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1

High-energy cosmic ray interactions  

NASA Astrophysics Data System (ADS)

Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand-due to the indirect observation of cosmic rays through air showers-the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

Engel, Ralph; Orellana, Mariana; Reynoso, Matías M.; Vila, Gabriela S.

2009-04-01

2

High-energy cosmic ray interactions  

SciTech Connect

Research into hadronic interactions and high-energy cosmic rays are closely related. On one hand--due to the indirect observation of cosmic rays through air showers--the understanding of hadronic multiparticle production is needed for deriving the flux and composition of cosmic rays at high energy. On the other hand the highest energy particles from the universe allow us to study the characteristics of hadronic interactions at energies far beyond the reach of terrestrial accelerators. This is the summary of three introductory lectures on our current understanding of hadronic interactions of cosmic rays.

Engel, Ralph [Forschungszentrum Karlsruhe, P.O. Box 3640, 76021 Karlsruhe (Germany); Orellana, Mariana [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina); Facultad de Ciencias Astronomicas y Geofisicas, Universidad Nacional de La Plata, Paseo del Bosque, 1900 La Plata (Argentina); Reynoso, Matias M. [Departamento de Fisica, Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, Funes 3350, (7600) Mar del Plata (Argentina); Instituto de Investigaciones Fisicas de Mar del Plata, (UNMdP-CONICET) (Argentina); Vila, Gabriela S. [Instituto Argentino de Radioastronomia (IAR), CCT La Plata (CONICET), C.C.5, 1894 Villa Elisa, Buenos Aires (Argentina)

2009-04-30

3

Terrestrial effects of high energy cosmic rays  

Microsoft Academic Search

On geological timescales, the Earth is likely to be exposed to higher than the usual flux of high energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma ray bursts or by galactic shocks. These high-energy particles strike the Earth's atmosphere, initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing

Dimitra Atri

2011-01-01

4

Chaotic Properties of High Energy Cosmic Rays  

Microsoft Academic Search

Using the dimension of correlation analysis, we study the time series intervals of the high-energy cosmic ray data, obtained in the mount of Chacaltaya, in the experiment S.Y.S. Some of the analyzed groups present a fractal dimension close to 3. This fractal dimension seems to show that the transport system of cosmic ray would be chaotic under some circumstances. Results

A. Ticona; R. Ticona; N. Martinic; I. Poma; R. Gutierrez; R. Calle; E. Rodriguez

2006-01-01

5

The Mystery of Ultra-High Energy Cosmic Rays  

SciTech Connect

Cosmic rays with energies well above 1019 eV are messengers of an unknown extremely high-energy universe. The current state and future prospects of ultra high energy cosmic ray physics are briefly reviewed.

Olinto, Angela V. [Department of Astronomy and Astrophysics, EFI, KICP, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637, Chicago (United States)

2006-07-11

6

EDITORIAL: Focus on High Energy Cosmic Rays FOCUS ON HIGH ENERGY COSMIC RAYS  

Microsoft Academic Search

The topic of high-energy cosmic rays has recently attracted significant attention. While the AGASA and HiRes Observatories have closed after many years of successful operation, the Pierre Auger Observatory began taking data in January 2004 and the first results have been reported. Plans for the next generation of instruments are in hand: funding is now being sought for the northern

Masahiro Teshima; Alan A. Watson

2009-01-01

7

EDITORIAL: Focus on High Energy Cosmic Rays FOCUS ON HIGH ENERGY COSMIC RAYS  

NASA Astrophysics Data System (ADS)

The topic of high-energy cosmic rays has recently attracted significant attention. While the AGASA and HiRes Observatories have closed after many years of successful operation, the Pierre Auger Observatory began taking data in January 2004 and the first results have been reported. Plans for the next generation of instruments are in hand: funding is now being sought for the northern phase of the Auger Observatory and plans for a space detector, JEM-EUSO, to be launched in 2013-14 are well advanced with the long-term target of a dedicated satellite for the 2020s. It therefore seemed an appropriate time to make a collection of outstanding and original research articles from the leading experimental groups and from some of the theorists who seek to interpret the hard-won data and to speculate on the origin of the highest energy cosmic rays. This focus issue in New Journal of Physics on the topic of high energy cosmic rays, contains a comprehensive account of the work of the Yakutsk group (A A Ivanov, S P Knurenko and I Ye Sleptsov) who have used Cerenkov radiation produced by shower particles in the air to provide the basis for energy calibration. This technique contrasts with that of detecting fluorescence radiation from space that is proposed for the JEM-EUSO instrument to be placed on the International Space Station in 2013, described by Y Takahashi. Supplementing this is an article by A Santangelo and A Petrolini describing the scientific goals, requirements and main instrument features of the Super Extreme Universe Space Observatory mission (S-EUSO). The use of fluorescence light to measure energies was the key component of the HiRes instrument and is also used extensively by the Pierre Auger Collaboration so an article, by F Arqueros, F Blanco and J Rosado, summarizing the properties of fluorescence emission, still not fully understood, is timely. M Nagano, one of the architects of the AGASA Observatory, has provided an overview of the experimental situation with regard to the energy spectrum of the highest energy cosmic rays. The remaining contributions are of a more theoretical nature and discuss propagation (T Stanev), the time structure of multi-messenger signals (G H W Sigl), ultra-high energy cosmic ray production near black holes (A Yu Neronov, D V Semikoz and I I Tkachev), production in jets associated with black holes (C D Dermer, S Razzaque, J Finke and A Atoyan) and emission from a specific object, Cen A (M Kachelriess, S S Ostapchenko and R Tomas). Additionally the potential of high energy cosmic rays to give information about features of hadronic interactions, specifically the cross-section for p-air collisions, is discussed in the paper by R Ulrich et al. We thank all our authors most sincerely for their efforts and Tim Smith and his editorial team for their hard work. We believe that this collection of articles will be of great value to workers in the field: further contributions to this focus issue will be published during the course of 2009. Focus on High Energy Cosmic Rays Contents The cosmic ray energy spectrum as measured using the Pierre Auger Observatory Giorgio Matthiae The northern site of the Pierre Auger Observatory Johannes Blümer and the Pierre Auger Collaboration Searching for new physics with ultrahigh energy cosmic rays Floyd W Stecker and Sean T Scully On the measurement of the proton-air cross section using air shower data R Ulrich, J Blümer, R Engel, F Schüssler and M Unger High energy radiation from Centaurus A M Kachelrieß, S Ostapchenko and R Tomàs Ultra-high-energy cosmic rays from black hole jets of radio galaxies C D Dermer, S Razzaque, J D Finke and A Atoyan Ultra-high energy cosmic ray production in the polar cap regions of black hole magnetospheres A Yu Neronov, D V Semikoz and I I Tkachev Time structure and multi-messenger signatures of ultra-high energy cosmic ray sources Günter Sigl Propagation of ultrahigh-energy cosmic rays Todor Stanev Search for the end of the energy spectrum of primary cosmic rays M Nagano Analysis of the fluorescence emission from atmospheric ni

Teshima, Masahiro; Watson, Alan A.

2009-06-01

8

Magnetic Fields and Ultra High Energy Cosmic Rays  

SciTech Connect

The current state and future prospects of ultra high energy cosmic ray physics and the role of magnetic fields in the Galactic and extragalactic medium are reviewed. These cosmic rays with energies well above 1018 eV are messengers of an unknown extremely high-energy universe.

Olinto, Angela V. [Department of Astronomy and Astrophysics, EFI, KICP, University of Chicago, 5640 S. Ellis Ave, Chicago, IL 60637 (United States)

2005-09-28

9

High energy neutrinos from astrophysical accelerators of cosmic ray nuclei  

Microsoft Academic Search

Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons would also generate neutrinos through interactions with ambient matter and\\/or photons. However, there will be a reduction in the predicted neutrino flux if cosmic ray sources accelerate not only protons but also significant numbers of heavier nuclei,

Luis A. Anchordoqui; Dan Hooper; Subir Sarkar; Andrew M. Taylor

2008-01-01

10

Propagation and Energy Spectrum of Ultra High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

We will review the main physical aspects of Ultra High Energy Cosmic Rays. We will discuss in particular their propagation through astrophysical backgrounds, focusing on the latest experimental observations of HiRes, Telescope Array and Auger. We will also review the issue of the transition between galactic and extra-galactic cosmic rays.

Aloisio, Roberto

2013-06-01

11

Detection techniques of ultra high energy cosmic rays  

SciTech Connect

Several detection techniques in current high-energy cosmic rays are examined. The results of some experiments are discussed and a review of the future projects is made, emphasizing their discovery potential in accordance with their aperture.

Salazar, H. [Facultad de Ciencias Fisico-Matemaaticas, Universidad Autonoma de Puebla, Puebla, Pue. (Mexico)

1998-10-05

12

Coplanar emission in very high energy cosmic ray interactions  

NASA Astrophysics Data System (ADS)

The alignment of very high energy secondary cosmic rays, implying coplanar emissions, was observed at both stratospheric and mountain altitudes by several x-ray emulsion chamber experiments. This paper investigates the physical relevance of the experimental observations through detailed Monte Carlo calculations carried out with the CORSIKA program combining different models of high energy hadronic interaction. The physical factors likely to induce or to influence this phenomenon are discussed.

Attallah, R.; Capdevielle, J. N.; Talai, M. C.

2005-05-01

13

Radar Detection of High Energy Cosmic Ray Showers  

NASA Astrophysics Data System (ADS)

The radar detection technique for High Energy Cosmic Ray Shower detection has been investigated in this collaborative work. High Energy Cosmic Ray Showers produce disk-like ionization front which moves with relativistic speed in our atmosphere. We study the reflection of radio waves such as the ones from commercial radio and TV stations from the relativistic moving front. The reflected wave experiences a high blue-shift in frequency due to relativistic Doppler Effect. The feasibility study of detection of showers via this method and the benefits will be presented.

Kryemadhi, Abaz; Bakunov, Michael; Maslov, Alex; Novokovskaya, Alina

2012-03-01

14

Some methods in high energy cosmic ray measurement  

NASA Astrophysics Data System (ADS)

Problems concerning ion chamber and emulsion detection techniques for high energy cosmic ray measurement are investigated. The calculation of the average energy actually deposited in an ion chamber by an ultra-high energy particle of large mass and charge is examined. A calculational scheme already applied successfully to particles of charge 1 is extended. Also, the calibration of a plate of plastic scintillator for measurement of the position of a cosmic ray shower passing through it is discussed. The method of calibration is to inject pulses of flight at known positions on the plate and record the responses of photomultiplier tubes at the corner of the plate.

Shand, J. B., Jr.

1980-10-01

15

Ultra High Energy Cosmic Ray Research with CASA-MIA  

Microsoft Academic Search

Ultra high energy (UHE) cosmic rays are particles reaching Earth that have energies greater than 1014 eV (1). These particles are produced in astrophysical sources that are sites of extreme particle acceleration but because they are largely charged, they bend in the mag- netic field of the Galaxy and their directional information is scrambled by the time they reach Earth.

Rene A. Ong

16

Microwave detection of Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

A novel detection technique for Ultra-High Energy Cosmic Rays based on microwave emission from the extensive air showers may provide large area coverage with 100% duty cycle at low cost. The status and prospects of several complementary R&D projects for GHz detectors is reviewed.

Privitera, P.

2011-09-01

17

Ultra-High Energy Cosmic Rays and Cosmogenic Neutrinos  

NASA Astrophysics Data System (ADS)

Although the sources and composition of ultra-high energies cosmic rays is unknown, in most scenarios a significant flux of very high energy neutrinos should be present throughout the universe. We show that even if ultra-high energy cosmic rays are composed of heavy nuclei from extragalactic sources, their propagation over cosmological distances generate a neutrino flux comparable to that of proton primaries depending on the maximum energy and cosmological evolution of the source. The resulting neutrino flux has a new peak at ˜ 1014 eV generated by neutron decay and reproduces the double peak structure due to photopion production at higher energies (˜ 1018 eV). The generated neutrino flux may be detected by future experiments.

Ave, M.; Busca, N.; Olinto, A. V.; Watson, A. A.; Yamamoto, T.

2004-11-01

18

Ultra-high-energy cosmic rays: the experimental situation  

NASA Astrophysics Data System (ADS)

The methods of detection of high-energy cosmic rays are briefly described and it is shown that results on the energy spectrum and arrival direction distribution obtained above 4×1019eV confound theoretical expectation. There is an urgent need for better statistics as only about 12 events above 1020eV have been detected and the limit to the energy which cosmic rays can reach is not known. The new, funded, instruments, the Pierre Auger Observatory and the Hi-Res fluorescence detector, are described and the plans for an ambitious satellite observatory (Airwatch/OWL) are outlined.

Watson, A. A.

2000-08-01

19

Ultra High Energy Cosmic Rays: Spectral Signatures and Observations  

NASA Astrophysics Data System (ADS)

We review the observations of Ultra High Energy Cosmic Rays (UHECR), focusing on the energy spectra as measured by HiRes, Telescope Array (TA) and Auger detectors. We found that highest energy Auger steepening does not agree with GZK cutoff, which is most probably explained by the nuclei mass composition detected by Auger. At present the difference in mass composition in Auger and HiRes/TA data remains the main unsolved problem of UHECR origin.

Grigorieva, S.

2013-02-01

20

On the Origin of Ultra High Energy Cosmic Rays  

SciTech Connect

Turbulence-driven plasma accelerators produced by magnetized accretion disks around black holes are proposed as the mechanism mainly responsible for observed cosmic ray protons with ultra high energies 10{sup 19}-10{sup 21} eV. The magnetized disk produces a voltage comparable to these cosmic ray energies. Here we present a Poynting model in which this voltage provides all of the energy to create the jet-like structures observed to be ejected from accretion disks, and this voltage also accelerates ions to high energies at the top of the expanding structure. Since the inductive electric field E = -v x B driving expansion has no component parallel to the magnetic field B, ion acceleration requires plasma wave generation - either a coherent wave accelerator as recently proposed, or instability-driven turbulence. We find that turbulence can tap the full inductive voltage as a quasi-steady accelerator, and even higher energies are produced by transient events on this structure. We find that both MHD modes due to the current and ion diffusion due to kinetic instability caused by the non-Maxwellian ion distribution contribute to acceleration. We apply our results to extragalactic giant radiolobes, whose synchrotron emissions serve to calibrate the model, and we discuss extrapolating to other astrophysical structures. Approximate calculations of the cosmic ray intensity and energy spectrum are in rough agreement with data and serve to motivate more extensive MHD and kinetic simulations of turbulence that could provide more accurate cosmic ray and synchrotron spectra to be compared with observations. A distinctive difference from previous models is that the cosmic ray and synchrotron emissions arise from different parts of the magnetic structure, thus providing a signature for the model.

Fowler, T; Colgate, S; Li, H

2009-07-01

21

Pulsars as the sources of high energy cosmic ray positrons  

NASA Astrophysics Data System (ADS)

Recent results from the PAMELA satellite indicate the presence of a large flux of positrons (relative to electrons) in the cosmic ray spectrum between approximately 10 and 100 GeV. As annihilating dark matter particles in many models are predicted to contribute to the cosmic ray positron spectrum in this energy range, a great deal of interest has resulted from this observation. Here, we consider pulsars (rapidly spinning, magnetized neutron stars) as an alternative source of this signal. After calculating the contribution to the cosmic ray positron and electron spectra from pulsars, we find that the spectrum observed by PAMELA could plausibly originate from such sources. In particular, a significant contribution is expected from the sum of all mature pulsars throughout the Milky Way, as well as from the most nearby mature pulsars (such as Geminga and B0656+14). The signal from nearby pulsars is expected to generate a small but significant dipole anisotropy in the cosmic ray electron spectrum, potentially providing a method by which the Fermi gamma-ray space telescope would be capable of discriminating between the pulsar and dark matter origins of the observed high energy positrons.

Hooper, Dan; Blasi, Pasquale; Dario Serpico, Pasquale

2009-01-01

22

On the Origin of Ultra High Energy Cosmic Rays II  

SciTech Connect

We show that accretion disks around Active Galactic Nuclei (AGNs) could account for the enormous power in observed ultra high energy cosmic rays {approx}10{sup 20} eV (UHEs). In our model, cosmic rays are produced by quasi-steady acceleration of ions in magnetic structures previously proposed to explain jets around Active Galactic Nuclei with supermassive black holes. Steady acceleration requires that an AGN accretion disk act as a dynamo, which we show to follow from a modified Standard Model in which the magnetic torque of the dynamo replaces viscosity as the dominant mechanism accounting for angular momentum conservation during accretion. A black hole of mass M{sub BH} produces a steady dynamo voltage V {proportional_to} {radical}M{sub BH} giving V {approx} 10{sup 20} volts for M{sub BH} {approx} 10{sup 8} solar masses. The voltage V reappears as an inductive electric field at the advancing nose of a dynamo-driven jet, where plasma instability inherent in collisionless runaway acceleration allows ions to be steadily accelerated to energies {approx} V, finally ejected as cosmic rays. Transient events can produce much higher energies. The predicted disk radiation is similar to the Standard Model. Unique predictions concern the remarkable collimation of jets and emissions from the jet/radiolobe structure. Given MBH and the accretion rate, the model makes 7 predictions roughly consistent with data: (1) the jet length; (2) the jet radius; (3) the steady-state cosmic ray energy spectrum; (4) the maximum energy in this spectrum; (5) the UHE cosmic ray intensity on Earth; (6) electron synchrotron wavelengths; and (7) the power in synchrotron radiation. These qualitative successes motivate new computer simulations, experiments and data analysis to provide a quantitative verification of the model.

Fowler, T K; Colgate, S; Li, H; Bulmer, R H; Pino, J

2011-03-08

23

Measurement of ultra-high energy cosmic rays with CHICOS  

NASA Astrophysics Data System (ADS)

The California HIgh school Cosmic ray ObServatory (CHICOS) is a ground-based scintillator array designed to measure the extended air showers of ultra-high energy cosmic rays. The goal of the project is to gain insight into the origin of ultra-high energy cosmic rays by measuring the energy spectrum and the distribution of arrival directions. The CHICOS array has been in operation since 2003. It consists of 77 pairs of scintillator dectectors deployed at schools in the San Fernando and San Gabriel valleys near Los Angeles, and is designed to observe cosmic ray air showers at energies of 10^18 eV and above. In addition, the Chiquita subarray is designed to observe smaller showers in the energy range of 10^16 - 10^19 eV. We present new descriptions of the air shower lateral distribution function and time distribution function, which have been derived from AIRES-generated simulated air showers. The new functions are specific to the CHICOS altitude and allow for a maximum likelihood shower reconstruction method, which is more appropriate to the CHICOS data than the chi-squared minimization method. We present several analyses of the accuracy of the reconstruction software in the energy ranges available to the Chiquita and CHICOS arrays. The energy spectrum between 10^17 eV and 10^19 eV has been measured by the Chiquita subarray. At the lowest energy range, it is found to agree with previous measurements, while the measured flux falls below previous experiments for energies greater than approximately 10^17.5 eV. The CHICOS energy spectrum above 10^18.4 eV is found to agree with previous results published by AGASA. However, we do not observe the cutoff in the spectrum at 10^20 eV reported more recently by the Auger and HiRes Collaborations. A correlation analysis between CHICOS data and nearby active galactic nuclei (AGN) was performed. No excess of cosmic rays was observed in the vicinity of nearby AGN. The maximum correlation was observed for cosmic ray events with E > 10^20 eV and for AGN with z < 0.009, with P_chance = 21%. This is consistent with random correlations from an isotropic distribution, a result also found by HiRes, but in disagreement with Auger.

Brobeck, Elina

24

Radar Detection of ultra high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We revisit the radar echo technique as an approach to detect ultra high energy cosmic rays (UHECR). The UHECR extensive air showers produce disk-like ionization fronts propagating with a relativistic speed and creating fast decaying plasma. We study the reflection of a radio wave, such as the one from a radar transmitter or commercial radio and TV station, from the ionization front. The reflected wave will be frequency up-shifted due to relativistic Doppler effect. The amplitude of the reflected wave depends strongly on velocity of the front, and density and collision frequency of the plasma behind it. The returned power will be shown for typical extensive air shower parameters. )

Kryemadhi, Abaz; Bakunov, Michael; Maslov, Alex; Novokovskaya, Alina

2010-02-01

25

The role of Cherenkov radiation in the detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

A brief historical overview of the role of Cherenkov radiation in the detection of cosmic rays is given. A current application, the detection of ultra-high-energy cosmic rays with the Pierre Auger Observatory, is described.

Watson, A. A.

2005-11-01

26

Exploring the High-Energy Cosmic Ray Spectrum with a Toy Model of Cosmic Ray Diffusion  

Microsoft Academic Search

We introduce a static toy model of the cosmic ray (CR) universe in which cosmic ray propagation is taken to be diffusive and cosmic ray sources are distributed randomly with a density the same as that of local L* galaxies, $5 \\\\times 10^{-3}$ Mpc$^{-3}$. These sources \\

Roger Clay; Roland M. Crocker

2007-01-01

27

Direct observations of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

Balloon-borne emulsion chambers are being used for direct observations of primary cosmic rays at energies up to about 10 to the 14th eV. So far, energy spectra measurements for individual species are available only for protons and helium, which apparently agree with single power law extrapolation of lower energy data, although the possibility of a bend in the proton spectrum has been revived recently. The composition of heavy nuclei around 10 to the 14th eV seems to be consistent with an E exp -1.7 power law extrapolation from 100 GeV/nucleon data. Some anomalous interactions provide evidence that high energy nucleus-nucleus collisions cannot be explained by simple superpositions of nucleon-nucleon collisions. Within about a decade, long exposures in space using the Space Transportation System and/or the Space Station/Space Platform could provide the opportunity for direct cosmic ray observations to energies as high as 10 to the 16th eV.

Jones, W. V.

28

Photodisintegration of ultra-high-energy cosmic rays revisited  

NASA Astrophysics Data System (ADS)

Recent microscopic and phenomenological calculations of giant dipole resonances for A ? 56 nuclei are presented. The derived photodisintegration cross sections are exhaustively compared to the photonuclear data available to date. An accurate description of the data is found. Our new calculations are also compared with the previous and widely-used estimates of Puget, Stecker and Bredekamp. The present calculations also include all the possible paths down the nuclear chart. The impact on the photodisintegration of ultra-high-energy cosmic rays (UHECR) is illustrated for a Fe source with typical energies of 10 20-10 21 eV. At energies around 10 20 eV, the new cross sections are found to modify the UHECR photodisintegration rates. At energies around 10 21 eV, it is recommended to solve a full reaction network to estimate the photodisintegration rate of the UHECR.

Khan, E.; Goriely, S.; Allard, D.; Parizot, E.; Suomijärvi, T.; Koning, A. J.; Hilaire, S.; Duijvestijn, M. C.

2005-03-01

29

Extremely high energy cosmic rays from relic particle decays  

NASA Astrophysics Data System (ADS)

The expected proton and neutrino fluxes from decays of massive metastable relic particles are calculated using the HERWIG QCD event generator. The predicted proton spectrum can account for the observed flux of extremely high energy cosmic rays beyond the Greisen-Zatsepin-Kuzmin cutoff, for a decaying particle mass of O(10 12) GeV. The lifetime required is of O(10 20) yr if such particles constitute all of the dark matter (with a proportionally shorter lifetime for a smaller contribution). Such values are plausible if the metastable particles are hadron-like bound states from the hidden sector of supersymmetry breaking which decay through nonrenormalizable interactions. The expected ratio of the proton to neutrino flux is given as a diagonistic of the decaying particle model for the forthcoming Pierre Auger Project.

Birkel, Michael; Sarkar, Subir

1998-12-01

30

Inductive acceleration of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

Ultra high energy cosmic rays (UHECRs) are charged particles that have energy in excess of 1018 eV and are mostly of extra-galactic origin. Their astrophysical origin and the acceleration mechanisms are still unknown, 50 years after their discovery and 100 years after cosmic rays in general were first identified. Lower energy cosmic rays (CRs), up to approximately 1015 eV ("the knee") are of galactic origin, presumably accelerated in supernova remnants. The UHECRs above "the ankle" at 1018 eV can't be contained by the Galactic magnetic field and are thus extragalactic. Considerable progress in CR research has recently been stimulated by the construction and the successful operation of the Pierre Auger observatory. Among the key yearly results is the correlation of the arrival directions of the UHECRs with the large scale structure, though the precise nature of the acceleration sites remains unknown. Noteworthy, a large number of UHECRs come from the direction of Cen A, the nearest AGN. The most commonly suggested mechanism of CR acceleration, initially due to Fermi, suggests that particles gain energy stochastically, by experiencing multiple scatterings off magnetohydrodynamic turbulence. Thus, the rate of the acceleration is low. In this work we investigate an alternative novel mechanism, specific to the UHECRs. We point out that relativistic outflows carrying large scale magnetic field have large inductive potential and may accelerate protons to ultra-high energies. We suggest that magnetized jets of Active Galactic Nuclei (AGN) can accelerate UHECRs via regular energy gain in the inductive electric fields. Cyclotron motion of a CR particle in a sheared magnetic field may become unstable for sufficiently large Larmor radii, comparable with the shear scales. As an unbound particle crosses the jet, it gains the inductive potential square root(L/c), where L is the Poynting luminosity of a jet. Key features of the mechanism are that (i) highest rigidity cosmic rays are accelerated most efficiently; (ii) maximum possible acceleration rate does reach the inverse relativistic gyro-frequency. In this work we study the kinetic motion of the UHECRs in realistic electromagnetic configurations of astrophysical jets. The key issue is the condition for particle motion to become unstable: large energy gains require stronger magnetic fields, which reduce the Larmor radius and make the motion more stable (bound). We find that large energy gains, more than an order of magnitude, are indeed possible for generic profiles of the magnetic field and the velocity shear inside the jet. On the other hand, the CRs that gained the full jet potential are typically beamed along the jet direction - this poses a problem, e.g., in the case of Cen A, whose jets are directed at large angles to the line of sight.

Alvarez, Jorge Alonso

31

Laboratory laser acceleration and high energy astrophysics: {gamma}-ray bursts and cosmic rays  

SciTech Connect

Recent experimental progress in laser acceleration of charged particles (electrons) and its associated processes has shown that intense electromagnetic pulses can promptly accelerate charged particles to high energies and that their energy spectrum is quite hard. On the other hand some of the high energy astrophysical phenomena such as extremely high energy cosmic rays and energetic components of {gamma}-ray bursts cry for new physical mechanisms for promptly accelerating particles to high energies. The authors suggest that the basic physics involved in laser acceleration experiments sheds light on some of the underlying mechanisms and their energy spectral characteristics of the promptly accelerated particles in these high energy astrophysical phenomena.

Tajima, T. [Univ. of Texas, Austin, TX (United States); Takahashi, Y. [Univ. of Alabama, Huntsville, AL (United States). Dept. of Physics

1998-08-20

32

High energy neutrinos from astrophysical accelerators of cosmic ray nuclei  

NASA Astrophysics Data System (ADS)

Ongoing experimental efforts to detect cosmic sources of high energy neutrinos are guided by the expectation that astrophysical accelerators of cosmic ray protons would also generate neutrinos through interactions with ambient matter and/or photons. However, there will be a reduction in the predicted neutrino flux if cosmic ray sources accelerate not only protons but also significant numbers of heavier nuclei, as is indicated by recent air shower data. We consider plausible extragalactic sources such as active galactic nuclei, gamma ray bursts and starburst galaxies and demand consistency with the observed cosmic ray composition and energy spectrum at Earth after allowing for propagation through intergalactic radiation fields. This allows us to calculate the expected neutrino fluxes from the sources, normalized to the observed cosmic ray spectrum. We find that the likely signals are still within reach of next generation neutrino telescopes such as IceCube.PACS95.85.Ry98.70.Rz98.54.Cm98.54.EpReferencesFor a review, see:F.HalzenD.HooperRep. Prog. Phys.6520021025A.AchterbergIceCube CollaborationPhys. Rev. Lett.972006221101A.AchterbergIceCube CollaborationAstropart. Phys.262006282arXiv:astro-ph/0611063arXiv:astro-ph/0702265V.NiessANTARES CollaborationAIP Conf. Proc.8672006217I.KravchenkoPhys. Rev. D732006082002S.W.BarwickANITA CollaborationPhys. Rev. Lett.962006171101V.Van ElewyckPierre Auger CollaborationAIP Conf. Proc.8092006187For a survey of possible sources and event rates in km3 detectors see e.g.,W.BednarekG.F.BurgioT.MontaruliNew Astron. Rev.4920051M.D.KistlerJ.F.BeacomPhys. Rev. D742006063007A. Kappes, J. Hinton, C. Stegmann, F.A. Aharonian, arXiv:astro-ph/0607286.A.LevinsonE.WaxmanPhys. Rev. Lett.872001171101C.DistefanoD.GuettaE.WaxmanA.LevinsonAstrophys. J.5752002378F.A.AharonianL.A.AnchordoquiD.KhangulyanT.MontaruliJ. Phys. Conf. Ser.392006408J.Alvarez-MunizF.HalzenAstrophys. J.5762002L33F.VissaniAstropart. Phys.262006310F.W.SteckerC.DoneM.H.SalamonP.SommersPhys. Rev. Lett.6619912697(Erratum-ibid. 69 (1992) 2738)F.W.SteckerPhys. Rev. D722005107301A.AtoyanC.D.DermerPhys. Rev. Lett.872001221102L.A.AnchordoquiH.GoldbergF.HalzenT.J.WeilerPhys. Lett. B6002004202E.WaxmanJ.N.BahcallPhys. Rev. Lett.7819972292C.D.DermerA.AtoyanPhys. Rev. Lett.912003071102D.GuettaD.HooperJ.Alvarez-MunizF.HalzenE.ReuveniAstropart. Phys.202004429J.Alvarez-MunizF.HalzenD.W.HooperPhys. Rev. D622000093015A.LoebE.WaxmanJCAP06052006003S. Inoue, G. Sigl, F. Miniati, E. Armengaud, arXiv:astro-ph/0701167.E.WaxmanJ.N.BahcallPhys. Rev. D591999023002Phys. Rev. D642001023002K.MannheimR.J.ProtheroeJ.P.RachenPhys. Rev. D632001023003arXiv:astro-ph/9908031M.AhlersL.A.AnchordoquiH.GoldbergF.HalzenA.RingwaldT.J.WeilerPhys. Rev. D722005023001E.WaxmanAstrophys. J.4521995L1Note that the neutrino spectral shape can deviate from that for protons if the Feynman plateau is not flat in pseudo-rapidity space;L.AnchordoquiH.GoldbergC.NunezPhys. Rev. D712005065014This is in fact suggested by Tevatron data;F.AbeCDF CollaborationPhys. Rev. D4119902330J.G.LearnedS.PakvasaAstropart. Phys.31995267F.HalzenD.SaltzbergPhys. Rev. Lett.8119984305J.F.BeacomN.F.BellD.HooperS.PakvasaT.J.WeilerPhys. Rev. D682003093005(Erratum-ibid. D 72 (2005) 019901)L.A.AnchordoquiH.GoldbergF.HalzenT.J.WeilerPhys. Lett. B593200442L.A.AnchordoquiH.GoldbergF.HalzenT.J.WeilerPhys. Lett. B621200518A.M.HillasAnn. Rev. Astron. Astrophys.221984425For a general discussion on the acceleration time-scale in these sources see, e.g.,D.F.TorresL.A.AnchordoquiRep. Prog. Phys.6720041663M.C.BegelmanB.RudakM.SikoraAstrophys. J.362199038M.J.ChodorowskiA.A.ZdziarskiM.SikoraAstrophys. J.4001992181S.MichalowskiD.AndrewsJ.EickmeyerT.GentileN.MistryR.TalmanK.UenoPhys. Rev. Lett.391977737J.L.PugetF.W.SteckerJ.H.BredekampAstrophys. J.2051976638D.HooperS.SarkarA.M.TaylorAstropart. Phys.272007199The non-thermal energy release in GRBs is much smaller than that output by AGN.P.L.BiermannP.A.StrittmatterAstrophys. J.3221987643R.J.ProtheroeA.P.SzaboPhys. Rev. Lett.6919922885J.P.RachenP.L.BiermannAstron. Astrophys.2721993161J.P.Ra

Anchordoqui, Luis A.; Hooper, Dan; Sarkar, Subir; Taylor, Andrew M.

2008-02-01

33

The anisotropy of the ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

Ultra-high energy cosmic rays (UHECRs) may originate from the decay of massive relic particles in the dark halo of the Galaxy, or they may be produced in nearby galaxies, for example by supermassive black holes in their nuclei. The anisotropy in the arrival directions is studied in four dark halo models (cusped, isothermal, triaxial and tilted) and in four galaxy samples (galaxies intrinsically brighter than Centaurus A within 50 and 100 Mpc, and galaxies intrinsically brighter than M32 within 50 and 100 Mpc). In decaying dark matter models, the amplitude of the anisotropy is controlled by the size of the Galactic halo, while the phase is controlled by the shape. As seen in the northern hemisphere, the amplitude is ˜0.5 for cusped haloes, but falls to ˜0.3 for isothermal haloes with realistic core radii. The phase points in the direction of the Galactic Centre, with deviations of ˜30° possible for triaxial and tilted haloes. The effect of the halo of M31 is too weak to provide conclusive evidence for the decaying dark matter origin of UHECRs. In extragalactic models, samples of galaxies brighter than Centaurus A produce substantial anisotropies (˜1.8), much larger than the limits set by the available data. If all galaxies brighter than M32 contribute, then the anisotropy is more modest (?0.5) and is directed towards mass concentrations in the supergalactic plane, like the Virgo cluster. Predictions are made for the south station (Malargüe) of the Pierre Auger Observatory. If the UHECRs have a Galactic origin, then the phase points towards the Galactic Centre. If they have an extragalactic origin, then it points in the rough direction of the Fornax cluster. This provides a robust discriminant between the two theories and requires ˜350-500 events at South Auger.

Evans, N. W.; Ferrer, F.; Sarkar, S.

2002-06-01

34

Generation, propagation, and detection of high energy solar cosmic rays  

Microsoft Academic Search

The data on energetic (E ? 1012eV) solar cosmic ray generation are presented for the event of September 29, 1989. Charged particle acceleration mechanisms in the flares of an energy below E = 1011 - 1012eV are substantiated.

V. V. Borog; A. Yu. Burinsky; V. V. Dronov; E. V. Kolomeets; V. M. Smirnov; E. A. Chebakova

1997-01-01

35

Physics and the Cosmos: The Origin of Cosmic Rays of ‘Low’ and ‘Very High’ Energies  

Microsoft Academic Search

The subject of 'cosmic rays' is one that embraces a vast range of particle and photon energies and is an ideal one for examining 'Physics and the Cosmos'. In the present work we examine the twin problems of the origin of cosmic rays of both low and very high energies and flnd that they are related by studies of the

Arnold W. Wolfendale

1997-01-01

36

High Energy Radiation From Black Holes: Gamma Rays, Cosmic Rays, and Neutrinos  

Microsoft Academic Search

Bright gamma-ray flares observed from sources far beyond our Milky Way Galaxy are best explained if enormous amounts of energy are liberated by black holes. The highest- energy particles in nature--the ultra-high-energy cosmic rays--cannot be confined by the Milky Way's magnetic field, and must originate from sources outside our Galaxy. In this talk, I summarize the themes of our book,

Charles D. Dermer; G. Menon

2010-01-01

37

The Acceleration of Ultra--High-Energy Cosmic Rays in Gamma-Ray Bursts  

Microsoft Academic Search

Ultra-high-energy cosmic rays (UHECRs) are roughly isotropic and attain very large energies, E ≳ 3 × 1020 eV. Conventional models fail to explain both facts. I show here that acceleration of UHECRs in gamma-ray bursts (GRBs) satisfies both observational constraints. Using the Mészáros & Rees model (see their recent work) of GRBs as due to hyperrelativistic shocks, I show that

Mario Vietri

1995-01-01

38

The angular deviation of ultra high energy cosmic rays in intergalactic magnetic fields  

Microsoft Academic Search

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

R. W. Clay; S. Cook; B. R. Dawson; A. G. K. Smith; R. Lampard

1998-01-01

39

High energy cosmic rays from the decay of gravitino dark matter  

SciTech Connect

We study high energy cosmic rays from the decay of the gravitino dark matter in the framework of supersymmetric model with R-parity violation. Even though R parity is violated, the lifetime of the gravitino, which is assumed to be the lightest superparticle, can be longer than the present age of the Universe if R-parity violating interactions are weak enough. We have performed a detailed calculation of the fluxes of gamma ray and positron from the decay of the gravitino dark matter. We also discuss the implication of such a scenario to present and future observations of high energy cosmic rays. In particular, we show that the excess of the gamma-ray flux observed by Energetic Gamma Ray Experiment Telescope and the large positron fraction observed by High Energy Antimatter Telescope can be simultaneously explained by the cosmic rays from the decay of the gravitino dark matter.

Ishiwata, Koji; Moroi, Takeo [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Matsumoto, Shigeki [Department of Physics, University of Toyama, Toyama 930-8555 (Japan)

2008-09-15

40

Observation of early photon conversions in high-energy cosmic-ray interactions  

SciTech Connect

High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied.

Asakimori, K. (Kobe Women's Junior College, Kobe (Japan)); Burnett, T.H. (University of Washington, Seattle, WA (United States)); Cherry, M.L. (Louisiana State University (United States)); Christl, M.J. (G. Marshall Space Flight Center/NASA (United States)); Dake, S. (Kobe Unibersity, Kobe (Japan)); Derrickson, J.H.; Fountain, W.F. (G. Marshall Space Flight Center/NASA (United States)); Fuki, M. (Kochi University (Japan)); Gregory, J.C.; Hayashi, T. (University of Alabama, Huntsville, AL (United States)); Holynski, R. (Institute for Nuclear Physics, Krakow (Poland)); Iwai, J. (University of Washington, Seattle, WA (United States)); Iyono, A. (Okayama University of Science (Japan)); Jones, W.V. (Louisiana State University (United States)); Jurak, A. (Institute for Nuclear Physics, Krakow (Poland)); Lord, J.J. (University of Washington,Seattle WA (United States)); Miyamura, O. (Hiroshima University, Hiroshima (Japan)); Oda, H. (Kobe University, Kobe (Japan)); Ogata, T. (I; The JACEE Collaboration

1993-06-15

41

Observation of early photon conversions in high-energy cosmic-ray interactions  

NASA Astrophysics Data System (ADS)

High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied.

Asakimori, K.; Burnett, T. H.; Cherry, M. L.; Christl, M. J.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Ho?Y?ski, R.; Iwai, J.; Iyono, A.; Jones, W. V.; Jurak, A.; Lord, J. J.; Miyamura, O.; Oda, H.; Ogata, T.; Olson, E. D.; Parnell, T. A.; Roberts, F. E.; Strausz, S. C.; Takahashi, Y.; Tominaga, T.; Watts, J. W.; Wefel, J. P.; Wilczy?ska, B.; Wilczy?ski, H.; Wilkes, R. J.; Wolter, W.; Wosiek, B.; Zager, E. L.

1993-06-01

42

Ultra-High Energy Cosmic Rays and Neutrinos  

NASA Astrophysics Data System (ADS)

In this paper, simulation of propagation of UHE-protons from nearby galaxies is presented. We found good parameter sets to explain the arrival distribution of UHECRs reported by AGASA and energy spectrum reported by HiRes. Using a good parameter set, we demonstrated how the distribution of arrival direction of UHECRs will be as a function of event numbers. We showed clearly that 1000-10000 events are necessary to see the clear source distribution. We also showed that effects of interactions and trapping of UHE-Nuclei in a galaxy cluster are very important. Especially, when a UHECR source is a bursting source such as GRB/AGN flare, heavy UHE-Nuclei are trapped for a long time in the galaxy cluster, which changes the spectrum and chemical composition of UHECRs coming from the galaxy cluster. We also showed that such effects can be also important when there have been sources of UHE-Nuclei in Milky Way. Since light nuclei escape from Milky Way in a short timescale, the chemical composition of UHECRs observed at the Earth can be heavy at high-energy range. Finally, we showed how much high-energy neutrinos are produced in GRBs. Since GRB neutrinos do not suffer from magnetic field bending, detection of high-energy neutrinos are very important to identify sources of UHECRs. Especially, for the case of GRBs, high-energy neutrinos arrive at the earth with gamma-rays simultaneously, which is very strong feature to identify the sources of UHECRs.

Nagataki, Shigehiro

2011-04-01

43

High-energy cosmic rays and neutrinos from semirelativistic hypernovae  

SciTech Connect

The origin of the ultrahigh-energy (UHE) cosmic rays (CRs) from the second knee ({approx}6x10{sup 17} eV) above in the CR spectrum is still unknown. Recently, there has been growing evidence that a peculiar type of supernovae, called hypernovae, are associated with subenergetic gamma-ray bursts, such as SN1998bw/GRB980425 and SN2003lw/GRB031203. Such hypernovae appear to have high (up to mildly relativistic) velocity ejecta, which may be linked to the subenergetic gamma-ray bursts. Assuming a continuous distribution of the kinetic energy of the hypernova ejecta as a function of its velocity E{sub k}{proportional_to}({gamma}{beta}){sup -{alpha}} with {alpha}{approx}2, we find that (1) the external shock wave produced by the high-velocity ejecta of a hypernova can accelerate protons up to energies as high as 10{sup 19} eV; (2) the cosmological hypernova rate is sufficient to account for the energy flux above the second knee; and (3) the steeper spectrum of CRs at these energies can arise in these sources. In addition, hypernovae would also give rise to a faint diffuse UHE neutrino flux, due to p{gamma} interactions of the UHE CRs with hypernova optical-UV photons.

Wang Xiangyu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Astronomy, Nanjing University, Nanjing 210093 (China); Razzaque, Soebur; Meszaros, Peter [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States); Dai Zigao [Department of Astronomy, Nanjing University, Nanjing 210093 (China)

2007-10-15

44

On ultra-high energy cosmic rays: Origin in AGN jets and transport in expanding universe  

NASA Astrophysics Data System (ADS)

The cosmic ray source spectrum produced by AGN (active galactic nucleus) jets is calculated. A distinctive feature of these calculations is the account for the jet distribution on kinetic energy. The expected cosmic ray spectrum at the Earth is determined with the use of a simple numerical code which takes into account interactions of ultra-high energy protons and nuclei with the background radiation in an expanding universe.

Ptuskin, Vladimir; Rogovaya, Svetlana; Zirakashvili, Vladimir

2013-01-01

45

Propagation of UltraHigh Energy Cosmic Rays in Extragalactic Magnetic Fields  

Microsoft Academic Search

In this paper we will discuss the problem of Ultra High Energy Cosmic Rays (UHECR) and show that the idea of a Single Source\\u000a Model established by Erlykin and Wolfendale (1997) to explain the features seen in cosmic ray energy spectra around the 1015 eV region can be successfully applied also for the much higher energies. The propagation of UHECR

Tadeusz Wibig

2004-01-01

46

Heavy Dark Matter and High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Conventional dark matter models assume that the dark matter is composed of new fundamental particles which interact only weakly with visible matter. One alternative to this picture is a model in which the dark matter is actually composed of standard model quarks (or antiquarks) bound into macroscopically large composite objects. If these objects are sufficiently massive they become unobservable due to their correspondingly small number density. For dark matter with very low density experimental searches are limited by detector size rather than sensitivity. I will outline the basic properties of quark nugget dark matter and analyze their interactions with molecules of earth's atmosphere. Depending on the nature of the quark matter involved the total energy deposited can be observably large. In this case the quark nugget will trigger an extensive air shower similar to that initiated by a single ultrahigh energy proton or nucleus. As such, it is possible that large scale cosmic ray experiments are capable of detecting this type of dark matter. A dark matter signal may be seen in both fluorescence and surface detectors as well as in radio detection experiments. I will offer a description of the potential signal in each of these channels and a brief summary of detection potential.

Lawson, Kyle

2012-10-01

47

The energy spectrum of ultra high energy cosmic rays measured by the High Resolution Fly's Eye observatory in stereoscopic mode  

Microsoft Academic Search

The High Resolution Fly's Eye cosmic ray observatory is designed to observe cosmic rays entering the Earth's atmosphere with energies above 10 18 eV. These ultra high energy cosmic rays produce a cascade of many particles called an extended air shower. Charged particles from the air shower deposit energy in the atmosphere, which acts as a calorimeter, causing atmospheric N

William F. Hanlon

2008-01-01

48

First measurements of cosmic-ray nuclei at high energy with CREAM  

NASA Astrophysics Data System (ADS)

The balloon-borne cosmic-ray experiment CREAM-I (Cosmic-Ray Energetics And Mass) recently completed a successful 42-day flight during the 2004 2005 NASA/NSF/NSBF Antarctic expedition. CREAM-I combines an imaging calorimeter with charge detectors and a precision transition radiation detector (TRD). The TRD component of CREAM-I is targeted at measuring the energy of cosmic-ray particles with charges greater than Z ˜ 3. A central science goal of this effort is the determination of the ratio of secondary to primary nuclei at high energy. This measurement is crucial for the reconstruction of the propagation history of cosmic rays, and consequently for the determination of their source spectra. First scientific results from this instrument are presented.

Wakely, S. P.; Ahn, H. S.; Allison, P.; Bagliesi, M. G.; Beatty, J. J.; Bigongiari, G.; Boyle, P.; Brandt, T. J.; Childers, J. T.; Conklin, N. B.; Coutu, S.; Duvernois, M. A.; Ganel, O.; Han, J. H.; Jeon, J. A.; Kim, K. C.; Lee, M. H.; Lutz, L.; Maestro, P.; Malinine, A.; Marrocchesi, P. S.; Minnick, S.; Mognet, S. I.; Nam, S. W.; Nutter, S.; Park, I. H.; Park, J. H.; Park, N. H.; Seo, E. S.; Sina, R.; Swordy, S. P.; Wu, J.; Yang, J.; Yoon, Y. S.; Zei, R.; Zinn, S. Y.

2008-08-01

49

Large scale structure in the intergalactic magnetic field and ultra-high energy cosmic ray propagation  

Microsoft Academic Search

The possibility that the magnetic field is strongly correlated with the large-scale structure of the universe has been recently proposed in the literature. In this scenario the intergalactic magnetic field has a strong (m Gauss) regular component spanning tens of Mpc. This could have severe consequences on the propagation of ultra-high energy cosmic rays, and the observed spectra, isotropy and

Gustavo Medina Tanco

1998-01-01

50

High Energy Neutrinos and Cosmic-Rays From Low-Luminosity Gamma-Ray Bursts?  

