnetized local supercluster can explain the spectrum and angular distribution of ultrahigh energy cosmic rays. We show that the spectrum of extragalactic cosmic rays with energies below ~10/sup 20/ eV may be due to the diffusive propagation in the local supercluster with fields of ~10/sup -8/-10/sup -7/ G. Above ~10/sup 20/ eV, cosmic rays propagate in an almost rectilinear way which is evidenced by the change in shape of the spectrum at the highest energies. The fit to the spectrum requires that at least one source be located relatively nearby at ~10-15 Mpc away from the Milky Way. We discuss the origin of magnetic fields in the local supercluster and the observable predictions of this model.  
31 Maximum Likelihood Analysis of Clusters of Ultra-High Energy Cosmic Rays Guenter Sigl, Martin Lemoine, Angela V. Olinto (Univ. of Chicago) Phys.Rev. D56 (1997) 4470-4479 1997   astro-ph/9704204
32 Measuring the UHE cosmic-ray composition with tracking detectors in air shower arrays Bernlohr-K Astroparticle-Physics. vol.5, no.2; Aug. 1996; p.139-46 1996 Measuring the angles of muons and electrons in air showers is proposed as a method for studying the primary cosmic-ray mass composition near the knee of the cosmic-ray energy spectrum at a few 10/sup 15/ eV. Conventional tracking detectors at existing air shower arrays could serve this purpose, like the CRT detectors at the HEGRA array. When the average radial muon angles are examined as a function of shower core distance, the experimental resolution can be very well calibrated from the tangential angle distribution. The method is particularly promising for measuring changes in the average mass number of the primary cosmic rays with energy. The method is described and experimental and theoretical constraints are discussed. astro-ph/9605177
33 Non-Diffusive Propagation of Ultra High Energy Cosmic Rays Gustavo A. Medina Tanco, Elisabete M. de Gouveia Dal Pino, Jorge E. Horvath Astropart.Phys. 6 (1997) 337-342 1997   astro-ph/9610172
34 On the acceleration of Ultra High Energy Cosmic Rays in Gamma Ray Bursts Mario Vietri (Osservatorio Astronomico di Roma) Astrophys.J. 453 (1995) 883-889 1995   astro-ph/9506081
35 On the injection energy distribution of ultra-high-energy cosmic rays Geddes-J; Quinn-TC; Wald-RM Astrophysical-Journal. vol.459, no.1, pt.1; 1 March 1996; p.384-92 1996 Investigates the injection spectrum of ultra-high-energy (>10/sup 15/ eV) cosmic rays under the hypotheses that (1) these cosmic rays are protons and (2) the sources of these cosmic rays are extragalactic and are distributed homogeneously in space, although they may have had a different strength in the past; furthermore, the authors assume that no individual sources are unusually close. The most puzzling aspect of the observed ultra-high-energy cosmic-ray spectrum is the apparent nonexistence of a "Greisen cutoff" at about 10/sup 19.8/ eV. Such a cutoff would be expected owing to rapid energy loss from photopion production caused by interactions with the microwave background. The authors show that this fact could be explained naturally if most (or all) of the cosmic rays presently observed above about 10/sup 19.6/ eV were initially injected with energy above the Greisen cutoff. However, the authors find that the injection of cosmic rays above the Greisen cutoff cannot account for the observed flux below  
36 On the problem of determining the mass composition of cosmic rays derived from air shower measurements Erlykin-AD; Wolfendale-AW Astroparticle-Physics. vol.9, no.3; Oct. 1998; p.213-20 1998 An analysis is made of a variety of cosmic ray data from the standpoint of making a "best estimate" of the mean logarithm of the primary cosmic ray mass (<ln A>) in the energy range 10/sup 5/-10/sup 8/ GeV. Reassuringly, the values of <ln A> join on well to the results of direct measurements at lower energies. There is also some modest support for our hypothesis of there having been a local, recent supernova. A by-product is the identification from five contenders of the best model of nuclear interactions of high energy (~10/sup 6/ GeV), although much remains to be done in this area.  