SciTech Connect

The recently discovered gamma-ray burst (GRB) 060218/SN 2006aj is classified as an X-ray Flash with very long duration driven possibly by a neutron star. Since GRB 060218 is very near {approx} 140 Mpc and very dim, one-year observation by Swift suggests that the true rate of GRB 060218-like events might be very high so that such low luminosity GRBs (LL-GRBs) might form a different population of GRBs from the cosmological high luminosity GRBs (HL-GRBs). We found that the high energy neutrino background from such LL-GRBs could be comparable with or larger than that from HL-GRBs. If each neutrino event is detected by IceCube, later optical-infrared follow-up observations such as by Subaru could identify a Type Ibc supernova associated with LL-GRBs, even if gamma- and X-rays are not observed by Swift. This is in a sense a new window from neutrino astronomy, which might enable us to confirm the existence of LL-GRBs and to obtain information about their rate and origin. We also argue LL-GRBs as high energy gamma-ray and cosmic-ray sources.

Murase, Kohta; /Kyoto U., Yukawa Inst., Kyoto; Ioka, Kunihito; /Kyoto U.; Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park; Nakamura, Takashi; /Kyoto U.

2006-07-10

51

Non-LTE astrophysics and the origin of high-energy cosmic rays  

SciTech Connect

The most startling aspects of the universe are the departures from the nonuniform, nonthermodynamic equilibrium state. Mass concentrations and high energy electromagnetic quanta and particles are the primary examples. Of these various departures the extremum of nonexplained phenomena is still the acceleration of cosmic rays. The usual explanations involving multiple mechanisms contributing to various regions of the spectrum is suggested as most unlikely. In particular, the suggestion of the acceleration of the very highest energy cosmic rays in distant active galactic nuclei is shown to be untenable because of photon particle interactions.

Colgate, S.A.

1982-01-01

52

Dark matter distribution in the universe and ultra-high energy cosmic rays  

SciTech Connect

Two of the greatest mysteries of modern physics are the origin of the dark matter in the universe and the nature of the highest energy particles in the cosmic ray spectrum. The authors discuss here possible direct and indirect connections between these two problems, with particular attention to two cases: in the first they study the local clustering of possible sources of ultra-high energy cosmic rays (UHECRs) driven by the local dark matter overdensity. In the second case they study the possibility that UHECRs are directly generated by the decay of weakly unstable super heavy dark matter.

Pasquale Blasi

2000-10-10

53

Chemical Composition of Ultra-High Energy Cosmic Rays Observed by AGASA  

NASA Astrophysics Data System (ADS)

We have observed ultra-high energy cosmic rays above the Greisen-ZatsepinKuz'min cut-off energy by Akeno Giant Air Shower Array. Their chemical composition is a key discriminator of origin models. In the present work, we estimate the average composition by an analysis of muons in air showers with AIRES+QGSJET simulation. The data matches the prediction for light hadron primaries and no indication has been found for a gamma-ray dominance.

Shinozaki, K.; Chikawa, M.; Fukushima, M.; Hayashida, N.; Honda, K.; Inoue, N.; Kadota, K.; Kakimoto, F.; Kamata, K.; Kawaguchi, S.; Kawakami, S.; Kawasaki, Y.; Kawasumi, N.; Mase, K.; Mizobuchi, S.; Nagano, M.; Ohoka, H.; Osone, S.; Sakaki, N.; Sakurai, N.; Sasaki, M.; Sasano, M.; Shimizu, H. M.; Takeda, M.; Teshima, M.; Torii, R.; Tsushima, I.; Uchihori, Y.; Yamamoto, T.; Yoshida, S.; Yoshii, H.

2003-07-01

54

High energy irradiations simulating cosmic-ray-induced planetary gamma ray production: I. Fe target.  

NASA Astrophysics Data System (ADS)

A series of 6 GeV proton irradiations at the Argonne National Laboratory's Zero Gradient Synchrocyclotron included the bombardment of two thick Fe targets for the purpose of simulating the cosmic ray bombardment of planetary objects in space. Cosmic ray bombardment leads to characteristic gamma ray production, from which, by measuring their energy and intensity, surface composition may be derived.

Metzger, A. E.; Parker, R. H.; Yellin, J.

1986-03-01

55

Possible Interpretations of the High Energy Cosmic Ray Electron Spectrum Measured with the Fermi Space Telescope  

SciTech Connect

The Fermi Large Area Telescope has provided the measurement of the high energy (20 GeV to 1 TeV) cosmic ray electrons and positrons spectrum with unprecedented accuracy. This measurement represents a unique probe for studying the origin and diffusive propagation of cosmic rays as well as for looking for possible evidences of Dark Matter. In this contribution we focus mainly on astrophysical sources of cosmic ray electrons and positrons which include the standard primary and secondary diffuse galactic contribution, as well as nearby point-sources which are expected to contribute more significantly to higher energies. In this framework, we discuss possible interpretations of Fermi results in relation with other recent experimental data on energetic electrons and positrons (specifically the most recent ones reported by PAMELA, ATIC, PPB-BETS and H.E.S.S.).

Grasso, D.; /INFN, Pisa; Profumo, S.; /UC, Santa Cruz; Strong, A.W.; /Garching, Max Planck Inst., MPE; Baldini, L.; /INFN, Pisa; Bellazzini, R.; /INFN, Pisa; Bloom, E.D.; /KIPAC, Menlo Park /SLAC; Bregeon, J.; /INFN, Pisa; Di Bernardo, G.; /INFN, Pisa /Pisa U.; Gaggero, D.; /INFN, Pisa /Pisa U.; Giglietto, N.; /Bari Polytechnic /INFN, Bari; Kamae, T.; /KIPAC, Menlo Park /SLAC; Latronico, L.; /INFN, Pisa; Longo, F.; /Trieste U.; Mazziotta, M.N.; /INFN, Bari; Moiseev, A.A.; /NASA, Goddard /Maryland U., College Park; Morselli, A.; /INFN, Rome2; Ormes, J.F.; /Denver U.; Pesce-Rollins, M.; /INFN, Pisa; Pohl, M.; /Iowa State U.; Razzano, M.; /INFN, Pisa; Sgro, C.; /INFN, Pisa /INFN, Pisa /NASA, Ames

2012-04-25

56

Identification of Gamma Ultra High Energy Cosmic Rays by Simulating Extensive Air Showers  

NASA Astrophysics Data System (ADS)

Among the most interesting tasks for the identification of Ultra High Energy Cosmic Rays (origin, mechanisms of acceleration, top down model, direction, and maximum energy) is their isotopic composition. For example, if they are protons, heavier nuclei, gammas or even exotic. Air Shower Extended Simulation code (AIRES) is used to simulate the Extended Atmospheric Showers. This code gives, among others, the maximum number of secondary particles within the atmosphere along the longitudinal direction of the showers. From the distribution of the depths of maximum number of shower particles and their content in muons, we can distinguish between proton and gamma primary cosmic rays, both of energy of 100 EeV. The results show a maximum at lower atmospheric depths for protons and at higher for gammas, respectively. Due to the bremsstrahlung and pair production effects, the muon content of gamma showers is much poorer than of protons. Both facts enable the distinction between proton and gamma cosmic rays. For the simulation of the atmospheric EAS due to the passage of an Ultra High Energy Cosmic Ray, the Linsley standard atmospheric model is used.

Geranios, A.; Fokitis, E.; Maltezos, S.; Mastichiadis, A.; Malandraki, O. E.; Antoniadou, I.

2006-08-01

57

The Connection Between Ultra-High-Energy Cosmic Rays and Fermi Gamma-Ray Sources  

NASA Astrophysics Data System (ADS)

We analyze the correlation of the positions of gamma-ray sources in the Fermi Large Area Telescope First Source Catalog (1FGL) and the First LAT Active Galactic Nuclei (AGN) Catalog (1LAC) with the arrival directions of ultra-high-energy cosmic rays (UHECRs) observed with the Pierre Auger Observatory, in order to investigate the origin of UHECRs. We find that Galactic sources and blazars identified in the 1FGL are not significantly correlated with UHECRs, while the 1LAC sources display a mild correlation (2.6sigma level) on an 2.4deg angular scale. When selecting only the 1LAC AGNs closer than 200 Mpc, we find a strong association (5.4sigma) between their positions and the directions of UHECRs on an 17deg angular scale; the probability of the observed configuration being due to an isotropic flux of cosmic rays is 5E-8. There is also a 5sigma correlation with nearby 1LAC sources on an 6.5deg scale. We identify 7 ``gamma-ray loud'' AGNs which are associated with UHECRs within 17deg and are likely candidates for the production sites of UHECRs: Centaurus A, NGC 4945, ESO 323-G77, 4C+04.77, NGC 1218, RX J0008.0+1450 and NGC 253. We interpret these results as providing additional support to the hypothesis of the origin of UHECRs in nearby extragalactic objects. As the angular scales of the correlations are large, we discuss the possibility that intervening magnetic fields might be considerably deflecting the trajectories of the particles on their way to Earth.

Nemmen, Rodrigo; Storchi-Bergmann, T.; Bonnatto, C.

2011-01-01

58

Large scale structure in the intergalactic magnetic field and ultra-high energy cosmic ray propagation  

Microsoft Academic Search

The possibility that the magnetic field is strongly correlated with the\\u000alarge-scale structure of the universe has been recently proposed in the\\u000aliterature. In this scenario the intergalactic magnetic field has a strong (m\\u000aGauss) regular component spanning tens of Mpc. This could have severe\\u000aconsequences on the propagation of ultra-high energy cosmic rays, and the\\u000aobserved spectra, isotropy and

Gustavo Medina Tanco

1998-01-01

59

Quasi-drift effects of high-energy solar cosmic rays in the magnetosphere  

SciTech Connect

The authors discuss a problem of the penetration of high energy cosmic rays into the magnetosphere, from a very anisotropic solar proton event in February, 1984, using data from riometers, from the satellite DMSP-F6, and from neutron monitors. They seek to explain the maxima observed at auroral latitudes in solar proton intensity. They propose the precipitation of quasi-trapped particles as the explanation of such phenomena.

Shumilov, O.I.; Vashenyuk, E.V. [Polar Geophysical Lab., St. Petersburg (Russian Federation); Henriksen, K. [Univ. of Tromso (Norway)

1993-10-01

60

Response Functions of Phoswich-Type Neutron Detector for High-Energy Cosmic Ray Neutron Measurement  

Microsoft Academic Search

A phoswich-type neutron detector was developed in order to measure high-energy cosmic ray neutron spectra in aircraft. The neutron detector consists of an EJ309 organic liquid scintillator that is 121.7mm in diameter and 121.7mm in length and is covered with a 15mm thick EJ299-13 outer plastic scintillator. The neutron response functions of the detector are required for the unfolding method

Masashi TAKADA; Kazuaki YAJIMA; Hiroshi YASUDA; Takashi NAKAMURA; Mamoru BABA; Toshihiro HONMA; Akira ENDO; Yoshihiko TANIMURA

2010-01-01

61

The AMY experiment to measure GHz radiation for Ultra-High Energy Cosmic Ray detection  

NASA Astrophysics Data System (ADS)

The Air Microwave Yield (AMY) project aims to measure the emission in the GHz regime from test-beam induced air-shower. The experiment is using the Beam Test Facility (BTF) of the Frascati INFN National Laboratories in Italy. The final purpose is to characterize a process to be used in a next generation of ultra-high energy cosmic rays (UHECRs) detectors. We describe the experimental apparatus and the first test performed in November 2011.

Alvarez-Muniz, J.; Bohacova, M.; Cataldi, G.; Coluccia, M. R.; Creti, P.; De Mitri, I.; Di Giulio, C.; Engel, R.; Facal San Luis, P.; Iarlori, M.; Martello, D.; Monasor, M.; Perrone, L.; Petrera, S.; Privitera, P.; Riegel, M.; Rizi, V.; Rodriguez Fernandez, G.; Salamida, F.; Salina, G.; Settimo, M.; Smida, R.; Verzi, V.; Werner, F.; Williams, C.

2013-02-01

62

Inverse problem for transport equation of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

Propagation of ultra-high energy nuclei in expending universe filled with background radiation is considered. We developed numerical code for solution of inverse problem for cosmic-ray transport equation that allows determination of source spectrum from the spectrum observed at the Earth. The injection spectra of protons and iron nuclei in extragalactic sources are found assuming that these species dominate in the source composition. Data from the Auger and Telescope Array experiments are used to illustrate the method.

Ptuskin, V. S.; Rogovaya, S. I.; Zirakashvili, V. N.; Klepach, E. G.

2013-02-01

63

Measurement of ultra-high energy cosmic rays: An experimental summary and prospects  

NASA Astrophysics Data System (ADS)

Measurements of Ultra-High Energy Cosmic Rays achieved remarkable progress in the last 10 years. Physicists, gathered from around the world in the symposium UHECR-2012 held at CERN on February 13-16 2012, reported their most up-to-date observations, discussed the meaning of their findings, and identified remaining problems and future challenges in this field. This paper is a part of the symposium proceedings on the experimental summary and future prospects of the UHECR study.

Fukushima, M.

2013-06-01

64

Double pair production by ultra-high-energy cosmic ray photons  

SciTech Connect

Using the CompHEP package, we provide a detailed estimate of the influence of double e{sup +}e{sup -} pair production (DPP) by photons on the propagation of ultra-high-energy electromagnetic cascades. We show that in the models where the cosmic ray photon energy reaches a few 10{sup 3} EeV, a refined DPP analysis may lead to a substantial difference in the predicted photon spectrum compared to the previous rough estimates.

Demidov, S. V., E-mail: demidov@ms2.inr.ac.ru; Kalashev, O. E. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)], E-mail: kalashev@ms2.inr.ac.ru

2009-05-15

65

A combined cosmic ray muon spectrometer and high energy air shower array  

SciTech Connect

Cosmic rays have been detected at energies in excess of 10/sup 20/ eV, and individual sources have been conclusively identified as intense emitters of gamma rays at energies up to 10/sup 16/ eV. There is clearly a great deal of exciting astrophysics to be learned from such studies, but it has been suggested that there may be particle physics to be learned from the cosmic beam as well. Based in particular on the reports of surprisingly high fluxes of underground muons from the direction of Cygnus X-3 modulated by the known orbital period, there have been several suggestions recently invoking stable supersymmetric particles produced at Cygnus X-3, enhanced muon production from high energy photons, quark matter, and ''cygnets.'' Although the underground muon results have been questioned, it may still be worthwhile to consider the possibility of new physics beyond the standard model with energy scale (G/sub F/)/sup -1/2/ greater than or equal to 0.25 TeV. For example, there have been recent discussions on the experimental signatures to be observed from new high energy photon couplings to matter, exchanges between constituent quarks and leptons, and stable gluinos and photinos mixed in with the cosmic gamma ray flux. We describe here a possible detector to search for such effects. We utilize the possibility that point sources like Cygnus X-3 can be used to provide a directional time-modulated ''tagged'' high energy photon beam.

Cherry, M.L.; Ayres, D.S.; Halzen, F.

1986-01-01

66

The ANITA experiment: new high-energy neutrino limits and detection of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

The ANITA (ANtarctic Impulsive Transient Antenna) instrument is a balloon-borne telescope designed to detect coherent radio Cherenkov emission in the frequency range of 200-1200 MHz from showers produced in the Antarctic ice by interaction of cosmogenic ultra-high energy neu-trinos with energy greater than about 3 x 1018 eV. We will discuss results from the second flight (ANITA-II), which was launched in December 2008 from Antarctica and included signif-icant improvements in sensitivity and efficiency for neutrino detection over that of ANITA-I, which was launched in December 2006. Additionally, the balloon trajectory of ANITA-II gave substantially more time over deep ice than that of ANITA-I. We will present upper limits on neutrinos that constrain models of neutrino origin. In addition, we have 16 events detected in the ANITA-I flight with strong evidence of their origin as geosynchrotron radio emission reflecting off of the Antarctic snow from ultra-high-energy (of order 1019 eV) cosmic-ray air showers. The increasing aperture of this technique with energy allows us to set limits on the presence of cosmic rays with energies beyond 1020 eV.

Binns, Walter; Gorham, P. W.; Allison, P.; Baughmann, B.; Beatty, J. J.; Belov, K.; Besson, D. Z.; Bevan, S.; Binns, W. R.; Chen, C.; Chen, P.; Clem, J. M.; Connolly, A.; Detrixhe, M.; Demarco, D.; Dowkontt, P. F.; Goodhue-Vieregg, A.; Grashorn, E.; Hill, N. Griffith. B.; Hoover, S.; Israel, M. H.; Javaid, A.; Liewer, K. M.; Matsuno, S.; Mercurio, B. C.; Miki, C.; Mottram, M.; Nam, J.; Nichol, R. J.; Palladino, K.; Romero-Wolf, A.; Ruckman, L.; Saltzberg, D.; Seckel, D.; Varner, G. S.; Wang, Y.

67

Ultra-high energy cosmic-rays: A fresh look at an old problem  

NASA Astrophysics Data System (ADS)

The nature of the ultra-high energy cosmic-rays (UHECR) is an old problem with many important issues still unresolved. The body of experimental evidence has increased significantly in recent years. Much of this new knowledge has come from the Pierre Auger Observatory and the Telescope Array Project, both are cosmic-ray observatories, but there are also interesting clues from gamma-ray and neutrino observatories. In this talk I will briefly outline the current experimental evidence. Then I will discuss several distinctly different pictures with regard to the nature of the UHECR. I will argue that there is no simple picture of the UHECR that is without difficulty. I will describe some possible ways forward on both the experimental and phenomenological fronts.

Younk, Patrick

2013-04-01

68

High energy cosmic-ray interactions with particles from the Sun  

SciTech Connect

Cosmic-ray protons with energies above 10{sup 16} eV passing near the Sun may interact with photons emitted by the Sun and be excited to a {Delta}{sup +} resonance. When the {Delta}{sup +} decays, it produces pions which further decay to muons and photons which may be detected with terrestrial detectors. A flux of muons, photon pairs (from {pi}{sup 0} decay), or individual high energy photons coming from near the Sun would be a rather striking signature, and the flux of these particles is a fairly direct measure of the flux of cosmic-ray nucleons, independent of the cosmic-ray composition. In a solid angle within 15 deg. around the Sun, the flux of photon pairs is about 1.3x10{sup -3} particles/(km{sup 2{center_dot}}yr), while the flux of muons is about 0.33x10{sup -3} particles/(km{sup 2{center_dot}}yr). This is beyond the reach of current detectors like the Telescope Array, Auger, KASCADE-Grande, or IceCube. However, the muon flux might be detectable by next-generation air-shower arrays or neutrino detectors such as ARIANNA or ARA. We discuss the experimental prospects in some detail. Other cosmic-ray interactions occurring close to the Sun are also briefly discussed.

Andersen, Kristoffer K. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Klein, Spencer R. [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Department of Physics, University of California, Berkeley, California 94720 (United States)

2011-05-15

69

High energy cosmic-ray interactions with particles from the Sun  

NASA Astrophysics Data System (ADS)

Cosmic-ray protons with energies above 1016eV passing near the Sun may interact with photons emitted by the Sun and be excited to a ?+ resonance. When the ?+ decays, it produces pions which further decay to muons and photons which may be detected with terrestrial detectors. A flux of muons, photon pairs (from ?0 decay), or individual high energy photons coming from near the Sun would be a rather striking signature, and the flux of these particles is a fairly direct measure of the flux of cosmic-ray nucleons, independent of the cosmic-ray composition. In a solid angle within 15° around the Sun, the flux of photon pairs is about 1.3×10-3particles/(km2·yr), while the flux of muons is about 0.33×10-3particles/(km2·yr). This is beyond the reach of current detectors like the Telescope Array, Auger, KASCADE-Grande, or IceCube. However, the muon flux might be detectable by next-generation air-shower arrays or neutrino detectors such as ARIANNA or ARA. We discuss the experimental prospects in some detail. Other cosmic-ray interactions occurring close to the Sun are also briefly discussed.

Andersen, Kristoffer K.; Klein, Spencer R.

2011-05-01

70

Monocular measurement of the ultra-high energy cosmic ray spectrum  

NASA Astrophysics Data System (ADS)

The Telescope Array Project was designed to observe cosmic rays with energies greater than 1018 eV. Its goals are to study the physics of cosmic rays by measuring their anisotropy, composition, and energy spectrum. This work makes a monocular measurement of the ultra high energy cosmic ray spectrum and analyzes the physics produced from that spectrum. The flux of cosmic rays observed on Earth follows a power law over 12 decades in energy and 32 decades in flux. At the highest energies, the spectrum has detailed structure. Studying these features can tell us about the astrophysics of the production and propagation of cosmic rays. First, it can tell us about the sources of cosmic rays such as they capable of producing a power law spectrum and the maximum energy of cosmic rays that they can produce. Second, the acceleration mechanisms that can boost cosmic rays to ultra high energies can be studied. Third, the spectral features themselves can tell us about their possible cause for formation. For example, the ankle feature in the ultra high energy regime can tell us if it is the galactic-extragalactic transition or if it is due to e+e- pair production. Fourth, the energy losses that cosmic rays incur can tell us about their physical interactions during propagation. Studying the physics of the cosmic ray spectrum in the ultra high energy regime with data from the Telescope Array Project is the goal of this analysis. The Telescope Array Project consists of three fluorescence detectors overlooking an array of 507 scintillation surface detectors. Due to their extremely low flux at these energies, cosmic rays can only be observed indirectly via an extensive air shower produced when they collide with the nucleus of an atom in the Earth's atmosphere. These charged secondary particles produce fluorescence light. The array of surface detectors observes the lateral footprint of the extensive air shower when it reaches the ground. The fluorescence detectors observe the longitudinal profile of this fluorescence light. This thesis analyzes the data from one of the fluorescence detectors, Middle Drum, using a different geometry reconstruction technique, the Time versus Angle geometry. The results of this analysis show an ultra high energy cosmic ray spectrum that is consistent with the results previously published by the High Resolution Fly's Eye (HiRes) experiment, the Telescope Array surface detectors, and other experiments in this energy region. Due to insufficient statistics at this date, the GZK cutoff cannot be confirmed in this analysis, but a fit shows the cutoff to be at log10 E (E/eV) = 19.56 ± 0.36, with a spectral index after the cutoff of – 3.86 ± 2.0. This is within the range determined previously by other measurements. This analysis shows that the feature known as the ankle occurs at log10 E (E/eV) = 18.63 ± 0.09, with a spectral index of – 3.27 ± 0.07 before the ankle and a spectral index of – 2.81 ± 0.10 after the ankle. The normalized log likelihood per degree of freedom is 0.90. The ankle is observed at the 4 — 5 ? confidence level. The fit to the ankle is also in excellent agreement with previous measurements, and even more remarkable given that some other measurements use different techniques. While this study cannot tell us information about the sources or the acceleration mechanisms of cosmic rays, it does show us a feature and tell us about energy losses during propagation. The dip at the ankle is clearly visible in the spectrum. The results of this study are consistent with the energy loss model of extragalactic protons interacting with the cosmic microwave background radiation and supports the idea that the ankle is excavated due to e+e- pair production. The location of the ankle at a threshold greater than for e+e- pair production supports that the ankle is a composite feature where the redshift energy losses begin to dominate the e+e- pair production losses. The location of the ankle also implies that sources at larger distances than the GZK cutoff contribute to its formation.

Shah, Priti Dhanesh

71

Significance of the second dip in the ultra-high energy cosmic ray spectrum  

NASA Astrophysics Data System (ADS)

A new feature in the spectrum of ultra high energy cosmic rays (UHECR) has been announced in the paper by Berezinsky, Gazizov and Kachelrie?. The ratio of the solution of the exact transport equation to its solution in the continuous energy loss limit shows intriguing features which, according to the Authors, are related to the very nature of the energy loss processes of UHECR: the very sharp second dip predicted at 6.3 × 1019 eV can be used as an energy calibration point and also as the UHECR mass indicator for big future cosmic ray experiments. In the present paper we would like to advocate that this statement is an overinterpretation. The second dip is a result of an inappropriate approximation used, and thus it cannot help to understand the nature of UHECR in any way.

Wibig, Tadeusz

2007-12-01

72

Effects of Cosmic Infrared Background on High Energy Delayed Gamma-Rays From Gamma-Ray Bursts  

SciTech Connect

Regenerated high energy emissions from gamma-ray bursts (GRBs) are studied in detail. If the primary emission spectrum extends to TeV range, these very high energy photons will be absorbed by the cosmic infrared background (CIB). The created high energy electron-positron pairs up-scatter not only cosmic microwave background (CMB) photons but also CIB photons, and secondary photons are generated in the GeV-TeV range. These secondary delayed photons may be observed in the near future, and useful for a consistency check for the primary spectra and GRB physical parameters. The up-scattered CIB photons cannot be neglected for low redshift bursts and/or GRBs with a relatively low maximum photon energy. The secondary gamma-rays also give us additional information on the CIB, which is uncertain in observations so far.

Murase, Kohta; /Kyoto U., Yukawa Inst., Kyoto; Asano, Katsuaki; /Natl. Astron. Observ. of Japan; Nagataki, Shigehiro; /Kyoto U., Yukawa Inst., Kyoto /KIPAC, Menlo Park

2007-04-06

73

Searching for supersymmetry in high-energy cosmic-ray interactions  

SciTech Connect

We survey the prospects for producing and detecting supersymmetric particles in high-energy cosmic-ray interactions. We find that the production and subsequent decay of light (approx.3 GeV) gluinos can lead to fluxes of neutral, weakly interacting superparticles, photinos or scalar neutrinos, which might be detected in large, underwater neutrino detectors. We identify several reactions, gamma-tildeN..-->..gqX in the 10--100-TeV region and the resonant process nu-tilde/sub e/e/sup -/..-->..W/sup -/, which can lead to measurable reaction rates in the discussed 10/sup 5/-kiloton DUMAND-type detector.

Robinett, R.W.

1986-03-01

74

New High-Energy Cosmic-Ray Observatory (HERO) project for studying the high-energy primary cosmic-ray radiation  

NASA Astrophysics Data System (ADS)

Proposal on high-power supply High-Energy cosmic-Ray Observatory (HERO) is considered. It is proposed to carry out long-term (>7 years) studies of the spectrum and charge composition of PCR nuclei up to E˜1016 eV, the energy spectra of electrons at E=1011-1013 eV and diffusive ?-rays at E<5?1012 eV. The HERO instrument is characterized by a geometrical factor of 6.0-9.0 m2sr depending on particle type; mass of ˜2800 kg; channel number of ˜8?105; power consumption of 16.5 kW. The device consists of (a) 3D image scintillator ionization calorimeter of 80-cm linear size, thickness of 22 X and 2.5 ?intp with an absorber from lead and admixture of Gd64; (b) multilayer silicon-microstrip track system; (c) multilayer silicon-pad charge detectors. Energy is measured by using (a) ionization and (b) neutron calorimetry techniques, (c) kinematics approach. The e±/?-initiated cascades are selected by using neutron-yield counting and cascade-shape analysis approaches.

Atkin, E. V.; Burylov, L. S.; Chubenko, A. P.; Kuznetsov, N. V.; Merkin, M. M.; Mukhamedshin, R. A.; Pavlov, A. Yu.; Podoroznhy, D. M.; Romanov, A. V.; Sveshnikova, L. G.; Tkachev, L. G.; Turundaevsky, A. N.; Voronin, A. G.

2009-12-01

75

Ultra High Energy Cosmic Rays in the North Some Results from the High Resolution Fly's Eye  

NASA Astrophysics Data System (ADS)

The High Resolution Fly's Eye (HiRes) observatory collected Ultra High Energy Cosmic Ray (UHECR) data between 5/1997 and 4/2006. The experiment observed cosmic ray air showers via the air fluorescence technique and consisted of two observatory sites separated by 12.6 km in the western Utah desert. The two stations each measured the cosmic ray showers in monocular mode, however, the data from the two stations can also be combined to form a stereo measurement of the air showers. The experiment measures such properties as the energy spectrum, chemical composition, and p-air cross-section of these cosmic rays. It also searches for point sources and other anisotropy. The spectrum is measured above ~3 × 1017 eV and shows significant structure including the ``ankle'' and a steep fall off which is consistent with the expectation of the GZK threshold. The spectrum is inconsistent with a continuing spectrum at the 5? level. The composition is measured using the Xmax technique. It was found to be predominantly light and unchanging above 1018 eV. Finally, several different styles of searches for anisotropy in the data were performed. There are tantalizing hints including potential correlation with BL Lac objects and the ``AGASA triplet'', however these will need to be confirmed with an independent data set. Many members from HiRes have now joined a contingent from the old AGASA collaboration and the new group - The Telescope Array (TA) Project - will merge the techniques of its two predecessors. TA data collection begins mid-2007.

Matthews, J. N.

2007-08-01

76

The Radiation Dose at Commercial Aircraft Altitudes During the January 2005 High-Energy Solar Cosmic ray Event and the Effects of the Solar Cosmic ray Anisotropy  

NASA Astrophysics Data System (ADS)

The radiation dose to aircrews and passengers is a phenomenon of societal interest. There is a requirement to provide alerts whenever the radiation dose exceeds 20 micro-sieverts per hour at flight altitudes. The possibility that this might occur during a large high-energy solar cosmic ray event has resulted in much speculation. During the 20 January 2005 ground-level event the FAA Solar Radiation Alert System would have issued such an alert for aircraft at high latitudes for flight altitudes above 40,000 feet. Analysis of the GOES high-energy proton data results in a predicted dose rate of 23 micro Sv per hour at 60,000 feet for the first hour of the event. We also predict that the maximum peak dose rate would have been higher at the geographical position corresponding to the peak anisotropic flux intensity and would be correspondingly lower at geographical positions receiving a lower high energy solar cosmic ray flux. The solar high-energy flux anisotropy is extremely variable among the observed solar cosmic ray ground-level events. The 20 January 2005 event had one of the most extreme anisotropies yet observed by ground-level cosmic ray neutron monitors. We discuss the effects of this anisotropy with respect to aircraft radiation dose.

Smart, D. F.; Shea, M. A.; Friedberg, W.; Copeland, K.; Sauer, H. H.

2005-12-01

77

HOW MANY ULTRA-HIGH ENERGY COSMIC RAYS COULD WE EXPECT FROM CENTAURUS A?  

SciTech Connect

The Pierre Auger Observatory has associated a few ultra-high energy cosmic rays (UHECRs) with the direction of Centaurus A. This source has been deeply studied in radio, infrared, X-ray, and {gamma}-rays (MeV-TeV) because it is the nearest radio-loud active galactic nucleus. Its spectral energy distribution or spectrum shows two main peaks, the low-energy peak, at an energy of 10{sup -2} eV, and the high-energy peak, at about 150 keV. There is also a faint very high energy (VHE; E {>=} 100 GeV) {gamma}-ray emission fully detected by the High Energy Stereoscopic System experiment. In this work, we describe the entire spectrum: the two main peaks with a synchrotron/synchrotron self-Compton model, and the VHE emission with a hadronic model. We consider p{gamma} and pp interactions. For the p{gamma} interaction, we assume that the target photons are those produced at 150 keV in leptonic processes. On the other hand, for the pp interaction we consider as targets the thermal particle densities in the lobes. Requiring a satisfactory description of the spectra at very high energies with p{gamma} interaction, we obtain an excessive luminosity in UHECRs (even exceeding the Eddington luminosity). However, when considering the pp interaction to describe the {gamma}-spectrum, the number of UHECRs obtained is in agreement with Pierre Auger observations. We also calculate the possible neutrino signal from pp interactions on a Km{sup 3} neutrino telescope using Monte Carlo simulations.

Fraija, N.; Gonzalez, M. M.; Perez, M. [Instituto de Astronomia, Universidad Nacional Autonoma de Mexico, Circuito Exterior, C.U., A. Postal 70-264, 04510 Mexico D.F. (Mexico); Marinelli, A., E-mail: nifraija@astro.unam.mx, E-mail: magda@astro.unam.mx, E-mail: jguillen@astro.unam.mx, E-mail: antonio.marinelli@fisica.unam.mx [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Circuito Exterior, C.U., A. Postal 70-264, 04510 Mexico D.F. (Mexico)

2012-07-01

78

Ultra-high-energy cosmic ray acceleration in engine-driven relativistic supernovae.  

PubMed

The origin of ultra-high-energy cosmic rays (UHECRs) remains an enigma. They offer a window to new physics, including tests of physical laws at energies unattainable by terrestrial accelerators. They must be accelerated locally, otherwise, background radiations would severely suppress the flux of protons and nuclei, at energies above the Greisen-Zatsepin-Kuzmin (GZK) limit. Nearby, gamma ray bursts (GRBs), hypernovae, active galactic nuclei and their flares have all been suggested and debated as possible sources. A local sub-population of type Ibc supernovae (SNe) with mildly relativistic outflows have been detected as sub-energetic GRBs, X-ray flashes and recently as radio afterglows without detected GRB counterparts. Here, we measure the size-magnetic field evolution, baryon loading and energetics, using the observed radio spectra of SN 2009bb. We place such engine-driven SNe above the Hillas line and establish that they can readily explain the post-GZK UHECRs. PMID:21285953

Chakraborti, S; Ray, A; Soderberg, A M; Loeb, A; Chandra, P

2011-02-01

79

Constraints on the Source of Ultra-high-energy Cosmic Rays Using Anisotropy versus Chemical Composition  

NASA Astrophysics Data System (ADS)

The joint analysis of anisotropy signals and chemical composition of ultra-high-energy cosmic rays offers strong potential for shedding light on the sources of these particles. Following up on an earlier idea, this paper studies the anisotropies produced by protons of energy >E/Z, assuming that anisotropies at energy >E have been produced by nuclei of charge Z, which share the same magnetic rigidity. We calculate the number of secondary protons produced through photodisintegration of the primary heavy nuclei. Making the extreme assumption that the source does not inject any proton, we find that the source(s) responsible for anisotropies such as reported by the Pierre Auger Observatory should lie closer than ~20-30, 80-100, and 180-200 Mpc if the anisotropy signal is mainly composed of oxygen, silicon, and iron nuclei, respectively. A violation of this constraint would otherwise result in the secondary protons forming a more significant anisotropy signal at lower energies. Even if the source were located closer than this distance, it would require an extraordinary metallicity >~ 120, 1600, and 1100 times solar metallicity in the acceleration zone of the source, for oxygen, silicon, and iron, respectively, to ensure that the concomitantly injected protons do not produce a more significant low-energy anisotropy. This offers interesting prospects for constraining the nature and the source of ultra-high-energy cosmic rays with the increase in statistics expected from next-generation detectors.

Liu, Ruo-Yu; Taylor, Andrew M.; Lemoine, Martin; Wang, Xiang-Yu; Waxman, Eli

2013-10-01

80

A Study of the Composition of Ultra-High-Energy Cosmic Rays Using the High-Resolution Fly's Eye  

Microsoft Academic Search

The composition of ultra-high-energy cosmic rays is measured with the High Resolution Fly's Eye cosmic-ray observatory data using the Xmax technique. Data were collected in stereo between 1999 November and 2001 September. The data are reconstructed with well-determined geometry. Measurements of the atmospheric transmission are incorporated in the reconstruction. The detector resolution is found to be 30 g cm-2 in

R. U. Abbasi; T. Abu-Zayyad; G. Archbold; R. Atkins; J. Bellido; K. Belov; J. W. Belz; S. BenZvi; D. R. Bergman; J. Boyer; G. W. Burt; Z. Cao; R. Clay; B. M. Connolly; B. Dawson; W. Deng; Y. Fedorova; J. Findlay; C. B. Finley; W. F. Hanlon; G. A. Hughes; P. Huntemeyer; C. C. H. Jui; K. Kim; M. A. Kirn; B. Knapp; E. C. Loh; M. M. Maetas; K. Martens; G. Martin; N. Manago; E. J. Mannel; J. A. J. Matthews; J. N. Matthews; A. O'Neill; L. Perera; K. Reil; R. Riehle; M. D. Roberts; M. Sasaki; M. Seman; S. R. Schnetzer; K. Simpson; J. D. Smith; R. Snow; P. Sokolsky; C. Song; R. W. Springer; B. T. Stokes; J. R. Thomas; S. B. Thomas; G. B. Thomson; S. Westerhoff; L. R. Wiencke; A. Zech

2005-01-01

81

TEV Burst of Gamma-Ray Bursts and Ultra-High-Energy Cosmic Rays  

Microsoft Academic Search

Some recent experiments detecting very high energy (VHE) gamma rays above 10-20 TeV independently reported VHE bursts for some bright gamma-ray bursts (GRBs). If these signals are truly from GRBs, these GRBs must emit a much larger amount of energy as VHE gamma rays than in the ordinary photon energy range of GRBs (keV-MeV). We show that such extreme phenomena

Tomonori Totani

1998-01-01

82

ULTRA-HIGH-ENERGY COSMIC RAYS FROM CENTAURUS A: JET INTERACTION WITH GASEOUS SHELLS  

SciTech Connect

Ultra-high-energy cosmic rays (UHECRs), with energies above {approx}6 x 10{sup 19} eV, seem to show a weak correlation with the distribution of matter relatively near to us in the universe. It has earlier been proposed that UHECRs could be accelerated in either the nucleus or the outer lobes of the nearby radio galaxy Cen A. We show that UHECR production at a spatially intermediate location about 15 kpc northeast from the nucleus, where the jet emerging from the nucleus is observed to strike a large star-forming shell of gas, is a plausible alternative. A relativistic jet is capable of accelerating lower energy heavy seed cosmic rays (CRs) to UHECRs on timescales comparable to the time it takes the jet to pierce the large gaseous cloud. In this model, many CRs arising from a starburst, with a composition enhanced in heavy elements near the knee region around PeV, are boosted to ultra-high energies by the relativistic shock of a newly oriented jet. This model matches the overall spectrum shown by the Auger data and also makes a prediction for the chemical composition as a function of particle energy. We thus predict an observable anisotropy in the composition at high energy in the sense that lighter nuclei should preferentially be seen toward the general direction of Cen A. Taking into consideration the magnetic field models for the Galactic disk and a Galactic magnetic wind, this scenario may resolve the discrepancy between HiRes and Auger results concerning the chemical composition of UHECRs.

Gopal-Krishna [National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune, 411 007 (India); Biermann, Peter L. [Max-Planck-Institute for Radioastronomy, Auf dem Huegel 69, 53121 Bonn (Germany); De Souza, Vitor [Instituto de Fisica de Sao Carlos, Universidade de Sao Paulo, Av. Trabalhador Sao-carlense 400, Centro, CEP 13566-590, Sao Carlos (Brazil); Wiita, Paul J., E-mail: krishna@ncra.tifr.res.i [Department of Physics, The College of New Jersey, P.O. Box 7718, Ewing, NJ 08628 (United States)

2010-09-10

83

EUSO: Using high energy cosmic rays and neutrinos as messengers from the unknown universe  

NASA Astrophysics Data System (ADS)

The mission ``Extreme Universe Space Observatory - EUSO'' is devoted to the investigation of the Extreme Energy Cosmic Rays (EECR with E>5×1019 eV) and of the High Energy Cosmic Neutrino flux looking at the streak of UV fluorescence light produced when the particles coming from Outer Space interact with the Earth's atmosphere. EUSO will observe the fluorescence signal looking downward from Space the dark Earth atmosphere under a 60 degrees full field of view; the Fluorescence light will be imaged by a large Fresnel lens optics into a finely segmented focal plane detector. The segmentation and the time resolution adopted will consent to reconstruct the shower arrival direction and energy with high precision, EUSO is a collaborating effort of 27 research groups from Europe, U.S.A, and Japan and it has been designed to operate for more than 3 years mission life-time; it is expected to detect of the order of 103/year EECRs with E>1020 eV and to open a window into the High Energy Neutrino Astronomy. Originally proposed to the European Space Agency as a Free Flyer Low Earth Orbit Mission, EUSO has been approved by ESA in march 2000 for an Accommodation Study on the International Space Station, with a goal for flight in 2006. .

Scarsi, Livio

2001-05-01

84

Patterns in ultra-high energy cosmic ray arrival directions: a possible footprint of large scale cosmic structures  

SciTech Connect

The public available data of cosmic ray arrival directions with energies above 4 x 10{sup 19} eV present a broad maximum in the cumulative two-point autocorrelation function around 25 degrees. This has been interpreted as the first imprint of the filamentary pattern of large scale structures (LSS) of matter in the near universe. We analyze this suggestion in light of the clustering properties expected from a catalogue of galaxies of the local universe (redshift z {approx}< 0:06). The data reproduce particularly well the clustering properties of the nearby universe within z {approx}< 0:02. There is no statistically significant cross-correlation between data and structures, although intriguingly the nominal cross-correlation chance probability for displacements within {approx}50 degree drops from O(50%) to O(10%) using the catalogue with a smaller horizon. Our results suggest a relevant role of magnetic fields (possibly extragalactic ones, too) and/or possibly some heavy nuclei fraction in the ultra-high energy cosmic rays.

Serpico, Pasquale Dario; /Fermilab

2007-07-01

85

Magnetic diffusion effects on the ultra-high energy cosmic ray spectrum and composition  

NASA Astrophysics Data System (ADS)

We discuss the effects of diffusion of high energy cosmic rays in turbulent extra-galactic magnetic fields. We find an approximate expression for the low energy suppression of the spectrum of the different mass components (with charge Z) in the case in which this suppression happens at energies below ~ Z EeV, so that energy losses are dominated by the adiabatic ones. The low energy suppression appears when cosmic rays from the closest sources take a time comparable to the age of the Universe to reach the Earth. This occurs for energies E < Z EeV (B/nG)?(lc/Mpc)(ds/70Mpc) in terms of the magnetic field RMS strength B, its coherence length lc and the typical separation between sources ds. We apply this to scenarios in which the sources produce a mixed composition and have a relatively low maximum rigidity (Emax ~ (2–10)Z EeV), finding that diffusion has a significant effect on the resulting spectrum, the average mass and on its spread, in particular reducing this last one. For reasonable values of B and lc these effects can help to reproduce the composition trends observed by the Auger Collaboration for source spectra compatible with Fermi acceleration.

Mollerach, Silvia; Roulet, Esteban

2013-10-01

86

Small Scale Clustering in Isotropic Arrival Distribution of Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

We present numerical simulations on the propagation of ultra-high energy (UHE) protons with energies of (1019.5 - 1022 ) eV in extragalactic magnetic fields (EGMF) over 1 Gp c. We use the Optical Redshit Survey (ORS) galaxy sample, which is corrected taking the selection effect and absence of galaxies in the zone of avoidance (|b| < 20° ) into account. We calculate the cosmic ray spectrum, harmonic amplitude, and two point correlation function, and compare the results of our numerical calculations with the observation. One of our conclusions is that a large fraction of cosmic rays above 1020 eV observed by the AGASA experiment might originate in the top-down scenarios, or that the energy spectrum measured by the HiRes experiment might be better. As for the UHECR arrival distribution, we can explain the AGASA observation when ˜ 1/50 of the ORS galaxies more luminous than Mlim = -20.5 is selected as UHECR sources, and in the case of weak EGMF (BRMS ? 1nG). In terms of the source number density, this constraint corresp onds to ˜ 10-6 Mp c-3 .

Yoshiguchi, H.; Nagataki, S.; Tsubaki, S.; Sato, K.

2003-07-01

87

Large doppler shift in radar detection of ultra-high energy cosmic rays.  

SciTech Connect

Radar detection of cosmic ray air showers has been discussed for 60 years, but never clearly observed. The topic was reexamined by Gorham in 2001 and some serious simulations were done by Takai, who also initiated the Mariachi project utilizing commercial television transmissions as a signal source. The air showers from ultra-high energy cosmic rays are expected to generate a plasma with plasma frequency in the high VHF region. One factor limiting the received signal strength is the short ion recombination time in air at low altitude. However, a major factor which has not been the center of attention so far is the possible large Doppler shifts for non-specular reflection, and the soft transition between specular and diffuse for small objects and short time scales. We discuss recent work on receivers, and simulations of the Doppler shift. These simulations assume a very short ion recombination time in the lower atmosphere, and use an extremely simple mathematical model. A central feature of our simulations is large Doppler shift from non-moving material.

Underwood, D. G.; High Energy Physics

2008-01-01

88

High energy irradiations simulating cosmic-ray-induced planetary gamma ray production: I. Fe target  

NASA Astrophysics Data System (ADS)

A series of 6 GeV proton irradiations at the Argonne National Laboratory's Zero Gradient Synchrocyclotron included the bombardment of two thick Fe targets for the purpose of simulating the cosmic ray bombardment of planetary objects in space. Cosmic ray bombardment leads to characteristic gamma ray production, from which, by measuring their energy and intensity, surface composition may be derived. In this experiment, gamma ray energy spectra were obtained with a germanium solid state detector during the bombardment. The spectra show much detail, with 46 of the gamma ray lines ascribed to the Fe targets. The background includes recoil-broadened lines due to energetic neutron interactions in the Ge detector. A comparison with values predicted by modeling shows good agreement for Fe lines from neutron inelastic scattering and spallation reactions, and less satisfactory agreement for neutron capture reactions, the latter found to be due primarily to the difference in composition between the Fe target and the mean lunar abundance used in the modeling. Analysis of the irradiation results combined with continuum data obtained in lunar orbit indicates that 100 hours of measurement with a state-of-the-art instrument should generate a spectrum containing approximately 20 lines due to Fe alone, with a 2? sensitivity for detection of about 0.2%.

Metzger, Albert E.; Parker, Richard H.; Yellin, Joseph

1986-09-01

89

Relativistic effects in radar detection of ionization fronts produced by ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We revisit the radar echo technique as an approach to detect ultra-high energy cosmic rays (UHECR). The UHECR extensive air showers generate disk-like ionization fronts propagating with a relativistic velocity and creating fast decaying plasma. We study the reflection of a radio wave, such as the one from a radar transmitter or commercial radio and TV station, from the relativistic ionization front. The reflected wave will be frequency upshifted due to the relativistic Doppler effect and propagate almost normally to the front due to relativistic aberration. The amplitude of the reflected wave depends strongly on the front velocity and parameters (density, collision frequency) of the plasma behind the front. We develop a theory that allows one to find the reflected wave. Using this theory and typical parameters of extensive air showers, we discuss the feasibility of UHECR detection.

Bakunov, M. I.; Maslov, A. V.; Novokovskaya, A. L.; Kryemadhi, A.

2010-06-01

90

HERMES: Simulating the propagation of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

The study of ultra-high energy cosmic rays (UHECR) at Earth cannot prescind from the study of their propagation in the Universe. In this paper, we present HERMES, the ad hoc Monte Carlo code we have developed for the realistic simulation of UHECR propagation. We discuss the modeling adopted to simulate the cosmology, the magnetic fields, the interactions with relic photons and the production of secondary particles. In order to show the potential applications of HERMES for astroparticle studies, we provide an estimation of the surviving probability of UHE protons, the GZK horizons of nuclei and the all-particle spectrum observed at Earth in different astrophysical scenarios. Finally, we show the expected arrival direction distribution of UHECR produced from nearby candidate sources. A stable version of HERMES will be released in the next future for public use together with libraries of already propagated nuclei to allow the community to perform mass composition and energy spectrum analysis with our simulator.