37 Origin and Propagation of Ultra-High Energy Cosmic Rays Gustavo A. Medina Tanco, Elisabete M. de Gouveia Dal Pino, Jorge E. Horvatth (Instituto Astronomico e Geofisico, University of Sao Paulo - IAG-USP) Paper presented at the 1998 International Conference on Plasma Physics 1999   astro-ph/9901053
38 Possible clustering of the most energetic cosmic rays within a limited space angle observed by the Akeno Giant Air Shower Array Hayashida-N; Honda-K; Honda-M; Inoue-N; Kadota-K; Kakimoto-F; Kamata-K; Kawaguchi-S; Kawasumi-N; Matsubara-Y; Murakami-K; Nagano-M; Ohoka-LH; Sakaki-N; Souma-N; Takeda-M; Teshima-M; Tsushima-I; Uchihori-Y; Yoshida-S; Yoshii-H Physical-Review-Letters. vol.77, no.6; 5 Aug. 1996; p.1000-3 1996 Accumulated data of the Akeno Giant Air Shower Array (AGASA) indicate that arrival directions of a significant fraction of extremely high energy cosmic rays (EHECR) are uniformly distributed over the observable sky. However, three pairs of showers with angular separation of less than 2.5 degrees within the pair are observed among the 36 events above 40 EeV (4*10/sup 19/ eV), corresponding to a chance probability of 2.9% from uniform distribution. It should be noted that two pairs of them are observed to be within 2.0 degrees of the supergalactic plane.  
39 Possible sources of ultrahigh-energy cosmic protons Uryson-AV JETP-Letters. vol.64, no.2; 25 July 1996; p.77-81.Translated from: Pis'ma-v-Zhurnal-Eksperimental'noi-i-Teoreticheskoi-Fiziki. vol.64, no.2; 25 July 1996; p.71-5 1996 The arrival directions of showers with energies above 3.2*10/sup 19/ eV, recorded by the Akeno and AGASA detectors, are analyzed. Their distributions over the celestial sphere are compared with the distributions of possible sources of protons of such high energies. An analysis using three standard deviations of uncertainty in the determination of the arrival directions of the showers shows that the sources of the protons initiating the showers are nuclei of active galaxies with red shifts z<or=0.0092, i.e. their distance from us does not exceed 40 Mpc, assuming the Hubble constant is H=75 km/s.Mpc.  
40 Predictions of the Gamma-Ray Burst Model of Ultra High Energy Cosmic Rays Eli Waxman (IAS, Princeton) Invited talk, to appear in Proc. ICRR Symposium on Extremely High Energy Cosmic Rays, ed. M. Nagano, Tokyo 1996 1996   astro-ph/9612061
41 Propagation of UHE cosmic rays in a structured universe Jorg P. Rachen Contributed Paper to the 18th Texas Symposium on Rel. Astrophysics and Cosmology, Chicago 1996 1997   astro-ph/9702046
42 Propagation of Ultra High Energy Protons over Cosmological Distances and Implications for Topological Defect Models R. J. Protheroe, P. A. Johnson Astropart.Phys. 4 (1996) 253 1996   astro-ph/9506119
43 Recent results from the CASA-MIA experiment Matthews-J AIP-Conference-Proceedings. no.338; 1995; p.823-7 1995 Results from the CASA-MIA cosmic ray experiment are presented. The author discusses the apparatus and its performance, including new results on the identification of the shadows of the Sun and Moon used to determine the angular resolution. Limits on the emission of 100 TeV gamma -rays from the Crab Nebula are well below extrapolations from TeV observations. A search for diffuse gamma -rays from the Galactic plane give limits approaching some recent predictions.  
44 Reconstruction of Source and Cosmic Magnetic Field Characteristics from Clusters of Ultra-High Energy Cosmic Rays Guenter Sigl (Univ. of Chicago, USA), Martin Lemoine (Univ. of Chicago, USA/DARC, CNRS, France) Astropart.Phys. 9 (1998) 65-78 1998   astro-ph/9711060
45 Results from the Fly's Eye experiment Bird-DJ; Corbato-SC; Dai-HY; Dawson-BR; Elber-JW; Gaisser-TK; Green-KD; Huang-MA; Kieda-DB; Ko-S; Larsen-CG; Loh-EC; Luo-M; Salamon-MH; Smith-JD; Sokolsky-P; Sommers-P; Stanev-T; Tang-JKK; Thomas-SB; Tilav-S AIP-Conference-Proceedings. no.338; 1995; p.839-54 1995 We report recently analyzed results on the energy spectrum, and composition of cosmic rays above 0.3 EeV. We observe a break in the spectrum at 3 EeV and a changing composition. The results can be explained by a simple two component model: galactic cosmic rays dominated by heavy primaries and an extragalactic component dominated by light primaries. The observed isotropic arrival direction distribution is consistent with the predictions of this model. A 320 EeV event was also recorded.  
46 Signatures of the origin of high-energy cosmic rays in cosmological gamma-ray bursts Miralda-Escude-J; Waxman-E Astrophysical-Journal,-Letters. vol.462, no.2, pt.2; 10 May 1996; p.L59-62 1996 We derive observational consequences for the hypothesis that cosmic rays (CRs) of energy greater than 10/sup 19/ eV originate in the same cosmological objects producing gamma-ray bursts (GRBs). Intergalactic magnetic fields >or approximately=10/sup -12/ G are required in this model to allow CRs to be observed continuously in time by producing energy-dependent delays in the CR arrival times. This results in individual CR sources having very narrow observed spectra, since at any given time only those CRs having a fixed time delay are observed. Thus, the brightest CR sources should be different at different energies. The average number of sources contributing to the total CR flux decreases with energy much more rapidly than in a model of steady CR sources, dropping to one at E/sub crit/ approximately=2*10/sup 20/ eV with very weak sensitivity to the intergalactic magnetic field strength. Below E/sub crit/, a very large number of sources is expected, consistent with observations. Above E/sub crit/, a source may b  
47 Some prospects of future ultra-high energy cosmic ray experiments Sigl-G Nuclear-Physics-B,-Proceedings-Supplements. vol.70; Jan. 1999; p.503-5 1999 We discuss the prospects of next generation ultra-high energy cosmic ray detectors to gain information both on the sources and on large-scale magnetic fields from the distribution in arrival times, directions, and energies of charged ultra-high energy cosmic rays from discrete sources.  
48 Strongly interacting neutrinos and the highest energy cosmic rays Domokos-G; Kovesi-Domokos-S Physical-Review-Letters. vol.82, no.7; 15 Feb. 1999; p.1366-9 1999 Cosmic rays of energies larger than the Greisen-Zatsepin-Kuzmin cutoff may be neutrinos if they acquire strong interactions due to a "precocious unification" of forces. A scenario for this to happen is outlined. There is no contradiction with precision measurements carried out at LEP and SLAC. Observable consequences at LHC and future neutrino detectors are discussed.  
49 TeV Burst of Gamma-Ray Bursts and Ultra High Energy Cosmic Rays Tomonori Totani to appear in ApJ Lett. 1998   astro-ph/9810206
50 The angular deviation of ultra high energy cosmic rays in intergalactic magnetic fields Clay-RW; Cook-S; Dawson-BR; Smith-AGK; Lampard-SR Astroparticle-Physics. vol.9, no.3; Oct. 1998; p.221-5 1998 The angular deviation associated with the propagation of ultra high energy cosmic ray protons through turbulent intergalactic magnetic fields is examined including the effect of interactions with the cosmic microwave background. It is found that the deviation of the particles is consistent with diffusion ideas but the magnitude of the deviation is appreciably less than suggested by simple models for a given mean field strength and observational energy.  
51 The anisotropy of EHE cosmic rays Lee-AA; Clay-RW Journal-of-Physics-G-(Nuclear-and-Particle-Physics). vol.21, no.12; Dec. 1995; p.1743-57 1995 The effects of magnetic field turbulence on the anisotropy of galactic cosmic rays of the highest energies are investigated. It is found that, if the cosmic ray flux at energies above 1 EeV is made up predominantly of galactic protons, neither the observed galactic magnetic field turbulence nor possible halo turbulence are sufficient for both the computed anisotropy and galactic flux gradient to agree with observation. The implication is that the origin of these cosmic rays is not within our galaxy.  