De Domenico, Manlio

2013-08-01

91

The MIDAS experiment: A prototype for the microwave emission of Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Recent measurements suggest that extensive air showers initiated by ultra-high energy cosmic rays (UHECR) emit signals in the microwave band of the electromagnetic spectrum caused by the collisions of the free-electrons with the atmospheric neutral molecules in the plasma produced by the passage of the shower. Such emission is isotropic and could allow the detection of air showers with 100% duty cycle and a calorimetric-like energy measurement, a significant improvement over current detection techniques. We have built MIDAS (MIcrowave Detection of Air Showers), a prototype of microwave detector, which consists of a 4.5 m diameter antenna with a cluster of 53 feed-horns in the 4 GHz range. The details of the prototype and first results will be presented.

Monasor, M.; Alekotte, I.; Alvarez-Muñiz, J.; Berlin, A.; Bertou, X.; Bodgan, M.; Bohacova, M.; Bonifazi, C.; Carvalho, W.; de Mello Neto, J. R. T.; Genat, J. F.; Facal San Luis, P.; Mills, E.; Rouille D'Orfeuil, B.; Wayne, S.; Reyes, L. C.; Santos, E. M.; Privitera, P.; Williams, C.; Zas, E.

2011-06-01

92

Workshop on Cosmic Ray and High Energy Gamma Ray Experiments for the Space Station Era, Louisiana State University, Baton Rouge, October 17-20, 1984, Proceedings  

Microsoft Academic Search

The potential of the Space Station as a platform for cosmic-ray and high-energy gamma-ray astronomy is discussed in reviews, reports, and specific proposals. Topics examined include antiparticles and electrons, science facilities and new technology, high-energy nuclear interactions, nuclear composition and energy spectra, Space Shuttle experiments, Space Station facilities and detectors, high-energy gamma rays, and gamma-ray facilities and techniques. Consideration is

W. V. Jones; J. P. Wefel

1985-01-01

93

High-Energy Cross Sections. II. Nucleon-Nucleon Cross Section at Cosmic-Ray Energies  

Microsoft Academic Search

Cosmic-ray measurements are capable of yielding reliable results for the cross section of a nucleus for proton or neutron collisions involving a not too small energy transfer. This cross section should therefore be less than, or at most equal to, the true nonelastic cross section (reaction cross section). Results of recent cosmic-ray work are assembled and compared with the reaction

Robert W. Williams

1955-01-01

94

Astrophysics of Ultra-High Energy Cosmic Rays, Photons, and Neutrinos  

NASA Astrophysics Data System (ADS)

This miniworkshop concentrates on the astrophysics of GeV to ZeV cosmic rays, photons and neutrinos from active galaxies, gamma ray bursts and other compact or diffuse sources, as well as the transport processes and the physics of acceleration mechanisms that determine their observed fluxes and spectra. SCIENCE and MOTIVATION There are a number of major issues which this workshop is aimed at: * What is the origin of the ultra-high energy(PeV to ZeV) cosmic rays? Independently of whether there are super-GZK events or not, the CR flux levels near 1E20 eV from AGASA and HIRES are within 3 sigma of each other, and there is an intense debate about the possible astrophysical sources. What is the contribution to these from gamma-ray bursts, active galaxies, galactic core sources? Can we reconcile the AGASA and HIRES discrepancies? Can Fermi acceleration explain particles at the GZK limit, and can we test shock acceleration? How strong is the case for alternative astrophysical acceleration mechanisms? What are the implications of Auger's accumulating data, as the array progresses towards completion? What can be learned about intergalactic matter from cosmic ray propagation effects? * What is the origin of GeV-TeV photons from AGN, GRB, SNRs? Are the jets in AGN and GRB hadronic or leptonic? What constraints can be imposed on these from TeV and correlated lower energy spectra and variability? What is the origin of the GeV-TeV emission from pulsars and possibly magnetars(polar cap or outer gap emittors?) Are there smoking gun signatures of Fermi(diffusive) or other, e.g. linear(wakefield, etc) acceleration of leptons? For scattering off magnetic turbulence, reconnection, etc? Is there strong evidence for proton acceleration and hadronic cascades? How realistic is it to detect gamma-ray signatures of the quantum-gravity energy scale, vacuum dispersion, etc., with GLAST, SWIFT, etc? * What is the TeV to EeV neutrino emission of AGN, GRB, micro- quasars and other sources? How will it take for AMANDA to set limits on the diffuse neutrino flux from these? What can we learn about interactions at > TeV CM energies from atmospheric or point source neutrinos with Auger and ICECUBE? Can we detect UHE tau neutrinos, and what will we learn from them? How far can TeV-nu measurements constrain the neutrino masses, mixing angles, etc?

Mészáros, Peter; Watson, Alan; Waxman, Eli

2005-05-01

95

High-energy cosmic-ray fluxes in the Earth atmosphere: Calculations vs experiments  

NASA Astrophysics Data System (ADS)

A new calculation of the atmospheric fluxes of cosmic-ray hadrons and muons in the energy range 10-105 GeV has been performed for the set of hadron production models, EPOS 1.6, QGSJET II-03, SIBYLL 2.1, and others that are of interest to cosmic-ray physicists. The fluxes of secondary cosmic rays at several levels in the atmosphere are computed using directly data of the ATIC-2, GAMMA experiments, and the model proposed recently by Zatsepin and Sokolskaya as well as the parameterization of the primary cosmic-ray spectrum by Gaisser and Honda. The calculated energy spectra of the hadrons and muon flux as a function of zenith angle are compared with measurements as well as other calculations. The effect of uncertainties both in the primary cosmic-ray flux and hadronic model predictions on the spectra of atmospheric hadrons and muons is considered.

Kochanov, A. A.; Sinegovskaya, T. S.; Sinegovsky, S. I.

2008-12-01

96

Perturbations to aquatic photosynthesis due to high-energy cosmic ray induced muon flux in the extragalactic shock model  

NASA Astrophysics Data System (ADS)

We modify a mathematical model of photosynthesis to quantify the perturbations that high energy muons could make on aquatic primary productivity. Then, we apply this in the context of the extragalactic shock model, according to which Earth receives an enhanced dose of high-energy cosmic rays when it is at the galactic north. We obtain considerable reduction in the photosynthesis rates, consistent with potential drops in biodiversity.

Rodriguez, Lien; Cardenas, Rolando; Rodriguez, Oscar

2013-10-01

97

Ultra High Energy Cosmic Rays in the North: Measurement of UHE Cosmic Rays with the High Resolution Fly's Eye (HiRes) Detector  

SciTech Connect

The High Resolution Fly's Eye (HiRes) observatory has been collecting Ultra High Energy Cosmic Ray (UHECR) data since 1997. The experiment observes cosmic ray air showers via the air fluorescence technique and consists of two observatory sites separated by 12.6 km in the western Utah desert. The two stations can each measure the cosmic rays in monocular mode. In addition, the data from the two stations can also be combined to form a stereo measurement of the air showers. The experiment measures such properties as the energy spectrum, chemical composition, and p-air cross-section of these cosmic rays. It also searches for point sources and other anisotropy. The spectrum is measured above {approx}3 x 1017 eV and shows significant structure including the 'ankle' and a steep fall off which is consistent with the expectation of the GZK. threshold. The spectrum is inconsistent with a continuing spectrum at the 5{sigma} level. The composition is measured using the Xmax technique. It was found to be predominantly light and unchanging over the range from 1018 to 3 x 1019 eV. Finally, several different styles of searches for anisotropy in the data were performed. There are some tantalizing hints including potential correlation with BL Lac objects and the 'AGASA triplet', however these will need to be confirmed with an independent data set.

Matthews, J. N. [University of Utah - Department of Physics, 115 South 1400 East no. 201 JFB, Salt Lake City, UT 84112 (United States); High Energy Astrophysics Institute, 115 South 1400 East no. 201 JFB, Salt Lake City, UT 84112 (United States)

2006-11-17

98

High Energy Gamma Rays from Ultrahigh Energy Cosmic Rays in Gamma Ray Bursts  

Microsoft Academic Search

It has recently been proposed that ultrahigh energy ($\\\\gtrsim 10^{19}$ eV)\\u000acosmic rays (UHECRs) are accelerated by the blast waves associated with GRBs.\\u000aWe calculate the observed synchrotron radiation spectrum from protons and\\u000aenergetic leptons formed in the cascades initiated by photopion production,\\u000ataking into account $\\\\gamma\\\\gamma$ attenuation at the source. Normalizing to\\u000athe emission characteristics of GRB~970508, we predict

M. Boettcher; C. D. Dermer

1998-01-01

99

Measurement of the flux of ultra high energy cosmic rays by the stereo technique  

NASA Astrophysics Data System (ADS)

The High Resolution Fly’s Eye (HiRes) experiment has measured the flux of ultrahigh energy cosmic rays using the stereoscopic air fluorescence technique. The HiRes experiment consists of two detectors that observe cosmic ray showers via the fluorescence light they emit. HiRes data can be analyzed in monocular mode, where each detector is treated separately, or in stereoscopic mode where they are considered together. Using the monocular mode the HiRes collaboration measured the cosmic ray spectrum and made the first observation of the Greisen-Zatsepin-Kuzmin cutoff. In this paper we present the cosmic ray spectrum measured by the stereoscopic technique. Good agreement is found with the monocular spectrum in all details.

High Resolution Fly'S Eye Collaboration; Abbasi, R. U.; Abu-Zayyad, T.; Al-Seady, M.; Allen, M.; Amann, J. F.; Archbold, G.; Belov, K.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Brusova, O. A.; Burt, G. W.; Cannon, C.; Cao, Z.; Deng, W.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Gray, R. C.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G.; Hüntemeyer, P.; Ivanov, D.; Jones, B. F.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Loh, E. C.; Maestas, M. M.; Manago, N.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; Moore, S. A.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Rodriguez, D.; Sasaki, M.; Schnetzer, S. R.; Scott, L. M.; Sinnis, G.; Smith, J. D.; Snow, R.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tupa, D.; Wiencke, L. R.; Zech, A.; Zhang, B. K.; Zhang, X.; Zhang, Y.; High Resolution Fly's Eye Collaboration

2009-08-01

100

Galactic anisotropy of UltraHigh Energy Cosmic Rays produced by CDM-related mechanisms  

Microsoft Academic Search

We briefly review current theoretical and experimental status of Ultra-High\\u000aEnergy Cosmic Rays. We show that ``top-down'' mechanisms of UHE CR which\\u000ainvolve heavy relic particle-like objects predict Galactic anisotropy of\\u000ahighest energy cosmic rays at the level of minimum $\\\\sim 20%$. This anisotropy\\u000ais large enough to be either observed or ruled out in the next generation of\\u000aexperiments.

S. L. Dubovsky; P. G. Tinyakov

1998-01-01

101

Measurement of the flux of ultra high energy cosmic rays by the stereo technique  

Microsoft Academic Search

The High Resolution Fly’s Eye (HiRes) experiment has measured the flux of ultrahigh energy cosmic rays using the stereoscopic air fluorescence technique. The HiRes experiment consists of two detectors that observe cosmic ray showers via the fluorescence light they emit. HiRes data can be analyzed in monocular mode, where each detector is treated separately, or in stereoscopic mode where they

R. U. Abbasi; T. Abu-Zayyad; M. Al-Seady; J. F. Amann; G. Archbold; K. Belov; J. W. Belz; D. R. Bergman; S. A. Blake; O. A. Brusova; G. W. Burt; C. Cannon; Z. Cao; W. Deng; Y. Fedorova; J. Findlay; C. B. Finley; R. C. Gray; W. F. Hanlon; C. M. Hoffman; M. H. Holzscheiter; G. Hughes; P. Hüntemeyer; D. Ivanov; B. F. Jones; C. C. H. Jui; K. Kim; M. A. Kirn; E. C. Loh; M. M. Maestas; N. Manago; L. J. Marek; K. Martens; J. A. J. Matthews; S. A. Moore; A. O’Neill; C. A. Painter; L. Perera; K. Reil; R. Riehle; M. D. Roberts; M. Sasaki; S. R. Schnetzer; L. M. Scott; G. Sinnis; J. D. Smith; R. Snow; P. Sokolsky; R. W. Springer; B. T. Stokes; S. R. Stratton; J. R. Thomas; S. B. Thomas; G. B. Thomson; D. Tupa; L. R. Wiencke; A. Zech; B. K. Zhang; X. Zhang; X. Zhang; Y. Zhang

2009-01-01

102

Cosmic Rays  

NSDL National Science Digital Library

This series of web pages, authored and curated by David P. Stern, gives an elementary discussion of cosmic rays, followed by sections on high energy particles in the universe and high-energy particles from the Sun. It describes the existence particles whose velocity approaches that of light, their probable sources, and their measurement. This is part of a large work, "The Exploration of the Earth's Magnetosphere", that gives a non-mathematical introduction to planetary and solar magnetic fields, space weather, aurora, and charged particle motion. A Spanish translation is available.

Peredo, Mauricio; Mendez, J.; Stern, David P. (David Peter), 1931-

2009-04-21

103

High-energy Cosmic-ray Diffusion in Molecular Clouds: A Numerical Approach  

NASA Astrophysics Data System (ADS)

The propagation of high-energy cosmic rays (CRs) through giant molecular clouds constitutes a fundamental process in astronomy and astrophysics. The diffusion of CRs through these magnetically turbulent environments is often studied through the use of energy-dependent diffusion coefficients, although these are not always well motivated theoretically. Now, however, it is feasible to perform detailed numerical simulations of the diffusion process computationally. While the general problem depends upon both the field structure and particle energy, the analysis may be greatly simplified by dimensionless analysis. That is, for a specified purely turbulent field, the analysis depends almost exclusively on a single parameter—the ratio of the maximum wavelength of the turbulent field cells to the particle gyration radius. For turbulent magnetic fluctuations superimposed over an underlying uniform magnetic field, particle diffusion depends on a second dimensionless parameter that characterizes the ratio of the turbulent to uniform magnetic field energy densities. We consider both of these possibilities and parametrize our results to provide simple quantitative expressions that suitably characterize the diffusion process within molecular cloud environments. Doing so, we find that the simple scaling laws often invoked by the high-energy astrophysics community to model CR diffusion through such regions appear to be fairly robust for the case of a uniform magnetic field with a strong turbulent component, but are only valid up to ~50 TeV particle energies for a purely turbulent field. These results have important consequences for the analysis of CR processes based on TeV emission spectra associated with dense molecular clouds.

Fatuzzo, M.; Melia, F.; Todd, E.; Adams, F. C.

2010-12-01

104

HIGH-ENERGY COSMIC-RAY DIFFUSION IN MOLECULAR CLOUDS: A NUMERICAL APPROACH  

SciTech Connect

The propagation of high-energy cosmic rays (CRs) through giant molecular clouds constitutes a fundamental process in astronomy and astrophysics. The diffusion of CRs through these magnetically turbulent environments is often studied through the use of energy-dependent diffusion coefficients, although these are not always well motivated theoretically. Now, however, it is feasible to perform detailed numerical simulations of the diffusion process computationally. While the general problem depends upon both the field structure and particle energy, the analysis may be greatly simplified by dimensionless analysis. That is, for a specified purely turbulent field, the analysis depends almost exclusively on a single parameter-the ratio of the maximum wavelength of the turbulent field cells to the particle gyration radius. For turbulent magnetic fluctuations superimposed over an underlying uniform magnetic field, particle diffusion depends on a second dimensionless parameter that characterizes the ratio of the turbulent to uniform magnetic field energy densities. We consider both of these possibilities and parametrize our results to provide simple quantitative expressions that suitably characterize the diffusion process within molecular cloud environments. Doing so, we find that the simple scaling laws often invoked by the high-energy astrophysics community to model CR diffusion through such regions appear to be fairly robust for the case of a uniform magnetic field with a strong turbulent component, but are only valid up to {approx}50 TeV particle energies for a purely turbulent field. These results have important consequences for the analysis of CR processes based on TeV emission spectra associated with dense molecular clouds.

Fatuzzo, M. [Physics Department, Xavier University, Cincinnati, OH 45207 (United States); Melia, F. [Department of Physics, Applied Math Program, and Steward Observatory, University of Arizona, AZ 85721 (United States); Todd, E. [Physics Department, University of Arizona, AZ 85721 (United States); Adams, F. C., E-mail: fatuzzo@xavier.ed, E-mail: melia@physics.arizona.ed, E-mail: etodd@physics.arizona.ed, E-mail: fca@umich.ed [Michigan Center for Theoretical Physics, University of Michigan Physics Department, Ann Arbor, MI 48109 (United States)

2010-12-10

105

Planck-scale Lorentz violation constrained by Ultra-High-Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

We investigate the consequences of higher dimension Lorentz violating, CPT even kinetic operators that couple standard model fields to a non-zero vector field in an Effective Field Theory framework. Comparing the ultra-high energy cosmic ray spectrum reconstructed in the presence of such terms with data from the Pierre Auger observatory allows us to establish two sided bounds on the coefficients of the mass dimension five and six operators for the proton and pion. Our bounds imply that for both protons and pions, the energy scale of Lorentz symmetry breaking must be well above the Planck scale. In particular, the dimension five operators are constrained at the level of 10-3MPlanck-1. The magnitude of the dimension six proton coefficient is bounded at the level of 10-6MPlanck-2 except in a narrow range where the pion and proton coefficients are both negative and nearly equal. In this small area, the magnitude of the dimension six proton coefficient must only be below 10-3MPlanck-2. Constraints on the dimension six pion coefficient are found to be much weaker, but still below MPlanck-2.

Maccione, Luca; Taylor, Andrew M.; Mattingly, David M.; Liberati, Stefano

2009-04-01

106

Correlation of Ultra-High Energy Cosmic Rays with Active Galactic Nuclei  

NASA Astrophysics Data System (ADS)

To verify that the active galactic nuclei (AGN) can be the sources of ultra-high energy cosmic rays (UHECR), we constructed three test statistics and tested the hypothesis that AGN are the origin of UHECR using the Monte-Carlo simulation. The observed data from Akeno Giant Air Shower Array (AGASA) and Pierre Auger Observatory (PAO) are used as our UHECR data sets and the AGN list compiled in the 12th edition of Véron-Cetty and Véron (VCV) catalog is used as our AGN data. Only the UHECR with energies above 5.7×1019 eV and AGN within Greisen-Zatsepin-Kuzmin (GZK) radius, 100 Mpc, were applied to our statistical tests. We generalized the hypothesis thus it is considered that a certain fraction of the sources is AGN and the rest are isotropic component, coming from the outside of GZK radius. The hypotheses were tested by Kolmogorov-Smirnov (KS) test in two ways, which are the dependence of fraction and that of smearing angles. The probabilities obtained by KS test are extremely small enough to reject the hypotheses that the UHECR come from the AGN within 100 Mpc totally or come from the completely isotropic distribution for the PAO data. In the case of AGASA, it seems there is no significant correlation with AGN. We look forward to solving the problem of the sources of UHECR using the data observed by Telescope Array (TA) experiment.

Kim, Hang Bae; Kim, Jihyun

2011-09-01

107

Revisit to centaurus a as a point source of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

The void regions found in the arrival direction distribution of ultra-high-energy cosmic rays (UHECRs) observed by the Pierre Auger Observatory (PAO) may be an important clue in UHECR source hunting. We claim that there is a circular void band structure around the Centaurus A (Cen A) direction. We incorporated this observed void structure in the background contribution into the Cen A dominance model to improve the fitting of the arrival direction distribution. The best fit is obtained for the Cen A contribution fraction f C = 0.14 (The observed fraction at PAO is f C,PAO = 0.27, which means that 18 out of 69 observed UHECR are contributed by Cen A.) and the smearing angle ? s = 12° with a maximum likelihood of L max= 0.68. The estimate for the intergalactic magnetic fields in the vicinity of the Cen A direction based on the UHECRs contributed by Cen A is B ? 24 Z -1(? c /Mpc)-1/2 nG.

Kim, Hang Bae

2013-02-01

108

Super-heavy X particle decay and Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

In this thesis, I describe in great detail the physics of the decay of any Super-Heavy X particle (with masses up to the grand unification scale 10^16 GeV and possibly beyond), and the computer code I developed to model this process - which currently is the most complete available one. The general framework for this work is the Minimal Supersymmetric Standard Model (MSSM). The results are presented in the form of fragmentation functions of any (s)particle of the MSSM into any final stable particle (proton, photon, electron, three types of neutrino, lightest superparticle LSP) at a virtuality Q = M_X, over a scaled energy range x = 2E/M_X in [10^{-13}, 1]. At very low x values, color coherence effects have been taken into account through the Modified Leading Log Approximation (MLLA). The whole process is explicitely shown to conserve energy with a numerical accuracy up to a few part per mille, which allows to make quantitative predictions for any N-body decay mode of any X particle. I then apply the results to the old - and yet unsolved - problem of Ultra High Energy Cosmic Rays (UHECRs). In particular, I provide quantitative predictions of generic ``top-down'' models for the neutrino and neutralino fluxes which could be observed in the next generation of detectors.

Barbot, Cyrille

2003-08-01

109

On the origin of ultra high energy cosmic rays: subluminal and superluminal relativistic shocks  

NASA Astrophysics Data System (ADS)

Aims: The flux of ultra high energy cosmic rays (UHECRs) at E > 1018.5 eV is believed to arise in plasma shock environments in extragalactic sources. In this paper, we present a systematic study of cosmic ray (CR) particle acceleration by relativistic shocks, in particular concerning the dependence on bulk Lorentz factor and the angle between the magnetic field and the shock flow. The contribution to the observed diffuse CR spectrum provided by the accelerated particles is discussed. Methods: For the first time, Monte Carlo simulations for super- and subluminal shocks are extended to boost factors up to ? = 1000 and systematically compared. The source spectra derived are translated into the expected diffuse proton flux from astrophysical sources by folding the spectra with the spatial distribution of active galactic nuclei (AGN) and gamma ray bursts (GRBs). Results of these predictions are compared with UHECR data. Results: While superluminal shocks are shown to be inefficient at providing acceleration to the highest energies (E > 1018.5 eV), subluminal shocks may provide particles up to 1021 eV, limited only by the Hillas-criterion. In the subluminal case, we find that mildly-relativistic shocks, thought to occur in jets of AGN (? ~ 10-30), yield energy spectra of dN/dE ~ E-2. Highly relativistic shocks expected in GRBs (100 < ? < 1000), on the other hand, produce spectra as flat as ~ E-1.0 above 109.5 GeV. The model results are compared with the measured flux of CRs at the highest energies and it is shown that, while AGN spectra provide an excellent fit, GRB spectra are too flat to explain the observed flux. The first evidence of a correlation between the CR flux above 5.7 × 1010 GeV and the distribution of AGN provided by Auger are explained by our model. Although GRBs are excluded as the principle origin of UHECRs, neutrino production is expected in these sources either in mildly or highly relativistic shocks. In particular, superluminal shocks in GRBs may be observable via neutrino and photon fluxes, rather than as protons.

Meli, A.; Becker, J. K.; Quenby, J. J.

2008-12-01

110

On the Possible Association of Ultra High Energy Cosmic Rays with Nearby Active Galaxies  

SciTech Connect

Data collected by the Pierre Auger Observatory provide evidence for anisotropy in the arrival directions of cosmic rays (CRs) with energies >57 EeV that suggests a correlation with the positions of active galactic nuclei (AGN) located within {approx}75 Mpc. However, this analysis does not take into account AGN morphology. A detailed study of the sample of AGN whose positions correlate with the CR events shows that most of them are classified as Seyfert 2 and low-ionization nuclear emission-line region (LINER) galaxies which do not differ from other local AGN of the same types. Therefore, the claimed correlation between the CR events observed by the Pierre Auger Observatory and local active galaxies should be considered as resulting from a chance coincidence, if the production of the highest energy CRs is not episodic in nature, but operates in a single object on long ({ge} Myr) timescales. Additionally, most of the selected sources do not show significant jet activity, and hence--in the framework of the jet paradigm--there are no reasons for expecting them to accelerate CRs up to the highest energies, {approx}10{sup 20} eV, at all. If the extragalactic magnetic fields and the sources of these CRs are coupled with matter, it is possible that the deflection angle is larger than expected in the case of a uniform source distribution due to effectively larger fields. A future analysis has to take into account AGN morphology and may yield a correlation with a larger deflection angle and/or more distant sources. We further argue that Cen A alone could be associated with at least 4 events due to its large radio extent, and Cen B can be associated with more than 1 event due to its proximity to the Galactic plane and, correspondingly, the stronger Galactic magnetic field the ultra high energy CRs (UHECRs) encounter during propagation. If the UHECRs associated with these events are indeed accelerated by Cen A and Cen B, their deflection angles may provide information on the structure of the magnetic field in the direction of these putative sources. Future -ray observations (by, e.g., Gamma-Ray Large Area Space Telescope [GLAST], High Energy Stereoscopic System [HESS]) may provide additional clues to the nature of the accelerators of the UHECRs in the local Universe.

Moskalenko, Igor V.; Stawarz, Lukasz; Porter, Troy A.; Cheung, Chi C.

2008-05-14

111

Astrophysics of UltraHigh Energy Cosmic Rays, Photons, and Neutrinos  

Microsoft Academic Search

This miniworkshop concentrates on the astrophysics of GeV to ZeV cosmic rays, photons and neutrinos from active galaxies, gamma ray bursts and other compact or diffuse sources, as well as the transport processes and the physics of acceleration mechanisms that determine their observed fluxes and spectra. SCIENCE and MOTIVATION There are a number of major issues which this workshop is

Peter Mészáros; Alan Watson; Eli Waxman

2005-01-01

112

The Microwave Air Yield Beam Experiment (MAYBE): measurement of GHz radiation for Ultra-High Energy Cosmic Rays detection  

NASA Astrophysics Data System (ADS)

We present measurements of microwave emission from an electron beam induced air plasma, performed at the electron Van de Graaff facility of the Argonne National Laboratory. Radio emission is studied over a wide range of frequencies between 1 and 15 GHz. This measurement provides further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

Williams, Christopher; Bohacova, Martina; Bonifazi, Carla; Cataldi, Gabriella; Chemerisov, Sergey; de Mello Neto, Joao; Facal San Luis, Pedro; Fox, Brendan; Gorham, Peter W.; Hojvat, Carlos; Hollon, Nick; Meyhandan, Rishi; Reyes, Luis; Rouille D'Orfeuil, Benjamin; Santos, Edivaldo M.; Pochez, James; Privitera, Paolo; Spinka, Hal; Verzi, Valerio; Monasor, Maria; Zhou, Jing

2012-03-01

113

Cosmic ray reentrant electron albedo - High-Energy Antimatter Telescope balloon measurements from Fort Sumner, New Mexico  

Microsoft Academic Search

The High-Energy Antimatter Telescope (HEAT) balloon cosmic ray detector flew from Fort Sumner, New Mexico on May 3-5, 1994. The instrument measured electron and positron abundances and spectra from about 1 to 100 GeV at a vertical geomagnetic cutoff rigidity that varied between 4.0 and 4.5 GV. The intensities of electrons and positrons have been measured as a function of

S. W. Barwick; J. J. Beatty; C. R. Bower; C. J. Chaput; S. Coutu; G. A. de Nolfo; M. A. DuVernois; D. Ficenec; J. Knapp; D. M. Lowder; S. McKee; D. Müller; J. A. Musser; S. L. Nutter; E. Schneider; S. P. Swordy; G. Tarlé; A. D. Tomasch; E. Torbet

1998-01-01

114

A study on active galactic nuclei correlated with the arrival directions of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

We study the correlation between active galactic nuclei (AGNs) and the arrival directions of ultra-high-energy cosmic rays (UHECRs) by using the nearest-source angular-distance distribution. Based on this, we search for a subset of the whole set of AGNs that improves the correlation. We investigate the distinguished features of AGNs of that subset, compared to the whole set of AGNs, in distance distribution, absolute magnitude distribution, and radio wave loudness.

Kim, Hang Bae

2013-04-01

115

Quark-gluon state of matter and positive excess of cosmic-ray muons at high energies  

Microsoft Academic Search

The problem of the relationship between the numbers of positively and negatively charged particles in the flux of cosmic-ray\\u000a muons arriving at sea level with energies in excess of 0.1 TeV (up to 100 TeV) is discussed. It is shown that the formation\\u000a of quark—gluon matter as the result of high-energy nuclear interactions leads to a reduction of the positive

L. V. Volkova; G. T. Zatsepin

2008-01-01

116

The coherent acceleration of ultra high energy cosmic rays and the galactic dynamo  

SciTech Connect

In order to accelerate cosmic rays to ultra high energy, >10{sup 18} ev, requires that the step size in energy in a diffusive process be very much larger than occurs in galactic or extra galactic hydrodynamic mechanisms where {Delta}E/F {approximately} v/c{approximately}1/300 per step. This step size requires >10{sup 5} scatterings per doubling in energy (the shock mechanism) and therefore <10{sup {minus}5} energy loss per scattering. Coherent acceleration (CA), on the other hand, is proposed in which the energy gained, {Delta}E per particle in the CA region is very much larger so that only one or several scatterings are required to reach the final energy. The power law spectrum is created by the probability of loss from the CA region where this probability is inversely proportional to the particle`s rigidity, E. Therefore the fractional loss in number per fractional gain in energy, dN/N {approximately} {minus}{Gamma} dE/E, results in a power law spectrum. CA depends upon the electric field, E = {eta}J, J, the current density, in a force free field, where magnetic helicity, J={alpha}B, arises universally in all evolving mass condensations due to twisting of magnetic flux by the large number of turns before pressure support. The acceleration process is E*v, where universe beam instabilities enhance {eta} leading to phased coherent acceleration (PCA). The result of the energy transfer from field energy to matter energy is the relaxation of the field helicity, or reconnection but with J{parallel}B rather than J{perpendicular}B.

Colgate, S.A.

1995-05-01

117

Ultra-high energy cosmic ray propagation in the local supercluster  

NASA Astrophysics Data System (ADS)

We present detailed numerical simulations and analytical approximations of the propagation of nucleons above 10 19 eV in the Local Supercluster, assuming that the ambient magnetic field is turbulent, and its strength 0.01 ?G ? Brms ? 1 ?G. In such strong magnetic fields, protons in the low energy part of the spectrum, 10 19 eV ? E ? EC, diffuse, while the higher energy particles, with E ? EC, propagate along nearly straight lines. The magnitude of the transition energy EC depends mainly on the strength of the magnetic field, the coherence length, and the distance to the source; for B rms ? 0.1 ? G, a largest eddy of length ˜ 10 Mpc, and a distance to the source ˜ 10 Mpc, E C ? 100 EeV. Our numerical treatment substantially improves on previous analytical approximations, as it allows one to treat carefully the transition between the two propagation regimes, as well as the effects due to inhomogeneities expected on scales of a few Mpc. We show that a turbulent magnetic field Brms ˜ 0.1 ?G, close to equipartition, would allow us to reproduce exactly the observed spectrum of ultra high energy cosmic rays, up to the highest energy observed, for a distance to the source d ? 10 Mpc, for the geometry of the Local Supercluster, i.e. a sheet of thickness ? 10 Mpc. Diffusion, in this case, allows us to reproduce the high flux beyond the Greisen Zatsepin Kuzmin cutoff, with a soft injection spectrum j( E) ? E-2.4. Moreover, the large deflection angles at the highest energies observed, typically ˜ 10 o for the above values, would explain why no close-by astrophysical counterpart could be associated with these events.

Sigl, Günter; Lemoine, Martin; Biermann, Peter

1999-03-01

118

Lensing of ultra-high energy cosmic rays in turbulent magnetic fields  

NASA Astrophysics Data System (ADS)

We consider the propagation of ultra high energy cosmic rays through turbulent magnetic fields and study the transition between the regimes of single and multiple images of point-like sources. The transition occurs at energies around Ec simeq Z 41 EeV(Brms/5 muG)(L/2 kpc)3/2(50 pc/Lc)1/2, where L is the distance traversed by the CR's with electric charge Ze in the turbulent magnetic field of root mean square strength Brms and coherence length Lc. We find that above 2Ec only sources located in a fraction of a few % of the sky can reach large amplifications of its principal image or start developing multiple images. New images appear in pairs with huge magnifications, and they remain amplified over a significant range of energies. At decreasing energies the fraction of the sky in which sources can develop multiple images increases, reaching about 50% for E > Ec/2. The magnification peaks become however increasingly narrower and for E < Ec/3 their integrated effect becomes less noticeable. If a uniform magnetic field component is also present it would further narrow down the peaks, shrinking the energy range in which they can be relevant. Below E simeq Ec/10 some kind of scintillation regime is reached, where many demagnified images of a source are present but with overall total magnification of order unity. We also search for lensing signatures in the AGASA data studying two-dimensional correlations in angle and energy and find some interesting hints.

Harari, Diego; Mollerach, Silvia; Roulet, Esteban; Sánchez, Federico

2002-03-01

119

ANOMALOUS TRANSPORT OF HIGH-ENERGY COSMIC RAYS IN GALACTIC SUPERBUBBLES. I. NUMERICAL SIMULATIONS  

SciTech Connect

We present a simple continuous-time random-walk model for the transport of energetic particles accelerated by a collection of supernova explosions in a galactic superbubble, developed to simulate and highlight signatures of anomalous transport on the particles' evolution and their spectra in a multi-shock context. We assume standard diffusive shock acceleration (DSA) theory for each shock encounter. The superbubble (an OB stars association) is idealized as a heterogeneous region of particle sources and sinks bounded by a random surface. The model is based on two coupled stochastic differential equations and is applied for protons and alpha particles. Using characteristic values for a typical bubble, our simulations suggest that acceleration and transport in the bubble may be sub-diffusive. In addition, a spectral break in the particles' evolution and spectra is evident located at Almost-Equal-To 10{sup 15} eV for protons and Almost-Equal-To 3 Multiplication-Sign 10{sup 15} eV for alphas. Our simulations are consistent with a bubble's mean magnetic field strength of Almost-Equal-To 1 {mu}G and a shock separation distance {approx}0.1 Multiplication-Sign the characteristic radius of the bubble. The simulations imply that the diffusion coefficient (for the elementary shock acceleration process) is {approx}< 10{sup 27} cm{sup 2} s{sup -1} at 1 GeV/c. While the sub-diffusive transport is readily attributed to the stochastic nature of the acceleration time according to DSA theory, the spectral break appears to be an artifact of transport in a finite medium. These simulations point to a new and intriguing phenomenon associated with the statistical nature of collective acceleration of high-energy cosmic rays in galactic superbubbles.

Barghouty, A. F. [Astrophysics Office, NASA-Marshall Space Flight Center, Huntsville, AL 35805 (United States); Schnee, D. A. [Department of Mathematics, University of Chicago, Chicago, Illinois 60637 (United States)

2012-04-20

120

Study of Small-Scale Anisotropy of Ultra-High-Energy Cosmic Rays Observed in Stereo by the High Resolution Fly's Eye Detector  

Microsoft Academic Search

The High Resolution Fly's Eye (HiRes) experiment is an air fluorescence detector which, operating in stereo mode, has a typical angular resolution of 0.6d and is sensitive to cosmic rays with energies above 1018 eV. The HiRes cosmic-ray detector is thus an excellent instrument for the study of the arrival directions of ultra-high-energy cosmic rays. We present the results of

R. U. Abbasi; T. Abu-Zayyad; J. F. Amann; G. Archbold; R. Atkins; J. A. Bellido; K. Belov; J. W. Belz; S. BenZvi; D. R. Bergman; J. H. Boyer; G. W. Burt; Z. Cao; R. W. Clay; B. M. Connolly; B. R. Dawson; W. Deng; Y. Fedorova; J. Findlay; C. B. Finley; W. F. Hanlon; C. M. Hoffman; M. H. Holzscheiter; G. A. Hughes; P. Hüntemeyer; C. C. H. Jui; K. Kim; M. A. Kirn; B. C. Knapp; E. C. Loh; M. M. Maestas; N. Manago; E. J. Mannel; L. J. Marek; K. Martens; J. A. J. Matthews; J. N. Matthews; A. O'Neill; C. A. Painter; L. Perera; K. Reil; R. Riehle; M. D. Roberts; M. Sasaki; S. R. Schnetzer; M. Seman; K. M. Simpson; G. Sinnis; J. D. Smith; R. Snow; P. Sokolsky; C. Song; R. W. Springer; B. T. Stokes; J. R. Thomas; S. B. Thomas; G. B. Thomson; D. Tupa; S. Westerhoff; L. R. Wiencke; A. Zech

2004-01-01

121

Workshop on Cosmic Ray and High Energy Gamma Ray Experiments for the Space Station Era, Louisiana State University, Baton Rouge, October 17-20, 1984, Proceedings  

SciTech Connect

The potential of the Space Station as a platform for cosmic-ray and high-energy gamma-ray astronomy is discussed in reviews, reports, and specific proposals. Topics examined include antiparticles and electrons, science facilities and new technology, high-energy nuclear interactions, nuclear composition and energy spectra, Space Shuttle experiments, Space Station facilities and detectors, high-energy gamma rays, and gamma-ray facilities and techniques. Consideration is given to universal-baryon-symmetry testing on the scale of galactic clusters, particle studies in a high-inclination orbit, balloon-borne emulsion-chamber results on ultrarelativistic nucleus-nucleus interactions, ionization states of low-energy cosmic rays, a large gamma-ray telescope for point-source studies above 1 GeV, and the possible existence of stable quark matter.

Jones, W.V.; Wefel, J.P.

1985-01-01

122

Workshop on Cosmic Ray and High Energy Gamma Ray Experiments for the Space Station Era, Louisiana State University, Baton Rouge, October 17-20, 1984, Proceedings  

NASA Astrophysics Data System (ADS)

The potential of the Space Station as a platform for cosmic-ray and high-energy gamma-ray astronomy is discussed in reviews, reports, and specific proposals. Topics examined include antiparticles and electrons, science facilities and new technology, high-energy nuclear interactions, nuclear composition and energy spectra, Space Shuttle experiments, Space Station facilities and detectors, high-energy gamma rays, and gamma-ray facilities and techniques. Consideration is given to universal-baryon-symmetry testing on the scale of galactic clusters, particle studies in a high-inclination orbit, balloon-borne emulsion-chamber results on ultrarelativistic nucleus-nucleus interactions, ionization states of low-energy cosmic rays, a large gamma-ray telescope for point-source studies above 1 GeV, and the possible existence of stable quark matter.

Jones, W. V.; Wefel, J. P.

123

A Fractal Scheme for Interaction Probabilities and the High Energy Cosmic Ray Spectrum  

Microsoft Academic Search

The present article is an attempt to provide a parametrization of particle production for the extreme energy range combining a fractal scheme for interaction probabilities and the observed power law energy spectrum for cosmic ray particles. As a first result towards a genuine transition matrix we conclude that for a scaling factor of d ~ 2 the matrix element |Mk|

B. E. J. Bodmann; L. P. Luna de Oliveira

2004-01-01

124

A Fractal Scheme for Interaction Probabilities and the High Energy Cosmic Ray Spectrum  

Microsoft Academic Search

The present article is an attempt to provide a parametrization of particle production for the extreme energy range combining a fractal scheme for interaction probabilities and the observed power law energy spectrum for cosmic ray particles. As a first result towards a genuine transition matrix we conclude that for a scaling factor of d ? 2 the matrix element |Mk|

B. E. J. Bodmann; L. P. Luna de Oliveira

2004-01-01

125

Detection of high energy cosmic rays with the resonant gravitational wave detectors NAUTILUS and EXPLORER  

NASA Astrophysics Data System (ADS)

The cryogenic resonant gravitational wave detectors NAUTILUS and EXPLORER, made of an aluminum alloy bar, can detect cosmic ray showers. At temperatures above 1 K, when the material is in the normal-conducting state, the measured signals are in good agreement with the expected values based on the cosmic rays data and on the thermo-acoustic model. When NAUTILUS was operated at the temperature of 0.14 K, in superconductive state, large signals produced by cosmic ray interactions, more energetic than expected, were recorded. The NAUTILUS data in this case are in agreement with the measurements done by a dedicated experiment on a particle beam. The biggest recorded event was in EXPLORER and excited the first longitudinal mode to a vibrational energy of ˜670 K, corresponding to ˜360 TeV absorbed in the bar. Cosmic rays can be an important background in future acoustic detectors of improved sensitivity. At present, they represent a useful tool to verify the gravitational wave antenna performance.

Astone, P.; Babusci, D.; Bassan, M.; Bonifazi, P.; Cavallari, G.; Coccia, E.; D'Antonio, S.; Fafone, V.; Giordano, G.; Ligi, C.; Marini, A.; Mazzitelli, G.; Minenkov, Y.; Modena, I.; Modestino, G.; Moleti, A.; Pallottino, G. V.; Pizzella, G.; Quintieri, L.; Rocchi, A.; Ronga, F.; Terenzi, R.; Visco, M.

2008-11-01

126

Analytic calculations of the spectra of ultra high energy cosmic ray nuclei. II. The general case of background radiation  

NASA Astrophysics Data System (ADS)

We discuss the problem of ultra high energy nuclei propagation in extragalactic background radiations. The present paper is the continuation of the accompanying paper I where we have presented three new analytic methods to calculate the fluxes and spectra of ultra high energy cosmic ray nuclei, both primary and secondary, and secondary protons. The computation scheme in this paper is based on the analytic solution of coupled kinetic equations, which takes into account the continuous energy losses due to the expansion of the universe and pair-production, together with photo-disintegration of nuclei. This method includes in the most natural way the production of secondary nuclei in the process of photo-disintegration of the primary nuclei during their propagation through extragalactic background radiations. In paper I, in order to present the suggested analytical schemes of calculations, we have considered only the case of the cosmic microwave background radiation, in the present paper we generalize this computation to all relevant background radiations, including infra-red and visible/ultra-violet radiations, collectively referred to as extragalactic background light. The analytic solutions allow transparent physical interpretation of the obtained spectra. Extragalactic background light plays an important role at intermediate energies of ultra high energy cosmic ray nuclei. The most noticeable effect of the extragalactic background light is the low-energy tail in the spectrum of secondary nuclei.

Aloisio, R.; Berezinsky, V.; Grigorieva, S.

2013-01-01

127

Cosmic Rays  

Microsoft Academic Search

For many years cosmic rays provided the most important source of energetic particles for studies of subatomic physics. Today, cosmic rays are being studied as a natural phenomenon that can tell us much about both the Earth's environment in space and distant astrophysical processes. Cosmic rays are naturally occurring energetic particles-mainly ions- with kinetic energies extending from just above thermal

J. R. Jokipii

1998-01-01

128

Energy spectrum of cosmic ray primaries at super high energies estimated from the recent balloon-borne calorimeter measurements  

NASA Astrophysics Data System (ADS)

The energy spectrum of primary cosmic ray particles is determined from the analysis of the chemical composition data of high energy cosmic rays using data obtained by the Japanese American cooperative emulsion experiments for proton and helium intensities and the Goddard Space Flight Center measurements for cosmic ray nuclei. The results indicate that no pronounced changes in the abundance ratios occur at high energies. The total primary spectrum in the range 2-300 TeV is calculated and follows the form N(E)dE = 2.24 x 10 to the 4th (E to the -2.7th)dE, where E is the energy expressed in GeV nucleons and N(E) is the intensity expressed in 1/(sq m s sr GeV/nucleon). The sea level proton and neutron spectra are estimated from this primary spectrum as the source of nucleons near the top of the atmosphere using the Feynman scaling hypothesis and the conventional nucleon-atmospheric diffusion equation. It is found that the derived spectra are in accord with previously measured proton and neutron spectra.

Bhattacharyya, D. P.

1983-03-01

129

A Fractal Scheme for Interaction Probabilities and the High Energy Cosmic Ray Spectrum  

SciTech Connect

The present article is an attempt to provide a parametrization of particle production for the extreme energy range combining a fractal scheme for interaction probabilities and the observed power law energy spectrum for cosmic ray particles. As a first result towards a genuine transition matrix we conclude that for a scaling factor of d {approx} 2 the matrix element vertical bar M{sub k} vertical bar {proportional_to} {radical}(Y(k))E{sub k}{sup 5}.

Bodmann, B.E.J. [IFM, Universidade Federal de Pelotas, Campus Universitario s/no, 96010-900 Pelotas, RS (Brazil); Luna de Oliveira, L.P. [ExaTec, Universidade do Vale do Rio dos Sinos, 93022-000 Sao Leopoldo, RS (Brazil)

2004-12-02

130

High energy cosmic ray physics with underground muons in MACRO. II. Primary spectra and composition  

Microsoft Academic Search

Multimuon data from the MACRO experiment at Gran Sasso have been analyzed using a new method, which allows one to estimate the primary cosmic ray fluxes. The estimated all-particle spectrum is higher and flatter than the one obtained from direct measurements but is consistent with EAS array measurements. The spectral indexes of the fitted energy spectrum are 2.56+\\/-0.05 for E5000

M. Ambrosio; R. Antolini; G. Auriemma; R. Baker; A. Baldini; G. C. Barbarino; B. C. Barish; G. Battistoni; R. Bellotti; C. Bemporad; P. Bernardini; H. Bilokon; V. Bisi; C. Bloise; T. Bosio; C. Bower; S. Bussino; F. Cafagna; M. Calicchio; D. Campana; M. Carboni; M. Castellano; S. Cecchini; F. Cei; V. Chiarella; A. Corona; S. Coutu; G. De Cataldo; H. Dekhissi; C. De Marzo; I. De Mitri; M. De Vincenzi; A. Di Credico; O. Erriquez; R. Fantini; C. Favuzzi; C. Forti; P. Fusco; G. Giacomelli; G. Giannini; N. Giglietto; M. Goretti; M. Grassi; A. Grillo; F. Guarino; P. Guarnaccia; C. Gustavino; A. Habig; K. Hanson; A. Hawthorne; R. Heinz; J. T. Hong; E. Iarocci; E. Katsavounidis; E. Kearns; S. Kyriazopoulou; E. Lamanna; D. S. Levin; P. Lipari; N. P. Longley; M. J. Longo; G. Mancarella; A. Margiotta-Neri; A. Margiotta-Neri; D. Martello; A. Marzari-Chiesa; M. N. Mazziotta; D. G. Michael; S. Mikheyev; L. Miller; P. Monacelli; T. Montaruli; M. Monteno; S. Mufson; J. Musser; D. Nicolo; R. Nolty; C. Okada; C. Okada; G. Osteria; O. Palamara; S. Parlati; V. Patera; L. Patrizii; R. Pazzi; C. W. Peck; S. Petrera; P. Pistilli; V. Popa; A. Raino; J. Reynoldson; M. Ricciardi; F. Ronga; U. Rubizzo; A. Sanzgiri; F. Sartogo; C. Satriano; L. Satta; E. Scapparone; K. Scholberg; A. Sciubba; P. Serra-Lugaresi; M. Severi; M. Severi; P. Spinelli; M. Spinetti; M. Spinetti; R. Steinberg; J. L. Stone; J. L. Stone; A. Surdo; G. Tarle; V. Valente; C. W. Walter; R. Webb

1997-01-01

131

Inelasticity of nucleus-nucleus collisions and composition of high-energy cosmic rays  

SciTech Connect

Current experiments to determine the chemical composition and energy spectra of primary-cosmic-ray nuclei around 10/sup 14/ eV maximize collecting power by using thin calorimeters of large area that measure primarily the electromagnetic fraction of the energy released when the nucleus interacts. Estimates of this fraction are model-dependent and differ by nearly a factor of 2 for a range of reasonable models. We discuss the consequences of this for composition studies using emulsion chambers.