52 The cosmic ray energy spectrum above 3*10/sup 18/ eV measured by the Akeno Giant Air Shower Array Yoshida-S; Hayashida-N; Honda-K; Imaizumi-S; Inoue-N; Kadota-K; Kakimoto-F; Kamata-K; Kawaguchi-S; Kawasumi-N; Matsubara-Y; Murakami-K; Nagano-M; Ohoka-H; Teshima-M; Tsushima-L; Yoshii-H; Honda-M Astroparticle-Physics. vol.3, no.2; March 1995; p.105-23 1995 Reports the first result on the cosmic ray energy spectrum above 3*10/sup 18/ eV measured by the Akeno Giant Air Shower Array (AGASA) from July 1990 to February 1994. The analysis method and the energy resolution of the AGASA experiment are described in some detail. The flattening of the spectrum around 10/sup 19/ eV (ankle) is observed with a significance of 2.9 sigma . If the authors express the differential energy spectrum of cosmic rays of energy E (in eV) with an ankle energy E/sub a/ as J(E)= kappa (E/E/sub a/)/sup - gamma / m/sup -2/ s/sup -1/ sr/sup -1/ eV/sup -1/, gamma for 10/sup 18.5/ eV<or=E<or=E/sub a/ is in good agreement with that from the previous experiment and is 3.2+or-.1. The slope gamma above E/sub a/ depends strongly on the value E/sub a/. For the case E/sub a/=10/sup 19/ eV, kappa =(/sub -0.2//sup +0.1/)*10/sup -33/ and gamma =2.3/sub -0.3//sup +0.5/ for 10/sup 19/ eV<or=E<or=10/sup 20/ eV. If E/sub a/=10/sup 18.8/ eV, then kappa =(1.0+or-0.1)*10/sup -32/ and gamma =2.7/sub -0.4//s  
53 The energy spectrum observed by the AGASA experiment and the spatial distribution of the sources of ultra-high energy cosmic rays Gustavo Medina Tanco (Inst.Astron.e Geof.-USP-Brasil & Univ.of Leeds-UK) Astrophys. J. Letters (submitted) 1998   astro-ph/9810366
54 The highest energy cosmic ray Halzen-F; Vazquez-RA; Stanev-T; Vankov-HP Astroparticle-Physics. vol.3, no.2; March 1995; p.151-6 1995 One should keep in mind that the highest energy cosmic rays may be photons or neutrinos. The authors discuss the particle assignment of the 3*10/sup 20/ eV shower recently observed by the Fly's Eye detector. They show that the event is not initiated by a photon and that the assignments of a proton and neutrino as the primary particle are, arguably, equally valid. Neither assignment is totally satisfactory.  
55 The origin of cosmic rays Biermann-PL Space-Science-Reviews. vol.74, no.3-4; Nov. 1995; p.385-96 1995 Describes progress in our understanding of the origin of cosmic rays. The authors propose that cosmic rays originate mainly in three sites, (a) normal supernova explosions into the interstellar medium, (b) supernova explosions into stellar winds, and (c) hot spots of powerful radio galaxies. The proposal depends on an assumption about the scaling of the turbulent diffusive transport in cosmic ray mediated shock regions; the proposal also uses a specific model for the interstellar transport of cosmic rays. The model has been investigated in some detail and compared to (i) the radio data of OB stars, Wolf-Rayet stars, radio supernovae, radio supernova remnants, Gamma-ray line and continuum emission from starforming regions, and the cosmic ray electron spectrum, (ii) the Akeno air shower data over the particle energy range from 10 TeV to EeV, and (iii) the Akeno and Fly`s Eye air shower data from 0.1 EeV to above 100 EeV.  
56 The origin of cosmic rays above 10/sup 18.5/ eV Norman-CA; Melrose-DB; Achterberg-A Astrophysical-Journal. vol.454, no.1, pt.1; 20 Nov. 1995; p.60-8 1995 Discusses the origin of ultra-high-energy cosmic rays (UHECRs) in the energy range above 10/sup 18.5/ eV where it is indicated that the spectrum becomes protonic and extends smoothly up to at least 10/sup 19.5/ eV and is consistent with a smooth extension to 10/sup 20.5/ eV. The acceleration of the 10/sup 19.5/ eV component must occur within ~1 Gpc. The authors rule out the production and escape of protons and neutrons from active galactic nuclei. Composition arguments make unlikely any origin in metal-rich environments such as rich clusters and the inner regions of galaxies. The authors dismiss the canonical extended halo models since such halos are almost never observed although diffuse halos have been seen in QSO absorption-line studies of metallic absorption lines. Large-scale shocks from explosions and winds are analyzed including those originating both recently and at earlier cosmological epochs. Large-scale shocks can work well only if they occur in microgauss fields. Hot spots and cocoons of radi  
57 The origin of high energy cosmic rays and the large scale structure of the Universe Biermann-PL Astrophysics-Reports. no.1; Jan. 1995; p.11-21 1995 A recent theoretical proposal for the origin of cosmic rays gives quantitative predictions, which can be tested with data. Specifically, it has been suggested, that all cosmic rays can be attributed to just three source sites: 1) supernova explosions into the interstellar medium, 2) supernova explosions into a stellar wind, and 3) powerful radiogalaxies. The cosmic rays from any extragalactic source suffer from interaction with the microwave background, leading to the Greisen-Zatsepin-Kuzmin cutoff. The author discusses here possible sources, and specifically asks whether powerful radiogalaxies are suitable candidates.  