Gaisser, T.K.; Stanev, T.

1983-08-01

132

TIERRAS: A package to simulate high energy cosmic ray showers underground, underwater and under-ice  

NASA Astrophysics Data System (ADS)

In this paper we present TIERRAS, a Monte Carlo simulation program based on the well-known AIRES air shower simulations system that enables the propagation of particle cascades underground, providing a tool to study particles arriving underground from a primary cosmic ray on the atmosphere or to initiate cascades directly underground and propagate them, exiting into the atmosphere if necessary. We show several cross-checks of its results against CORSIKA, FLUKA, GEANT and ZHS simulations and we make some considerations regarding its possible use and limitations. The first results of full underground shower simulations are presented, as an example of the package capabilities. Catalogue identifier: AEFO_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEFO_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.html No. of lines in distributed program, including test data, etc.: 36?489 No. of bytes in distributed program, including test data, etc.: 3?261?669 Distribution format: tar.gz Programming language: Fortran 77 and C Computer: PC, Alpha, IBM, HP, Silicon Graphics and Sun workstations Operating system: Linux, DEC Unix, AIX, SunOS, Unix System V RAM: 22 Mb bytes Classification: 1.1 External routines: TIERRAS requires AIRES 2.8.4 to be installed on the system. AIRES 2.8.4 can be downloaded from http://www.fisica.unlp.edu.ar/auger/aires/eg_AiresDownload.html. Nature of problem: Simulation of high and ultra high energy underground particle showers. Solution method: Modification of the AIRES 2.8.4 code to accommodate underground conditions. Restrictions: In AIRES some processes that are not statistically significant on the atmosphere are not simulated. In particular, it does not include muon photonuclear processes. This imposes a limitation on the application of this package to a depth of 1 km of standard rock (or 2.5 km of water equivalent). Neutrinos are not tracked on the simulation, but their energy is taken into account in decays. Running time: A TIERRAS for AIRES run of a 1020 eV shower with statistical sampling (thinning) below 1012 eV and 0.2 weight factor (see [1]) uses approximately 1 h of CPU time on an Intel Core 2 Quad Q6600 at 2.4 GHz. It uses only one core, so 4 simultaneous simulations can be run on this computer. Aires includes a spooling system to run several simultaneous jobs of any type. References:S. Sciutto, AIRES 2.6 User Manual, http://www.fisica.unlp.edu.ar/auger/aires/.

Tueros, Matías; Sciutto, Sergio

2010-02-01

133

Detection techniques of radio emission from ultra high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We discuss recent and future efforts to detect radio signals from extended air showers at the Pierre Auger Observatory in Malargue, Argentina. With the advent of low-cost, high-performance digitizers and robust digital signal processing software techniques, radio detection of cosmic rays has resurfaced as a promising measurement system. The inexpensive nature of the detector media (metallic wires, rods or parabolic dishes) and economies of scale working in our favor (inexpensive high-quality C-band amplifiers and receivers) make an array of radio antennas an appealing alternative to the expense of deploying an array of Cherenkov detector water tanks or 'fly's eye' optical telescopes for fluorescence detection. The calorimetric nature of the detection and the near 100% duty cycle gives the best of both traditional detection techniques. The history of cosmic ray detection detection will be discussed. A short review on the astrophysical properties of cosmic rays and atmospheric interactions will lead into a discussion of two radio emission channels that are currently being investigated.

Morris, Chad M.

134

Axions and high-energy cosmic rays: can the relic axion density be measured?  

NASA Astrophysics Data System (ADS)

In a previous work we investigated the propagation of fast moving charged particles in a spatially constant but slowly time dependent pseudoscalar background, such as the one provided by cold relic axions. The background induces cosmic rays to radiate in the low-energy spectrum. While the energy loss caused by this mechanism on the primary cosmic rays is negligible, we investigate the hypothetical detection of the photons radiated and how they could provide an indirect way of verifying the cosmological relevance of axions. Assuming that the cosmic ray flux is of the form J(E) ~ E-? we find that the energy radiated via this mechanism has a power spectrum k to the power of minus gamma minus 1 over 2 for proton primaries and k to the power of minus gamma over 2 for electron primaries, which dominate for low values of k where the effect is maximized. Unfortunately this radiation is shadowed by the synchrotron radiation background making the observation of this effect very difficult. Yet its detection would constitute direct evidence of the presence of a cold axion background.

Espriu, D.; Mescia, F.; Renau, A.

2011-08-01

135

ACCELERATION OF ULTRA-HIGH-ENERGY COSMIC RAYS IN THE COLLIDING SHELLS OF BLAZARS AND GAMMA-RAY BURSTS: CONSTRAINTS FROM THE FERMI GAMMA-RAY SPACE TELESCOPE  

SciTech Connect

Fermi Gamma-ray Space Telescope measurements of spectra, variability timescales, and maximum photon energies give lower limits to the apparent jet powers and, through {gamma}{gamma} opacity arguments, the bulk Lorentz factors of relativistic jets. The maximum cosmic-ray particle energy is limited by these two quantities in Fermi acceleration scenarios. Recent data are used to constrain the maximum energies of cosmic-ray protons and Fe nuclei accelerated in colliding shells of gamma-ray bursts (GRBs) and blazars. The Fermi results indicate that Fe rather than protons are more likely to be accelerated to ultra-high energies in active galactic nuclei (AGNs), whereas powerful GRBs can accelerate both protons and Fe to {approx}>10{sup 20} eV. Emissivity of nonthermal radiation from radio galaxies and blazars is estimated from the First Fermi AGN Catalog, and shown to favor BL Lac objects and FR1 radio galaxies over flat spectrum radio quasars, FR2 radio galaxies, and long-duration GRBs as the sources of ultra-high-energy cosmic rays.

Dermer, Charles D.; Razzaque, Soebur, E-mail: dermer@nrl.navy.mi [Space Science Division, Code 7653, Naval Research Laboratory, Washington, DC 20375-5352 (United States)

2010-12-01

136

Energy Spectrum and Composition of Ultra High Energy Cosmic Ray Showers Using Hybrid Analysis from Telescope Array  

NASA Astrophysics Data System (ADS)

The Telescope Array studies ultra high energy cosmic rays using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated by a primary cosmic ray particle, while scintillator detectors measure the lateral distribution of secondary particles that hit the ground. The Middle Drum (MD) fluorescence telescope consists of 14 refurbished telescopes from the High Resolution Fly's Eye experiment (HiRes), providing a direct link back to the HiRes experiment and data. Using the scintillator detector data in conjunction with the MD data improves the geometrical reconstruction of the showers significantly, and hence, provides a more accurate reconstruction of the energy of the primary particle. The Middle Drum hybrid spectrum will be presented. In addition, a MD hybrid composition study was also performed, and results will be shown.

Allen, Monica; Abu-Zayyad, Tareq; Stokes, Benjamin T.

2012-10-01

137

JACEE emulsion chambers for studying the energy spectra of high energy cosmic ray protons and helium  

NASA Astrophysics Data System (ADS)

Emulsion chambers are being used in a series of stratospheric balloon flights to study nuclear interactions, charge composition, and energy spectra of cosmic ray nuclei over the energy range 1012-1015 eV. Charge identification involves grain, gap, and/or delta-ray counting in emulsion plates having different sensitivities on two sides of an acrylic base. Electromagnetic cascade energies are measured with resolutions of about 25% by the three-dimensional track counting method. This report describes the apparatus, the measurement techniques, and the analysis methods used to determine the primary proton and helium spectra.

Burnett, T. H.; Dake, S.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Holynski, R.; Iwai, J.; Jones, W. V.; Jurak, A.; Lord, J. J.; Miyamura, O.; Oda, H.; Ogata, T.; Parnell, T. A.; Saito, T.; Tabuki, T.; Takahashi, Y.; Tominaga, T.; Watts, J. W.; Wilczynska, B.; Wilkes, R. J.; Wolter, W.; Wosiek, B.

1986-11-01

138

Topics in Particle Astrophysics: Dark Matter, Gamma-Ray Bursts, and the Origin of Ultra-High-Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Since the first observation of cosmic rays in the early 1900's, intensive astronomical and cosmological observations, and improvements in particle detectors have generated important discoveries such as the existence of gamma-ray bursts and pulsars; they have also generated puzzling evidence for dark matter and dark energy, and for the existence of particles in the interstellar medium with energy beyond 1020 eV. In this dissertation, I will investigate some of the current theoretical challenges posed by the latest cosmological and astrophysical observations, and attempt to provide a unifying solution to the problems. X-ray and gamma-ray observations can help understand the origin of the electron and positron signals reported by ATIC, PAMELA, PPB-BETS , and Fermi. It remains unclear whether the observed high-energy electrons and positrons are produced by relic particles, or by astrophysical sources. To distinguish between the two possibilities, one can compare the electron population in the local neighborhood with that in Dwarf Spheroidal Galaxies (dSphs), which are not expected to host as many gamma-ray bursts, pulsars, or other astrophysical sources. This can be accomplished using X-ray and gamma-ray observations. Assuming the signal detected by Fermi and ATIC comes from dark matter, we calculate the photon spectrum produced by electrons via inverse Compton scattering with the Cosmic Microwave Background radiation (CMB). Since little is known about the magnetic fields in dwarf spheroidals, we consider the propagation of charged particles with and without diffusion. Extending the analysis of the Fermi collaboration for the Draco dwarf spheroidal galaxy, we find that even in the absence of diffusion, the expected gamma-ray signal lies above the upper limits set by the Fermi telescope, thus favoring astrophysical sources such as gamma-ray bursts and pulsars. Furthermore, if one assumes that a local magnetic field exists in the dwarf spheroidal galaxy, the diffusion of the electrons gives rise to a signal that could also be detectable by future X-ray telescope experiments. Besides being one of the preferred explanation for the high-energy electron and positron excess suggested by ATIC, PAMELA, and Fermi, Gamma-Ray Bursts (GRBs) have also been invoked to explain the 511 keV emission from the galactic bulge. While independent explanations can be responsible for these phenomena, we explore the possibility of their common GRB-related origin, by modeling the GRB distribution and estimating their rates. For an expected long GRB rate in the Milky Way, neither of the two signals is generic; the local electron excess requires a 2% coincidence while the signal from the galactic center requires a 20% coincidence with respect to the timing of the latest GRB. The simultaneous explanation requires a 0.4% coincidence. Considering the large number of statistical "trials" created by multiple searches for new physics, the coincidences of a few per cent cannot be dismissed as unlikely. Alternatively, both phenomena can be explained by GRBs if the galactic rate is higher than expected. We also show that a similar result is difficult to obtain assuming a simplified short GRB distribution. Recent results from the Pierre Auger Observatory ( PAO), showing energy-dependent chemical composition of Ultra-High-Energy Cosmic Rays (UHECRs) with a growing fraction of heavy elements at high energies, suggest a possible non-negligible contribution to the spectrum from galactic sources. We show that in the case of UHECRs produced by gamma-ray bursts, or by rare types of supernova explosions that took place in the Milky Way in the past, the change in composition of the UHECR, spectrum can result from the difference in diffusion times for different species. The anisotropy in the direction of the galactic center is expected to be a few percent on average, but the locations of the most recent/closest bursts can be associated with the possible observed clustering of UHECRs.

Calvez, Antoine

139

Influence of hadronic interaction models and the cosmic ray spectrum on the high energy atmospheric muon and neutrino flux  

NASA Astrophysics Data System (ADS)

The recent observations of muon charge ratio up to about 10 TeV and of atmospheric neutrinos up to energies of about 400 TeV have triggered a renewed interest into the high-energy interaction models and cosmic-ray primary composition. A reviewed calculation of lepton spectra produced in cosmic-ray-induced extensive air showers is carried out with a primary cosmic-ray spectrum that fits the latest direct measurements below the knee. In order to achieve this, we used a full Monte Carlo method to derive the inclusive differential spectra (yields) of muons, muon neutrinos and electron neutrinos at the surface for energies between 80 GeV and hundreds of PeV. Using these results, the differential flux and the flavor ratios of leptons were calculated. The air shower simulator CORSIKA 6.990 was used for showering and propagation of the secondary particles through the atmosphere, employing the established high-energy hadronic interaction models SIBYLL 2.1, QGSJet-01 and QGSJet-II-03. We show that the performance of the interaction models makes it possible to predict the spectra within experimental uncertainties, while SIBYLL generally yields a higher flux at the surface than the QGSJet models. The calculation of the flavor and charge ratios has lead to inconsistent results, mainly influenced by the different representations of the K/? ratio within the models. The influence of the knee of cosmic rays is reflected in the secondary spectra at energies between 100 and 200 TeV. Furthermore, we could quantify systematic uncertainties of atmospheric muon and neutrino fluxes, associated to the models of the primary cosmic-ray spectrum and the interaction models. For most recent parametrizations of the cosmic-ray primary spectrum, atmospheric muons can be determined with an uncertainty smaller than (+15)/(-13)% of the average flux. Uncertainties of the muon and electron neutrino fluxes can be calculated within an average error of (+32)/(-22)% and (+25)/(-19)%, respectively.

Fedynitch, Anatoli; Becker Tjus, Julia; Desiati, Paolo

2012-12-01

140

Searching for high energy cosmic ray electrons using the Earth's magnetic field.  

NASA Astrophysics Data System (ADS)

The Cosmic Ray Electron Synchrotron Telescope (CREST) instrument is a balloon payload designed to measure the flux of primary cosmic ray electrons at energies greater than 2 TeV. Because electrons at these energies lose energy rapidly during propagation through the interstellar medium, their detection would indicate the existence of sources which are within a few kiloparsecs. In order to obtain the needed large exposure time and aperture of the detector, we use an approach that depends on the detection of synchrotron photons emitted when the electrons travel through the earth's magnetic field. Such photons have energies in the x-ray and gamma-ray region, hence CREST incorporates an array of inorganic scintillators. Since the primary electrons do not need to pass through the detector, the effective detection area is much larger than the actual detector array size. To verify the technique and to determine background count rates, a prototype array of BGO and BaF2 crystals was flown on high altitude balloon from Ft. Sumner, N.M. in autumn 2005. The full detector system is currently under construction. It will consist of a 1600 crystal array, and will be carried on Long-Duration Balloons on circumpolar trajectory.

Nutter, S.; Bower, C.; Coutu, S.; Duvernois, M.; Martell, A.; Muller, D.; Musser, J.; Schubnell, M.; Tarle, G.; Yagi, A.

2006-04-01

141

Ultra-high energy cosmic ray correlations with active galactic nuclei in the world dataset  

NASA Astrophysics Data System (ADS)

The Pierre Auger collaboration have recently put forward the hypothesis that the arrival directions of the highest energy cosmic rays correlate with the subset of local active galactic nuclei (AGNs). We perform a blind test of AGN hypothesis using publicly available event sets collected by Yakutsk, AGASA, and HiRes experiments. The consistency of the procedure requires the event energies to be normalized towards the common energy scale. The number of correlating events in resulting data-set is 3 of 21 which is consistent with expected random background.

Rubtsov, G. I.; Tkachev, I. I.; Dolgov, A. D.

2012-07-01

142

Cosmic-Ray Muon and Atmospheric Neutrino Fluxes at Very High Energies  

SciTech Connect

Estimates of cosmic-ray muon and atmospheric neutrino fluxes at TeV energies are obtained taking into account a 'prompt' production of muons and neutrinos through charmed-particle decays and a 'direct' lepton-pair production through the Drell-Yan mechanism and resonances. It is found that the contribution of charmed particles to the muon flux is equal to that from the conventional sources (pion and kaon decays) at 60 TeV, and the same equality can take place at 10 and 1 TeV for muon and electron neutrinos, respectively (for particles coming to sea level in the vertical direction). This 'direct' production contribution to muon and neutrino fluxes is estimated very arbitrarily, but it cannot be excluded that this contribution is equal to that from the conventional source at energies of 0.5 and 0.05 PeV for muons and muon neutrinos, respectively. Currently, the estimates of the 'prompt' and the 'direct' contributions to cosmic-ray muons and atmospheric neutrinos are only qualitative. This is true especially for the 'direct' contribution. Nevertheless, it seems reasonable to attract attention to these potentially important sources of atmospheric muons and neutrinos.

Volkova, L.V. [Institute for Nuclear Research, Russian Academy of Sciences, pr. Shestidesyatiletiya Oktyabrya 7a, Moscow, 117312 (Russian Federation)

2004-11-01

143

Ultra High Energy Cosmic Rays from Engine-driven Relativistic Supernovae  

NASA Astrophysics Data System (ADS)

The sources of the highest energy cosmic rays remain an enigma half a century after their discovery. Understanding their origin is a crucial step in probing new physics at energies unattainable by terrestrial accelerators. They must be accelerated in the local universe as otherwise interaction with cosmic background radiations would severely deplete the flux of protons and nuclei at energies above the Greisen-Zatsepin-Kuzmin (GZK) limit. Hypernovae, nearby GRBs, AGNs and their flares have all been suggested and debated in the literature as possible sources. Type Ibc supernovae have a local sub-population with mildly relativistic ejecta which are known to be sub-energetic GRBs or X-Ray Flashes for sometime and more recently as those with radio afterglows but without detected GRB counterparts, such as SN 2009bb. In this talk we present the size-magnetic field evolution, baryon loading and energetics of SN 2009bb using its radio spectra obtained with VLA and GMRT. We show that the engine-driven SNe lie above the Hillas line and they can explain the characteristics of post-GZK UHECRs.

Chakraborti, Sayan

2012-09-01

144

PeV neutrinos from the propagation of ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We discuss the possibility that the PeV neutrinos recently observed by IceCube are produced by the interactions of extragalactic cosmic rays during their propagation through the radiation backgrounds. We show that the fluxes resulting from the decays of neutrons produced in the interactions of cosmic ray protons with the CMB background are suppressed (E?2d??/dE < 10-10 GeV/cm2 s sr), with those resulting from the decays of pions produced in the interactions with the UV/optical/IR backgrounds being the dominant ones at PeV energies. The anti-neutrino fluxes produced by the decay of neutrons resulting from the photodisintegration of heavy nuclei with CMB photons are also shown to be quite suppressed (E?2d??/dE < 10-11 GeV/cm2 s sr), while those produced by photo-pion processes with UV/optical/IR backgrounds may be larger, although they are not expected to be above those achievable in the pure proton case. Scenarios with mixed composition and low cutoff rigidities can lead to PeV neutrino fluxes enhanced with respect to those in the pure Fe scenarios. We also discuss the possible impact of the Glashow resonance for the detection of these scenarios, showing that it plays a moderate role.

Roulet, Esteban; Sigl, Guenter; van Vliet, Arjen; Mollerach, Silvia

2013-01-01

145

On Gamma Ray Burst and Blazar AGN Origins of the UltraHigh Energy Cosmic Rays in Light of First Results from Auger  

Microsoft Academic Search

The discoveries of the GZK cutoff with the HiRes and Auger Observatories and the discovery by Auger of clustering of >~60 EeV ultra-high energy cosmic rays (UHECRs) towards nearby <~75 Mpc) AGNs along the supergalactic plane establishes the astrophysical origin of the UHECRs. The likely sources of the UHECRs are gamma-ray bursts and radio-loud AGNs because: (1) they are extragalactic;

Charles D. Dermer

2007-01-01

146

A search for anisotropy in the arrival directions of ultra high energy cosmic rays recorded at the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

Observations of cosmic ray arrival directions made with the Pierre Auger Observatory have previously provided evidence of anisotropy at the 99% CL using the correlation of ultra high energy cosmic rays (UHECRs) with objects drawn from the Véron-Cetty Véron catalog. In this paper we report on the use of three catalog independent methods to search for anisotropy. The 2pt-L, 2pt+ and 3pt methods, each giving a different measure of self-clustering in arrival directions, were tested on mock cosmic ray data sets to study the impacts of sample size and magnetic smearing on their results, accounting for both angular and energy resolutions. If the sources of UHECRs follow the same large scale structure as ordinary galaxies in the local Universe and if UHECRs are deflected no more than a few degrees, a study of mock maps suggests that these three methods can efficiently respond to the resulting anisotropy with a P-value = 1.0% or smaller with data sets as few as 100 events. Using data taken from January 1, 2004 to July 31, 2010 we examined the 20,30,...,110 highest energy events with a corresponding minimum energy threshold of about 49.3 EeV. The minimum P-values found were 13.5% using the 2pt-L method, 1.0% using the 2pt+ method and 1.1% using the 3pt method for the highest 100 energy events. In view of the multiple (correlated) scans performed on the data set, these catalog-independent methods do not yield strong evidence of anisotropy in the highest energy cosmic rays.

Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahlers, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Antici'c, T.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohácová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brancus, I.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Caballero-Mora, K. S.; Caccianiga, B.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chirinos Diaz, J.; Chudoba, J.; Cilmo, M.; Clay, R. W.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; del Peral, L.; del Río, M.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Díaz Castro, M. L.; Diep, P. N.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Fajardo Tapia, I.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fick, B.; Filevich, A.; Filipcic, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fratu, O.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; Garcia Roca, S. T.; Garcia-Gamez, D.; Garcia-Pinto, D.; Gascon, A.; Gemmeke, H.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gómez Vitale, P. F.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Gorgi, A.; Gouffon, P.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Guzman, A.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harrison, T. A.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Horvath, P.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jarne, C.; Jiraskova, S.; Josebachuili, M.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lauer, R.; Lautridou, P.; Le Coz, S.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Agüera, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Lyberis, H.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Mi'canovi'c, S.; Micheletti, M. I.; Minaya, I. A.; Miramonti, L.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Mostafá, M.; Moura, C. A.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nhung, P. T.; Niechciol, M.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Pastor, S.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.

2012-04-01

147

A search for anisotropy in the arrival directions of ultra-high-energy cosmic rays observed by the High Resolution Fly's Eye detector  

Microsoft Academic Search

Although the existence of cosmic rays with energies extending well above 10^19 eV has been confirmed, their origin remains one of the most important questions in astro-particle physics today. The High Resolution Fly's Eye Detector (HiRes) detects Ultra High Energy Cosmic Rays (UHECRs) by employing the air- fluorescence technique to observe Extensive Air Showers (EAS) in the atmosphere over Dugway,

Benjamin Taylor Stokes

2006-01-01

148

MEASUREMENTS OF THE RELATIVE ABUNDANCES OF HIGH-ENERGY COSMIC-RAY NUCLEI IN THE TeV/NUCLEON REGION  

SciTech Connect

We present measurements of the relative abundances of cosmic-ray nuclei in the energy range of 500-3980 GeV/nucleon from the second flight of the Cosmic Ray Energetics And Mass balloon-borne experiment. Particle energy was determined using a sampling tungsten/scintillating-fiber calorimeter, while particle charge was identified precisely with a dual-layer silicon charge detector installed for this flight. The resulting element ratios C/O, N/O, Ne/O, Mg/O, Si/O, and Fe/O at the top of atmosphere are 0.919 {+-} 0.123{sup stat} {+-} 0.030{sup syst}, 0.076 {+-} 0.019{sup stat} {+-} 0.013{sup syst}, 0.115 {+-} 0.031{sup stat} {+-} 0.004{sup syst}, 0.153 {+-} 0.039{sup stat} {+-} 0.005{sup syst}, 0.180 {+-} 0.045{sup stat} {+-} 0.006{sup syst}, and 0.139 {+-} 0.043{sup stat} {+-} 0.005{sup syst}, respectively, which agree with measurements at lower energies. The source abundance of N/O is found to be 0.054 {+-} 0.013{sup stat} {+-} 0.009{sup syst+0.010esc} {sub -0.017}. The cosmic-ray source abundances are compared to local Galactic (LG) abundances as a function of first ionization potential and as a function of condensation temperature. At high energies the trend that the cosmic-ray source abundances at large ionization potential or low condensation temperature are suppressed compared to their LG abundances continues. Therefore, the injection mechanism must be the same at TeV/nucleon energies as at the lower energies measured by HEAO-3, CRN, and TRACER. Furthermore, the cosmic-ray source abundances are compared to a mixture of 80% solar system abundances and 20% massive stellar outflow (MSO) as a function of atomic mass. The good agreement with TIGER measurements at lower energies confirms the existence of a substantial fraction of MSO material required in the {approx}TeV per nucleon region.

Ahn, H. S.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Malinin, A. [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States); Allison, P. S.; Beatty, J. J.; Brandt, T. J. [Department of Physics, Ohio State University, Columbus, OH 43210 (United States); Bagliesi, M. G.; Bigongiari, G.; Maestro, P.; Marrocchesi, P. S. [Department of Physics, University of Siena and INFN, Via Roma 56, 53100 Siena (Italy); Barbier, L. [Astroparticle Physics Laboratory, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Childers, J. T.; DuVernois, M. A. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Conklin, N. B.; Coutu, S. [Department of Physics, Penn State University, University Park, PA 16802 (United States); Jeon, J. A.; Lee, J., E-mail: ipark@ewha.ac.k [Department of Physics, Ewha Womans University, Seoul 120-750 (Korea, Republic of)

2010-06-01

149

A Study of the Composition of Ultra-High-Energy Cosmic Rays Using the High-Resolution Fly's Eye  

NASA Astrophysics Data System (ADS)

The composition of ultra-high-energy cosmic rays is measured with the High Resolution Fly's Eye cosmic-ray observatory data using the Xmax technique. Data were collected in stereo between 1999 November and 2001 September. The data are reconstructed with well-determined geometry. Measurements of the atmospheric transmission are incorporated in the reconstruction. The detector resolution is found to be 30 g cm-2 in Xmax and 13% in energy. The Xmax elongation rate between 1018.0 and 1019.4 eV is measured to be 54.5+/-6.5(stat)+/-4.5(sys) g cm-2 per decade. This is compared with predictions using the QGSJet01 and SIBYLL 2.1 hadronic interaction models for both protons and iron nuclei. CORSIKA-generated extensive air showers are incorporated directly into a detailed detector Monte Carlo program. The elongation rate and the Xmax distribution widths are consistent with a constant or slowly changing and predominantly light composition. A simple model containing only protons and iron nuclei is compared with QGSJet and SIBYLL. The best agreement between the model and the data is for 80% protons for QGSJet and 60% protons for SIBYLL.

Abbasi, R. U.; Abu-Zayyad, T.; Archbold, G.; Atkins, R.; Bellido, J.; Belov, K.; Belz, J. W.; BenZvi, S.; Bergman, D. R.; Boyer, J.; Burt, G. W.; Cao, Z.; Clay, R.; Connolly, B. M.; Dawson, B.; Deng, W.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Hanlon, W. F.; Hughes, G. A.; Huntemeyer, P.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Knapp, B.; Loh, E. C.; Maetas, M. M.; Martens, K.; Martin, G.; Manago, N.; Mannel, E. J.; Matthews, J. A. J.; Matthews, J. N.; O'Neill, A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Sasaki, M.; Seman, M.; Schnetzer, S. R.; Simpson, K.; Smith, J. D.; Snow, R.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Westerhoff, S.; Wiencke, L. R.; Zech, A.; High Resolution Fly's Eye Collaboration

2005-04-01

150

Cosmic Rays  

NASA Astrophysics Data System (ADS)

For many years cosmic rays provided the most important source of energetic particles for studies of subatomic physics. Today, cosmic rays are being studied as a natural phenomenon that can tell us much about both the Earth's environment in space and distant astrophysical processes. Cosmic rays are naturally occurring energetic particles-mainly ions- with kinetic energies extending from just above thermal energies to more than 1020 electron volts (eV). They constantly bombarded the Earth from all directions, with more than 10's particles having energies greater than 1 MeV striking the top of the Earth's atmosphere each second. The broad maximum in the spectrum at 108 - 109 eV defines the typical cosmic rays proton having approximately 109 eV. The abundances of certain unstable isotopes in meteorites show that cosmic rays have been present at nearly their current level for hundreds of millions of years. Studies of electromagnetic waves produced by cosmic rays in distant astrophysical sources reveal that they are present throughout the disk and halo of our galaxy and in other galaxies as well. Cosmic rays are now believed to be produced naturally in astrophysical plasmas, nearly all by a process called diffusive shock acceleration, which occurs naturally at collisionless shock waves. Observations of cosmic rays began in the early part of this century when C.TR. Wilson, using his cloud chamber, studied the puzzlingly high level of atmospheric ionization. In 1912, with balloon-borne ionization detectors, Victor Hess showed that this ionization increased with increasing altitude and concluded that radiation was coming from above the atmosphere, a discovery which earned him the Nobel Prize in 1936.

Jokipii, J. R.

1998-01-01

151

Extragalactic Ultra-High Energy Cosmic-Rays - Part One - Contribution from Hot Spots in Fr-II Radio Galaxies  

NASA Astrophysics Data System (ADS)

The hot spots of Fanaroff-Riley class II radio galaxies, considered as working surfaces of highly collimated plasma jets, are proposed to be the dominant sources of the cosmic rays at energies above 1 EeV^a^. We apply the model of first order Fermi acceleration at strong, nonrelativistic shock waves to the hot spot region. The strength of the model has been demonstrated by Biermann & Strittmatter (1987) and by Meisenheimer et al. (1989), who explain their radio-to optical spectra and infer the physical conditions of the radiating plasma. Using synchrotron radiating electrons as a trace, we can calculate the spectrum and the maximum energy of protons accelerated under the same conditions. For simplicity, we disregard heavy nuclei, but their probable role is discussed. The normalization of proton flux injected in extragalactic space is performed by using estimates from Rawlings & Saunders (1991) for the total energy stored in relativistic particles inside the jets and radio galaxy evolution models given by Peacock (1985). We calculate the spectral modifications due to interactions of the protons with the microwave background photons in an evolving universe, following Berezinsky & Grigor'eva (1988). Constraints on the extragalactic magnetic field can be imposed, since it must permit an almost homogeneous filling of the universe with energetic protons. The observed ultra-high energy cosmic ray spectrum is reproduced in slope and flux, limited at high energies by the Greisen-cutoff at about 80 EeV. The requirements on the content of relativistic protons in jets and the constraints to the extragalactic magnetic field are consistent with common estimates. The data beyond the Greisen cutoff for protons may be explained by including heavy nuclei in our model, since they can propagate over cosmological distances up to more than 100 EeV.

Rachen, J. P.; Biermann, P. L.

1993-05-01

152

Upper limit on the cosmic gamma-ray burst rate from high energy diffuse neutrino background  

NASA Astrophysics Data System (ADS)

We derive upper limits on the ratio fGRB/CCSN(z)?RGRB(z)/RCCSN(z)?fGRB/CCSN(0)(1+z)?, the ratio of the rate, RGRB, of long-duration gamma-ray bursts (GRBs) to the rate, RCCSN, of core-collapse supernovae (CCSNe) in the Universe (z being the cosmological redshift and ??0), by using the upper limit on the diffuse TeV-PeV neutrino background given by the AMANDA-II experiment in the South Pole, under the assumption that GRBs are sources of TeV-PeV neutrinos produced from decay of charged pions produced in p? interaction of protons accelerated to ultrahigh energies at internal shocks within GRB jets. For the assumed “concordance model” of cosmic star formation rate, RSF, with RCCSN(z)?RSF(z), our conservative upper limits are fGRB/CCSN(0)?5.0×10-3 for ?=0, and fGRB/CCSN(0)?1.1×10-3 for ?=2, for example. These limits are already comparable to (and, for ??1, already more restrictive than) the current upper limit on this ratio inferred from other astronomical considerations, thus providing a useful independent probe of and constraint on the CCSN-GRB connection. Nondetection of a diffuse TeV PeV neutrino background by the upcoming IceCube detector in the South Pole after three years of operation, for example, will bring down the upper limit on fGRB/CCSN(0) to below a few ×10-5 level, while a detection will confirm the hypothesis of proton acceleration to ultrahigh energies in GRBs and will potentially also yield the true rate of occurrence of these events in the Universe.

Bhattacharjee, Pijushpani; Chakraborty, Sovan; Das Gupta, Srirupa; Kar, Kamales

2008-02-01

153

Peculiar high energy cosmic ray stratospheric event reveals a heavy primary origin particle above the knee region of the cosmic ray spectrum  

SciTech Connect

We wish to put forward an explanation for a peculiar cosmic ray event with energy {sigma}E{sub {gamma}}{>=}2x10{sup 15} eV detected in 1975 by the balloon borne emulsion chamber experiment performed in the stratosphere, at the altitude {>=}30 km above sea level. For almost 30 years the event has been described as unusual, invoking new exotic mechanisms or models. In our opinion there is no need for an extraordinary explanation. Contrary to the widespread belief, the event gives us an example of 'unrecognized standard physics'. At the same time this event revealed a variety of features which are of considerable interest for cosmic rays, nuclear physics, and astrophysics. Here we show that the observed family is most likely to be a result of a heavy nucleus interaction with an air nucleus. In this case a primary particle would originally have been in the energy region above 'the knee' of the cosmic ray spectrum.

Kopenkin, V.; Fujimoto, Y. [Advanced Research Institute for Science and Engineering, Waseda University, Shinjuku, Tokyo, 169 (Japan)

2005-01-15

154

Peculiar high energy cosmic ray stratospheric event reveals a heavy primary origin particle above the knee region of the cosmic ray spectrum  

NASA Astrophysics Data System (ADS)

We wish to put forward an explanation for a peculiar cosmic ray event with energy ?E??2×1015eV detected in 1975 by the balloon borne emulsion chamber experiment performed in the stratosphere, at the altitude ?30km above sea level. For almost 30 years the event has been described as unusual, invoking new exotic mechanisms or models. In our opinion there is no need for an extraordinary explanation. Contrary to the widespread belief, the event gives us an example of “unrecognized standard physics”. At the same time this event revealed a variety of features which are of considerable interest for cosmic rays, nuclear physics, and astrophysics. Here we show that the observed family is most likely to be a result of a heavy nucleus interaction with an air nucleus. In this case a primary particle would originally have been in the energy region above “the knee” of the cosmic ray spectrum.

Kopenkin, V.; Fujimoto, Y.

2005-01-01

155

FERMI LAT OBSERVATION OF DIFFUSE GAMMA RAYS PRODUCED THROUGH INTERACTIONS BETWEEN LOCAL INTERSTELLAR MATTER AND HIGH-ENERGY COSMIC RAYS  

SciTech Connect

Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse gamma-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200 deg. to 260 deg. and latitude |b| from 22 deg. to 60 deg.) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of gamma-ray point sources and inverse Compton scattering are estimated and subtracted. The residual gamma-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated gamma-ray emissivity is (1.63 +- 0.05) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} and (0.66 +- 0.02) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} above 100 MeV and above 300 MeV, respectively, with an additional systematic error of {approx}10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred from direct measurements at the Earth within {approx}10%.

Abdo, A. A. [Space Science Division, Naval Research Laboratory, Washington, DC 20375 (United States); Ackermann, M.; Ajello, M. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States)

2009-10-01

156

Upper limit on the cosmic gamma-ray burst rate from high energy diffuse neutrino background  

SciTech Connect

We derive upper limits on the ratio f{sub GRB/CCSN}(z){identical_to}R{sub GRB}(z)/R{sub CCSN}(z){identical_to}f{sub GRB/CCSN}(0)(1+z){sup {alpha}}, the ratio of the rate, R{sub GRB}, of long-duration gamma-ray bursts (GRBs) to the rate, R{sub CCSN}, of core-collapse supernovae (CCSNe) in the Universe (z being the cosmological redshift and {alpha}{>=}0), by using the upper limit on the diffuse TeV-PeV neutrino background given by the AMANDA-II experiment in the South Pole, under the assumption that GRBs are sources of TeV-PeV neutrinos produced from decay of charged pions produced in p{gamma} interaction of protons accelerated to ultrahigh energies at internal shocks within GRB jets. For the assumed ''concordance model'' of cosmic star formation rate, R{sub SF}, with R{sub CCSN}(z){proportional_to}R{sub SF}(z), our conservative upper limits are f{sub GRB/CCSN}(0){<=}5.0x10{sup -3} for {alpha}=0, and f{sub GRB/CCSN}(0){<=}1.1x10{sup -3} for {alpha}=2, for example. These limits are already comparable to (and, for {alpha}{>=}1, already more restrictive than) the current upper limit on this ratio inferred from other astronomical considerations, thus providing a useful independent probe of and constraint on the CCSN-GRB connection. Nondetection of a diffuse TeV-PeV neutrino background by the upcoming IceCube detector in the South Pole after three years of operation, for example, will bring down the upper limit on f{sub GRB/CCSN}(0) to below a few x10{sup -5} level, while a detection will confirm the hypothesis of proton acceleration to ultrahigh energies in GRBs and will potentially also yield the true rate of occurrence of these events in the Universe.

Bhattacharjee, Pijushpani; Chakraborty, Sovan; Das Gupta, Srirupa; Kar, Kamales [Theory Division, Saha Institute of Nuclear Physics, 1/AF Bidhannagar, Kolkata 700064 (India)

2008-02-15

157

On Gamma Ray Burst and Blazar AGN Origins of the UltraHigh Energy Cosmic Rays in Light of First Results from Auger  

Microsoft Academic Search

The discoveries of the GZK cutoff with the HiRes and Auger Observatories and\\u000athe discovery by Auger of clustering of >~60 EeV ultra-high energy cosmic rays\\u000a(UHECRs) towards nearby <~75 Mpc) AGNs along the supergalactic plane\\u000aestablishes the astrophysical origin of the UHECRs. The likely sources of the\\u000aUHECRs are gamma-ray bursts and radio-loud AGNs because: (1) they are\\u000aextragalactic;

Charles D. Dermer

2007-01-01

158

Coleman-Glashow Massive Photon and Ultra-HighEnergy Cosmic Rays beyond the GZK Cutoff  

NASA Astrophysics Data System (ADS)

Very high-energy gamma rays and neutrinos could be probes of quantum gravity (QG) nature of vacuum [Amelio-Camella, et al, 1998]. Extreme Energy (EE) photons lose energy by pair production in a vacuum due to the ubiquitous microwave photons. Their path length at EE energies is limited to less than 10 Mpc in ordinary space and they are believed to be unable to reach earth from Gamma Ray BurstUs (GRB) of cosmological distances. However, EE gamma rays in the QG vacuum can pass through a large distance exceeding many Gpc, because electron-pair production with 2.7K (E') microwave background may be kinematically prohibited above 10 TeV under the QG structure of vacuum. The energy-momentum conservation for the pair process does not hold for E >> 10 TeV for E' = 10-3 (Kifune, 1999), because 4 mc^4 = E^2 - (pc)^2 = E^2 (E'/E - k E/E0) < 0, where k = 1. The reported observation of EECRUs above 4 4 10^eV with unaccounted pair or triple coincidence in spatial and temporal ( ~ 2 years) coordinates is also a mystery. They also seem to be correlated with high luminosity GRBUs within 1 year [Milgrom and Usov, 1995; Takahashi, 1998]. If this correlation is true, then the ballpark correlation of one-year is hard to understand with any theory, while a possible explanation is available if Quantum Gravity (QG) is considered with Planck mass (10^28eV/c^2) grain of spacetime (10-33 cm). The QG scheme [Amelio-Camella, et al, 1998] leads to a delay time of gamma rays of the order of 1 year at 5 x 10^19 eV from cosmological distance (L) of GRB's (typically, L ~ 1 Gpc). The reduced speed of EHE gamma rays in QG is v = (1 - k 4 E/E0)c, where E0 is the Planck mass (10^20 eV/c^2) or gravitino mass (E0/k, k as a parameter O(1)). The fundamental question is whether such high energy particle acceleration occurs in GRBUs. Studies of photonic acceleration in extreme photon outburst sites, GRBUs, might lead to an even more profound cosmological test of the vacuum of Universe; in particular, concerning the existence (or non-existence) of quantum gravity. High-intensity, short-pulse lasers (from 10 Terawatt to 1 Petawatt at 0.5 ~ 1 picosec) permit experimental studies of the photonic acceleration processes. Attainable laser power density have risen in the 1990's to the nonlinear optical domain, >1020 W/cm2, e.g., NOVA of the Lawrence Livermore National Laboratory (LLNL). The high-intensity of the photo n beams at laser facilities was achieved by the Chirped-pulse Amplification technology (CPA) since late 1980's, by which the laser power jumped over 108 times that of 1970's. The Petawatt experiments have already demonstrated wakefield (and snowplow) accelerations to about 1 GeV. The electromagnetic fields generated by the ponderomotive potential are EL = 10 GV/cm and ET = 1 TV/cm. Its theory was established in 1980's (which began with the Dawson-Tajima Beat-Wave theory). The monochromatic waves do not make beat waves or wakefields but forward Raman scattering of monochromatic laser injected into plasma or matter makes a variety of incoherent photons with different wavelengths, and form self-modulated beats, and consequently, wakefields. The wakefield acceleration per unit length is proportional to the photon intensity. A straightforward extrapolation of the wakefields to the non-linear QED regime (10^30 W/cm^2) approaches the critical Schwinger field (E = 10^16.5 V/cm). The physics of high fields encounters such a nonlinear QED regime when the irradiance exceeds 10^30 W/cm^2. It is still billion times beyond the capability of current terrestrial laboratories, but observations of GRBUs already imply such a high field in nature. Thus, the highest power laser experiments might shed some light in diagnosing photonic acceleration in GRBUs; and therefore, (via EHE observation), quantum gravity research.

Takahashi, Yoshiyuki

2000-04-01

159

Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment  

NASA Astrophysics Data System (ADS)

We present new measurements of heavy cosmic-ray nuclei at high energies performed during the first flight of the balloon-borne cosmic-ray experiment Cosmic-Ray Energetics and Mass (CREAM). This instrument uses multiple charge detectors and a transition radiation detector to provide the first high accuracy measurements of the relative abundances of elements from boron to oxygen up to energies around 1 TeV/n. The data agree with previous measurements at lower energies and show a relatively steep decline (˜ E-0.6 to E-0.5) at high energies. They further show the source abundance of nitrogen relative to oxygen is ˜10% in the TeV/n region.

Ahn, H. S.; Allison, P. S.; Bagliesi, M. G.; Beatty, J. J.; Bigongiari, G.; Boyle, P. J.; Brandt, T. J.; Childers, J. T.; Conklin, N. B.; Coutu, S.; Duvernois, M. A.; Ganel, O.; Han, J. H.; Hyun, H. J.; Jeon, J. A.; Kim, K. C.; Lee, J. K.; Lee, M. H.; Lutz, L.; Maestro, P.; Malinin, A.; Marrocchesi, P. S.; Minnick, S. A.; Mognet, S. I.; Nam, S.; Nutter, S. L.; Park, I. H.; Park, N. H.; Seo, E. S.; Sina, R.; Swordy, S. P.; Wakely, S. P.; Wu, J.; Yang, J.; Yoon, Y. S.; Zei, R.; Zinn, S. Y.

2008-10-01

160

Fermi LAT Observation of Diffuse Gamma-Rays Produced through Interactions Between Local Interstellar Matter and High Energy Cosmic Rays  

SciTech Connect

Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse {gamma}-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200{sup o} to 260{sup o} and latitude |b| from 22{sup o} to 60{sup o}) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system. The contributions of {gamma}-ray point sources and inverse Compton scattering are estimated and subtracted. The residual {gamma}-ray intensity exhibits a linear correlation with the atomic gas column density in energy from 100 MeV to 10 GeV. The measured integrated {gamma}-ray emissivity is (1.63 {+-} 0.05) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} and (0.66 {+-} 0.02) x 10{sup -26} photons s{sup -1}sr{sup -1} H-atom{sup -1} above 100 MeV and above 300 MeV, respectively, with an additional systematic error of {approx}10%. The differential emissivity from 100 MeV to 10 GeV agrees with calculations based on cosmic ray spectra consistent with those directly measured, at the 10% level. The results obtained indicate that cosmic ray nuclei spectra within 1 kpc from the solar system in regions studied are close to the local interstellar spectra inferred from direct measurements at the Earth within {approx}10%.

Abdo, A.A.; /Naval Research Lab, Wash., D.C. /Federal City Coll.; Ackermann, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Ajello, M.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Atwood, W.B.; /UC, Santa Cruz; Axelsson, M.; /Stockholm U. /Stockholm U., OKC; Baldini, L.; /INFN, Pisa; Ballet, J.; /DAPNIA, Saclay; Barbiellini, G.; /INFN, Trieste /Trieste U.; Bastieri, D.; /INFN, Padua /Padua U.; Baughman, B.M.; /Ohio State U.; Bechtol, K.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bellazzini, R.; /INFN, Pisa; Berenji, B.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bloom, E.D.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bonamente, E.; /INFN, Perugia /Perugia U.; Borgland, A.W.; /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept.; Bregeon, J.; /INFN, Pisa; Brez, A.; /INFN, Pisa; Brigida, M.; /Bari U. /INFN, Bari; Bruel, P.; /Ecole Polytechnique; Burnett, T.H.; /Washington U., Seattle /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /IASF, Milan /Milan Polytechnic /Royal Inst. Tech., Stockholm /Stockholm U., OKC /DAPNIA, Saclay /INFN, Perugia /Perugia U. /NASA, Goddard /Naval Research Lab, Wash., D.C. /George Mason U. /NASA, Goddard /INFN, Perugia /Perugia U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Montpellier U. /Stockholm U. /Stockholm U., OKC /Royal Inst. Tech., Stockholm /ASDC, Frascati /Naval Research Lab, Wash., D.C. /INFN, Trieste /Bari U. /INFN, Bari /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /CENBG, Gradignan /CENBG, Gradignan /Montpellier U. /Bari U. /INFN, Bari /Ecole Polytechnique /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /INFN, Trieste /Hiroshima U. /Stanford U., HEPL /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Bari U. /INFN, Bari /INFN, Bari; /more authors..

2012-03-30

161

A study of the composition of ultra-high-energy cosmic rays using the High-Resolution Fly's Eye  

NASA Astrophysics Data System (ADS)

The composition of Ultra High Energy Cosmic Rays (UHECR) was studied with the High Resolution Fly's Eye cosmic ray observatory (HiRes). HiRes is an air fluorescence detector comprised of two sites separated by 12.6 km on the U.S. Army's Dugway Proving Ground in the West Desert of Utah. Utilizing the atmosphere as a calorimeter, the longitudinal development of Extensive Air Showers (EAS) is measured and the energies, composition, flux, and anisotropy in arrival direction of the highest energy particles are determined. The QGSJet01 and SIBYLL 2.1 hadronic interaction models were used in versions 6.005 and 6.010 of the CORSIKA event generator to determine which measurable EAS parameters were correlated with UHECR compositon and to study predicted elongation rates and Xmax distribution widths in the UHECR regime. The CORSIKA-generated EAS were incorporated directly into a detailed atmospheric and detector Monte Carlo. Data were collected in stereo between November 1999 and September 2001. The data were reconstructed using measurements of the atmosphere, well-determined geometry, a global profile fit, and a detailed Monte Carlo. Monte Carlo resolution is 30 gm/cm2 in Xmax and 13% in Energy. The Elongation Rate between 1017.7 eV and 1020 eV is 55.2 ± 5.0 (stat) ± 3.6 (sys). Xmax distribution widths are consistent with a slowly changing and predominantly light composition. A simple composition model containing only protons and iron nuclei was compared to QGSJet and SIBYLL. The best agreement between the model and the data is at 77% protons for QGSJet and 57% protons for SIBYLL.

Archbold, Gregory Clark

2002-11-01

162

Color Glass Condensate in Brane Models or Don't Ultra High Energy Cosmic Rays Probe 1015 ev Scale?  

NASA Astrophysics Data System (ADS)

In a previous work1 we have studied the propagation of relativistic particles in the bulk for some of the most popular brane models. Constraints have been put on the parameter space of these models by calculating the time delay due to propagation in the bulk of particles created during the interaction of Ultra High Energy Cosmic Rays (UHECRs) with protons in the terrestrial atmosphere. The question was, however, raised that probability of hard processes in which bulk modes can be produced is small and consequently, the tiny flux of UHECRs cannot constrain brane models. Here we use Color Glass Condensate (CGC) model to show that effects of extra dimensions are visible not only in hard processes when the incoming photon/parton hits a massive Kaluza-Klein mode but also through the modification of soft/semi-hard parton distribution. At classical level, for an observer in the CM frame of UHECR and atmospheric hadrons, color charge sources are contracted to a thin sheet with a width inversely proportional to the energy of the ultra energetic cosmic ray hadron and consequently they can see an extra dimension with comparable size. Due to QCD interaction, a short life swarm of partons is produced in front of the sheet and its partons can penetrate to the extra-dimension bulk. This reduces the effective density of partons on the brane or in a classical view creates a delay in the arrival of the most energetic particles if they are reflected back due to the warping of the bulk. In CGC approximation the density of swarm at different distances from the classical sheet can be related and therefore it is possible (at least formally) to determine the relative fraction of partons in the bulk and on the brane at different scales. Results of this work are also relevant to the test of brane models in hadron colliders like LHC.

Ziaeepour, Houri

163

A method for establishing constraints on galactic magnetic field models using ultra high energy cosmic rays and results from the data of the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

The Galactic magnetic field is poorly understood. Essentially the only reliable measurements of its properties are the local orientation and field strength. Its behavior at galactic scales is unknown. Historically, magnetic field measurements have been performed using radio astronomy techniques which are sensitive to certain regions of the Galaxy and rely upon models of the distribution of gas and dust within the disk. However, the deflection of trajectories of ultra high energy cosmic rays arriving from extragalactic sources depends only on the properties of the magnetic field. In this work, a method is developed for determining acceptable global models of the Galactic magnetic field by backtracking cosmic rays through the field model. This method constrains the parameter space of magnetic field models by comparing a test statistic between backtracked cosmic rays and isotropic expectations for assumed cosmic ray source and composition hypotheses. Constraints on Galactic magnetic field models are established using data from the southern site of the Pierre Auger Observatory under various source distribution and cosmic ray composition hypotheses. Field models possessing structure similar to the stellar spiral arms are found to be inconsistent with hypotheses of an iron cosmic ray composition and sources selected from catalogs tracing the local matter distribution in the universe. These field models are consistent with hypothesis combinations of proton composition and sources tracing the local matter distribution. In particular, strong constraints are found on the parameter space of bisymmetric magnetic field models scanned under hypotheses of proton composition and sources selected from the 2MRS-VS, Swift 39-month, and VCV catalogs. Assuming that the Galactic magnetic field is well-described by a bisymmetric model under these hypotheses, the magnetic field strength near the Sun is less than 3-4 muG and magnetic pitch angle is less than -8°. These results comprise the first measurements of the Galactic magnetic field using ultra-high energy cosmic rays and supplement existing radio astronomical measurements of the Galactic magnetic field.

Sutherland, Michael Stephen

2010-12-01

164

Nuclear interactions of super high energy cosmic-rays observed in mountain emulsion chambers  

Microsoft Academic Search

Here we present a summary of joint discussions on the results of three mountain experiments with large-scale emulsion chambers, at Pamir, Mt. Fuji and Chacaltaya. Observations cover gamma quanta, hadrons and their clusters (called ``families''). The following topics are covered, concerning the characteristics of nuclear interactions the energy region 1014-1016 eV: (i) rapid dissipation seen in atmospheric diffusion of high-energy

S. G. Bayburina; A. S. Borisov; K. V. Cherdyntseva; Z. M. Guseva; V. G. Denisova; A. M. Dunaevskii; E. A. Kanevskaya; V. M. Maximenko; S. V. Pashkov; V. S. Puchkov; S. B. Shaulov; S. A. Slavatinsky; M. D. Smirnova; Yu. A. Smorodin; A. V. Urysson; N. G. Zelevinskaya; G. B. Zhdanov; L. G. Afanasjeva; L. T. Baradzei; E. I. Gorochova; I. P. Ivanenko; N. P. Iljina; G. B. Khristiansen; T. V. Lazareva; A. K. Managadze; E. A. Murzina; I. V. Rakobolskaya; T. M. Roganova; N. G. Ryabova; G. T. Zatsepin; R. A. Mukhamedshin; S. D. Cananov; L. A. Khisanishvili; N. N. Roinishvili; M. S. Svanidge; J. A. Tecliashvili; T. V. Varsimashvili; Z. A. Azimov; I. B. Bodojanov; N. E. Gubar; Yu. A. Gulov; F. Normuradov; Kh. Shobaronov; N. A. Dobrotin; Yu. A. Emeljanov; Yu. T. Lukin; B. F. Shorin; E. G. Zaitseva; S. A. Azimov; A. R. Dzhuraev; E. G. Mulladjanov; Kh. Nutritdinov; D. A. Talipov; I. Shamansurov; T. S. Juldashbaev; Z. Buja; E. Gladysz; J. Mazurkiewicz; S. Mikocki; M. Szarska; L. Zawiejski; H. Bielawska; R. Juskiewicz; J. L. Kacperski; A. Krys; J. Malinowski; K. Milczarek; J. Sroka; A. Tomaszewski; J. A. Wrotniak; K. Maluszynska; Z. Wlodarczyk; M. Akashi; M. Amenomori; E. Konishi; H. Nanjo; Z. Watanabe; K. Mizutani; K. Kasahara; S. Torii; T. Yuda; T. Shirai; N. Tateyama; T. Taira; I. Mito; M. Shibata; H. Sugimoto; K. Taira; N. Hotta; M. Ballester; C. Santos; J. Bellandi Filho; J. A. Chinellato; C. Dobrigkeit; C. M. G. Lattes; A. Marques; M. J. Menon; C. E. Navia O; K. Sawayanagi; E. Silva; E. H. Shibuya; A. Turtelli; N. M. Amato; F. M. Oliveira Castro; R. H. C. Maldonado; H. Aoki; Y. Fuyimoto; S. Hasegawa; H. Kumano; H. Semba; T. Tabuki; M. Tamada; K. Tanaka; S. Yamashita; N. Arata; T. Shibata; K. Yokoi; A. Ohsawa

1981-01-01

165

Charm and beauty production in high energy cosmic ray interaction with air nuclei  

Microsoft Academic Search

We calculate the A-dependences of open charm and beauty production cross sections on air nuclear targets taking into account the difference of quark and gluon distributions in free and bound nucleons. The results are presented for the cases of nucleon, 14N and iron beams. For the case of heavy flavour production at high energies, if sigma~Aalpha, the values of alpha

C. Pajares; C. A. Salgado; Yu. M. Shabelski

1999-01-01

166

Mass entrainment and turbulence-driven acceleration of ultra-high energy cosmic rays in Centaurus A  

NASA Astrophysics Data System (ADS)

Observations of the FR I radio galaxy Centaurus A in radio, X-ray, and gamma-ray bands provide evidence for lepton acceleration up to several TeV and clues about hadron acceleration to tens of EeV. Synthesising the available observational constraints on the physical conditions and particle content in the jets, inner lobes and giant lobes of Centaurus A, we aim to evaluate its feasibility as an ultra-high-energy cosmic-ray source. We apply several methods of determining jet power and affirm the consistency of various power estimates of ~1 × 1043 erg s-1. Employing scaling relations based on previous results for 3C 31, we estimate particle number densities in the jets, encompassing available radio through X-ray observations. Our model is compatible with the jets ingesting ~3 × 1021 g s-1 of matter via external entrainment from hot gas and ~7 × 1022 g s-1 via internal entrainment from jet-contained stars. This leads to an imbalance between the internal lobe pressure available from radiating particles and magnetic field, and our derived external pressure. Based on knowledge of the external environments of other FR I sources, we estimate the thermal pressure in the giant lobes as 1.5 × 10-12 dyn cm-2, from which we deduce a lower limit to the temperature of ~1.6 × 108 K. Using dynamical and buoyancy arguments, we infer ~440-645 Myr and ~560 Myr as the sound-crossing and buoyancy ages of the giant lobes respectively, inconsistent with their spectral ages. We re-investigate the feasibility of particle acceleration via stochastic processes in the lobes, placing new constraints on the energetics and on turbulent input to the lobes. The same "very hot" temperatures that allow self-consistency between the entrainment calculations and the missing pressure also allow stochastic UHECR acceleration models to work.

Wykes, Sarka; Croston, Judith H.; Hardcastle, Martin J.; Eilek, Jean A.; Biermann, Peter L.; Achterberg, Abraham; Bray, Justin D.; Lazarian, Alex; Haverkorn, Marijke; Protheroe, Ray J.; Bromberg, Omer

2013-10-01

167

Cosmic Ray Dosimetry  

NASA Astrophysics Data System (ADS)

Radiation levels at aircraft cruising altitudes are twenty times higher than at sea level. Thus, on average, a typical airline pilot receives a larger annual radiation dose than some one working in nuclear industry. The main source of this radiation is from galactic cosmic radiation, high energy particles generated by exploding stars within our own galaxy. In this work we study cosmic rays dosimetry at various aviation altitudes using the PARMA model.

Si Belkhir, F.; Attallah, R.

2010-10-01

168

Measurement of the speed of Ultra-High Energy Cosmic-Ray Extensive Air Showers with the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

At the Pierre Auger Observatory, the reconstruction of Extensive Air Showers (EAS) induced by Ultra-High Energy Cosmic-Rays (UHECR) relies on the very reasonable assumption that all EASs develop at the speed of light. However, because potential exotic species could in principle induce detectable, subluminal EASs, this assumption would lead to poor reconstructions in these rare cases. Additionally, the results of a speed-dependent reconstruction can be useful in monitoring the operation of the array, for instance if a systematic shift from the speed of light in normal showers was observed. In this context, the code for reconstructing optically detected events was modified to find the shower velocity along with the other EAS parameters. This method was first benchmarked with lasers shots fired into the sky from laser facilities located within the array. It was then employed in the multiple levels of shower reconstruction (Monocular, Stereo and Hybrid). Preliminary results from these analyses and an exotic candidate search will be presented.

Mayotte, Eric

2013-04-01

169

Study of Small-Scale Anisotropy of Ultra-High-Energy Cosmic Rays Observed in Stereo by the High Resolution Fly's Eye Detector  

NASA Astrophysics Data System (ADS)

The High Resolution Fly's Eye (HiRes) experiment is an air fluorescence detector which, operating in stereo mode, has a typical angular resolution of 0.6d and is sensitive to cosmic rays with energies above 1018 eV. The HiRes cosmic-ray detector is thus an excellent instrument for the study of the arrival directions of ultra-high-energy cosmic rays. We present the results of a search for anisotropies in the distribution of arrival directions on small scales (<5°) and at the highest energies (>1019 eV). The search is based on data recorded between 1999 December and 2004 January, with a total of 271 events above 1019 eV. No small-scale anisotropy is found, and the strongest clustering found in the HiRes stereo data is consistent at the 52% level with the null hypothesis of isotropically distributed arrival directions.

Abbasi, R. U.; Abu-Zayyad, T.; Amann, J. F.; Archbold, G.; Atkins, R.; Bellido, J. A.; Belov, K.; Belz, J. W.; BenZvi, S.; Bergman, D. R.; Boyer, J. H.; Burt, G. W.; Cao, Z.; Clay, R. W.; Connolly, B. M.; Dawson, B. R.; Deng, W.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G. A.; Hüntemeyer, P.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Knapp, B. C.; Loh, E. C.; Maestas, M. M.; Manago, N.; Mannel, E. J.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Sasaki, M.; Schnetzer, S. R.; Seman, M.; Simpson, K. M.; Sinnis, G.; Smith, J. D.; Snow, R.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tupa, D.; Westerhoff, S.; Wiencke, L. R.; Zech, A.; HIRES Collaboration

2004-08-01

170

Metodicheskie voprosy issledovaniya pervichnykh kosmicheskikh luchej vysokoj ehnergii s apparaturoj Sokol na ISZ Kosmos-1543 i Kosmos-1713. Chast' 2. Pogreshnosti ehnergeticheskikh izmerenij. (Methodical problems of high-energy primary cosmic ray investigation with Sokol device at Kosmos-1543 and Kosmos-1713 satellites. Part 2. Errors of energy measurements).  

National Technical Information Service (NTIS)

Methodical questions of investigating the primary high energy cosmic rays at the Kosmos-1543 and Kosmos-1713 satellites using the Sokol device are discussed. Accuracy of energy measurements when recording the high energy primary cosmic ray particles, perf...

I. P. Ivanenko I. D. Rapoport V. Shestoperov

1988-01-01

171

Discrepancies in the Monte Carlo simulations of propagation of ultra-high energy cosmic-ray photons in the geomagnetic field  

NASA Astrophysics Data System (ADS)

The discrepancies in the results produced by the two most commonly used Monte Carlo programs for simulation of propagation of ultra-high energy cosmic ray photons in the presence of the geomagnetic field are presented. Although photons have not yet been discovered in the cosmic ray flux at highest energies, the capabilities of the present cosmic ray detectors make their discovery possible, according to the predictions of conventional models, within the next few years. It is therefore necessary to have a reliable and well maintained software for relevant simulations. The results of this paper are important for simulations of propagation of photons at energies above 1019 eV. Photons of such high energies might interact with the geomagnetic field giving rise to a cascade of particles even above the atmosphere. This effect is called a "preshower effect". The preshower effect is important for air shower evolution and has to be accounted for in full Monte Carlo simulations of propagation of highest energy cosmic-ray photons. In this paper we compare the two most frequently used Monte Carlo codes for preshower simulations: PRESHOWER, used as a stand-alone program or as a part of CORSIKA, and MaGICS, used as a part of AIRES.

Homola, P.; Rygielski, M.

2013-05-01

172

High energy phenomena associated with gamma ray burst sources  

Microsoft Academic Search

Gamma-ray burst (GRB) spectrum is known to extend upto GeV energies, indicating the occurrence of transient high energy phenomena near GRB sources. Here we present evidence of statistical association between the locations of ultra high energy cosmic rays and GRBs. We examine our earlier finding that bright GRBs are associated with high energy cosmic rays (Energy > 3 × 1019

A. R. Rao; M. N. Vahia

1998-01-01

173

Measurement of the shadowing of high-energy cosmic rays by the Moon: A search for TeV-energy antiprotons  

Microsoft Academic Search

The shadowing of high-energy cosmic rays by the Moon has been observed with a significance of 9.4 standard deviations with the L3+C muon spectrometer at CERN. A significant effect of the Earth magnetic field is observed. Since no event deficit on the east side of the Moon has been observed, an upper limit at 90% confidence level on the antiproton

P. Achard; O. Adriani; M. Aguilar-Benitez; J. Alcaraz; G. Alemanni; J. Allaby; A. Aloisio; M. G. Alviggi; H. Anderhub; V. P. Andreev; F. Anselmo; A. Arefiev; T. Azemoon; P. Bagnaia; A. Bajo; G. Baksay; L. Baksay; J. Bähr; S. V. Baldew; S. Banerjee; Sw. Banerjee; A. Barczyk; R. Barillère; P. Bartalini; M. Basile; N. Batalova; R. Battiston; A. Bay; F. Becattini; U. Becker; F. Behner; L. Bellucci; R. Berbeco; J. Berdugo; P. Berges; B. Bertucci; M. Biasini; M. Biglietti; A. Biland; J. J. Blaising; S. C. Blyth; G. J. Bobbink; A. Böhm; L. Boldizsar; B. Borgia; S. Bottai; D. Bourilkov; M. Bourquin; S. Braccini; J. G. Branson; F. Brochu; J. D. Burger; W. J. Burger; X. D. Cai; M. Capell; G. Cara Romeo; G. Carlino; A. Cartacci; J. Casaus; F. Cavallari; N. Cavallo; C. Cecchi; M. Cerrada; T. Chiarusi; Y. H. Chang; M. Chemarin; A. Chen; G. Chen; H. F. Chen; H. S. Chen; G. Chiefari; L. Cifarelli; F. Cindolo; I. Clare; G. Coignet; N. Colino; S. Costantini; B. de la Cruz; S. Cucciarelli; R. de Asmundis; P. Déglon; J. Debreczeni; A. Degré; K. Dehmelt; D. della Volpe; E. Delmeire; P. Denes; F. DeNotaristefani; A. De Salvo; M. Diemoz; M. Dierckxsens; L. K. Ding; C. Dionisi; M. Dittmar; A. Doria; M. T. Dova; D. Duchesneau; M. Duda; I. Duran; B. Echenard; A. Eline; A. El Hage; H. El Mamouni; A. Engler; F. J. Eppling; P. Extermann; G. Faber; M. A. Falagan; S. Falciano; A. Favara; J. Fay; O. Fedin; M. Felcini; T. Ferguson; H. Fesefeldt; E. Fiandrini; J. H. Field; F. Filthaut; P. H. Fisher; W. Fisher; I. Fisk; G. Forconi; K. Freudenreich; C. Furetta; Yu. Galaktionov; S. N. Ganguli; P. Garcia-Abia; M. Gataullin; S. Gentile; Z. F. Gong; H. J. Grabosch; G. Grenier; O. Grimm; H. Groenstege; M. W. Gruenewald; M. Guida; Y. N. Guo; V. K. Gupta; A. Gurtu; L. J. Gutay; D. Haas; Ch. Haller; D. Hatzifotiadou; Y. Hayashi; Z. X. He; T. Hebbeker; A. Hervé; J. Hirschfelder; H. Hofer; M. Hohlmann; G. Holzner; S. R. Hou; A. X. Huo; N. Ito; B. N. Jin; P. Jindal; C. L. Jing; L. W. Jones; P. de Jong; I. Josa-Mutuberría; V. Kantserov; M. Kaur; S. Kawakami; M. N. Kienzle-Focacci; J. K. Kim; J. Kirkby; W. Kittel; A. Klimentov; E. Kok; A. Korn; M. Kopal; V. Koutsenko; M. Kräber; H. H. Kuang; R. W. Kraemer; A. Krüger; J. Kuijpers; A. Kunin; P. Ladron de Guevara; I. Laktineh; G. Landi; M. Lebeau; A. Lebedev; P. Lebrun; P. Lecomte; P. Le Coultre; J. M. Le Goff; Y. Lei; H. Leich; R. Leiste; M. Levtchenko; P. Levtchenko; C. Li; L. Li; Z. C. Li; S. Likhoded; C. H. Lin; W. T. Lin; F. L. Linde; Z. A. Liu; W. Lohmann; E. Longo; Y. S. Lu; C. Luci; L. Luminari; W. Lustermann; W. G. Ma; X. H. Ma; Y. Q. Ma; L. Malgeri; A. Malinin; C. Maña; J. Mans; J. P. Martin; F. Marzano; K. Mazumdar; R. R. McNeil; S. Mele; X. W. Meng; L. Merola; M. Meschini; W. J. Metzger; A. Mihul; A. van Mil; H. Milcent; G. Mirabelli; J. Mnich; G. B. Mohanty; B. Monteleoni; G. S. Muanza; A. J. M. Muijs; B. Musicar; M. Musy; S. Nagy; R. Nahnhauer; V. A. Naumov; S. Natale; M. Napolitano; F. Nessi-Tedaldi; H. Newman; A. Nisati; T. Novak; H. Nowak; R. Ofierzynski; G. Organtini; I. Pal; C. Palomares; P. Paolucci; R. Paramatti; J.-F. Parriaud; G. Passaleva; S. Patricelli; T. Paul; M. Pauluzzi; C. Paus; F. Pauss; M. Pedace; S. Pensotti; D. Perret-Gallix; B. Petersen; D. Piccolo; F. Pierella; M. Pieri; M. Pioppi; P. A. Piroué; E. Pistolesi; V. Plyaskin; M. Pohl; V. Pojidaev; J. Pothier; D. Prokofiev; J. Quartieri; C. R. Qing; G. Rahal-Callot; M. A. Rahaman; P. Raics; N. Raja; R. Ramelli; P. G. Rancoita; R. Ranieri; A. Raspereza; K. C. Ravindran; P. Razis; D. Ren; M. Rescigno; S. Reucroft; P. Rewiersma; S. Riemann; K. Riles; B. P. Roe; A. Rojkov; L. Romero; A. Rosca; C. Rosemann; S. Rosier-Lees; C. Rosenbleck; S. Roth; J. A. Rubio; G. Ruggiero; H. Rykaczewski; R. Saidi; A. Sakharov; S. Saremi; J. Salicio; E. Sanchez; C. Schäfer; V. Schegelsky; V. Schmitt; B. Schoeneich; H. Schopper; D. J. Schotanus; C. Sciacca; L. Servoli; C. Q. Shen; S. Shevchenko; N. Shivarov; V. Shoutko; E. Shumilov; A. Shvorob; D. Son; C. Souga; P. Spillantini; M. Steuer; D. P. Stickland; B. Stoyanov; A. Straessner; K. Sudhakar; H. Sulanke; G. Sultanov; L. Z. Sun; S. Sushkov; H. Suter; J. D. Swain; Z. Szillasi; X. W. Tang; P. Tarjan; L. Tauscher; B. Tellili; D. Teyssier; C. Timmermans; Samuel C. C. Ting; S. M. Ting; S. C. Tonwar; J. Tóth; G. Trowitzsch; C. Tully; K. L. Tung; J. Ulbricht; M. Unger; E. Valente; H. Verkooijen; R. T. Van de Walle; R. Vasquez; V. Veszpremi; G. Vesztergombi; I. Vetlitsky; D. Vicinanza; G. Viertel; S. Villa; M. Vivargent; S. Vlachos; I. Vodopianov; H. Vogel; H. Vogel; I. Vorobiev; A. A. Vorobyov; M. Wadhwa; R. G. Wang; Q. Wang; X. L. Wang; X. W. Wang; Z. M. Wang; Z. M. Wang; R. van Wijk; T. A. M. Wijnen; H. Wilkens; S. Wynhoff; L. Xia; Y. P. Xu; J. S. Xu; Z. Z. Xu; J. Yamamoto; B. Z. Yang; C. G. Yang; H. J. Yang; M. Yang; X. F. Yang; Z. G. Yao; S. C. Yeh; Z. Q. Yu

2005-01-01

174

Measurement of the Shadowing of High-Energy Cosmic Rays by the Moon:A Search for TeV-Energy Antiprotons  

Microsoft Academic Search

The shadowing of high-energy cosmic rays by the Moon has been observed with a significance of 9.4 standard deviations with the L3+C muon spectrometer at CERN. A significant effect of the Earth magnetic field is observed. Since no event deficit on the east side of the Moon has been observed, an upper limit at 90% confidence level on the antiproton

P Achard; O Adriani; M Aguilar-Benítez; J Alcaraz; G Alemanni; James V Allaby; A Aloisio; M G Alviggi; H Anderhub; V P Andreev; F Anselmo; A Arefev; T Azemoon; T Aziz; P Bagnaia; A Bajo; G Baksay; L Baksay; S V Baldew; S Banerjee; A Barczyk; R Barillère; P Bartalini; M Basile; N Batalova; R Battiston; A Bay; F Becattini; U Becker; F Behner; L Bellucci; R Berbeco; J Berdugo; P Berges; B Bertucci; B L Betev; M Biasini; M Biglietti; A Biland; J J Blaising; S C Blyth; G J Bobbink; A Böhm; L Boldizsar; B Borgia; S Bottai; D Bourilkov; Maurice Bourquin; S Braccini; J G Branson; F Brochu; J D Burger; W J Burger; X D Cai; M Capell; G Cara Romeo; G Carlino; A Cartacci; J Casaus; F Cavallari; N Cavallo; C Cecchi; M Cerrada; M Chamizo-Llatas; Y H Chang; M Chemarin; A Chen; G Chen; H F Chen; H S Chen; G Chiefari; Luisa Cifarelli; F Cindolo; I Clare; R Clare; G Coignet; N Colino; S Costantini; B de la Cruz; S Cucciarelli; J A van Dalen; R De Asmundis; P L Déglon; J Debreczeni; A Degré; K Dehmelt; K Deiters; D Della Volpe; E Delmeire; P Denes; F De Notaristefani; A De Salvo; M Diemoz; M Dierckxsens; C Dionisi; M Dittmar; A Doria; M T Dova; D Duchesneau; M Duda; B Echenard; A Eline; A El-Hage; H El-Mamouni; A Engler; F J Eppling; P Extermann; M A Falagán; S Falciano; A Favara; J Fay; O Fedin; M Felcini; T Ferguson; H S Fesefeldt; E Fiandrini; J H Field; F Filthaut; P H Fisher; W Fisher; I Fisk; G Forconi; Klaus Freudenreich; C Furetta; Yu Galaktionov; S N Ganguli; P García-Abia; M Gataullin; S Gentile; S Giagu; Z F Gong; G Grenier; O Grimm; M W Grünewald; M Guida; V K Gupta; A Gurtu; L J Gutay; D Haas; D Hatzifotiadou; T Hebbeker; A Hervé; J Hirschfelder; H Hofer; M Hohlmann; G Holzner; S R Hou; Y Hu; B N Jin; L W Jones; P de Jong; I Josa-Mutuberria; M Kaur; M N Kienzle-Focacci; J K Kim; Jasper Kirkby; E W Kittel; A Klimentov; A C König; M Kopal; V F Koutsenko; M Kraber; R W Krämer; A Krüger; A Kunin; P Ladrón de Guevara; I Laktineh; G Landi; M Lebeau; A Lebedev; P Lebrun; P Lecomte; P Lecoq; P Le Coultre; J M Le Goff; R Leiste; M Levtchenko; P M Levchenko; C Li; S Likhoded; C H Lin; W T Lin; Frank L Linde; L Lista; Z A Liu; W Lohmann; E Longo; Y S Lü; C Luci; L Luminari; W Lustermann; Ma Wen Gan; L Malgeri; A Malinin; C Maña; J Mans; J P Martin; F Marzano; K Mazumdar; R R McNeil; S Mele; L Merola; M Meschini; W J Metzger; A Mihul; H Milcent; G Mirabelli; J Mnich; G B Mohanty; G S Muanza; A J M Muijs; B Musicar; M Musy; S Nagy; S Natale; M Napolitano; F Nessi-Tedaldi; H Newman; A Nisati; T Novák; H Nowak; R A Ofierzynski; G Organtini; I Pal; C Palomares; P Paolucci; R Paramatti; G Passaleva; S Patricelli; T Paul; M Pauluzzi; C Paus; Felicitas Pauss; M Pedace; S Pensotti; D Perret-Gallix; B Petersen; D Piccolo; F Pierella; M Pioppi; P A Piroué; E Pistolesi; V Plyaskin; M Pohl; V Pozhidaev; J Pothier; D Prokofev; D O Prokofiev; J Quartieri; G Rahal-Callot; M A Rahaman; P Raics; N Raja; R Ramelli; P G Rancoita; R Ranieri; A V Raspereza; P Razis; D Ren; M Rescigno; S Reucroft; S Riemann; K Riles; B P Roe; L Romero; A Rosca; C Rosemann; C Rosenbleck; S Rosier-Lees; S Roth; J A Rubio; G Ruggiero; H Rykaczewski; A Sakharov; S Saremi; S Sarkar; J Salicio; E Sánchez; C Schäfer; V Shchegelskii; Herwig Franz Schopper; D J Schotanus; C Sciacca; L Servoli; S Shevchenko; N Shivarov; V Shoutko; E Shumilov; A Shvorob; D Son; C Souga; P Spillantini; M Steuer; D P Stickland; B Stoyanov; A Strässner; K Sudhakar; G G Sultanov; L Z Sun; S Sushkov; H Suter; J D Swain; Z Szillási; X W Tang; P Tarjan; L Tauscher; L Taylor; B Tellili; D Teyssier; C Timmermans; Samuel C C Ting; S M Ting; S C Tonwar; J Tóth; C Tully; K L Tung; J Ulbricht; E Valente; R T Van de Walle; R Vásquez; V Veszpremi; G Vesztergombi; I Vetlitskii; D Vicinanza; Gert M Viertel; S Villa; M Vivargent; S Vlachos; I Vodopyanov; H Vogel; H Vogt; I Vorobev; A A Vorobyov; M Wadhwa; Q Wang; X L Wang; Z M Wang; M Weber; H Wilkens; S Wynhoff; L Xia; Z Z Xu; J Yamamoto; B Z Yang; C G Yang; H J Yang; M Yang; S C Yeh; A Zalite; Yu Zalite; Z P Zhang; J Zhao; G Y Zhu; R Y Zhu; H L Zhuang; A Zichichi; B Zimmermann; M Zöller

2004-01-01

175

Formation of the spectrum of ultra-high-energy cosmic rays: Effect of extragalactic magnetic fields and expected contribution of individual sources  

Microsoft Academic Search

The effect of the extragalactic magnetic field on the propagation of ultra-high-energy cosmic rays (UHECRs) is investigated.\\u000a We use the infrared galaxy catalog IRAS PSCz to reconstruct the magnetic field distribution in the Local Universe. The magnetic\\u000a field induction is considered as a power function of the galactic infrared luminosity density: B = K??. In contrast to some earlier studies

A. A. Elyiv; B. I. Hnatyk

2007-01-01

176

First results from the microwave air yield beam experiment (MAYBE): Measurement of GHz radiation for ultra-high energy cosmic ray detection  

NASA Astrophysics Data System (ADS)

We present measurements of microwave emission from an electron-beam induced air plasma performed at the 3 MeV electron Van de Graaff facility of the Argonne National Laboratory. Results include the emission spectrum between 1 and 15 GHz, the polarization of the microwave radiation and the scaling of the emitted power with respect to beam intensity. MAYBE measurements provide further insight on microwave emission from extensive air showers as a novel detection technique for Ultra-High Energy Cosmic Rays.

Williams, C.; Bohá?ová, M.; Bonifazi, C.; Cataldi, G.; Chemerisov, S.; de Mello Neto, J. R. T.; Facal San Luis, P.; Fox, B.; Gorham, P. W.; Hojvat, C.; Hollon, N.; Meyhandan, R.; Monasor, M.; Rouillé d'Orfeuil, B.; Santos, E. M.; Pochez, J.; Privitera, P.; Spinka, H.; Verzi, V.; Zhou, J.

2013-06-01

177

High energy cosmic ray spectroscopy. IV. The evidence from direct observations at lower energies and directional anisotropies  

Microsoft Academic Search

In previous papers (A.D. Erlykin, A.W. Wolfendale, Astropart. Phys. 7 (1997) 1, 203; 8 (1998) 265; J. Phys. G 23 (1997) 979), we presented evidence for structure in the size spectrum of cosmic ray air showers which we interpreted as due to the presence of oxygen and iron nuclei from a local, recent, supernova remnant. Although the energies in question

A. D. Erlykin; M. Lipski; A. W. Wolfendale

1998-01-01

178

Observation of the ankle and evidence for a high-energy break in the cosmic ray spectrum  

Microsoft Academic Search

We have measured the cosmic ray spectrum at energies above 1017eV using the two air fluorescence detectors of the High Resolution Fly's Eye experiment operating in monocular mode. We describe the detector, PMT and atmospheric calibrations, and the analysis techniques for the two detectors. We fit the spectrum to models describing galactic and extragalactic sources. Our measured spectrum gives an

R. U. Abbasi; T. Abuzayyad; J. F. Amman; G. Archbold; R. Atkins; J. A. Bellido; K. Belov; J. W. Belz; S. Y. Ben Zvi; D. R. Bergman; G. W. Burt; Z. Cao; R. W. Clay; B. C. Connolly; W. Deng; B. R. Dawson; Y. Fedorova; J. Findlay; C. B. Finley; W. F. Hanlon; C. M. Hoffman; G. A. Hughes; M. H. Holzscheiter; P. Hüntemeyer; C. C. H. Jui; K. Kim; M. A. Kirn; E. G. Loh; M. M. Maestas; N. Manago; L. J. Marek; K. Martens; J. A. J. Matthews; J. N. Matthews; A. O'Neill; C. A. Painter; L. Perera; K. Reil; R. Riehle; M. Roberts; M. Sasaki; S. R. Schnetzer; K. M. Simpson; G. Sinnis; J. D. Smith; R. Snow; P. Sokolsky; C. Song; R. W. Springer; B. T. Stokes; J. R. Thomas; S. B. Thomas; G. B. Thomson; D. Tupa; S. Westerhoff; L. R. Wiencke; A. Zech

2005-01-01

179

A theoretical analysis of the semiannual component in the heliocentric dependence of high-energy galactic cosmic rays  

Microsoft Academic Search

Annual and semiannual variations of the galactic cosmic rays and estimates of their radial derivatives have been used to determine the most significant terms at 1 AU in the convection-diffusion equation. It turns out that both the changes in sign and the absolute value of the semiannual variation may be explained through the interplay of convection, diffusion across magnetic field

G. E. Perona; E. Antonucci

1976-01-01

180

Analysis of Large-scale Anisotropy of Ultra-high Energy Cosmic Rays in HiRes Data  

NASA Astrophysics Data System (ADS)

Stereo data collected by the HiRes experiment over a six-year period are examined for large-scale anisotropy related to the inhomogeneous distribution of matter in the nearby universe. We consider the generic case of small cosmic-ray deflections and a large number of sources tracing the matter distribution. In this matter tracer model the expected cosmic-ray flux depends essentially on a single free parameter, the typical deflection angle ? s . We find that the HiRes data with threshold energies of 40 EeV and 57 EeV are incompatible with the matter tracer model at a 95% confidence level unless ? s > 10° and are compatible with an isotropic flux. The data set above 10 EeV is compatible with both the matter tracer model and an isotropic flux.

Abbasi, R. U.; Abu-Zayyad, T.; Allen, M.; Amann, J. F.; Archbold, G.; Belov, K.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Brusova, O. A.; Burt, G. W.; Cannon, C.; Cao, Z.; Deng, W.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Gray, R. C.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G.; Hüntemeyer, P.; Ivanov, D.; Jones, B. F.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Koers, H.; Loh, E. C.; Maestas, M. M.; Manago, N.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; Moore, S. A.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Rodriguez, D.; Sasaki, M.; Schnetzer, S. R.; Scott, L. M.; Sinnis, G.; Smith, J. D.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tupa, D.; Wiencke, L. R.; Zech, A.; Zhang, X.; High Resolution Fly's Eye Collaboration

2010-04-01

181

The Calibration of an Ultra-High Energy Muon Hodoscope and Search for Cosmic Gamma Ray Anisotropies.  

NASA Astrophysics Data System (ADS)

The Homestake Deep Underground Hodoscope is a liquid scintillation detector that lies at a depth of 4200 mwe within a cavernous chamber of granite within the Homestake Gold Mine. At this depth, it is shielded from all but the most energetic elementary particles, in particular, muons with an energy of less than 27 TeV. Consequently, primaries with energies greater than 1 PeV are indirectly detected. The detector has two tiers of detectors each comprised of 40 scintillation modules of dimension.305 m x.305 m x 7.925 m, separated by a distance of 8.047 m. With this geometrical arrangement and the use of fast timing triggers (2.5 ns resolution), a directional study of ultra -high energy particles was conducted. By exploiting the fact that these particles enter the detector at very nearly the speed of light and that the trigger window has a fixed timing limit, a methodology was developed to fine tune the detector using these constraints. Once calibration was established, noisy events are easily eliminated and the resulting data is used to compute the flux of muons entering the detector, to plot the number of muons entering the detector as a function of angle and to compare this with theoretical profiles and, finally, to extrapolate the muon's velocity vector back onto the celestial sphere to search for anisotropies. The results of this study indicate a flux that is constant in time and is consistent with other, independent measurements. The angular profile is consistent with theoretical models, although a different scale factor was required to make a precise agreement. This may be due to the particular nature of the Homestake stratum. There was no indication for discrete gamma ray sources of cosmic origin, supporting earlier work using the same detector. Lastly, the methodology developed can be applied to similar detection facilities that are in operation on a long term basis. With its use of a personal computer, on site, a large facility could be monitored quite effectively.

McCarthy, Thomas K.

182

AugerNext: innovative research studies for the next generation ground-based ultra-high energy cosmic ray experiment  

NASA Astrophysics Data System (ADS)

The findings so far of the Pierre Auger Observatory and also of the Telescope Array define the requirements for a possible next generation experiment: it needs to be considerably increased in size, it needs a better sensitivity to composition, and it should cover the full sky. AugerNext aims to perform innovative research studies in order to prepare a proposal fulfilling these demands. Such R&D studies are primarily focused in the following areas consolidation of the detection of cosmic rays using MHz radio antennas; proof-of-principle of cosmic-ray microwave detection; test of the large-scale application of a new generation photo-sensors; generalization of data communication techniques; development of new ways of muon detection with surface arrays. These AugerNext studies on new innovative detection methods for a next generation cosmic-ray experiment are performed at the Pierre Auger Observatory. The AugerNext consortium consists presently of fourteen partner institutions from nine European countries supported by a network of European funding agencies and it is a principal element of the ASPERA/ApPEC strategic roadmaps.

Haungs, Andreas

2013-06-01

183

Correlation between ultra-high-energy cosmic rays and active galactic nuclei from the fermi large-area telescope  

NASA Astrophysics Data System (ADS)

We study the possibility that ?-ray loud active galactic nuclei (AGNs) are the sources of ultrahigh-energy cosmic rays (UHECRs) by using a correlation analysis of their locations and the arrival directions of UHECR. We use data for ?-ray loud AGN with d ? 100 Mpc from the second Fermi Large-area Telescope AGN catalog and UHECR data with E ? 55 EeV observed by the Pierre Auger Observatory. The distribution of arrival directions expected from the?-ray loud AGN is compared with that of the observed UHECR by using the correlational angular distance distribution and the Kolmogorov-Smirnov test. We conclude that the hypothesis that the ?-ray loud AGN are the dominant sources of UHECR is disfavored unless there is a large smearing effect due to intergalactic magnetic fields.

Kim, Jihyun; Kim, Hang Bae

2012-12-01

184

Ground level radiation from cosmic ray shower secondaries  

NASA Astrophysics Data System (ADS)

Most cosmic ray secondaries never reach ground level, however high energy cosmic rays produce muons and neutrons which do. These particles are known to cause increased radiation and cancer rates under current day cosmic ray flux. Episodic increases in the high energy cosmic ray flux increase this radiation, and thus the risk to biological life. Our work models the flux of neutrons and muons produced by high energy cosmic rays, exploring the possibility of biological impact due to extended periods of increase high energy cosmic ray muon flux. Our results find secondary muon radiation to be significant in cosmic ray flux increasing events.

Overholt, Andrew

2013-04-01

185

Physics from the Very-High Energy Cosmic-Ray Shadows of the Moon and Sun with Milagro  

NASA Astrophysics Data System (ADS)

The shadows of the Moon and Sun in TeV cosmic rays are unique probes of the character of these particles and the magnetic fields they traverse. Milagro was a water-Cerenkov cosmic-ray observatory at an elevation of 2630 m, near Los Alamos New Mexico, which operated from 2000-2008. With continuous operation and a large field of view, the Milagro detector was an ideal instrument for observations of these shadows. The Milagro data analyzed here are primarily a sample of 700 million events within +/-10° of the Moon and 650 million events within +/-10° of the Sun, collected in 2.5 years from 2005 to 2008. We investigate the possibility of using the Milagro-measured Moon shadow to perform the first energy scale calibration of an air shower array that is independent of shower and detector simulations. A Moon shadow simulation is found to agree well with data where magnetic field effects are small, but a better model of the magnetic field will have to be implemented in order for a conclusive energy scale determination to be made. An antiproton component is expected in TeV cosmic rays as a result of spallation in the interstellar medium. This gives rise to a Moon shadow deflected in the opposite direction to the particle shadow. A simulation-free fit is performed over a probable range of parameters describing the antiproton Moon shadow. Using the simulation-determined proton trigger fraction of 72% yields 95% upper limits on p¯/p of 3.4 to 3.9%. This is currently the most stringent upper limit at TeV energies. The Milagro-measured solar shadow probes the Sun's magnetic field, as solar activity and the sunspot number decreases over the second half of solar cycle 23, in the first study of the coronal magnetic field using the cosmic-ray shadow. We find a strong time dependence of the depth of Sun's shadow, which is anti-correlated with sunspot number. Simulating the Sun's shadow, using a dipole model of the coronal field, results in a good fit to data close to solar minimum.

Christopher, Grant E.

186

The Search for Anisotropy in the Arrival Directions of UltraHigh Energy Cosmic Rays Observed by the High Resolution Fly's Eye Detector in Monocular Mode  

Microsoft Academic Search

The High Resolution Fly's Eye HiRes-I detector has now been in operation in\\u000amonocular mode for over six years. During that time span, HiRes-I has\\u000aaccumulated a larger exposure to Ultra-High Energy Cosmic Rays (UHECRs) above\\u000a10^19 eV than any other experiment built to date. This presents an\\u000aunprecedented opportunity to search for anisotropy in the arrival directions of\\u000aUHECRs.

Benjamin T. Stokes

2004-01-01

187

On the Cosmological Aspects of Observed High Energy Cosmic Phenomena  

Microsoft Academic Search

Super-high energy corpuscular and gamma rays as well as cosmic high--power density sources are hard to explain in a galaxy model framework. Attempts to include some of those phenomena in the Standard Cosmological Model also encounter serious difficulties. In the present paper an alternative cosmological concept is discussed. There are several features in it. First of all, the whole Universe

Anatoli Vankov

1999-01-01

188

Fermi LAT Observation of Diffuse Gamma Rays Produced Through Interactions Between Local Interstellar Matter and High-energy Cosmic Rays  

Microsoft Academic Search

Observations by the Large Area Telescope (LAT) on the Fermi mission of diffuse gamma-rays in a mid-latitude region in the third quadrant (Galactic longitude l from 200° to 260° and latitude |b| from 22° to 60°) are reported. The region contains no known large molecular cloud and most of the atomic hydrogen is within 1 kpc of the solar system.

A. A. Abdo; M. Ackermann; M. Ajello; W. B. Atwood; M. Axelsson; L. Baldini; J. Ballet; G. Barbiellini; D. Bastieri; B. M. Baughman; K. Bechtol; R. Bellazzini; B. Berenji; E. D. Bloom; E. Bonamente; A. W. Borgland; J. Bregeon; A. Brez; M. Brigida; P. Bruel; T. H. Burnett; G. A. Caliandro; R. A. Cameron; P. A. Caraveo; P. Carlson; J. M. Casandjian; C. Cecchi; Ö. Çelik; A. Chekhtman; C. C. Cheung; S. Ciprini; R. Claus; J. Cohen-Tanugi; J. Conrad; S. Cutini; C. D. Dermer; A. de Angelis; F. de Palma; S. W. Digel; E. do Couto e. Silva; P. S. Drell; R. Dubois; D. Dumora; C. Farnier; C. Favuzzi; S. J. Fegan; W. B. Focke; M. Frailis; Y. Fukazawa; S. Funk; P. Fusco; F. Gargano; D. Gasparrini; N. Gehrels; S. Germani; B. Giebels; N. Giglietto; F. Giordano; T. Glanzman; G. Godfrey; I. A. Grenier; M.-H. Grondin; J. E. Grove; L. Guillemot; S. Guiriec; Y. Hanabata; A. K. Harding; M. Hayashida; E. Hays; R. E. Hughes; G. Jóhannesson; A. S. Johnson; R. P. Johnson; W. N. Johnson; T. Kamae; H. Katagiri; N. Kawai; M. Kerr; J. Knödlseder; M. L. Kocian; F. Kuehn; M. Kuss; J. Lande; L. Latronico; M. Lemoine-Goumard; F. Longo; F. Loparco; B. Lott; M. N. Lovellette; P. Lubrano; A. Makeev; M. N. Mazziotta; J. E. McEnery; C. Meurer; P. F. Michelson; W. Mitthumsiri; T. Mizuno; A. A. Moiseev; C. Monte; M. E. Monzani; A. Morselli; I. V. Moskalenko; S. Murgia; P. L. Nolan; J. P. Norris; E. Nuss; T. Ohsugi; A. Okumura; N. Omodei; E. Orlando; J. F. Ormes; M. Ozaki; D. Paneque; J. H. Panetta; D. Parent; M. Pepe; M. Pesce-Rollins; F. Piron; M. Pohl; T. A. Porter; S. Rainò; R. Rando; M. Razzano; A. Reimer; O. Reimer; T. Reposeur; S. Ritz; L. S. Rochester; A. Y. Rodriguez; F. Ryde; H. F.-W. Sadrozinski; D. Sanchez; A. Sander; P. M. Saz Parkinson; T. L. Schalk; A. Sellerholm; C. Sgrò; D. A. Smith; P. D. Smith; G. Spandre; P. Spinelli; J.-L. Starck; F. W. Stecker; M. S. Strickman; A. W. Strong; D. J. Suson; H. Tajima; H. Takahashi; T. Takahashi; T. Tanaka; J. B. Thayer; J. G. Thayer; D. J. Thompson; L. Tibaldo; D. F. Torres; G. Tosti; A. Tramacere; Y. Uchiyama; T. L. Usher; V. Vasileiou; N. Vilchez; V. Vitale; A. P. Waite; P. Wang; B. L. Winer; K. S. Wood; T. Ylinen; M. Ziegler

2009-01-01

189

Cosmic-Rays and Gamma Ray Bursts  

NASA Astrophysics Data System (ADS)

Cosmic-rays are subatomic particles of energies ranging between a few eV to hundreds of TeV. These particles register a power-law spectrum, and it seems that most of them originate from astrophysical galactic and extragalactic sources. The shock acceleration in superalfvenic astrophysical plasmas, is believed to be the main mechanism responsible for the production of the non-thermal cosmic-rays. Especially, the importance of the very high energy cosmic-ray acceleration, with its consequent gamma-ray radiation and neutrino production in the shocks of the relativistic jets of Gamma Ray Bursts, is a favourable theme of study. I will discuss the cosmic-ray shock acceleration mechanism particularly focusing on simulation studies of cosmic-ray acceleration occurring in the relativistic shocks of GRB jets.