58 The Pierre Auger Project Mantsch-PM AIP-Conference-Proceedings. no.359; 1996; p.370-82 1996 The Pierre Auger project is a broadly based international effort to make a detailed study of cosmic rays at the highest energies. Two air shower detectors are proposed, one to be placed in the Northern Hemisphere and one in the Southern Hemisphere. Each installation will consist of an array of 1600 particle detectors spread over 3000 km/sup 2/ with a solid angle acceptance of 2 sr for cosmic ray air showers. Each installation will also have an atmospheric fluorescence detector viewing the volume above the surface array. These two air shower detector techniques working together form a powerful instrument for the proposed research. The objectives of the Pierre Auger project are to measure the arrival direction, energy, and mass composition of 60 events per year above an energy of 10/sup 20/ eV and 6000 events per year above 10/sup 19/ eV. A collaboration is now being formed with the goal of having the Pierre Auger observatory in operation by 2001.  
59 Topological Defect Models of Ultra-High Energy Cosmic Rays Guenter Sigl (Univ. of Chicago) to appear in proceedings of the "International School of Cosmic-Ray Astrophysics", Erice, 16-23 June 1996 (World Scientific) 1996   astro-ph/9611190
60 Ultra high energy cosmic rays Berezinsky-V Nuclear-Physics-B,-Proceedings-Supplements. vol.70; Jan. 1999; p.419-30 1999 The current status of ultra high energy cosmic rays (UHECR) is reviewed, with emphasis given to theoretical interpretation of the observed events. The Galactic and extragalactic origin, in case of astrophysical sources of UHE particles, have the problems either with acceleration to the observed energies or with the fluxes and spectra. Topological defects can naturally produce particles with energies as observed and much higher, but in most cases fail to produce the observed fluxes. Cosmic necklaces and monopole-antimonopole pairs are identified as most plausible sources, which can provide the observed flux and spectrum. The relic superheavy particles are shown to be clustering in the Galactic halo, producing UHECR without Greisen-Zatsepin-Kuz'min cutoff. The lightest supersymmetric particles are discussed as UHE carriers in the Universe. hep-ph/9802351
61 Ultra high energy cosmic rays and the large scale structure of the galactic magnetic field Todor Stanev submitted to The Astrophysical Journal 1996   astro-ph/9607086
62 Ultra high energy cosmic rays from cosmological relics V.Berezinsky Invited talk at 10th Int. Symposium on Very High Energy Cosmic Ray Interactions, July 12 - 17, 1998, Gran Sasso 1998   astro-ph/9811268
63 Ultra High Energy Cosmic Rays from Decaying Superheavy Particles V.Berezinsky ?? 1998   astro-ph/9801046
64 ULTRA HIGH ENERGY COSMIC RAYS: PHYSICS ISSUES AND POTENTIALITIES OF THE AUGER HYBRID DETECTOR The AUGER Collaboration (P. Billoir for the collaboration) "Jerusalem 1997, High energy physics" 1011-1014 (1997) 1997   ??
65 Ultra-High Energy Cosmic Ray Propagation in the Local Supercluster Guenter Sigl (Univ. of Chicago, USA), Martin Lemoine (DARC, CNRS, France), Peter Biermann (MPI fuer Radioastronomie, Bonn, Germany) to appear in Astroparticle Physics 1998   astro-ph/9806242
66 Ultra-high energy cosmic ray sources and large scale magnetic fields Martin Lemoine, Guenter Sigl, Angela V. Olinto, David N. Schramm (Univ. of Chicago) Astrophys.J. 486 (1997) L115-L118 1997   astro-ph/9704203
67 Ultra-high energy cosmic rays without GZK cutoff V. Berezinsky, M. Kachelriess, A.Vilenkin Phys.Rev.Lett. 79 (1997) 4302-4305 1997   astro-ph/9708217
68 Why not cosmological cosmic rays? Sato-H New-Astronomy-Reviews. vol.42, no.3-4; Sept. 1998; p.287-8 1998 Cosmic rays were once considered to be an indication of unknown cosmological processes, but they have turned out to be a minor product of astrophysical processes. However, the puzzle of the high-energy end of the cosmic-ray flux might bring about a radical change in physics, including a discovery of violation of the principle of relativity.  


Last Updated on 4/28/99
By Jeff Wilkes