Meli, A.

2013-07-01

190

Cosmic-Ray Underground. I  

Microsoft Academic Search

Behaviour of elementary particles in the cosmic-ray in moderate high energy region can be infered by the analysis of cosmic-ray phenomena underground, but few such attempts have ever been made and all of them have failed in giving a satisfactory understanding of the problem. Several years ago one of us (S.T.) tried without success to explain the remarkable bend of

Satio Hayakawa; Sin-Itiro Tomonaga

1949-01-01

191

Energy Spectrum and Composition of Ultra High Energy Cosmic Ray Showers Using Hybrid Analysis from Telescope Array  

NASA Astrophysics Data System (ADS)

The Telescope Array (TA) consists of 38 fluorescence telescopes spread over three detector sites. The three sites at located the periphery of a surface array of 507 scintillation counters, covering 700 square km, with a spacing of 1.2 km. TA is designed to study the energy spectrum, composition, and arrival direction anisotropy of ultrahigh energy cosmic rays (UHECR). A unique feature of TA is that one of three fluorescence detector (FD) sites, Middle Drum (MD), is instrumented with 14 refurbished telescopes from the High Resolution Fly's Eye (HiRes) experiment. This commonality provides TA with a direct link back to the HiRes experiment and data. Using the scintillator detector data in conjunction with the MD data improves the geometrical reconstruction and hence provides a more accurate reconstruction of the energy of the primary particle and shower profile. The Middle Drum hybrid spectrum composition results will be presented.

Jui, Charles; Allen, Monica; Abu-Zayyad, Tareq; Stokes, Benjamin; Ivanov, Dmitri

2013-04-01

192

North-south asymmetry for high-energy cosmic-ray electrons measured with the PAMELA experiment  

NASA Astrophysics Data System (ADS)

The north-south asymmetry for cosmic-ray particles was measured with one instrument of the PAMELA satellite-borne experiment in the period June 2006-May 2009. The analysis has been performed by two independent methods: by comparing the count rates in regions with identical geomagnetic conditions and by comparing the experimental distribution of particle directions with the simulated distribution that would be in the case of an isotropic particle flux. The dependences of the asymmetry on energy release in the PAMELA calorimeter and on time have been constructed. The asymmetry ( N n - N s )/( N n + N s ) is 0.06 ± 0.004 at the threshold energy release in the calorimeter and gradually decreases with increasing energy release. The observed effect is shown to be produced by electrons in the energy range 10-100 GeV.

Karelin, A. V.; Adriani, O.; Barbarino, G. C.; Bazilevskaya, G. A.; Bellotti, R.; Boezio, M.; Bogomolov, E. A.; Bonechi, L.; Bongi, M.; Bonvicini, V.; Bottai, S.; Bruno, A.; Vacchi, A.; Vannuccini, E.; Vasilyev, G. I.; Voronov, S. A.; Galper, A. M.; Danilchenko, I. A.; De Donato, C.; De Santis, C.; De Simone, N.; Di Felice, V.; Zverev, V. G.; Zampa, G.; Zampa, N.; Cafagna, F.; Campana, D.; Carbone, R.; Carlson, P.; Casolino, M.; Castellini, G.; Kvashnin, A. N.; Koldashov, S. V.; Koldobskiy, S. A.; Krutkov, S. Y.; Leonov, A. A.; Malvezzi, V.; Marcelli, L.; Martucci, M.; Mayorov, A. G.; Malakhov, V. V.; Menn, W.; Merge, M.; Mikhailov, V. V.; Mocchiutti, E.; Monaco, A.; Mori, N.; Osteria, G.; Palma, F.; Papini, P.; Pearce, M.; Picozza, P.; Pizzolotto, C.; Ricci, M.; Ricciarini, S. B.; Runtso, M. F.; Sarkar, R.; Simon, M.; Sparvoli, R.; Spillantini, P.; Yurkin, Y. T.

2013-08-01

193

Anisotropy and chemical composition of ultra-high energy cosmic rays using arrival directions measured by the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

The Pierre Auger Collaboration has reported evidence for anisotropy in the distribution of arrival directions of the cosmic rays with energies E > Eth = 5.5 × 1019 eV. These show a correlation with the distribution of nearby extragalactic objects, including an apparent excess around the direction of Centaurus A. If the particles responsible for these excesses at E > Eth are heavy nuclei with charge Z, the proton component of the sources should lead to excesses in the same regions at energies E/Z. We here report the lack of anisotropies in these directions at energies above Eth/Z (for illustrative values of Z = 6,13,26). If the anisotropies above Eth are due to nuclei with charge Z, and under reasonable assumptions about the acceleration process, these observations imply stringent constraints on the allowed proton fraction at the lower energies.

Pierre Auger Collaboration; Abreu, P.; Aglietta, M.; Ahn, E. J.; Albuquerque, I. F. M.; Allard, D.; Allekotte, I.; Allen, J.; Allison, P.; Alvarez Castillo, J.; Alvarez-Muñiz, J.; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Anti?i?, T.; Anzalone, A.; Aramo, C.; Arganda, E.; Arqueros, F.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Bäcker, T.; Balzer, M.; Barber, K. B.; Barbosa, A. F.; Bardenet, R.; Barroso, S. L. C.; Baughman, B.; Bäuml, J.; Beatty, J. J.; Becker, B. R.; Becker, K. H.; Bellétoile, A.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bertou, X.; Biermann, P. L.; Billoir, P.; Blanco, F.; Blanco, M.; Bleve, C.; Blümer, H.; Bohá?ová, M.; Boncioli, D.; Bonifazi, C.; Bonino, R.; Borodai, N.; Brack, J.; Brogueira, P.; Brown, W. C.; Bruijn, R.; Buchholz, P.; Bueno, A.; Burton, R. E.; Caballero-Mora, K. S.; Caramete, L.; Caruso, R.; Castellina, A.; Catalano, O.; Cataldi, G.; Cazon, L.; Cester, R.; Chauvin, J.; Cheng, S. H.; Chiavassa, A.; Chinellato, J. A.; Chou, A.; Chudoba, J.; Clay, R. W.; Coluccia, M. R.; Conceição, R.; Contreras, F.; Cook, H.; Cooper, M. J.; Coppens, J.; Cordier, A.; Cotti, U.; Coutu, S.; Covault, C. E.; Creusot, A.; Criss, A.; Cronin, J.; Curutiu, A.; Dagoret-Campagne, S.; Dallier, R.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; De La Vega, G.; de Mello Junior, W. J. M.; de Mello Neto, J. R. T.; De Mitri, I.; de Souza, V.; de Vries, K. D.; Decerprit, G.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Diaz, J. C.; Díaz Castro, M. L.; Diep, P. N.; Dobrigkeit, C.; Docters, W.; D'Olivo, J. C.; Dong, P. N.; Dorofeev, A.; dos Anjos, J. C.; Dova, M. T.; D'Urso, D.; Dutan, I.; Ebr, J.; Engel, R.; Erdmann, M.; Escobar, C. O.; Etchegoyen, A.; Facal San Luis, P.; Fajardo Tapia, I.; Falcke, H.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Ferrero, A.; Fick, B.; Filevich, A.; Filip?i?, A.; Fliescher, S.; Fracchiolla, C. E.; Fraenkel, E. D.; Fröhlich, U.; Fuchs, B.; Gaior, R.; Gamarra, R. F.; Gambetta, S.; García, B.; García Gámez, D.; Garcia-Pinto, D.; Gascon, A.; Gemmeke, H.; Gesterling, K.; Ghia, P. L.; Giaccari, U.; Giller, M.; Glass, H.; Gold, M. S.; Golup, G.; Gomez Albarracin, F.; Gómez Berisso, M.; Gonçalves, P.; Gonzalez, D.; Gonzalez, J. G.; Gookin, B.; Góra, D.; Gorgi, A.; Gouffon, P.; Gozzini, S. R.; Grashorn, E.; Grebe, S.; Griffith, N.; Grigat, M.; Grillo, A. F.; Guardincerri, Y.; Guarino, F.; Guedes, G. P.; Guzman, A.; Hague, J. D.; Hansen, P.; Harari, D.; Harmsma, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Herve, A. E.; Hojvat, C.; Hollon, N.; Holmes, V. C.; Homola, P.; Hörandel, J. R.; Horneffer, A.; Hrabovský, M.; Huege, T.; Insolia, A.; Ionita, F.; Italiano, A.; Jarne, C.; Jiraskova, S.; Kadija, K.; Kampert, K. H.; Karhan, P.; Kasper, P.; Kégl, B.; Keilhauer, B.; Keivani, A.; Kelley, J. L.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Koang, D.-H.; Kotera, K.; Krohm, N.; Krömer, O.; Kruppke-Hansen, D.; Kuehn, F.; Kuempel, D.; Kulbartz, J. K.; Kunka, N.; La Rosa, G.; Lachaud, C.; Lautridou, P.; Leão, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Lemiere, A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; López, R.; Lopez Aüera, A.; Louedec, K.; Lozano Bahilo, J.; Lucero, A.; Ludwig, M.; Lyberis, H.; Maccarone, M. C.; Macolino, C.; Maldera, S.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, J.; Marin, V.; Maris, I. C.; Marquez Falcon, H. R.; Marsella, G.; Martello, D.; Martin, L.; Martinez, H.; Martínez Bravo, O.; Mathes, H. J.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurizio, D.; Mazur, P. O.; Medina-Tanco, G.; Melissas, M.; Melo, D.; Menichetti, E.; Menshikov, A.; Mertsch, P.; Meurer, C.; Mi?anovi?, S.; Micheletti, M. I.; Miller, W.; Miramonti, L.; Mollerach, S.; Monasor, M.; Monnier Ragaigne, D.; Montanet, F.; Morales, B.; Morello, C.; Moreno, E.; Moreno, J. C.; Morris, C.; Mostafá, M.; Moura, C. A.; Mueller, S.; Muller, M. A.; Müller, G.; Münchmeyer, M.; Mussa, R.; Navarra, G.; Navarro, J. L.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Nhung, P. T.; Niemietz, L.; Nierstenhoefer, N.; Nitz, D.; Nosek, D.; Nožka, L.; Nyklicek, M.; Oehlschläger, J.; Olinto, A.; Oliva, P.; Olmos-Gilbaja, V. M.; Ortiz, M.; Pacheco, N.; Pakk Selmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Parente, G.; Parizot, E.; Parra, A.; Parsons, R. D.; Pastor, S.; Paul, T.; Pech, M.; P?kala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Pesce, R.; Petermann, E.; Petrera, S.; Petrinca, P.; Petrolini, A.; Petrov, Y.; Petrovic, J.; Pfendner, C.; Phan, N.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.

2011-06-01

194

Ultrahigh Energy Cosmic Rays Detection  

SciTech Connect

The paper describes methods used for the detection of cosmic rays with energies above 1018 eV (UHECR, UltraHigh Energy Cosmic Rays). It had been anticipated there would be a cutoff in the energy spectrum of primary cosmic rays around 3{center_dot}1019 eV induced by their interaction with the 2.7 deg. K primordial photons. This has become known as the GZK cutoff. However, several showers have been detected with estimated primary energy exceeding this limit.

Aramo, Carla [Istituto Nazionale di Fisica Nucleare - Sezione di Napoli, Complesso Universitario di Monte Sant'Angelo, Via Cintia, 80126 - Naples (Italy)

2005-10-12

195

Axions and cosmic rays  

NASA Astrophysics Data System (ADS)

We investigate the propagation of a charged particle in a spatially constant but time-dependent pseudoscalar background. Physically, this pseudoscalar background could be provided by a relic axion density. The background leads to an explicit breaking of Lorentz invariance; processes such as p ? p? or e ? e? are consequently possible under some kinematic constraints. The phenomenon is described by the QED Lagrangian extended with a Chern-Simons term that contains a four-vector characterizing the breaking of Lorentz invariance induced by the time-dependent background. While the induced radiation (similar to the Cherenkov effect) is too small to influence the propagation of cosmic rays significantly, the hypothetical detection of the photons radiated by high-energy cosmic rays via this mechanism would provide an indirect way to verify the cosmological relevance of axions. We discuss the order of magnitude of the effect.

Espriu, D.; Renau, A.

2012-02-01

196

Solar cosmic ray phenomena  

Microsoft Academic Search

This review attempts to present an integrated view of the several types of solar cosmic ray phenomena. The relevant large and small scale properties of the interplanetary medium are first surveyed, and their use in the development of a quantitative understanding of the cosmic ray propagation processes summarised. Solar cosmic ray events, in general, are classified into two phenomenological categories:

K. G. McCracken; U. R. Rao

1970-01-01

197

The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular mode  

NASA Astrophysics Data System (ADS)

We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array's third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array's middle drum detector and the direct comparison to the high resolution fly's eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Myers, I.; Minamino, M.; Miyata, K.; Murano, Y.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ogura, J.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Sonley, T. J.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T. A.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zollinger, R.; Zundel, Z.

2013-08-01

198

A Method to Search for Correlations of Ultra-high Energy Cosmic-Ray Masses with the Large-scale Structures in the Local Galaxy Density Field  

NASA Astrophysics Data System (ADS)

One of the main goals of investigations using present and future giant extensive air shower (EAS) arrays is the mass composition of ultra-high energy cosmic rays (UHECRs). A new approach to the problem is presented, combining the analysis of arrival directions with the statistical test of the paired EAS samples. One of the ideas of the method is to search for possible correlations between UHECR masses and their separate sources; for instance, if there are two sources in different areas of the celestial sphere injecting different nuclei, but the fluxes are comparable so that arrival directions are isotropic, then the aim is to reveal a difference in the mass composition of cosmic-ray fluxes. The method is based on a non-parametric statistical test—the Wilcoxon signed-rank routine—which does not depend on the populations fitting any parameterized distributions. Two particular algorithms are proposed: first, using measurements of the depth of the EAS maximum position in the atmosphere; and second, relying on the age variance of air showers initiated by different primary particles. The formulated method is applied to the Yakutsk array data, in order to demonstrate the possibility of searching for a difference in average mass composition between the two UHECR sets, arriving particularly from the supergalactic plane and a complementary region.

Ivanov, A. A.

2013-02-01

199

Composition of primary cosmic rays at energies ~1015 eV from data on high-energy muons in extensive air showers  

NASA Astrophysics Data System (ADS)

A critical analysis of experimental data on high-energy muons in air showers is carried out to derive information about the composition of primary cosmic rays near the bend in the energy spectrum at ~1015 eV. A set of Monte Carlo simulated air showers from different elemental species have been used to study expectations for three different experiments: the Tien Shan study of muons with energy above 5 GeV at an altitude of 690 g/cm2, the Moscow State University experiment for muons with energy above 10 GeV at sea level, and the Kolar-gold-field experiment for muons with energy above 220 GeV at 930 g/cm2. The results show that when showers are grouped according to shower size the sensitivity of the total number of high-energy muons to primary composition is greatly reduced. In fact, it is found that the data cannot discriminate between models which assume energy-independent low-energy composition and those which assume energy spectra which steepen above some value of rigidity cutoff around 1014 eV/nucleon. In order to make a compositionsensitive measurement of the high-energy muon component it is necessary to make these measurements at fixed energy rather than at fixed shower size.

Yodh, G. B.; Goodman, J. A.; Tonwar, S. C.; Ellsworth, R. W.

1984-03-01

200

Detecting ultra-high energy cosmic rays from space with unprecedented acceptance: objectives and design of the JEM-EUSO mission  

NASA Astrophysics Data System (ADS)

The Extreme Universe Space Observatory on the Japanese Experiment Module (JEM-EUSO) of the International Space Station (ISS) is the first mission that will study from space Ultra High-Energy Cosmic Rays (UHECR). JEM-EUSO will observe Extensive Air Showers (EAS) produced by UHECRs traversing the Earth's atmosphere from above. For each event, the detector will make accurate measurements of the energy, arrival direction and nature of the primary particle using a target volume far greater than what is achievable from ground. The corresponding increase in statistics will help to clarify the origin and sources of UHECRs as well as the environment traversed during production and propagation. Possibly this will bring new light onto particle physics mechanisms operating at energies well beyond those achievable by man-made accelerators. The spectrum of scientific goals of the JEM-EUSO mission includes as exploratory objectives the detection of high-energy gamma rays and neutrinos, the study of cosmic magnetic fields, and tests of relativity and quantum gravity effects at extreme energies. In parallel JEM-EUSO will systematically perform observation of the surface of the Earth in the infra-red and ultra-violet ranges, studying also atmospheric phenomena (Transient Luminous Effects). The apparatus is a 2 t detector using Fresnel-based optics to focus the UV-light from EAS on a focal surface composed of about 6 000~multianode photomultipliers for a total of ~3 · 105 channels. A multi-layer parallel architecture has been devised to handle the data flow and select valid triggers, reducing it to a rate compatible with downlink constraints. Each processing level filters the event with increasingly complex algorithms using ASICs, FPGAs and DSPs in this order to reject spurious triggers and reduce the data rate.

Casolino, M.; Adams, J. H.; Bertaina, M. E.; Christl, M. J.; Ebisuzaki, T.; Gorodetzky, P.; Hachisu, Y.; Kajino, F.; Kawasaki, Y.; Medina-Tanco, G.; Miyamoto, H.; Ohomori, H.; Parizot, E.; Park, I.; Picozza, P.; Sakaki, N.; Santangelo, A.; Shinozaki, K.; Takizawa, Y.; Tsuno, K.; JEM-EUSO Collaboration

2011-10-01

201

The Highest Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

I refuse to start yet another abstract saying that the origin of cosmic rays is a mystery. Instead, I would like to highlight the progress made by ultra-high energy cosmic ray experiments in the last three years. The Pierre Auger Observatory and the Telescope Array are the largest cosmic ray detectors ever built, and together they cover the entire sky at the highest energies. I will present the most recent experimental results, and discuss their implications toward an understanding of the origin of Extragalactic cosmic rays. Finding the transition between Galactic and Extragalactic origin is an important step forward because it will allow us to concentrate our searches on specific energy ranges and specific objects in the sky.

Mostafa, Miguel

2012-03-01

202

A Simplified Model for the Acceleration of Cosmic Ray Particles  

ERIC Educational Resources Information Center

|Two important questions concerning cosmic rays are: Why are electrons in the cosmic rays less efficiently accelerated than nuclei? How are particles accelerated to great energies in ultra-high energy cosmic rays? In order to answer these questions we construct a simple model of the acceleration of a charged particle in the cosmic ray. It is not…

Gron, Oyvind

2010-01-01

203

Interacting Cosmic Rays with Molecular Clouds: A Bremsstrahlung Origin of Diffuse High-energy Emission from the Inner 2°×1° of the Galactic Center  

NASA Astrophysics Data System (ADS)

The high-energy activity in the inner few degrees of the Galactic center is traced by diffuse radio, X-ray, and ?-ray emission. The physical relationship between different components of diffuse gas emitting at multiple wavelengths is a focus of this work. We first present radio continuum observations using the Green Bank Telescope and model the nonthermal spectrum in terms of a broken power-law distribution of ~GeV electrons emitting synchrotron radiation. We show that the emission detected by Fermi is primarily due to nonthermal bremsstrahlung produced by the population of synchrotron emitting electrons in the GeV energy range interacting with neutral gas. The extrapolation of the electron population measured from radio data to low and high energies can also explain the origin of Fe I 6.4 keV line and diffuse TeV emission, as observed with Suzaku, XMM-Newton, Chandra, and the H.E.S.S. observatories. The inferred physical quantities from modeling multiwavelength emission in the context of bremsstrahlung emission from the inner ~300 × 120 pc of the Galactic center are constrained to have the cosmic-ray ionization rate ~1-10 × 10-15 s-1, molecular gas heating rate elevating the gas temperature to 75-200 K, fractional ionization of molecular gas 10-6-10-5, large-scale magnetic field 10-20 ?G, the density of diffuse and dense molecular gas ~100 and ~103 cm-3 over 300 pc and 50 pc path lengths, and the variability of Fe I K? 6.4 keV line emission on yearly timescales. Important implications of our study are that GeV electrons emitting in radio can explain the GeV ?-rays detected by Fermi and that the cosmic-ray irradiation model, like the model of the X-ray irradiation triggered by past activity of Sgr A*, can also explain the origin of the variable 6.4 keV emission from Galactic center molecular clouds.

Yusef-Zadeh, F.; Hewitt, J. W.; Wardle, M.; Tatischeff, V.; Roberts, D. A.; Cotton, W.; Uchiyama, H.; Nobukawa, M.; Tsuru, T. G.; Heinke, C.; Royster, M.

2013-01-01

204

The Plasma Physics of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Cosmic rays are responsible for some of the most energetic emissions in the Universe, and new tools for studying them abound. Cosmic rays play a key role in galactic gas dynamics and energy balance, and allow us to probe galactic and intergalactic magnetic fields both in the present epoch and over cosmic time. The acceleration and propagation of high energy particles in astrophysical environments, and the mechanisms through which they interact collectively with the host medium, are largely plasma physics phenomena. I will briefly review some salient aspects of cosmic ray astrophysics, and describe recent progress in understanding cosmic ray plasma physics.

Gould Zweibel, Ellen

2012-05-01

205

Very High-Energy Gamma-Ray Sources.  

ERIC Educational Resources Information Center

|Discusses topics related to high-energy, gamma-ray astronomy (including cosmic radiation, gamma-ray detectors, high-energy gamma-ray sources, and others). Also considers motivation for the development of this field, the principal results to date, and future prospects. (JN)|

Weekes, Trevor C.

1986-01-01

206

Cosmic rays: 1912-2012  

NASA Astrophysics Data System (ADS)

One hundred years ago, using balloon flights up to 5 kilometers altitude, Victor Hess demonstrated that the intensity of penetrating ionizing radiation increased with altitude, indicating that Earth is exposed to high-energy radiation from space [Hess, 1912]. Since that observation, these “cosmic rays” have enabled discoveries basic to elementary particle physics and astrophysics. This discovery earned Hess the 1936 Nobel Prize in Physics, shared with Carl Anderson, who discovered the positron among the secondary cosmic rays near the ground [Anderson, 1933]. Then, the only known ionizing radiation with range in air more than about 30 centimeters was the ? ray (electromagnetic radiation with energy above about 100 kiloelectron volts), so the radiation from space was assumed to be ? rays and was called “cosmic rays.” That name has stuck, although the “cosmic rays” studied today are not actually rays but particles. Indeed, ? rays do impinge on Earth, and ? ray astronomy is a burgeoning area of astrophysics, but the term “cosmic rays” continues to apply to the charged particles that make up the bulk of the incident ionizing radiation.

Israel, Martin H.

2012-09-01

207

The cosmic triad: Cosmic rays, gamma-rays and neutrinos  

NASA Astrophysics Data System (ADS)

The existence of ultra-high energy (UHE) cosmic rays (CRs) with energies up to 100 EeV is a strong motivation for neutrino astronomy at the EeV energy scale. It seems unavoidable that UHE CRs undergo hadronic interactions with radiation backgrounds and ambient matter prior to their arrival at Earth. These interactions result in a flux of secondary neutrinos and ?-rays with energies up to a few percent of the initial CR energy. So far, no high-energy neutrino source could be unambiguously identified. We will review the various indirect neutrino limits that arise from the cosmic connection of UHE CRs, ?-rays and neutrinos. At the EeV energy scale the diffuse flux of cosmogenic neutrinos associated with the propagation of ultra-high energy cosmic rays in the cosmic radiation background seems to be the most promising candidate for a future detection. We will discuss its model dependence w.r.t. nuclear composition and evolution of the sources.

Ahlers, Markus

2013-05-01

208

The Heliosphere and Galactic Cosmic Rays  

NASA Video Gallery

The heliosphere deflects galactic cosmic rays from entering the system. Galactic cosmic rays are a very high energy form of particle radiation that are extremely difficult to shield against and are harmful to astronauts. The boundaries surrounding our heliosphere deflect the majority of galactic radiation from the inner solar system.

Holly Zell

2010-09-28

209

Introduction to Cosmic Rays  

NASA Astrophysics Data System (ADS)

These lecturers were done to introduce the students of the Third School of Cosmic Rays and Astrophysics to the world of Cosmic Rays. In these proceedings, I am covering the basic of what we covered in these lecturers. We discussed also about neutrino physics, gamma ray physics and detection of cosmic rays, but we are not covering these last topics, since are the main topics of other lecturers of the School. We include in these proceedings an introduction to the importance and history of the cosmic rays, a description of the spectrum of the cosmic rays, the geomagnetic effects, acceleration mechanisms, extensive air shower generation and the physical processes involved, resulting in the explanation of a toy model of the development of the air shower.

Chirinos, J.

2009-04-01

210

Origin of Cosmic Rays  

Microsoft Academic Search

Contents Introduction S 1. Primary Cosmic Rays Near the Earth a) Chemical composition b) Energy spectrum S 2. Radio-Astronomical Data a) Magnetic bremsstrahlung (synchrotron radiation) b) Certain results of observations and their interpretation (structure of the Galaxy, discrete sources) S 3. Lifetime of Cosmic Rays and Character of Their Motion in the Galaxy and the Metagalaxy a) Nuclear lifetime of

V. L. Ginzburg; S. I. Syrovatsky

1961-01-01

211

On the influence of statistics on the determination of the mean value of the depth of shower maximum for ultra high energy cosmic ray showers  

NASA Astrophysics Data System (ADS)

The chemical composition of ultra high energy cosmic rays is still uncertain. The latest results obtained by the Pierre Auger Observatory and the HiRes collaboration, concerning the measurement of the mean value and the fluctuations of the atmospheric depth at which the showers reach the maximum development, Xmax, are inconsistent. From comparison with air shower simulations it can be seen that, while the Auger data may be interpreted as a gradual transition to heavy nuclei for energies larger than ˜2-3 × 1018 eV, the HiRes data are consistent with a composition dominated by protons. In Wilk and Wlodarczyk (2011 J. Phys. G: Nucl. Part. Phys. 38 085201), it is suggested that a possible explanation for the observed deviation of the mean value of Xmax from the proton expectation, observed by Auger, could originate in a statistical bias arising from the approximated exponential shape of the Xmax distribution, combined with the decrease of the number of events as a function of primary energy. In this paper, we consider a better description of the Xmax distribution and show that the possible bias in the Auger data is at least one order of magnitude smaller than the one obtained when assuming an exponential distribution. Therefore, we conclude that the deviation of the Auger data from the proton expectation is unlikely to be explained by such statistical effect.

Supanitsky, A. D.; Medina-Tanco, G.

2012-09-01

212

Correlations of the Arrival Directions of Ultra-high Energy Cosmic Rays with Extragalactic Objects as Observed by the Telescope Array Experiment  

NASA Astrophysics Data System (ADS)

We search for correlations between the positions of extragalactic objects and the arrival directions of ultra-high energy cosmic rays (UHECRs) with primary energy E >= 40 EeV as observed by the surface detector array of the Telescope Array (TA) experiment during the first 40 months of operation. We examine several public astronomical object catalogs, including the Veron-Cetty and Veron catalog of active galactic nuclei. We count the number of TA events correlated with objects in each catalog as a function of three parameters: the maximum angular separation between a TA event and an object, the minimum energy of the events, and the maximum redshift of the objects. We determine the combination of these parameters that maximizes the correlations, and we calculate the probability of having the same levels of correlations from an isotropic distribution of UHECR arrival directions. No statistically significant correlations are found when penalties for scanning over the above parameters and for searching in several catalogs are taken into account.

Abu-Zayyad, T.; Aida, R.; Allen, M.; Anderson, R.; Azuma, R.; Barcikowski, E.; Belz, J. W.; Bergman, D. R.; Blake, S. A.; Cady, R.; Cheon, B. G.; Chiba, J.; Chikawa, M.; Cho, E. J.; Cho, W. R.; Fujii, H.; Fujii, T.; Fukuda, T.; Fukushima, M.; Hanlon, W.; Hayashi, K.; Hayashi, Y.; Hayashida, N.; Hibino, K.; Hiyama, K.; Honda, K.; Iguchi, T.; Ikeda, D.; Ikuta, K.; Inoue, N.; Ishii, T.; Ishimori, R.; Ito, H.; Ivanov, D.; Iwamoto, S.; Jui, C. C. H.; Kadota, K.; Kakimoto, F.; Kalashev, O.; Kanbe, T.; Kasahara, K.; Kawai, H.; Kawakami, S.; Kawana, S.; Kawata, K.; Kido, E.; Kim, H. B.; Kim, H. K.; Kim, J. H.; Kim, J. H.; Kitamoto, K.; Kitamura, S.; Kitamura, Y.; Kobayashi, K.; Kobayashi, Y.; Kondo, Y.; Kuramoto, K.; Kuzmin, V.; Kwon, Y. J.; Lan, J.; Lim, S. I.; Lundquist, J. P.; Machida, S.; Martens, K.; Matsuda, T.; Matsuura, T.; Matsuyama, T.; Matthews, J. N.; Minamino, M.; Miyata, K.; Murano, Y.; Myers, I.; Nagasawa, K.; Nagataki, S.; Nakamura, T.; Nam, S. W.; Nonaka, T.; Ogio, S.; Ohnishi, M.; Ohoka, H.; Oki, K.; Oku, D.; Okuda, T.; Ono, M.; Oshima, A.; Ozawa, S.; Park, I. H.; Pshirkov, M. S.; Rodriguez, D. C.; Roh, S. Y.; Rubtsov, G.; Ryu, D.; Sagawa, H.; Sakurai, N.; Sampson, A. L.; Scott, L. M.; Shah, P. D.; Shibata, F.; Shibata, T.; Shimodaira, H.; Shin, B. K.; Shin, J. I.; Shirahama, T.; Smith, J. D.; Sokolsky, P.; Springer, R. W.; Stokes, B. T.; Stratton, S. R.; Stroman, T.; Suzuki, S.; Takahashi, Y.; Takeda, M.; Taketa, A.; Takita, M.; Tameda, Y.; Tanaka, H.; Tanaka, K.; Tanaka, M.; Thomas, S. B.; Thomson, G. B.; Tinyakov, P.; Tkachev, I.; Tokuno, H.; Tomida, T.; Troitsky, S.; Tsunesada, Y.; Tsutsumi, K.; Tsuyuguchi, Y.; Uchihori, Y.; Udo, S.; Ukai, H.; Urban, F.; Vasiloff, G.; Wada, Y.; Wong, T.; Yamakawa, Y.; Yamane, R.; Yamaoka, H.; Yamazaki, K.; Yang, J.; Yoneda, Y.; Yoshida, S.; Yoshii, H.; Zhou, X.; Zollinger, R.; Zundel, Z.

2013-11-01

213

Cosmic-ray astrochemistry.  

PubMed

Gas-phase chemistry in the interstellar medium is driven by fast ion-molecule reactions. This, of course, demands a mechanism for ionization, and cosmic rays are the ideal candidate as they can operate throughout the majority of both diffuse and dense interstellar clouds. Aside from driving interstellar chemistry via ionization, cosmic rays also interact with the interstellar medium in ways that heat the ambient gas, produce gamma rays, and produce light element isotopes. In this paper we review the observables generated by cosmic-ray interactions with the interstellar medium, focusing primarily on the relevance to astrochemistry. PMID:23812538

Indriolo, Nick; McCall, Benjamin J

2013-06-28

214

A Model for Non High Energy Gamma Ray Bursts and Sources of Ultra High Energy Cosmic Rays -super strongly magnetized milli-second pulsar formed from a (C+O) star and a neutron star (black hole) close binary system  

Microsoft Academic Search

As a progenitor of NHE (Non High Energy) GRBs (Gamma Ray Bursts), we propose a (C+O) star and a neutron star (black hole) close binary system with separation ? 0.2 R?. Since the (C+O) star is tidally locked, the collapsing core should have a spin angular momentum ? 6 ×1048cgs so that a new born pulsar should be a milli-second

Takashi NAKAMURA

215

Charged Cosmic Rays and Neutrinos  

NASA Astrophysics Data System (ADS)

High-energy neutrino astronomy has grown up, with IceCube as one of its main experiments having sufficient sensitivity to test "vanilla" models of astrophysical neutrinos. I review predictions of neutrino fluxes as well as the status of cosmic ray physics. I comment also briefly on an improvement of the Fermi-LAT limit for cosmogenic neutrinos and on the two neutrino events presented by IceCube first at "Neutrino 2012".

Kachelrieß, M.

2013-04-01

216

A search for correlation of ultra-high energy cosmic rays with IRAS-PSCz and 2MASS-6dF galaxies  

NASA Astrophysics Data System (ADS)

We study the arrival directions of 69 ultra-high energy cosmic rays (UHECRs) observed at the Pierre Auger Observatory (PAO) with energies exceeding 55 EeV. We investigate whether the UHECRs exhibit the anisotropy signal expected if the primary particles are protons that originate in galaxies in the local universe, or in sources correlated with these galaxies. We cross-correlate the UHECR arrival directions with the positions of IRAS-PSCz and 2MASS-6dF galaxies taking into account particle energy losses during propagation. This is the first time that the 6dF survey is used in a search for the sources of UHECRs and the first time that the PSCz survey is used with the full 69 PAO events. The observed cross-correlation signal is larger for the PAO UHECRs than for 94% (98%) of realisations from an isotropic distribution when cross-correlated with the PSCz (6dF). On the other hand the observed cross-correlation signal is lower than that expected from gtrsim85% of realisations, had the UHECRs originated in galaxies in either survey. The observed cross-correlation signal does exceed that expected by 50% of the realisations if the UHECRs are randomly deflected by intervening magnetic fields by 5° or more. We propose a new method of analysing the expected anisotropy signal, by dividing the predicted UHECR source distribution into equal predicted flux radial shells, which can help localise and constrain the properties of UHECR sources. We find that the 69 PAO events are consistent with isotropy in the nearest of three shells we define, whereas there is weak evidence for correlation with the predicted source distribution in the two more distant shells in which the galaxy distribution is less anisotropic.

Oikonomou, Foteini; Connolly, Amy; Abdalla, Filipe B.; Lahav, Ofer; Thomas, Shaun A.; Waters, David; Waxman, Eli

2013-05-01

217

Science with the new generation high energy gamma- ray experiments  

Microsoft Academic Search

This Conference is the fifth of a series of Workshops on High Energy Gamma- ray Experiments, following the Conferences held in Perugia 2003, Bari 2004, Cividale del Friuli 2005, Elba Island 2006. This year the focus was on the use of gamma-ray to study the Dark Matter component of the Universe, the origin and propagation of Cosmic Rays, Extra Large

M. Alvarez; D. D'Armiento; G. Agnetta; A. Alberdi; A. Antonelli; A. Argan; P. Assis; E. A. Baltz; C. Bambi; G. Barbiellini; H. Bartko; M. Basset; D. Bastieri; P. Belli; G. Benford; L. Bergstrom; R. Bernabei; G. Bertone; A. Biland; B. Biondo; F. Bocchino; E. Branchini; M. Brigida; T. Bringmann; P. Brogueira; A. Bulgarelli; J. A. Caballero; G. A. Caliandro; P. Camarri; F. Cappella; P. Caraveo; R. Carbone; M. Carvajal; S. Casanova; A. J. Castro-Tirado; O. Catalano; R. Catena; F. Celi; A. Celotti; R. Cerulli; A. Chen; R. Clay; V. Cocco; J. Conrad; E. Costa; A. Cuoco; G. Cusumano; C. J. Dai; B. Dawson; B. De Lotto; G. De Paris; A. de Ugarte Postigo; E. Del Monte; C. Delgado; A. Di Ciaccio; G. Di Cocco; S. Di Falco; G. Di Persio; B. L. Dingus; A. Dominguez; F. Donato; I. Donnarumma; M. Doro; J. Edsjo; J. M. Espino Navas; M. C. Espirito Santo; Y. Evangelista; C. Evoli; D. Fargion; C. Favuzzi; M. Feroci; M. Fiorini; L. Foggetta; N. Fornengo; T. Froysland; M. Frutti; F. Fuschino; J. L. Gomez; M. Gomez; D. Gaggero; N. Galante; M. I. Gallardo; M. Galli; J. E. Garcia; M. Garczarczyk; F. Gargano; M. Gaug; F. Gianotti; S. Giarrusso; B. Giebels; N. Giglietto; P. Giommi; F. Giordano; A. Giuliani; J. Glicenstein; P. Goncalves; D. Grasso; M. Guerriero; H. L. He; A. Incicchitti; J. Kirk; H. H. Kuang; A. La Barbera; G. La Rosa; C. Labanti; G. Lamanna; I. Lapshov; F. Lazzarotto; S. Liberati; F. Liello; P. Lipari; F. Longo; F. Loparco; M. Lozano; P. G. Lucentini De Sanctis; J. M. Ma; M. C. Maccarone; L. Maccione; V. Malvezzi; A. Mangano; M. Mariotti; M. Marisaldi; I. Martel; A. Masiero; E. Massaro; M. Mastropietro; E. Mattaini; F. Mauri; M. N. Mazziotta; S. Mereghetti; T. Mineo; S. Mizobuchi; A. Moiseev; M. Moles; C. Monte; F. Montecchia; E. Morelli; A. Morselli; I. Moskalenko; F. Nozzoli; J. F. Ormes; M. A. Peres-Torres; L. Pacciani; A. Pellizzoni; F. Perez-Bernal; F. Perotti; P. Picozza; L. Pieri; M. Pietroni; M. Pimenta; A. Pina; C. Pittori; C. Pontoni; G. Porrovecchio; F. Prada; M. Prest; D. Prosperi; R. Protheroe; G. Pucella; J. M. Quesada; J. M. Quintana; J. R. Quintero; S. Raino; M. Rapisarda; M. Rissi; J. Rodriguez; E. Rossi; G. Rowell; A. Rubini; F. Russo; M. Sanchez-Conde; B. Sacco; V. Scapin; M. Schelke; A. Segreto; A. Sellerholm; X. D. Sheng; A. Smith; P. Soffitta; R. Sparvoli; P. Spinelli; V. Stamatescu; L. S. Stark; M. Tavani; G. Thornton; L. G. Titarchuk; B. Tome; A. Traci; M. Trifoglio; A. Trois; P. Vallania; E. Vallazza; S. Vercellone; S. Vernetto; V. Vitale; N. Wild; Z. P. Ye; A. Zambra; F. Zandanel; D. Zanello

2007-01-01

218

Observations of High-energy Cosmic-Ray Electrons from 30 GeV to 3 TeV with Emulsion Chambers  

NASA Astrophysics Data System (ADS)

We have performed a series of cosmic-ray electron observations using balloon-borne emulsion chambers since 1968. While we previously reported the results from subsets of the exposures, the final results of the total exposures up to 2001 are presented here. Our successive experiments have yielded a total exposure of 8.19 m2 sr day at altitudes of 4.0-9.4 g cm-2. The performance of the emulsion chambers was examined by accelerator beam tests and Monte Carlo simulations, and the on-board calibrations were carried out by using the flight data. In this work, we present the cosmic-ray electron spectrum in the energy range from 30 GeV to 3 TeV at the top of the atmosphere, which is well represented by a power-law function with an index of -3.28 ± 0.10. The observed data can also be interpreted in terms of diffusive propagation models. The evidence of cosmic-ray electrons up to 3 TeV suggests the existence of cosmic-ray electron sources at distances within ~1 kpc and times within ~1 × 105 yr ago.

Kobayashi, T.; Komori, Y.; Yoshida, K.; Yanagisawa, K.; Nishimura, J.; Yamagami, T.; Saito, Y.; Tateyama, N.; Yuda, T.; Wilkes, R. J.

2012-12-01

219

Possible experiments with very high energy cosmic neutrinos - The Dumand project  

Microsoft Academic Search

The deep ocean water DUMAND (deep underwater muon neutrino detection) experiment and the related ATENA (atmosphere high energy neutrino experiment) and UNICORN (underwater interstellar cosmic ray neutrinos) projects are discussed, with attention centered on: detection of showers, detector grid constants, muon detection, spectra of atmospheric neutrinos, neutrino-nucleon cross sections at high energies, frequency of occurrence of neutrino events, W-boson searches,

V. S. Berezinskii; G. T. Zatsepin

1977-01-01

220

The galactic origin of cosmic rays. II  

NASA Astrophysics Data System (ADS)

The cosmic ray pressure limit to cosmic ray acceleration in the interstellar medium (ISM) is considered. It is found that the beta equals 1 Alfven speed streaming limit imposes a new and strong constraint on supernova-ISM shock models of cosmic-ray acceleration. A more detailed analysis is, therefore, required. Ultra-high energy cosmic rays are also discussed, giving attention to sources of cosmic rays inside and outside the Galaxy. In connection with complexities and constraints, one source for all energies within all galaxies is finally considered, taking into account a flattening of the source in slope and the characteristics of spectrum and flux produced by the shock ejection of the envelope of a type I supernova.

Colgate, S. A.

221

Cosmic ray propagation in the local superbubble  

NASA Astrophysics Data System (ADS)

It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.

Steitmatter, R. E.; Balasubrahmanyan, V. K.; Protheroe, R. J.; Ormes, J. F.

1984-09-01

222

Cosmic ray propagation in the local superbubble  

NASA Astrophysics Data System (ADS)

It is suggested that a ring of HI gas lying in the galactic plane is part of a supershell which formed some 3 x 10 to the 7th power years ago. The consequences of a closed magnetic supershell for cosmic ray propagation are examined and it is concluded that there is no evidence which precludes the production and trapping of cosmic rays in such a region. A consequence of superbubble confinement is that the mean age of cosmic rays would be independent of energy. This can be tested by high energy observations of the isotopic composition of Be.

Streitmatter, R. E.; Balasubrahmanyan, V. K.; Ormes, J. F.; Protheroe, R. J.

1985-02-01

223

Introduction to Cosmic Rays  

Microsoft Academic Search

Energetic particles, traditionally called Cosmic Rays, were discovered nearly a hundred years ago, and their origin is still uncertain. Their main constituents are the normal\\u000a nuclei as in the standard cosmic abundances of matter, with some enhancements for the heavier elements; there are also electrons,\\u000a positrons and antiprotons. Today we also have information on isotopic abundances, which show some anomalies,

Peter L. Biermann; Guenter Sigl

2001-01-01

224

Search for Point Sources of Ultra-High-Energy Cosmic Rays above 4.0 × 1019 eV Using a Maximum Likelihood Ratio Test  

Microsoft Academic Search

We present the results of a search for cosmic-ray point sources at energies in excess of 4.0×1019 eV in the combined data sets recorded by the Akeno Giant Air Shower Array and High Resolution Fly's Eye stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an

S. Westerhoff; T. Abu-Zayyad; J. F. Amann; G. Archbold; R. Atkins; J. A. Bellido; K. Belov; J. W. Belz; S. Y. Ben-Zvi; D. R. Bergman; J. H. Boyer; G. W. Burt; Z. Cao; R. W. Clay; B. M. Connolly; B. R. Dawson; W. Deng; G. R. Farrar; Y. Fedorova; J. Findlay; C. B. Finley; W. F. Hanlon; C. M. Hoffman; M. H. Holzscheiter; G. A. Hughes; P. Hüntemeyer; C. C. H. Jui; K. Kim; M. A. Kirn; B. C. Knapp; E. C. Loh; M. M. Maestas; N. Manago; E. J. Mannel; L. J. Marek; K. Martens; J. A. J. Matthews; J. N. Matthews; A. O'Neill; C. A. Painter; L. Perera; K. Reil; R. Riehle; M. D. Roberts; M. Sasaki; S. R. Schnetzer; M. Seman; K. M. Simpson; G. Sinnis; J. D. Smith; R. Snow; P. Sokolsky; C. Song; R. W. Springer; B. T. Stokes; J. R. Thomas; S. B. Thomas; G. B. Thomson; D. Tupa; L. R. Wiencke; A. Zech

2005-01-01

225

The intergalactic propagation of ultrahigh energy cosmic ray nuclei  

SciTech Connect

We investigate the propagation of ultra-high energy cosmic ray nuclei (A = 1-56) from cosmologically distant sources through the cosmic radiation backgrounds. Various models for the injected composition and spectrum and of the cosmic infrared background are studied using updated photodisintegration cross-sections. The observational data on the spectrum and the composition of ultra-high energy cosmic rays are jointly consistent with a model where all of the injected primary cosmic rays are iron nuclei (or a mixture of heavy and light nuclei).

Hooper, Dan; /Fermilab; Sarkar, Subir; /Oxford U., Theor. Phys.; Taylor, Andrew M.; /Oxford U.

2006-08-01

226

Cosmic Ray Acceleration in Astrophysical Environments  

NASA Astrophysics Data System (ADS)

Cosmic ray acceleration in astrophysical shocks is important. We discuss these shocks' properties and we perform Monte Carlo simulations studying their efficiency in accelerating particles (i.e. protons or electrons) up to very high energies with an application to astrophysical regions such as Super Novae, Active Galactic Nuclei hot spots and Gamma Ray Bursts. The efficiency of the acceleration mechanism at shocks varies in regard to the inclination of the magnetic field to the shock normal (e.g. subluminal shocks, superluminal shocks). This fact could have consequences to the contribution of the very high energy cosmic rays to the observed cosmic ray spectrum and the relevant neutrino and gamma-ray emission.

Meli, A.; Mastichiadis, A.

2008-01-01

227

Astrophysical High-Energy Neutrinos and Gamma-Ray Bursts  

SciTech Connect

High-energy neutrinos from gamma-ray bursts (GRBs) have been expected in various scenarios. Many predictions for prompt and afterglow emission were done in the pre-Swift era. After the launch of Swift, several new discoveries such as flares have allowed us to expect additional new possibilities of high-energy neutrino emission from GRBs. In this paper, we overview various predictions of GRB neutrino emission, and discuss feature prospects. High-energy neutrino signals may be detected by future-coming large neutrino detectors such as IceCube and KM3Net. If detected, they should be very useful to know the nature of cosmic-ray acceleration sites. It would also help us to reveal the possible connection between ultra-high-energy cosmic rays (UHECRs) and GRBs. Finally, we also compare a prediction of GRB neutrinos with several predictions for other sources such as active galactic nuclei (AGN) and clusters of galaxies.

Murase, Kohta

2008-10-22

228

Energy loss measurement of cosmic ray muons  

NASA Astrophysics Data System (ADS)

Measurements of energy losses of high energy cosmic ray muons in an ionization chamber are presented. The chamber consists of 16 single gap layers, and the liquid tetra methyl silane (TMS) was used as active medium. The absolute energy loss and the relativistic rise were measured and compared with theoretical calculations. The importance of the measurements within the framework of the cosmic ray experiment KASCADE (German acronym for Karlsruhe Shower Core and Array Detector) are discussed, especially with respect to energy calibration of hadrons and high energy muons above 1 TeV.

Unger, Joseph

1993-02-01

229

Cosmic ray ionization of lower Venus atmosphere  

NASA Astrophysics Data System (ADS)

The high energy solar and galactic cosmic rays are known to ionize Earth's atmosphere. The cosmic ray degradation and production of electron-ion pairs in Venus ionosphere are computed. At lower altitudes, the Venus atmosphere is dense and cosmic ray particles are known to decay and give rise to various charged and neutral particles. The flux and degradation of dominant cascade particles, namely neutrinos and pions, are computed and ionization contributions at lower altitudes are estimated. Using the height profile of pion flux, the muon ray flux is computed and used to estimate ionization at lower altitudes. It is shown that cosmic-ray produced ionization descends to much lower altitudes intercepting the thickness of the Venus cloud deck. The dynamical features of the Venus cloud deck are used to show the likely charging and charge separation processes resulting in cloud-to-cloud lightning discharges.

Upadhyay, H. O.; Singh, R. N.

1995-04-01

230

In Search of Cosmic Rays  

NSDL National Science Digital Library

The authors discuss the Cosmic Ray Observatory Project (CROP), focusing on their high school's participation in the project. Students build and monitor cosmic ray detectors to count and study cosmic rays and to determine whether or not the time of day inf

Streich, Derek; Antonelli, Jamie; Liebl, Michael; Mahoney, Sean

2001-11-01

231

Galactic cosmic rays and nucleosynthesis  

SciTech Connect

The nucleosynthesis of the light elements Li, Be and B by galactic cosmic rays is presented. Observations of cosmic rays and the nuclear reactions responsible for Li, Be and B nucleosynthesis are described, followed by some words on propagation. At the end, some open questions concerning galactic cosmic rays are discussed.

Kiener, Juergen [CSNSM, CNRS-IN2P3 and Universite Paris-Sud, Bat. 104-108, 91405 Orsay Campus (France)

2010-03-01

232

Cosmic Ray Studies of Antimatter  

Microsoft Academic Search

Forty years after the discovery of the antiproton the study of cosmic-ray antimatter continues to be an exciting and fertile field. Sensitive searches for heavy cosmic-ray antimatter continue, although in recent years their value as a probe of universal baryon symmetry has all but evaporated. Antiprotons and positrons have opened new windows on the origin and history of cosmic rays.

Gregory Tarlé

1996-01-01

233

Atmospheric Cosmic Ray Detectors  

NASA Astrophysics Data System (ADS)

This document is part of Part 2 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '6.1 Atmospheric Cosmic Ray Detectors' of Chapter '6 Detectors for Special Applications' with the content:

Blümer, J.; Engler, J.

234

Search for Point Sources of Ultra-High-Energy Cosmic Rays above 4.0 × 1019 eV Using a Maximum Likelihood Ratio Test  

NASA Astrophysics Data System (ADS)

We present the results of a search for cosmic-ray point sources at energies in excess of 4.0×1019 eV in the combined data sets recorded by the Akeno Giant Air Shower Array and High Resolution Fly's Eye stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.

Abbasi, R. U.; Abu-Zayyad, T.; Amann, J. F.; Archbold, G.; Atkins, R.; Bellido, J. A.; Belov, K.; Belz, J. W.; Ben-Zvi, S. Y.; Bergman, D. R.; Boyer, J. H.; Burt, G. W.; Cao, Z.; Clay, R. W.; Connolly, B. M.; Dawson, B. R.; Deng, W.; Farrar, G. R.; Fedorova, Y.; Findlay, J.; Finley, C. B.; Hanlon, W. F.; Hoffman, C. M.; Holzscheiter, M. H.; Hughes, G. A.; Hüntemeyer, P.; Jui, C. C. H.; Kim, K.; Kirn, M. A.; Knapp, B. C.; Loh, E. C.; Maestas, M. M.; Manago, N.; Mannel, E. J.; Marek, L. J.; Martens, K.; Matthews, J. A. J.; Matthews, J. N.; O'Neill, A.; Painter, C. A.; Perera, L.; Reil, K.; Riehle, R.; Roberts, M. D.; Sasaki, M.; Schnetzer, S. R.; Seman, M.; Simpson, K. M.; Sinnis, G.; Smith, J. D.; Snow, R.; Sokolsky, P.; Song, C.; Springer, R. W.; Stokes, B. T.; Thomas, J. R.; Thomas, S. B.; Thomson, G. B.; Tupa, D.; Westerhoff, S.; Wiencke, L. R.; Zech, A.

2005-04-01

235

Cosmic rays from pulsars and magnetars  

NASA Astrophysics Data System (ADS)

We compare the expected abundance of cosmic ray electrons and positrons from pulsars and magnetars. We assume that the distribution of infant pulsars and magnetars follows that of high-mass stars in the Milky Way and that the production rate of cosmic rays is proportional to the spin-down and magnetic-decay power of pulsars and magnetars, respectively. In combination with primary and secondary cosmic ray leptons from other sources (especially supernova remnants), we find that both magnetars and pulsars can easily account for the observed cosmic ray spectrum, in particular the dip seen by HESS (High-Energy Stereoscopic System) at several TeV and the increase in positron fraction found by PAMELA (Payload for Antimatter Exploration and Light Nuclei Astrophysics).

Heyl, Jeremy S.; Gill, Ramandeep; Hernquist, Lars

2010-07-01

236

Cosmic Rays in Galactic and Extragalactic Magnetic Fields  

NASA Astrophysics Data System (ADS)

We briefly review sources of cosmic rays, their composition and spectra as well as their propagation in the galactic and extragalactic magnetic fields, both regular and fluctuating. A special attention is paid to the recent results of the X-ray and gamma-ray observations that shed light on the origin of the galactic cosmic rays and the challenging results of Pierre Auger Observatory on the ultra high energy cosmic rays. The perspectives of both high energy astrophysics and cosmic-ray astronomy to identify the sources of ultra high energy cosmic rays, the mechanisms of particle acceleration, to measure the intergalactic radiation fields and to reveal the structure of magnetic fields of very different scales are outlined.

Aharonian, Felix; Bykov, Andrei; Parizot, Etienne; Ptuskin, Vladimir; Watson, Alan

2012-05-01

237

Fermi-LAT and cosmic rays  

NASA Astrophysics Data System (ADS)

The Fermi Gamma-ray Space Telescope was launched on June 11, 2008; within days of full activation, the first Large Area Telescope (LAT) all-sky map of the sky revealed new high-energy sources and since the start of science operations in August 2008, the LAT has been observing the entire sky once every three hours. These observations have revealed more than 1,873 high-energy gamma-ray sources, including several classes of active galaxies, pulsars, pulsar wind nebulae, supernova remnants, binary sources, high-energy gamma-ray bursts, a nova, the Sun and most recently Terrestrial Gamma Ray Flashes. Fermi-LAT has mapped the Galactic diffuse gamma-ray emission created by cosmic-ray interactions in the interstellar medium, and measured the spectrum of isotropic emission. In addition, Fermi-LAT is a capable detector of high-energy electrons. It has measured electrons in cosmic rays with unprecedented accuracy and used Earth's shadow and geomagnetic field to measure cosmic ray positrons. I will give an overview of the latest results of the Fermi mission.

Michelson, Peter

2012-07-01

238

Investigation of primary cosmic rays at the Moon's surface  

NASA Astrophysics Data System (ADS)

The possibility of experimentally studying primary cosmic rays at the Moon's surface is considered. A mathematical simulations of showers initiated in the lunar regolith by high-energy particles of primary cosmic rays is performed. It is shown that such particles can in principle be recorded by simultaneously detecting three components of backscattered radiation (secondary neutrons, gamma rays, and radio emission).

Kalmykov, N. N.; Konstantinov, A. A.; Muhamedshin, R. A.; Podorozhniy, D. M.; Sveshnikova, L. G.; Turundaevskiy, A. N.; Tkachev, L. G.; Chubenko, A. P.; Vasilyev, O. A.

2013-01-01

239

X-Rays from NGC 3256: High-Energy Emission in Starburst Galaxies and Their Contribution to the Cosmic X-Ray Background  

Microsoft Academic Search

The infrared-luminous galaxy NGC 3256 is a classic example of a merger-induced nuclear starburst system. We find here that it is the most X-ray-luminous star-forming galaxy yet detected (L{sub 0.5-10keV} =1.6x10⁴² ergs s-1). Long-slit optical spectroscopy and a deep, high-resolution ROSAT X-ray image show that the starburst is driving a ''superwind'' which accounts for â20% of the observed soft X-ray

Edward C. Moran; Matthew D. Lehnert; David J. Helfand

1999-01-01

240

Cosmic Rays: "A Thin Rain of Charged Particles."  

ERIC Educational Resources Information Center

|Discussed are balloons and electroscopes, understanding cosmic rays, cosmic ray paths, isotopes and cosmic-ray travel, sources of cosmic rays, and accelerating cosmic rays. Some of the history of the discovery and study of cosmic rays is presented. (CW)|

Friedlander, Michael

1990-01-01

241

Cosmic ray astrophysics and hadronic interactions  

NASA Astrophysics Data System (ADS)

Research in cosmic rays is now nearly a century old, but most of the fundamental questions in this field remain unanswered, on the other hand the perspectives of future studies in the next decade are very bright. New detectors will provide higher quality data in the entire energy range from 108 to 1020 eV (or more if particles of higher energy have non negligible fluxes), moreover cosmic ray astrophysics must now be considered, together with gamma, neutrino and gravitational wave astronomy, as one of the subfields of the high energy astrophysics, and using information from these four ``messengers'' there is the potential of a detailed understanding of the origin of the high energy radiation in the universe. High energy cosmic rays are measured indirectly observing the showers they generate in the atmosphere, and a correct and detailed interpretation of these measurements will require an improved understanding of the properties of hadronic interactions. The new collider experiments, and in particular the LHC project at CERN offer the unique possibility to perform measurements of great value for cosmic ray astrophysics. It is of great importance for cosmic research that this possibility is fully exploited with the appropriate instrumentation and analysis.

Lipari, Paolo

2003-07-01

242

Cosmic ray nonlinear processes in gamma-ray sources  

Microsoft Academic Search

The interaction of cosmic ray (CR) particles (protons, nuclei and electrons) with matter determine the main processes of high energy gamma-ray (GR) generation through neutral pions decay and bremsstrahlung emission. On the other side, the acceleration and propagation of these particles is mainly determined by nonlinear processes of CR in GR sources: the influence of CR pressure on plasma dynamics;

L. I. Dorman

1996-01-01

243

Catching Cosmic Rays with a DSLR  

ERIC Educational Resources Information Center

|Cosmic rays are high-energy particles from outer space that continually strike the Earth's atmosphere and produce cascades of secondary particles, which reach the surface of the Earth, mainly in the form of muons. These particles can be detected with scintillator detectors, Geiger counters, cloud chambers, and also can be recorded with commonly…

Sibbernsen, Kendra

2010-01-01

244

Green River Community College Cosmic Ray Detector  

Microsoft Academic Search

The Washington Area Large scale Time coincidence Array (WALTA) researches high-energy cosmic ray and has placed particle detector arrays around the Seattle area to increase the accuracy of muon information. Green River Community College is one of the schools in collaboration with WALTA and offers its students under-graduate research by working with the particle detector arrays, data collecting and reporting.

Andrea Roma; Crissy Harrington; Mirela Isic; Andrew Adams; Ron Draper

2008-01-01

245

Life Extinctions by Cosmic Ray Jets  

Microsoft Academic Search

High energy cosmic ray jets from nearby mergers or accretion induced collapse of neutron stars that hit the atmosphere can produce lethal fluxes of atmospheric muons at ground level, underground and underwater, destroy the ozone layer, and radioactivate the environment. They could have caused some of the massive life extinctions on planet Earth in the past 570 Myr. Biological mutations

Arnon Dar; Ari Laor; Nir J. Shaviv

1998-01-01

246

Modeling galactic cosmic rays at lunar orbit  

Microsoft Academic Search

High-energy particles such as galactic cosmic rays (GCRs) and solar energetic particles (SEPs) have sufficient kinetic energy to produce undesirable biological effects in astronauts as well as environmental effects on spacecraft electronic systems. In low Earth orbit, such radiation effects are minimized owing to the strong geomagnetic cutoff from Earth's internal magnetic field. However, the risks increase at higher altitudes

Chia-Lin Huang; Harlan Spence; Brian Kress; Simon Shepherd

2008-01-01

247

Cosmic Rays in Thunderstorms  

NASA Astrophysics Data System (ADS)

Cosmic Rays in Thunderstorms Cosmic rays are protons and heavier nuclei that constantly bombard the Earth's atmosphere with energies spanning a vast range from 109 to 1021 eV. At typical altitudes up to 10-20 km they initiate large particle cascades, called extensive air showers, that contain millions to billions of secondary particles depending on their initial energy. These particles include electrons, positrons, hadrons and muons, and are concentrated in a compact particle front that propagates at relativistic speed. In addition, the shower leaves behind a trail of lower energy electrons from ionization of air molecules. Under thunderstorm conditions these electrons contribute to the electrical and ionization processes in the cloud. When the local electric field is strong enough the secondary electrons can create relativistic electron run-away avalanches [1] or even non-relativistic avalanches. Cosmic rays could even trigger lightning inception. Conversely, strong electric fields also influence the development of the air shower [2]. Extensive air showers emit a short (tens of nanoseconds) radio pulse due to deflection of the shower particles in the Earth's magnetic field [3]. Antenna arrays, such as AERA, LOFAR and LOPES detect these pulses in a frequency window of roughly 10-100 MHz. These systems are also sensitive to the radiation from discharges associated to thunderstorms, and provide a means to study the interaction of cosmic ray air showers and the electrical processes in thunderstorms [4]. In this presentation we discuss the involved radiation mechanisms and present analyses of thunderstorm data from air shower arrays [1] A. Gurevich et al., Phys. Lett. A 165, 463 (1992) [2] S. Buitink et al., Astropart. Phys. 33, 1 (2010) [3] H. Falcke et al., Nature 435, 313 (2005) [4] S. Buitink et al., Astron. & Astrophys. 467, 385 (2007)

Buitink, Stijn; Scholten, Olaf; van den Berg, Ad; Ebert, Ute

2013-04-01

248

Muons from high-energy cosmic photinos  

SciTech Connect

The generation of muons in photino--nucleon (gamma-tildeN) scattering is investigated at a high photino energy Eapprox. >10/sup 4/ GeV. Generation of muons occurs as the result of production and subsequent decay of charmed hadrons. The quark subprocesses considered are the reactions gamma-tilde+g..-->..c(c-bar)+c-bar(c-italic-tilde), where g is a gluon, c is a charmed quark, and c-italic-tilde is a scalar charmed quark. Photinos generate muons less efficiently than do neutrinos, but on the other hand the gamma-tildeN cross section at ultrahigh energies is two orders of magnitude higher than the ..nu..N cross section. This gives a certain signature of the photino flux from a source when it is comprehensively observed by means of extensive-air-shower and deep-underwater detectors. The signature is a large flux of EAS with a small flux of high-energy underground muons.

Berezinskii, V.S.; Bugaev, E.V.; Zaslavskaya, E.S.

1988-10-01

249

Cosmic ray acceleration in young supernova remnants  

NASA Astrophysics Data System (ADS)

We investigate the appearance of magnetic field amplification resulting from a cosmic ray escape current in the context of supernova remnant shock waves. The current is inversely proportional to the maximum energy of cosmic rays, and is a strong function of the shock velocity. Depending on the evolution of the shock wave, which is drastically different for different circumstellar environments, the maximum energy of cosmic rays as required to generate enough current to trigger the non-resonant hybrid instability that confines the cosmic rays follows a different evolution and reaches different values. We find that the best candidates to accelerate cosmic rays to ˜ few PeV energies are young remnants in a dense environment, such as a red supergiant wind, as may be applicable to Cassiopeia A. We also find that for a typical background magnetic field strength of 5 ?G the instability is quenched in about 1000 years, making SN1006 just at the border of candidates for cosmic ray acceleration to high energies.

Schure, K. M.; Bell, A. R.

2013-10-01

250

Gamma-Ray Lines and High-Energy Sources  

SciTech Connect

Gamma-ray lines may provide diagnostic information on cosmic high energy sources: They originate from the decay of radioactive nucleosynthesis products, from positron annihilations, and from atomic nuclei which have been excited by energetic collisions. Shortlived isotopes such as 56Ni and 44Ti are produced in supernovae, their gamma-ray line intensities and line profiles reflect kinematics and morphology of the exploding star. Long-lived isotopes such as 26Al, and also the positron annihilation gamma-rays, can be used to study propagation processes in the interstellar medium near high-energy sources, complementing observational time scales at the long end of the range of interest. Such annihilation emission and also lines from excited nuclei near accreting compact stars should reflect energetic conditions at environments which are believed to inject suprathermal particles into relativistic accelerators to produce cosmic rays. New INTEGRAL measurements on these frontiers are discussed in this paper.

Diehl, Roland [Max Planck Institut fuer extraterrestrische Physik, D-85741 Garching (Germany)

2005-11-22

251

10Be Production in the Atmosphere by Galactic Cosmic Rays  

Microsoft Academic Search

Galactic cosmic ray nuclei and energetic protons produced in solar flares and accelerated by coronal mass ejections are the main sources of high-energy particles of extraterrestrial origin in near-Earth space and inside the Earth's atmosphere. The intensity of galactic cosmic rays inside the heliosphere is strongly influenced by the modulation of the interstellar source particles on their way through interplanetary

Daniel Matthiä; Klaudia Herbst; Bernd Heber; Thomas Berger; Günther Reitz

2011-01-01

252

Cosmic rays and space weather  

NASA Astrophysics Data System (ADS)

It is well known that in periods of great FEP (Flare Energetic Particle), fluxes can be so big that memory of computers and other electronics in space may be destroyed, satellites and spacecrafts became dead (each year insurance companies paid more than 500,000,000 dollars for these failures). In these periods is necessary to switch off some part of electronics for short time to protect computer memories. These periods are also dangerous for astronauts on space-ships, and passengers and crew in commercial jets (especially during S5 radiation storms according to classification of NOAA). The problem is how to forecast exactly these dangerous phenomena. We show that exact forecast can be made by using high-energy particles (about 5-10 GeV/nucleon and higher) which transportation from the Sun is characterized by much bigger diffusion coefficient than for small and middle energy particles. Therefore high energy particles came from the Sun much more early (8-20 minutes after acceleration and escaping into solar wind) than main part of smaller energy particles caused dangerous situation for electronics and people health (about 30-60 minutes later). We describe here principles and experience of automatically working programs "FEP-Search-1 min", "FEP-Search-2 min","FEP-Search-5 min", developed and checked in the Emilio Segre' Observatory of Israel Cosmic Ray Center (2025 m above sea level, cut-off rigidity 10.8 GV). The second step is automatically determination of flare energetic particle spectrum, and then automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere and on the ground. We will describe also the theory and experience of high energy cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects (what influenced very much on communications, working of navigation systems, satellites and high-level technology systems in space and, the atmosphere, and on the ground). The review and original part will contain following parts: 1. Introduction (cosmic rays as object and instrument of space weather monitoring and forecasting). 2. On-line search of the start of great Flare Energetic Particle (FEP) events, automatically formation of Alerts, estimation of probability of false alerts and probability of missing alerts (realized in Israel Cosmic Ray Center and Emilio Segre’ Observatory). 3. On-line determination of flare energetic particle spectrum by the method of coupling functions. 4. Automatically determination of diffusion coefficient in the interplanetary space, time of ejection and energy spectrum of FEP in source; forecasting of expected FEP flux and radiation hazard for space-probes in space, satellites in the magnetosphere, jets and various objects in the atmosphere, and on the ground in dependence of cut-off rigidity. 5. Cosmic ray using for forecasting of major geomagnetic storms accompanied by Forbush-effects.

Dorman, L. I.

2003-04-01

253

Research Concerning Detection of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Throughout my academic career at Loyola I have carried out research with the Loyola University Cosmic Event Detection System concerning the possibility of detection of ultra high energy cosmic rays (UHECRs) based on radio meteor scattering methods. This research was furthered through summer internships and research fellowships at Adler Planetarium Chicago and Stony Brook University in New York. At Adler Planetarium we used a helium balloon carrying a Geiger counter and other equipment to record the cosmic ray flux at various points in the atmosphere. The results clearly show the flux depends on the atmospheric density. At Stony Brook University I studied their advanced system for detecting cosmic rays in similar manner to radio meteor scattering principles. Research there focused on detection algorithms and also on the possibility of utilizing Digital Tv (DTv) signals for further research. Through the research a solid understanding of cosmic rays was formed including topics such as origins and energy scales of cosmic rays, both of which pose unanswered questions. )

Grady, Maxwell; Cunningham, John; Kuhlmann, Steve; Spinka, Hal; Underwood, Dave; Hammergren, Mark

2010-02-01

254

High energy gamma ray balloon instrument  

Microsoft Academic Search

The High Energy Gamma Ray Balloon Instrument was built in part to verify certain subsystems' performance for the Energetic Gamma Ray Experiment Telescope (EGRET) instrument, the high energy telescope to be carried on the Gamma Ray Observatory. This paper describes the instrument, the performance of some subsystems, and some relevant results.

D. J. Thompson; R. G. Baker; D. L. Bertsch; J. R. Chesney; S. M. Derdeyn; C. H. Ehrmann; C. E. Fichtel; S. D. Hunter; J. S. Jacques; N. A. Laubenthal

1985-01-01

255

6Li and Gamma Rays: Complementary Constraints on Cosmic-Ray History  

Microsoft Academic Search

The rare isotope 6Li is made only by cosmic rays, predominantly in alphaalpha-->6Li fusion reactions with interstellar medium (ISM) helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays in our Galaxy. The same hadronic cosmic-ray interactions also produce high-energy gamma-rays (mostly via pp-->pi0-->gammagamma). Thus, hadronic gamma-rays and 6Li are intimately linked. Specifically, 6Li directly encodes

Brian D. Fields; Tijana Prodanovic

2005-01-01

256

The HEAO-3 Cosmic Ray Isotope spectrometer  

NASA Astrophysics Data System (ADS)

This paper describes the Cosmic Ray Isotope instrument launched aboard the HEAO-3 satellite on September 20, 1979. The primary purpose of the experiment is to measure the isotopic composition of cosmic ray nuclei from Be-7 to Fe-58 over the energy range 0.5 to 7 GeV/nucleon. In addition charge spectra will be measured between beryllium and tin over the energy range 0.5 to 25 GeV/nucleon. The charge and isotope abundances measured by the experiment provide essential information needed to further our understanding of the origin and propagation of high energy cosmic rays. The instrument consists of 5 Cerenkov counters, a 4 element neon flash tube hodoscope and a time-of-flight system. The determination of charge and energy for each particle is based on the multiple Cerenkov technique and the mass determination will be based upon a statistical analysis of particle trajectories in the geomagnetic field.

Bouffard, M.; Engelmann, J. J.; Koch, L.; Soutoul, A.; Lund, N.; Peters, B.; Rasmussen, I. L.

257

The Origin of Cosmic Rays  

Microsoft Academic Search

Cosmic Rays reach the Earth from space with energies of up to more than 1020 eV, carrying information on the most powerful particle accelerators that Nature has been able to assemble. Understanding where and how cosmic rays originate has required almost one century of investigations, and, although the last word is not written yet, recent observations and theory seem now

Blasi; Pasquale

2008-01-01

258

Forbush decreases in cosmic rays  

Microsoft Academic Search

The cosmic-ray time variation called Forbush decreases are examined in an overview of observational data with attention given to the three species of Forbush decreases. References are made to the satellite observations of magnetic fields associated with Forbush decreases and of the interactions between interplanetary shock and coronal ejection. The 27-day variations of cosmic rays are discussed in terms of

D. Venkatesan; A. G. Ananth

1991-01-01

259

Cosmic Ray Neutron Flux Measurements  

NASA Astrophysics Data System (ADS)

Cosmic rays are high-energetic particles originating from outer space that bombard the upper atmosphere of the Earth. Almost 90% of cosmic ray particles consist of protons, electrons and heavy ions. When these particles hit the Earth's atmosphere, cascade of secondary particles are formed. The most abundant particles reach to the surface of the Earth are muons, electrons and neutrons. In recent years many research groups are looking into potential applications of the effects of cosmic ray radiation at the surface of the Earth [1, 2]. At Georgia State University we are working on a long-term measurement of cosmic ray flux distribution. This study includes the simultaneous measurement of cosmic ray muons, neutrons and gamma particles at the Earth surface in downtown Atlanta. The initial effort is focusing on the correlation studies of the cosmic ray particle flux distribution and the atmospheric weather conditions. In this presentation, I will talk about the development of a cosmic ray detector using liquid scintillator and the preliminary results. [4pt] [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, ``Radiographic imaging with cosmic-ray muons'', Nature, Vol.422, p.277, Mar.2003[0pt] [2] Svensmark Henrik, Physical Review 81, 3, (1998)

Dayananda, Mathes

2009-11-01

260

Comparison of experimental data with predictions of various models for silicon and aluminum fragmentation under the effect of high-energy cosmic rays  

SciTech Connect

The accuracy attained in theoretically estimating the yields of isotopes and isobars and their energy, charge, and mass distributions in silicon fragmentation that occurs in spacecraft electronics under the effect of cosmic-ray protons is an important factor in forecasting the probability for single-event upsets in the electronics and the reliability of spacecraft operation in general. In previous studies of our group, it was shown that the results of the calculations are highly sensitive to the choice of parameters for opticalmodel potentials. In addition to cross sections for elastic and inelastic proton scattering and charge, mass, and energy distributions of heavy nuclear-reaction products, the results of our calculations for doubledifferential spectra of protons originating from the interaction of highly energetic (30-400 MeV) protons with aluminum and double-differential spectra of other particles (neutrons and alpha particles) arising in competing channels of the p + {sup 27}Al reaction are also described in the present article. The calculations in question were performed on the basis of the EMPIRE-II-19 code by using various optical-model potentials, including the Becchetti-Greenlees potential for the (p, n) channel, the Wilmore-Hodgson potential for the (p, n) channel, the Madland potential for the (p, p) channel, the Koning-Delaroche potential for the (p, p) channel, and the McFadden-Satchler potential for the (p, {alpha}) channel. A comparative analysis of the double-differential spectra obtained for outgoing protons, neutrons, and alpha particles experimentally and in the calculations of various authors was performed.

Chechenin, N. G., E-mail: chechenin@sinp.msu.ru; Chuvilskaya, T. V.; Shirokova, A. A.; Kadmenskii, A. G. [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation)

2011-12-15

261

On the transition from Galactic to extragalactic cosmic rays  

NASA Astrophysics Data System (ADS)

The Earth is permanently exposed to a flux of high-energy ionized nuclei - the cosmic rays. Most of these particles are accelerated in our Galaxy, most probably in supernova remnants. Cosmic rays are magnetically bound to our Galaxy up to energies of about 10^17 to 10^18 eV. At higher energies the observed particles most likely originate in other galaxies and are usually referred to as extra-galactic cosmic rays. Thus, the energy region between 10^17 and 10^18 eV is of great astrophysical interest. From a detailed measurement of the composition of cosmic rays in this energy regime we expect deeper insight into both, the origin of Galactic and extra-galactic cosmic rays. The status of the actual research will be reviewed and implications on our understanding of the origin of cosmic rays will be discussed.

Hoerandel, Joerg

2012-03-01

262

Cosmic gamma Radiation of Ultra High Energy of Primordial Origin.  

National Technical Information Service (NTIS)

The quantum mechanical effects near a collapsing black hole as shown by Stephen W. Hawking in 1974 to produce streaming particles through tunneling effect was explored in the context of cosmic gamma ray production. In this thesis, we show the possible pro...

1984-01-01

263

Size distributions of air showers accompanied with high energy gamma ray bundles observed at Mt. Chacaltaya  

Microsoft Academic Search

Size distributions of air showers accompanied with bundle of high energy gamma rays and\\/or large size bursts under emulsion chambers, to study the composition of primary cosmic rays and also characteristics of high energy nuclear interaction. Air showers initiated by particles with a large cross section of interaction may develop from narrow region of the atmosphere near the top. Starting

T. Matano; M. Machida; I. Tsuchima; N. Kawasumi; K. Honda; K. Hashimoto; N. Martinic; J. Zapata; C. E. Navia; C. Aquirre

1985-01-01

264

Gamma-ray bursts, cosmic-rays and neutrinos  

Microsoft Academic Search

The ?-ray burst (GRB) model for production of ultra-high energy, > 1019 eV, cosmic-rays is based on the hypothesis that GRBs arise from the dissipation of the kinetic energy of relativistic fireballs at cosmological distances. Recent observations of delayed low energy emission, “afterglow,” from GRB sources strongly support the validity of this hypothesis. Observations also provide quantitative support for the

Eli Waxman

2000-01-01

265

Supernova Remnants, Cosmic Rays, and GLAST  

SciTech Connect

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

Reynolds, Steve (North Carolina State University)

2006-02-13

266

Supernova Remnants, Cosmic Rays, and GLAST  

ScienceCinema

The shock waves of supernova remnants (SNRs) are the traditional sources of Galactic cosmic rays, at least up to about 3000 TeV (the 'knee' energy in the cosmic-ray spectrum). In the last decade or so, X-ray observations have confirmed in a few SNRs the presence of synchrotron-X-ray-emitting electrons with energies of order 100 TeV. TeV photons from SNRs have been observed with ground-based air Cerenkov telescopes as well, but it is still unclear whether they are due to hadronic processes (inelastic p-p scattering of cosmic-ray protons from thermal gas, with secondary neutral pions decaying to gamma rays), or to leptonic processes (inverse-Compton upscattering of cosmic microwave background photons, or bremsstrahlung). The spatial structure of synchrotron X-rays as observed with the Chandra X-ray Observatory suggests the remarkable possibility that magnetic fields are amplified by orders of magnitude in strong shock waves. The electron spectra inferred from X-rays reach 100 TeV, but at that energy are cutting off steeply, well below the 'knee' energy. Are the cutoff processes due only to radiative losses so that ion spectra might continue unsteepened? Can we confirm the presence of energetic ions in SNRs at all? Are typical SNRs capable of supplying the pool of Galactic cosmic rays? Is strong magnetic-field amplification a property of strong astrophysical shocks in general? These major questions require the next generation of observational tools. I shall outline the theoretical and observational framework of particle acceleration to high energies in SNRs, and shall describe how GLAST will advance this field.

267

The Origin of Cosmic Rays  

Microsoft Academic Search

The isotropy and composition of the primary cosmic radiation suggest that cosmic rays are trapped within the galaxy for an average time of the order of 106 years,-a long time compared with the time of escape along straight-line paths, but short compared with the mean life against nuclear collisions with interstellar matter. If one accepts this conclusion, it appears possible

Philip Morrison; Stanislaw Olbert; Bruno Rossi

1954-01-01

268

Thunderstorm correlated enhancements of Cosmic Ray flux, detected at mt. Aragats  

Microsoft Academic Search

The cosmic rays ionize enough the at- mosphere to be questioned as possible triggers of the thunderstorms. A mechanism proposed by A. Gurevich and his collaborators suggest that show- ers of energetic particles produced by high-energy cosmic rays in the terrestrial atmosphere might provide a conductive path that initiates lightning. Because cosmic-ray air showers do not produce enough particles for

Ashot Chilingarian; Ara Daryan; Laura Melkumyan

269

Flux limits for high energy cosmic photinos from underground experiments  

NASA Astrophysics Data System (ADS)

Underground experiments, which detect the interactions of atmospheric neutrinos, could also be sensitive to photinos. Using data from the Fréjus and Kamiokande detectors we give upper limits on the possible flux of high-energy relativistic photinos incident on the Earth, as functions of the squark or selectron masses. These limits improve considerably the existing ones, by four to nine orders of magnitude or more, especially for very energetic photinos. Although not yet very constraining, they may be used to eliminate the possibility that high-energy cosmic photinos could contribute significantly to the energy density of the Universe. Laboratoire Propre du Centre National de la Recherche Scientifique, associé à l'École Normale Supérieure et à l'Université de Paris-Sud.

Fayet, P.

1989-03-01

270

A theory of cosmic rays  

NASA Astrophysics Data System (ADS)

We present a theory of non-solar cosmic rays (CRs) in which the bulk of their observed flux is due to a single type of CR source at all energies. The total luminosity of the Galaxy, the broken power-law spectra with their observed slopes, the position of the ‘knee(s)’ and ‘ankle’, and the CR composition and its variation with energy are all predicted in terms of very simple and completely ‘standard’ physics. The source of CRs is extremely ‘economical’: it has only one parameter to be fitted to the ensemble of all of the mentioned data. All other inputs are ‘priors’, that is, theoretical or observational items of information independent of the properties of the source of CRs, and chosen to lie in their pre-established ranges. The theory is part of a ‘unified view of high-energy astrophysics’ — based on the ‘Cannonball’ model of the relativistic ejecta of accreting black holes and neutron stars. The model has been extremely successful in predicting all the novel properties of Gamma Ray Bursts recently observed with the help of the Swift satellite. If correct, this model is only lacking a satisfactory theoretical understanding of the ‘cannon’ that emits the cannonballs in catastrophic processes of accretion.

Dar, Arnon; de Rújula, A.

2008-09-01

271

A cosmic ray propagation model  

NASA Astrophysics Data System (ADS)

This work describes a stepwise program of interstellar cosmic ray propagation that is used to study the sensitivity of propagation models of ultra heavy cosmic ray nuclei (UH nuclei). We have evaluated the uncertainties introduced in the predicted abundances by calculating the fragmentation cross sections using different procedures, by varying the input energy, and by varying the escape length of the cosmic ray nuclei. These uncertainties have been compared with the predicted differences introduced by assuming that the source abundances resemble either solar system, pure r-, or pure s-process material. These comparisons allow us to determine how the uncertainties in the above mentioned parameters affect the abundances of the cosmic ray nuclei. We conclude that the uncertainties in nuclear cross sections presently prevent us from drawing any but the broadest conclusions from the measured abundances.

Clinton, Robert Russell

272

Cosmic rays in the Milky Way and other galaxies  

NASA Astrophysics Data System (ADS)

Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and evolution of galaxies. Diffuse emissions from radio to high-energy gamma rays (> 100 MeV) arising from various interactions between cosmic rays and the interstellar medium, interstellar radiation field, and magnetic field, are currently the best way to trace the intensities and spectra of cosmic rays in the Milky Way and other galaxies. In this talk, I will give an overview of the observations of the cosmic-ray induced emissions from our own and other galaxies, in particular, results from the Fermi-LAT and Imaging Air Cerenkov telescopes. I will also talk about what can be deduced about the cosmic-ray origin and propagation from these observations.

Porter, Troy

2012-07-01

273

Observation of high-energy jet showers and high-energy gamma-rays by means of large emulsion chamber  

Microsoft Academic Search

Two large emulsion chambers were constructed and exposed to cosmic ; radiation at the Mt. Norikura Laboratory (2740 ml from Sept. 1958 to Feb. 1959. ; Basic design of the chambers is shown and the results of observations on high-; energy jet showers and gamma rays are discussed. (W.D.M.);

Y. Fujimoto; S. Hasegawa; M. Kazuno; J. Nishimura; K. Niu; N. Ogita

1960-01-01

274

ASPIRE - Cloud Chambers as an Introduction to Cosmic Ray Observation  

NASA Astrophysics Data System (ADS)

ASPIRE is the K12 - Education & Public Outreach program for the Telescope Array ultra-high energy cosmic ray research project in Utah. The Telescope Array experiment studies ultra-high energy cosmic rays with an array of ˜500 surface scintillator detectors and three fluorescence telescope stations observing over 300 square miles in the West Desert of Utah. Telescope Array is a collaboration of international institutions from the United States, Japan, Korea, Russia and Belgium. Cloud chambers are an inexpensive and easy demonstration to visually observe evidence of charged particles and cosmic ray activity both for informal events as well as for K12 classroom activities. Join us in building a cloud chamber and observe cosmic rays with these table-top demonstrations. A brief overview of the Telescope Array project in Millard County, Utah will also be presented.

Callahan, Julie; Matthews, John; Jui, Charles

2012-03-01

275

Cosmic ray modulation by interplanetary disturbances  

NASA Astrophysics Data System (ADS)

Interplanetary disturbances such as ICMEs (Interplanetary Coronal Mass Ejections) and CIRs (Corotating Interaction Regions), modulate high-energy cosmic rays reaching the Earth. Prior to the arrival of the disturbances at the Earth, ground based high-energy muon detectors can detect precursory effects in cosmic-ray anisotropy, such as precursory deficit and/or excess of intensity along the sunward IMF (Interplanetary Magnetic Field) direction. With suitable analyses, these precursors are found typically around 8 hours prior to the disturbance arrival at the Earth. The objective of this work is to analyze these precursors by using the Global Muon Detector Network (GMDN), an international network formed by four multidirectional muon detectors viewing a full range of the pitch angle measured from the sunward IMF direction. By analyzing the variation of the count rate global distribution of the observed intensity (instead of analyzing the count rate) precursory signatures can be enhanced when compared with analyses of count rates. For some events, it is possible to make almost a global distribution map of cosmic ray density using all the directional channels of the detectors. Precursory signature is generally accompanied by the interplanetary shock, but there are also some signatures not associated with the shock.

Braga, Carlos Roberto; Dal Lago, Alisson; Schuch, Nelson Jorge; da Silva, Marlos; Echer, Ezequiel; Demítrio Gonzalez Alarcon, Walter; Munakata, Kazuoki; Kuwabara, Takao; Kato, Chihiro; Bieber, John W.

276

Photon-axion mixing and ultra-high energy cosmic rays from BL Lac type objects: Shining light through the Universe  

NASA Astrophysics Data System (ADS)

Photons may convert into axion-like particles and back in the magnetic field of various astrophysical objects, including active galaxies, clusters of galaxies, intergalactic space and the Milky Way. This is a potential explanation for the candidate neutral ultra-high energy (E>1018eV) particles from distant BL Lac type objects which probably have been observed by the High Resolution Fly’s Eye experiment. Axions of the same mass and coupling may explain also TeV photons detected from distant blazars.

Fairbairn, M.; Rashba, T.; Troitsky, S.

2011-12-01

277

Detectors for cosmic rays on ground and in Space  

NASA Astrophysics Data System (ADS)

The origin of cosmic rays has been a great mystery since they were discovered by Victor Hess in 1912. AGASA's observation of ultra-high-energy cosmic-rays (UHECR) possibly beyond the GZK (Greisen, Zatsepin and Kuzmin) cutoff stimulated the field in great deal. In addition, Kamiokande's detection of neutrinos from SN1987A and the detection of TeV gamma-rays from supernova remnants at H.E.S.S. have demonstrated the viability of neutrino and TeV gamma-ray astronomy for cosmic-ray research. A new generation of currently operating or soon-to-be-operating detectors for charged particles, gamma rays and neutrinos from cosmos will get us even closer to understanding the nature and origin of cosmic rays. Detectors for UHECRs, gamma rays and neutrinos are of particular importance in order to study the origins of cosmic rays since these particles are free from deflection due to magnetic fields. Detectors for antiparticles and gamma rays would be useful to detect cosmic rays originating from the decay of dark matter in the Universe. I will review these cosmic-ray detectors with particular emphasis on the differences of ground-based, balloon-borne and satellite-borne detectors.

Tajima, Hiroyasu

2007-10-01

278

Cosmic Rays from Cygnus X-3  

Microsoft Academic Search

Today many investigators adhere to the idea that cosmic rays receive all their energy from discrete sources with interstellar space acting only as a diffusive medium. An object that accelerates particles to cosmic-ray velocities will almost inevitably produce gamma rays as well. Hence, gamma rays are therefore an effective probe of the source of cosmic radiation even though they account

P. Kevin MacKeown; Trevor C. Weekes

1985-01-01

279

Characteristics of high energy interactions I. High energy gamma-ray spectra near the top of the atmosphere  

Microsoft Academic Search

An emulsion chamber was used to study the characteristics of high energy nuclear interactions from the production spectra\\u000a of?-rays. The emulsion chamber, which comprised of two parts, namely the detector and the graphite producer unit, was exposed\\u000a to cosmic rays for about 7 hr at an atmospheric depth of 10 g cm?2 at Hyderabad (geomagnetic latitude 7·6°N). 720 electromagnetic cascades

R Hasan; A K Agrawal; M S Swami

1979-01-01

280

The microphysics and macrophysics of cosmic rays  

NASA Astrophysics Data System (ADS)

This review paper commemorates a century of cosmic ray research, with emphasis on the plasma physics aspects. Cosmic rays comprise only ~10-9 of interstellar particles by number, but collectively their energy density is about equal to that of the thermal particles. They are confined by the Galactic magnetic field and well scattered by small scale magnetic fluctuations, which couple them to the local rest frame of the thermal fluid. Scattering isotropizes the cosmic rays and allows them to exchange momentum and energy with the background medium. I will review a theory for how the fluctuations which scatter the cosmic rays can be generated by the cosmic rays themselves through a microinstability excited by their streaming. A quasilinear treatment of the cosmic ray-wave interaction then leads to a fluid model of cosmic rays with both advection and diffusion by the background medium and momentum and energy deposition by the cosmic rays. This fluid model admits cosmic ray modified shocks, large scale cosmic ray driven instabilities, cosmic ray heating of the thermal gas, and cosmic ray driven galactic winds. If the fluctuations were extrinsic turbulence driven by some other mechanism, the cosmic ray background coupling would be entirely different. Which picture holds depends largely on the nature of turbulence in the background medium.

Zweibel, Ellen G.

2013-05-01

281

Cosmic Rays and Global Warming  

SciTech Connect

Some workers have claimed that the observed temporal correlations of (low level) terrestrial cloud cover with the cosmic ray intensity changes, due to solar modulation, are causal. The possibility arises, therefore, of a connection between cosmic rays and Global Warming. If true, the implications would be very great. We have examined this claim in some detail. So far, we have not found any evidence in support and so our conclusions are to doubt it. From the absence of corroborative evidence we estimate that less than 15% at the 95% confidence level, of the 11-year cycle warming variations are due to cosmic rays and less than 2% of the warming over the last 43 years is due to this cause. The origin of the correlation itself is probably the cycle of solar irradiance although there is, as yet, no certainty.

Sloan, T. [Physics Department, University of Lancaster, Lancaster, UK (United Kingdom); Wolfendale, A. W. [Physics Department, Durham University, Durham (United Kingdom)

2008-01-24

282

Cosmic Rays and Sunspot Numbers  

NSDL National Science Digital Library

In this activity students analyze and compare two or more graphs to determine if there is a correlation between sunspot number and the variation of cosmic ray flux. They discover that cosmic rays are very energetic particles, mostly protons and electrons, that enter the solar system from the depths of interstellar space and that although the Earth's magnetic field partially shields us from these particles, so too does the much more extended solar wind with its own magnetic field. This is a three-part lesson in which students will construct line graphs displaying the cosmic ray flux and sunspot numbers for a period of time, and then determine if there is a correlation. In order to compare these two sets of data, students will need to scale the data in order to visualize the results. Teacher and student notes for the graphing calculator are included.

Higley, Susan

283

Nineteenth International Cosmic Ray Conference. HE Sessions, volume 6  

SciTech Connect

Papers contributed to the 19th International Cosmic Ray Conference which address high energy interactions and related phenomena are compiled. Particular topic areas include cross sections; particle production; nuclei and nuclear matter; nucleus-nucleus collisions; gamma ray and hadron spectra; C-jets, a-jets, and super families; and emulsion chamber simulations.

Jones, F.C.

1985-08-01

284

Scintillator Cosmic Ray Super Telescope  

NASA Astrophysics Data System (ADS)

The Scintillator Cosmic Ray Super Telescope (SciCRST) is a new experiment to detect solar neutrons, and also it is expected to work as a muon and cosmic ray detector. The SciCRST consist of 14,848 plastic scintillator bars, and it will be installed at the top of Sierra Negra volcano, Mexico, 4580 m.a.s.l. We use a prototype, called as miniSciBar, to test the hardware and software of the final experiment. In this paper, we present the status and details of the experiment, and results of the prototype.

González, L. X.; Valdés-Galicia, J. F.; Matsubara, Y.; Nagai, Y.; Itow, Y.; Sako, T.; López, D.; Mitsuka, G.; Munakata, K.; Kato, C.; Yasue, S.; Kosai, M.; Tsurusashi, M.; Nakamo, Y.; Shibata, S.; Takamaru, H.; Kojima, H.; Tsuchiya, H.; Watanabe, K.; Koi, T.; Fragoso, E.; Hurtado, A.; Musalem, O.

2013-04-01

285

Cosmic Ray Anisotropy with KASCADE  

NASA Astrophysics Data System (ADS)

The anisotropy of cosmic rays with energies in the region of the knee in the energy spectrum is investigated in three different persp ectives based on the arrival directions of about 150 Mio. extensive air showers measured by KASCADE. The different analyses are a harmonic analysis of the right ascension distribution and a point source search of showers above 0.5 PeV as well as an auto correlation analysis of showers above 100 PeV. All three analyses agree inside the statistical limits with an isotropic distribution of the arrival directions of cosmic rays.

Maier, G.; Antoni, T.; Apel, W. D.; Badea, F.; Bekk, K.; Bercuci, A.; Blümer, H.; Bozdog, H.; Brancus, I. M.; Büttner, C.; Chilingarian, A.; Daumiller, K.; Doll, P.; Engel, R.; Engler, J.; Feßler, F.; Gils, H. J.; Glasstetter, R.; Haungs, A.; Heck, D.; Hörandel, J. R.; Iwan, A.; Kampert, K. H.; Klages, H. O.; Mathes, H. J.; Mayer, H. J.; Milke, J.; Müller, M.; Obenland, R.; Oehlschläger, J.; Ostapchenko, S.; Petcu, M.; Rebel, H.; Risse, M.; Schatz, G.; Schieler, H.; Scholz, J.; Thouw, T.; Ulrich, H.; van Buren, J.; Vardanyan, A.; Weindl, A.; Wochele, J.; Zabierowski, J.

2003-07-01

286

People Interview: Cosmic rays uncover universe theories  

NASA Astrophysics Data System (ADS)

INTERVIEW Cosmic rays uncover universe theories David Smith talks to Paula Chadwick about why she is fascinated by cosmic and gamma rays, and how this is the year that their profile is going to be raised

2012-07-01

287

Very High Energy ?-rays from AGN  

NASA Astrophysics Data System (ADS)

Evidence of TeV ?-ray emission has been found for only a handful of active galactic nuclei, with detailed investigations limited to the blazars Mrk 421 and Mrk 501. TeV ?-ray astronomy, as the highest energy band, provides important information that is hard to obtain from longer wavelength electromagnetic radiation. The current status of TeV ?-ray studies of active galactic nuclei is summarized and our understanding of the high energy phenomena taking place in active galactic nuclei is outlined, with the prospects for future TeV ?-ray observations also considered.

Kifune, Tadashi

288

Secular changes in the cosmic ray equator  

Microsoft Academic Search

Data of a number of latitude surveys of cosmic ray intensity with several crossings of the equator in the Atlantic Ocean, conducted during the 1954-1987 time period are analyzed to obtain the locations of the cosmic ray equator at different longitudes and epochs. These experimentally determined cosmic-ray-equator locations are compared with locations derived from simulated cosmic-ray intensities calculated as a

A. J. van der Walt; P. H. Stoker

1990-01-01

289

Green River Community College Cosmic Ray Detector  

NASA Astrophysics Data System (ADS)

The Washington Area Large scale Time coincidence Array (WALTA) researches high-energy cosmic ray and has placed particle detector arrays around the Seattle area to increase the accuracy of muon information. Green River Community College is one of the schools in collaboration with WALTA and offers its students under-graduate research by working with the particle detector arrays, data collecting and reporting. The student's work ranges from polishing scintillators and planning the physical setup of detector components to solving data acquisition problems.

Roma, Andrea; Harrington, Crissy; Isic, Mirela; Adams, Andrew; Draper, Ron

2008-05-01

290

Cygnus X-3 - Cosmic-ray powerhouse  

NASA Astrophysics Data System (ADS)

Cyg X-3, a high-energy X-ray binary located at the outskirts of the Galaxy which has been identified as the probable source of gamma rays of energies up to 10 PeV, is characterized in a survey of recent observational and theoretical investigations. The relationship between gamma rays and cosmic rays is reviewed; the observations establishing the 4.8-h periodicity of the gamma emissions are summarized; twin-jet/accretion-disk, pulsar, and dynamo models proposed to explain the Cyg X-3 emission are discussed; and the implications of very recent detections of secondary muons produced by neutrinos or some unknown primary particles (or by some unknown interaction of known particles) from Cyg X-3 are considered.

Smith, D. H.

1985-06-01

291

Search for Antimatter in Primary Cosmic Rays  

Microsoft Academic Search

COSMIC rays provide the only sample of the material outside the solar system which is available for examination and it even seems likely that some part of the cosmic ray flux originates outside our own galaxy. In the circumstances, it is understandable that there have been several searches for anti-nuclei in primary cosmic rays, partly so as to throw light

J. G. Greenhill; A. R. Clarke; H. Elliot

1971-01-01

292

Cosmic ray propagation in interstellar space  

Microsoft Academic Search

The astrophysics of cosmic rays is a very broad field of research, concerned with questions like where and how cosmic rays are accelerated, how they propagate and interact with the interstellar medium. In recent years a huge number of studies have been devoted to cosmic rays and to questions related to them as new and accurate observational data become available.

Ashraf Mohamed Samir Farahat

2005-01-01

293

Cosmology, Relativity and Cosmic Rays  

NASA Astrophysics Data System (ADS)

This is a short review of the evolution of ideas and concepts about the Universe. It is based on the introductory talk given on the 25 of July 2008 within the Third School on Cosmic Rays and Astrophysics held in Arequipa, Peru.

López, Rebeca; Martínez, Humberto; Zepeda, Arnulfo

2009-04-01

294

Cosmic Ray Anisotropy with KASCADE  

Microsoft Academic Search

The anisotropy of cosmic rays with energies in the region of the knee in the energy spectrum is investigated in three different persp ectives based on the arrival directions of about 150 Mio. extensive air showers measured by KASCADE. The different analyses are a harmonic analysis of the right ascension distribution and a point source search of showers above 0.5

G. Maier; T. Antoni; W. D. Apel; F. Badea; K. Bekk; A. Bercuci; H. Blümer; H. Bozdog; I. M. Brancus; C. Büttner; A. Chilingarian; K. Daumiller; P. Doll; R. Engel; J. Engler; F. Feßler; H. J. Gils; R. Glasstetter; A. Haungs; D. Heck; J. R. Hörandel; A. Iwan; K. H. Kampert; H. O. Klages; H. J. Mathes; H. J. Mayer; J. Milke; M. Müller; R. Obenland; J. Oehlschläger; S. Ostapchenko; M. Petcu; H. Rebel; M. Risse; G. Schatz; H. Schieler; J. Scholz; T. Thouw; H. Ulrich; J. van Buren; A. Vardanyan; A. Weindl; J. Wochele; J. Zabierowski

2003-01-01

295

Cosmic Rays as Electrical Particles  

Microsoft Academic Search

Positive evidence that the primary cosmic rays consist of electrical particles is drawn from three types of experiments: 1. Latitude and directional asymmetry effects. Clay finds 83 percent as intense ionization at the equatorial minimum as in high latitudes. Of the remainder, Rossi's directional experiments show that about 12 percent at least is due to positively charged particles. Corresponding to

Arthur H. Compton

1936-01-01

296

Cosmic-ray sum rules  

SciTech Connect

We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays; we show how they can be used to predict the positron fraction at energies not yet explored by current experiments, and to constrain specific models.

Frandsen, Mads T. [Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Masina, Isabella [Dip. di Fisica dell'Universita di Ferrara and INFN Sez. di Ferrara, Via Saragat 1, I-44100 Ferrara (Italy); CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark); Sannino, Francesco [CP3-Origins, University of Southern Denmark, Campusvej 55, DK-5230 Odense M (Denmark)

2011-06-15

297

Cosmic gamma-ray bursts  

Microsoft Academic Search

The results of the observation of cosmic gamma-ray bursts are discussed and available theoretical models are presented. Emphasis is placed on a cosmological model in which a gamma burst results from a powerful (? 1051–1053 erg) and very short ( ?10 –100 s) energy release which occurs in a compact ( ? 106–107 cm) region and gives rise to a

Konstantin A Postnov

1999-01-01

298

Electrons and Positrons in Cosmic Rays  

NASA Astrophysics Data System (ADS)

This review concentrates on the results obtained, over the last ten years, on the astrophysics of high-energy cosmic ray electrons and positrons. The anomalies, observed in the data of recent experiments (possible bump in the electron spectrum and the PAMELA anomaly in the positron fraction) are discussed through the systematic use of simple analytical solutions of the transport equations for cosmic ray electrons. Three main ways of explaining the origin of the anomalies are considered: the conservative way supposing the positrons to be pure secondary particles; the nearby sources like pulsars origin; and the dark matter origin. This review discusses, also, the inability to select the pulsars model or the dark matter model to explain the electron anomalies on the basis of the electron spectra with the usual large energy binning ( 15%). It is argued that the signature of nearby pulsars origin of the anomalies against the dark matter origin could be the fine structure of the cosmic ray electron spectrum predicted in the Malyshev et al. paper (2009) and which was observed in the data from the high-resolution ATIC experiment (2009-2011). To date, the high-resolution ATIC data was the only experimental result of this type published in the literature. Therefore, they should be tested by other experiments as soon as possible. Generally, there is, also, rather controversial situations between the data of the majority of recent experiments and, consequently, there is a noted urgent need for new high-precision and high-statistical experiments.

Panov, A. D.

2013-02-01

299

Cosmic-Ray Accelerators in Milky Way studied with the Fermi Gamma-ray Space Telescope  

SciTech Connect

High-energy gamma-ray astrophysics is now situated at a confluence of particle physics, plasma physics and traditional astrophysics. Fermi Gamma-ray Space Telescope (FGST) and upgraded Imaging Atmospheric Cherenkov Telescopes (IACTs) have been invigorating this interdisciplinary area of research. Among many new developments, I focus on two types of cosmic accelerators in the Milky-Way galaxy (pulsar, pulsar wind nebula, and supernova remnants) and explain discoveries related to cosmic-ray acceleration.

Kamae, Tuneyoshi; /SLAC /KIPAC, Menlo Park

2012-05-04

300

EXTRAGALACTIC VERY HIGH ENERGY GAMMA-RAY BACKGROUND  

SciTech Connect

We study the origin of the extragalactic diffuse gamma-ray background using the data from the Fermi telescope. To estimate the background level, we count photons at high Galactic latitudes |b| > 60 Degree-Sign . Subtracting photons associated with known sources and the residual cosmic-ray and Galactic diffuse backgrounds, we estimate the extragalactic gamma-ray background (EGB) flux. We find that the spectrum of EGB in the very high energy band above 30 GeV follows the stacked spectrum of BL Lac objects. Large Area Telescope data reveal the positive (1 + z) {sup k}, 1 < k < 4 cosmological evolution of the BL Lac source population consistent with that of their parent population, Fanaroff-Riley type I radio galaxies. We show that EGB at E > 30 GeV could be completely explained by emission from unresolved BL Lac objects if k {approx_equal} 3.

Neronov, A. [ISDC Data Center for Astrophysics, Chemin d'Ecogia 16, CH-1290 Versoix (Switzerland); Semikoz, D. V. [APC, 10 rue Alice Domon et Leonie Duquet, F-75205 Paris Cedex 13 (France)

2012-09-20

301

Prompt High-Energy Emission from Proton-Dominated Gamma-Ray Bursts  

Microsoft Academic Search

The prompt emission of gamma-ray bursts (GRBs) is widely thought to be radiation from accelerated electrons, but an appreciably larger amount of energy could be carried by accelerated protons, particularly if GRBs are the sources of ultra-high-energy cosmic rays (UHECRs). We model the expected photon spectra for such \\

Katsuaki Asano; Susumu Inoue; Peter Mészáros

2009-01-01

302

OBSERVATIONS ON HIGH ENERGY JETS AND GAMMA-RAYS WITH LARGE EMULSION CHAMBER  

Microsoft Academic Search

S>Large emulsion chambers of several square meters were constructed and ; exposed to cosmic rays to study the high energy jets and the gamma spectra. ; About 1000 gamma rays with energy higher than 10¹² were observed, and the ; spectrunn showed the gradual increase of the exponent with increasing energy. ; Direct observations were also made for the high

M. Akashi; K. Shimizu; Z. Watanabe; T. Ogata; N. Ogita; A. Misaki; I. Mito; S. Oyama; S. Tokunaga; M. Tamura; Y. Fujimoto; S. Hasegawa; J. Nishimura; K. Yokoi

1961-01-01

303

The study of high-energy gamma-rays produced by cosmic radiation at 40000 feet part i. experimental disposition, and determination of energy and nature of electromagnetic cascades  

Microsoft Academic Search

Two composite stacks of alternate sheets of nuclear emulsion were used ; to investigate electromagnetic cascades in the cosmic radiation. The stacks were ; exposed in BOAC Comet aircraft for a total of 1400 hours at about 38,000 ft. ; Approximately 600 cascades were observed, and a sample of these was classified as ; arising either from gamma rays incident

J. G. Duthie; C. M. Fisher; P. H. Fowler; A. Kaddoura; D. H. Perkjns; K. Pinkau

1961-01-01

304

Cosmic Topological Defects, Highest Energy Cosmic Rays, and the Baryon Asymmetry of the Universe  

NASA Astrophysics Data System (ADS)

It is pointed out that the observed extremely high energy cosmic rays (EHECR) above 1011 GeV and the observed baryon asymmetry of the Universe (BAU) may have a common origin in baryon number violating decays of supermassive X particles released from cosmic topological defects (TDs) such as cosmic strings and monopoles. The X particles produced by TDs in the recent epochs produce the EHECR, while the BAU is created by X particles released from TDs mainly in the very early Universe. In this scenario the EHECR is predicted to contain baryons as well as antibaryons with a small asymmetry between the two.

Bhattacharjee, Pijushpani

1998-07-01

305

Development of the Cosmic-Ray Muon Detection System for Probing Internal-Structure of a Volcano  

Microsoft Academic Search

Very high-energy cosmic-ray muons penetrating through a mountain enable us to probe the internal structure of volcanoes. An\\u000a improved cosmic-ray muon detection system comprising two segmented detectors with multiplicity cut of the soft components\\u000a of cosmic rays was developed. The test measurement for the volcano Mt. Asama is described.

H. Tanaka; K. Nagamine; N. Kawamura; S. N. Nakamura; K. Ishida; K. Shimomura; I. Katsuhiko; S. Koichiro

2001-01-01

306

The Plasma Physics of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Cosmic rays produce some of the most energetic emission in the Universe. They play a key role in the dynamics and energy balance of galactic gas, and allow us to probe galactic and intergalactic magnetic fields in the present epoch and over cosmic time. The acceleration and propagation of cosmic rays, and the mechanisms by which they interact collectively with their environments, are largely plasma physics problems. I will briefly review some salient aspects of cosmic ray astrophysics and describe recent progress toward understanding cosmic ray plasma physics.

Zweibel, Ellen

2012-03-01

307

Gamma ray bursts and cosmic ray origin  

Microsoft Academic Search

This paper presents the theoretical basis of the fireball\\/blast wave model, and some implications of recent results on GRB source models and cosmic-ray production from GRBs. BATSE observations of the prompt gamma-ray luminous phase, and Beppo-SAX and long wavelength afterglow observations of GRBs are briefly summarized. Derivation of spectral and temporal indices of an adiabatic blast wave decelerating in a

C. D. Dermer

2001-01-01

308

Gamma Ray Bursts and Cosmic Ray Origin  

Microsoft Academic Search

This paper presents the theoretical basis of the fireball\\/blast wave model, and some implications of recent results on GRB source models and cosmic-ray production from GRBs. BATSE observations of the prompt gamma-ray luminous phase, and Beppo-SAX and long wavelength afterglow observations of GRBs are briefly summarized. Derivation of spectral and temporal indices of an adiabatic blast wave decelerating in a

C. D. Dermer

2002-01-01

309

Gamma Ray Bursts and Cosmic Ray Origin  

Microsoft Academic Search

This paper presents the theoretical basis of the fireball\\/blast wave model,\\u000aand some implications of recent results on GRB source models and cosmic-ray\\u000aproduction from GRBs. BATSE observations of the prompt gamma-ray luminous\\u000aphase, and Beppo-SAX and long wavelength afterglow observations of GRBs are\\u000abriefly summarized. Derivation of spectral and temporal indices of an adiabatic\\u000ablast wave decelerating in a

C. D. Dermer

2002-01-01

310

Concepts of ``age'' and ``universality'' in cosmic ray showers  

Microsoft Academic Search

The concept of ``age'' as a parameter for the description of the state of development of high energy showers in the atmosphere has been in use in cosmic ray studies for several decades. In this work we briefly discuss how this concept, originally introduced to describe the average behavior of electromagnetic cascades, can be fruitfully applied to describe individual showers

Paolo Lipari

2009-01-01

311

Cosmic Ray research in Armenia  

NASA Astrophysics Data System (ADS)

Cosmic Ray research on Mt. Aragats began in 1934 with the measurements of East-West anisotropy by the group from Leningrad Physics-Technical Institute and Norair Kocharian from Yerevan State University. Stimulated by the results of their experiments in 1942 Artem and Abraham Alikhanyan brothers organized a scientific expedition to Aragats. Since that time physicists were studying Cosmic Ray fluxes on Mt. Aragats with various particle detectors: mass spectrometers, calorimeters, transition radiation detectors, and huge particle detector arrays detecting protons and nuclei accelerated in most violent explosions in Galaxy. Latest activities at Mt. Aragats include Space Weather research with networks of particle detectors located in Armenia and abroad, and detectors of Space Education center in Yerevan.

Chilingarian, A.; Mirzoyan, R.; Zazyan, M.

2009-11-01

312

Background modelling in very-high-energy gamma-ray astronomy  

Microsoft Academic Search

Context: Ground based Cherenkov telescope systems measure astrophysical gamma-ray emission against a background of cosmic-ray induced air showers. The subtraction of this background is a major challenge for the extraction of spectra and morphology of gamma-ray sources. Aims: The unprecedented sensitivity of the new generation of ground based very-high-energy gamma-ray experiments such as HESS has lead to the discovery of

D. Berge; S. Funk; J. Hinton

2007-01-01

313

Background Modelling in Very-High-Energy gamma-ray Astronomy  

Microsoft Academic Search

Ground based Cherenkov telescope systems measure astrophysical gamma-ray emission against a background of cosmic-ray induced air showers. The subtraction of this background is a major challenge for the extraction of spectra and morphology of gamma-ray sources. The unprecedented sensitivity of the new generation of ground based very-high-energy gamma-ray experiments such as H.E.S.S. has lead to the discovery of many previously

David Berge; S. Funk; J. Hinton

2006-01-01

314

The discovery of cosmic rays  

NASA Astrophysics Data System (ADS)

The work leading to the discovery of cosmic rays by Victor Hess on August 7, 1912 is reviewed. In particular the almost forgotten work of the Italian Dominico Pacini in 1909-10 is described. Hess was awarded the Nobel Prize in Physics 1936, shared with Carl Anderson for the discovery of the positron. The reason for the long delay is discussed as well as the nominations and discussions put forward in the Nobel Committee's report to the Royal Swedish Academy of Sciences.

Carlson, Per; de Angelis, Alessandro

2011-04-01

315

Cosmic rays in the classroom  

NASA Astrophysics Data System (ADS)

We use the context of astroparticle physics to introduce several fundamental concepts in physics and astrophysics. An activity has been developed using inexpensive materials that allows the reconstruction of the impact point and arrival direction of a cosmic ray particle measured by the Pierre Auger Observatory. The activity includes the discussion of fundamental concepts such as conservation of energy and momentum, centre of mass, trajectory, coordinate systems, speed, geo-orientation, time references and sky observation.

de Souza, Vitor; Alves Barros, Marcelo; César Marques Filho, Edson; Rodrigo Garbelotti, Cristiano; Alexandre João, Herbert

2013-03-01

316

The isotopic composition of cosmic-ray beryllium and its implication for the cosmic ray's age  

NASA Astrophysics Data System (ADS)

We report a new measurement of the cosmic-ray isotopic composition of beryllium in the low-energy range from 35 to 113 MeV per nucleon. This measurement was made using the High Energy Telescope of the CRS experiment on the Voyager 1 and 2 spacecraft during the time period from 1977 to 1991. In this overall time period of 14 years the average solar modulation level was about 500 MV. The cosmic-ray beryllium isotopes were completely separated with an average mass resolution sigma of 0.185 amu. The isotope fractions of Be-7, Be-9, and Be-10 obtained are 52.4 +/- 2.9%, 43.3 +/- 3.7%, and 4.3 +/- 1.5%, respectively. The measured cosmic-ray abundances of Be-7 and Be-9 are found to be in agreement with calculations based on standard Leaky-Box model for the interstellar propagation of cosmic-ray nuclei using the recent cross sections of the New Mexico-Saclay collaboration. From our observed ratio Be-10/Be = 4.3 +/- 1.5% we deduce an average interstellar density of about 0.28 (+0.14, -0.11) atoms/cu cm, and a cosmic-ray lifetime for escape of 27 (+19, -9) x 106 years. The surviving fraction of Be-10 is found to be 0.19 +/- 0.07. Modifications to the conclusions of the Leaky-Box model when a diffusion + convection halo model for propagation is used are also considered.

Lukasiak, A.; Ferrando, P.; McDonald, F. B.; Webber, W. R.

1994-03-01

317

Cosmic Connections: from Cosmic Rays to Gamma Rays, Cosmic Backgrounds and Magnetic Fields  

NASA Astrophysics Data System (ADS)

Combined data from gamma-ray telescopes and cosmic-ray detectors have produced some new surprising insights regarding intergalactic and galactic magnetic fields, as well as extragalactic background light. We review some recent advances, including a theory explaining the hard spectra of distant blazars and the measurements of intergalactic magnetic fields based on the spectra of distant sources. Furthermore, we discuss the possible contribution of transient galactic sources, such as past gamma-ray bursts and hypernova explosions in the Milky Way, to the observed flux of ultrahigh-energy cosmic-rays nuclei. The need for a holistic treatment of gamma rays, cosmic rays, and magnetic fields serves as a unifying theme for these seemingly unrelated phenomena.

Kusenko, Alexander

2013-01-01

318

Effects of neutrino mixing on high-energy cosmic neutrino flux  

Microsoft Academic Search

Several cosmologically distant astrophysical sources may produce high-energy cosmic neutrinos (E >=106 GeV) of all flavors above the atmospheric neutrino background. We study the effects of vacuum neutrino mixing in the three flavor framework on this cosmic neutrino flux. We also consider the effects of possible mixing between the three active neutrinos and the (fourth) sterile neutrino with or without

H. Athar; M. Jezabek; O. Yasuda

2000-01-01

319

Cosmic-Ray Positive and Negative Electrons  

Microsoft Academic Search

A determination of the specific ionization of cosmic-ray particles, first, by a count of the number of drops per cm along cosmic-ray tracks on cloud-chamber photographs and, second, by measurements of the energy loss in lead has shown that the great bulk of the cosmic-ray particles of positive charge are positive electrons. The primary ionization was found to be about

Carl D. Anderson

1933-01-01

320

An absence of neutrinos associated with cosmic-ray acceleration in ?-ray bursts  

NASA Astrophysics Data System (ADS)

Very energetic astrophysical events are required to accelerate cosmic rays to above 1018electronvolts. GRBs (?-ray bursts) have been proposed as possible candidate sources. In the GRB `fireball' model, cosmic-ray acceleration should be accompanied by neutrinos produced in the decay of charged pions created in interactions between the high-energy cosmic-ray protons and ?-rays. Previous searches for such neutrinos found none, but the constraints were weak because the sensitivity was at best approximately equal to the predicted flux. Here we report an upper limit on the flux of energetic neutrinos associated with GRBs that is at least a factor of 3.7 below the predictions. This implies either that GRBs are not the only sources of cosmic rays with energies exceeding 1018electronvolts or that the efficiency of neutrino production is much lower than has been predicted.

Abbasi, R.; Abdou, Y.; Abu-Zayyad, T.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Andeen, K.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Bay, R.; Bazo Alba, J. L.; Beattie, K.; Beatty, J. J.; Bechet, S.; Becker, J. K.; Becker, K.-H.; Bell, M.; Benabderrahmane, M. L.; Benzvi, S.; Berdermann, J.; Berghaus, P.; Berley, D.; Bernardini, E.; Bertrand, D.; Besson, D. Z.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Brown, A. M.; Buitink, S.; Caballero-Mora, K. S.; Carson, M.; Casier, M.; Chirkin, D.; Christy, B.; Clevermann, F.; Cohen, S.; Colnard, C.; Cowen, D. F.; Cruz Silva, A. H.; D'Agostino, M. V.; Danninger, M.; Daughhetee, J.; Davis, J. C.; de Clercq, C.; Degner, T.; Descamps, F.; Desiati, P.; de Vries-Uiterweerd, G.; Deyoung, T.; Díaz-Vélez, J. C.; Dierckxsens, M.; Dreyer, J.; Dumm, J. P.; Dunkman, M.; Eisch, J.; Ellsworth, R. W.; Engdegård, O.; Euler, S.; Evenson, P. A.; Fadiran, O.; Fazely, A. R.; Fedynitch, A.; Feintzeig, J.; Feusels, T.; Filimonov, K.; Finley, C.; Fischer-Wasels, T.; Flis, S.; Franckowiak, A.; Franke, R.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Goodman, J. A.; Góra, D.; Grant, D.; Griesel, T.; Groß, A.; Grullon, S.; Gurtner, M.; Ha, C.; Haj Ismail, A.; Hallgren, A.; Halzen, F.; Han, K.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, B.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hül?, J.-P.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Japaridze, G. S.; Johansson, H.; Kappes, A.; Karg, T.; Karle, A.; Kiryluk, J.; Kislat, F.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Kowarik, T.; Krasberg, M.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Laihem, K.; Landsman, H.; Larson, M. J.; Lauer, R.; Lünemann, J.; Madsen, J.; Marotta, A.; Maruyama, R.; Mase, K.; Matis, H. S.; Meagher, K.; Merck, M.; Mészáros, P.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Montaruli, T.; Morse, R.; Movit, S. M.; Nahnhauer, R.; Nam, J. W.; Naumann, U.; Nowicki, S. C.; Nygren, D. R.; Odrowski, S.; Olivas, A.; Olivo, M.; O'Murchadha, A.; Panknin, S.; Paul, L.; Pérez de Los Heros, C.; Piegsa, A.; Pieloth, D.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rawlins, K.; Redl, P.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rizzo, A.; Rodrigues, J. P.; Rothmaier, F.; Rott, C.; Ruhe, T.; Rutledge, D.; Ruzybayev, B.; Ryckbosch, D.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Schmidt, T.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schultes, A.; Schulz, O.; Schunck, M.; Seckel, D.; Semburg, B.; Seo, S. H.; Sestayo, Y.; Seunarine, S.; Silvestri, A.; Smith, M. W. E.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Stüer, M.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Ter-Antonyan, S.; Tilav, S.; Toale, P. A.; Toscano, S.; Tosi, D.; van Eijndhoven, N.; van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Walter, M.; Wasserman, R.; Weaver, Ch.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wischnewski, R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, C.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Zoll, M.; IceCube Collaboration

2012-04-01

321

Cosmic ray Implications for Human Health  

NASA Astrophysics Data System (ADS)

There appears to be concern among some people about the possible effects of cosmic radiation on everyday life. The amount of cosmic radiation that reaches the Earth and its environment is a function of solar cycle, altitude and latitude. The possible effect of naturally occurring cosmic radiation on airplane crews and space flight personal is a subject of current study. This paper discusses the variables controlling the cosmic ray flux in the atmosphere and describes models and software that have been developed that provide quantitative information about the cosmic radiation exposure at flight altitudes. The discussion is extended to include the cosmic radiation exposure to manned spacecraft.

Shea, M. A.; Smart, D. F.

2000-07-01

322

Kinetic theory of cosmic rays and gamma rays in supernova remnants. I. Uniform interstellar medium  

Microsoft Academic Search

Kinetic models of particle acceleration in supernova remnants (SNRs) are used to determine the cosmic ray (CR) nucleon and, for the first time, also the associated ?-ray spectrum during SN shock propagation in a uniform interstellar medium. SNR evolution is followed numerically taking into account the backreaction of accelerated CRs on the overall dynamics. The high energy CRs also produce

E. G. Berezhko; H. J. Völk

1997-01-01

323

Very high energy gamma ray astrophysics  

SciTech Connect

The second reflector (project GRANITE) is on schedule. At present (January 1992) it and the 10 m reflector are obtaining stereoscopic views of gamma-ray air showers from the Crab Nebula which verify the expected performance of the twin reflector telescopes. With the additional improvements of the upgrade (a pending DOE proposal) the twin reflectors should reach a limiting intensity of 1% that of the Crab. The astonishing early results from the EGRET detector aboard the Compton Gamma Ray Observatory indicate that distant quasars (powered by supermassive black holes) are active at GeV energies. The Whipple instruments are poised to see if such behavior continues above 100 GeV, as well as perform sensitive observations of previously reported GeV (Geminga) and TeV (Hercules X-1, etc.) sources. In addition to observing sources and identifying their location in the sky to one arcminute, experiments are planned to search for WIMPS in the mass range 0.1 to 1 TeV, and to determine the abundance of anti-protons in the cosmic rays. The successful performance of the stereoscopic reflectors demonstrates the feasibility of the concept of arrays of Cherenkov receivers. Design studies for a much larger array (CASITA) are just beginning.

Lamb, R.C.; Lewis, D.A.

1992-02-01

324

Cosmic Ray Acceleration in Supernova Remnants  

NASA Astrophysics Data System (ADS)

We review the main observational and theoretical facts about acceleration of Galactic cosmic rays in supernova remnants, discussing the arguments in favor and against a connection between cosmic rays and supernova remnants, the so-called supernova remnant paradigm for the origin of Galactic cosmic rays. Recent developments in the modeling of the mechanism of diffusive shock acceleration are discussed, with emphasis on the role of 1) magnetic field amplification, 2) acceleration of nuclei heavier than hydrogen, 3) presence of neutrals in the circumstellar environment. The status of the supernova-cosmic ray connection in the time of Fermi-LAT and Cherenkov telescopes is also discussed.

Blasi, P.

2011-06-01

325

Cosmic ray energy spectrum from measurements of air showers  

NASA Astrophysics Data System (ADS)

This review focuses on high-energy cosmic rays in the PeV energy range and above. Of particular interest is the knee of the spectrum around 3 PeV and the transition from cosmic rays of Galactic origin to particles from extra-galactic sources. Our goal is to establish a baseline spectrum from 1014 to 1020 eV by combining the results of many measurements at different energies. In combination with measurements of the nuclear composition of the primaries, the shape of the energy spectrum places constraints on the number and spectra of sources that may contribute to the observed spectrum.

Gaisser, T. K.; Stanev, T.; Tilav, S.

2013-04-01

326

Cosmogenic gamma rays and the composition of cosmic rays  

SciTech Connect

We discuss the prospects of detecting the sources of ultrahigh energy (UHE) cosmic ray (CR) nuclei via their emission of cosmogenic {gamma} rays in the GeV to TeV energy range. These {gamma} rays result from electromagnetic cascades initiated by high energy photons, electrons, and positrons that are emitted by CRs during their propagation in the cosmic radiation background and are independent of the simultaneous emission of {gamma} rays in the vicinity of the source. The corresponding production power by UHE CR nuclei (with mass number A and charge Z) is dominated by pion photo production ({proportional_to}A) and Bethe-Heitler pair production ({proportional_to}Z{sup 2}). We show that the cosmogenic {gamma}-ray signal from a single steady UHE CR source is typically more robust with respect to variations of the source composition and injection spectrum than the accompanying signal of cosmogenic neutrinos. We study the diffuse emission from the sum of extragalactic CR sources as well as the point-source emission of the closest sources.

Ahlers, Markus [C. N. Yang Institute for Theoretical Physics, SUNY at Stony Brook, Stony Brook, New York 11794-3840 (United States); Salvado, Jordi [Departament d'Estructura i Constituents de la Materia and Institut de Ciencies del Cosmos, Universitat de Barcelona, 647 Diagonal, E-08028 Barcelona (Spain)

2011-10-15

327

Cosmic Rays and Terrestrial Planetary Atmospheres  

NASA Astrophysics Data System (ADS)

Planetary atmospheres are constantly irradiated by both photon and particle radiation sources. These high-energy particles strike the Earth's atmosphere, initiating an extensive air shower. As the air shower propagates deeper, it ionizes the atmosphere by producing charged secondary particles and photons. Increased ionization leads to changes in atmospheric chemistry, resulting in ozone depletion. This increases the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit, which could enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of hadronic interactions of the primary cosmic rays with the atmosphere are able to reach the ground, enhancing the biological radiation dose. I will present results obtained from a massive computer simulation using a Monte Carlo code CORSIKA to quantify these effects. Results are available in form of look-up tables for use by the scientific community.

Atri, D.

2011-12-01

328

Ultra-high Energy Source Contributions to the Extragalactic Gamma-Ray Background  

NASA Astrophysics Data System (ADS)

The ingredients of the extragalactic gamma-ray background (EGB) at GeV-TeV energies must contain contributions from all source classes that are known to emit at these energies, including blazars, radio galaxies, star-forming galaxies, pulsars, and gamma-ray bursts. An uncertain contribution should be provided by cosmic-rays accelerated in cluster formation shocks, as well as from exotic processes, including dark matter annihilation and decay. After presenting an overview, the focus of this talk will be on contributions to the EGB from blazars emitting at >>TeV energies as well as from ultra-high energy cosmic rays. These ultra-high energy sources induce secondary radiations that cascade into the TeV and GeV band. Measurements of the EGB at very high gamma-ray energies can be used to constrain the number and distribution of such sources.

Dermer, Charles D.

2012-05-01

329

Portable high energy gamma ray imagers  

NASA Astrophysics Data System (ADS)

To satisfy the needs of high energy gamma ray imagers for industrial nuclear imaging applications, three high energy gamma cameras are presented. The RMD-Pinhole camera uses a lead pinhole collimator and a segmented BGO detector viewed by a 3 in. square position sensitive photomultiplier tube (PSPMT). This pinhole gamma camera displayed an energy resolution of 25.0% FWHM at the center of the camera at 662 keV and an angular resolution of 6.2° FWHM at 412 keV. The fixed multiple hole collimated camera (FMCC), used a multiple hole collimator and a continuous slab of NaI(Tl) detector viewed by the same PSPMT. The FMCC displayed an energy resolution of 12.4% FWHM at 662 keV at the center of the camera and an angular resolution of 6.0° FWHM at 412 keV. The rotating multiple hole collimated camera (RMCC) used a 180° antisymmetric rotation modulation collimator and CsI(Tl) detectors coupled to PIN silicon photodiodes. The RMCC displayed an energy resolution of 7.1% FWHM at 662 keV and an angular resolution of 4.0° FWHM at 810 keV. The performance of these imagers is discussed in this paper.

Guru, S. V.; He, Z.; Wehe, D. K.; Knoll, G. F.; Redus, R. H.; Squillante, M. R.

1996-02-01

330

Heliospheric modulation of cosmic rays in solar cycles 19-23  

NASA Astrophysics Data System (ADS)

The previously developed basic theory of the heliospheric modulation of high-energy cosmic rays is generalized to lower energies. Comparison of the theory with the results of long-term observations of cosmic rays in the stratosphere carried out by the group from the Lebedev Institute of Physics inMoscow andMurmansk shows satisfactory agreement. The cosmic rays are shown to behave quite differently when even and odd solar cycles alternate. Possible causes of the anomalously high cosmic-ray intensity recorded during the last solar activity minimum are discussed.

Krymsky, G. F.; Krivoshapkin, P. A.; Gerasimova, S. K.; Gololobov, P. Yu.; Grigor'ev, V. G.; Starodubtsev, S. A.

2012-09-01

331

21st European Cosmic Ray Symposium  

NASA Astrophysics Data System (ADS)

European cosmic ray symposia (ECRS) are traditionally organised in years between those of international cosmic ray conferences (ICRC). The general topics are similar in both series, but European projects, and specifically the research preferences of the host country, are somewhat emphasised in European symposia. Precedence is also given to the discussion of effects that might be related to cosmic influences and are important for society, such as the global change of climate.

Király, P.; Kudela, K.; Stehlík, M.; Wolfendale, A. W.

2009-01-01

332

Solar Modulation of Cosmic Rays  

NASA Astrophysics Data System (ADS)

This is an overview of the solar modulation of cosmic rays in the heliosphere. It is a broad topic with numerous intriguing aspects so that a research framework has to be chosen to concentrate on. The review focuses on the basic paradigms and departure points without presenting advanced theoretical or observational details for which there exists a large number of comprehensive reviews. Instead, emphasis is placed on numerical modeling which has played an increasingly significant role as computational resources have become more abundant. A main theme is the progress that has been made over the years. The emphasis is on the global features of CR modulation and on the causes of the observed 11-year and 22-year cycles and charge-sign dependent modulation. Illustrative examples of some of the theoretical and observational milestones are presented, without attempting to review all details or every contribution made in this field of research. Controversial aspects are discussed where appropriate, with accompanying challenges and future prospects. The year 2012 was the centennial celebration of the discovery of cosmic rays so that several general reviews were dedicated to historical aspects so that such developments are briefly presented only in a few cases.

Potgieter, Marius

2013-06-01

333

Cosmic Ray Diffusion Tensor Throughout the Heliosphere  

Microsoft Academic Search

We calculate the cosmic ray diffusion tensor based on a recently developed model of magnetohydrodynamic (MHD) turbulence in the expanding solar wind [Breech et al., 2008.]. Parameters of this MHD model are tuned by using published observations from Helios, Voyager 2, and Ulysses. We present solutions of two turbulence parameter sets and derive the characteristics of the cosmic ray diffusion

C. Pei; J. W. Bieber; B. Breech; R. A. Burger; J. Clem; W. H. Matthaeus

2008-01-01

334

Pulsars and possible local cosmic ray origin.  

National Technical Information Service (NTIS)

On the basis of the diffusion model of cosmic ray propagation in interstellar space the density of cosmic ray energy in the circumterrestrial space is calculated under assumption that the pulsars are indicators of place and time of supernovae explosions w...

H. M. Martirosyan

1987-01-01

335

Early cosmic ray research in France  

NASA Astrophysics Data System (ADS)

The French research on cosmic rays in the first half of the 20th century is summarized. The main experiments are described as the discovery of air cosmic ray showers by Pierre Auger. The results obtained at the French altitude laboratories like the ``Pic du Midi de Bigorre'' are also briefly presented.

Ravel, Olivier

2013-02-01

336

Early history of cosmic rays at Chicago  

NASA Astrophysics Data System (ADS)

Cosmic ray studies at the University of Chicago were started by Arthur Compton during the late 1920s. The high points of cosmic ray studies at Chicago under Compton and Marcel Schein are the focus of this report, which summarizes the research done at Chicago up to the end of World War II.

Yodh, Gaurang B.

2013-02-01

337

The Highest-Energy Cosmic Rays  

Microsoft Academic Search

The search for the origin of cosmic rays with energies above 1018 eV has made considerable progress during the past few years. With new data from the High Resolution Fly's Eye experiment in Utah and the Pierre Auger Observatory in Argentina, a suppression of the cosmic ray flux above 5 × 1019 eV consistent with the predicted suppression arising from

James J. Beatty; Stefan Westerhoff

2009-01-01

338

Satellite Anomalies from Galactic Cosmic Rays  

Microsoft Academic Search

Anomalies in communication satellite operation have been caused by the unexpected triggering of digital circuits. Interactions with galactic cosmic rays were investigated as a mechanism for a number of these events. The mechanism assumed was the charging of the base-emitter capacitance of sensitive transistors to the turn-on voltage. The calculation of the cosmic ray event rate required the determination of

D. Binder; E. C. Smith; A. B. Holman

1975-01-01

339

The Corpuscular Explanation of Cosmic Rays  

Microsoft Academic Search

WITH reference to the attempts that are being made to determine whether the cosmic radiations are corpuscular or undulatory in character, such as those described by Bruno Rossi,1 there is one point which I have vainly tried to understand. Why is it assumed that such rays would or could have the high penetrating power of cosmic rays? As I tried

Frederick Soddy

1931-01-01

340

Measuring TeV Cosmic-Ray Electrons with CREST  

NASA Astrophysics Data System (ADS)

There is strong indirect evidence for the supernova shock acceleration of galactic cosmic-ray electrons through observations of non-thermal X-rays and TeV gamma rays from supernova remnants (SNRs). Current and past electron detectors, typically flown by high altitude balloons, have been limited in their ability to study high energy electrons in the local cosmic-ray flux by their short exposure times and small apertures. To date, no measurements have been made at energies greater than 2 TeV. Yet the detection of high-energy electrons would be extremely significant, yielding information about the spatial distribution of nearby cosmic ray sources. High-energy electrons lose energy rapidly during propagation in the Galaxy through synchrotron and inverse Compton processes and thus TeV electrons reaching the solar system have to originate at distances < 1 kpc, leaving few known supernova remnants from which these particles could originate. The spectral shape of high-energy electrons should, therefore, be strongly affected by the number of nearby sources, and their distance distribution. Conversely, if no such features in the high-energy electron spectrum are observed it will call into question our understanding of cosmic ray sources and propagation. The balloon-borne Cosmic Ray Electron Synchrotron Telescope (CREST) will detect high-energy electrons by measuring the X-ray synchrotron photons generated by these electrons in the Earth's magnetic field. This technique results in a substantial increase in the acceptance and sensitivity of the apparatus compared to the traditional direct detection of electrons. The instrument will consist of a 2m x 2m array of BGO crystals. Simulation studies indicate that with an ultra-long duration (100 day) flight, as many as 250 such electrons will be detected with energies greater than 2 TeV, with an expected background of only 1 event. A prototype instrument is currently being developed and will be flown in 2005 on a conventional balloon. The full CREST instrument will be flown in 2007 in Antarctica. This work is supported by a grant from the National Aeronautics and Space Administration.

Schubnell, M.; Bower, C.; Coutu, S.; DuVernois, M.; McKee, S.; Muller, D.; Musser, J.; Nutter, S.; Swordy, S.; Tarle, G.; Tomasch, A.; Yagi, A.

2004-08-01

341

Cosmic ray effects in microcalorimeter arrays  

Microsoft Academic Search

We have identified signals resulting from cosmic rays and environmental gamma rays depositing energy in the pixels and in the silicon frame of the Astro-E2\\/X-Ray Spectrometer microcalorimeter array. Coincidences between pixels and between the array and an anti-coincidence detector determined the nature of the events. Pulse shapes and amplitudes from the cosmic ray events helped refine the thermal model of

C. K. Stahle; K. R. Boyce; G. V. Brown; J. Cottam; E. Figueroa-Feliciano; M. Galeazzi; R. L. Kelley; D. McCammon; F. S. Porter; A. E. Szymkowiak; W. A. Tillotson

2004-01-01

342

PREFACE: 23rd European Cosmic Ray Symposium (and 32nd Russian Cosmic Ray Conference)  

NASA Astrophysics Data System (ADS)

The 23rd European Cosmic Ray Symposium (ECRS) took place in Moscow at the Lomonosov Moscow State University (3-7 July 2012), and was excellently organized by the Skobeltsyn Institute of Nuclear Physics of the Lomonosov Moscow State University, with the help of the Russian Academy of Sciences and the Council on the Complex Problem of Cosmic Rays of the Russian Academy of Sciences. The first symposia were held in 1968 in Lodz, Poland (high energy, extensive air showers and astrophysical aspects) and in Bern (solar and heliospheric phenomena) and the two 'strands' joined together in 1976 with the meeting in Leeds. Since then the symposia, which have been very successful, have covered all the major topics with some emphasis on European collaborations and on meeting the demands of young scientists. Initially, a driving force was the need to overcome the divisions caused by the 'Cold War' but the symposia continued even when that threat ceased and they have shown no sign of having outlived their usefulness. 2012 has been an important year in the history of cosmic ray studies, in that it marked the centenary of the discovery of enigmatic particles in the perilous balloon ascents of Victor Hess. A number of conferences have taken place in Western Europe during the year, but this one took place in Moscow as a tribute to the successful efforts of many former USSR and other Eastern European scientists in discovering the secrets of the subject, often under very difficult conditions. The symposium covers a wide range of scientific issues divided into the following topics: PCR-IPrimary cosmic rays I (E < 1015 eV) PCR-IIPrimary cosmic rays II (E > 1015 eV) MNCosmic ray muons and neutrinos GAGeV and TeV gamma astronomy SHEnergetic particles in the heliosphere (solar and anomalous CRs and GCR modulation) GEOCosmic rays and geophysics (energetic particles in the atmosphere and magnetosphere of the Earth) On a personal note, as I step down as co-founder and chairman of the International Advisory Committee, I should like to thank those very many colleagues and friends with whom I have had the pleasure of working over the past 45 years. These thanks are extended to the present organizers. The organizers are very grateful to the Russian Foundation of Basic Research and to the Dynasty non-profit foundation for financial support. Arnold Wolfendale

Erlykin, A. D.; Kokoulin, R. P.; Lidvansky, A. S.; Meroshnichenko, L. I.; Panasyuk, M. I.; Panov, A. D.; Wolfendale, A. W.

2013-02-01

343

The H.E.S.S. measurement of the cosmic-ray electron spectrum  

NASA Astrophysics Data System (ADS)

The measurement of very-high-energy cosmic-ray electrons is intrinsically difficult due to their very steep spectrum with low fluxes and an enormous background of hadronic cosmic rays. The large collection areas needed for such a measurement can be provided by ground-based imaging atmospheric Cherenkov telescopes. The High Energy Stereoscopic System (H.E.S.S.) has performed the first ground-based cosmic-ray electron measurement and thereby extended the measured range of the spectrum to several TeV.

Egberts, Kathrin; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Behera, B.; Bernlühr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bühler, R.; Bulik, T.; Büsching, I.; Boutelier, T.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Conrad, J.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Domainko, A. Djannati-Ataü W.; Drury, L. O'c.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fürster, A.; Fontaine, G.; Füssling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Güring, D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jung, I.; Katarzynski, K.; Katz, U.; Kaufmann, S.; Kerschhaggl, M.; Khangulyan, D.; Khálifi, B.; Keogh, D.; Klochkov, D.; Kluzniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J.-P.; Lohse, T.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Ona Wilhelmi, E.; Opitz, B.; Orford, K. J.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raubenheimer, B. C.; Raue, M.; Rayner, S. M.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schück, F. M.; Schünwald, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sushch, I.; Sikora, M.; Skilton, J. L.; Sol, H.; Stawarz, L.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Szostek, A.; Tam, P. H.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Venter, L.; Vialle, J. P.; Viana, A.; Vincent, P.; Vivier, M.; Vülk, H. J.; Volpe, F.; Vorobiov, S.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

344

Cosmic Rays: A Review for Astrobiologists  

NASA Astrophysics Data System (ADS)

Cosmic rays represent one of the most fascinating research themes in modern astronomy and physics. Significant progress is being made toward an understanding of the astrophysics of the sources of cosmic rays and the physics of interactions in the ultrahigh-energy range. This is possible because several new experiments in these areas have been initiated. Cosmic rays may hold answers to a great number of fundamental questions, but they also shape our natural habitat and influence the radiation environment of our planet Earth. The importance of the study of cosmic rays has been acknowledged in many fields, including space weather science and astrobiology. Here, we concentrate on the astrobiological aspects of cosmic rays with regard to the enormous amount of new data available, some of which may, in fact, improve our knowledge about the radiation of cosmic origin on Earth. We focus on fluxes arriving at Earth and doses received, and will guide the reader through the wealth of scientific literature on cosmic rays. We have prepared a concise and self-contained source of data and recipes useful for performing interdisciplinary research in cosmic rays and their effects on life on Earth.

Ferrari, Franco; Szuszkiewicz, Ewa

2009-05-01

345

Using GEANT4 to model the photonic component of cosmic ray air showers.  

NASA Astrophysics Data System (ADS)

The CREST (Cosmic Ray Electron Synchrotron Telescope) project uses a high altitude balloon to carry a cosmic ray detector into Earth's upper atmosphere. The purpose of the project is to understand more about the local galactic sources that produce high-energy electron cosmic rays by detecting the linear pattern of synchrotron radiation emitted as the electrons are diverted by Earth's magnetic field. While this pattern is very distinct, there is a possibility that a similar pattern could be mimicked by cosmic ray air showers, which also produce temporally and spatially correlated photons. To estimate the background event rate due to air showers at balloon altitudes, GEANT4 is used to simulate cosmic ray air showers. The simulation entails modeling the composition and structure of earth's atmosphere by representing it as hundreds of variable density layers, along with reproducing the cosmic ray incident energy spectrum and composition. Information about photons is recorded as they pass through different depths in the atmosphere.

Bench, J.; Nutter, S.

2006-04-01

346

Origin of Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

The origin of the bulk of cosmic rays (CRs) observed at Earth is the topic of a century long investigation, paved with successes and failures. From the energetic point of view, supernova remnants (SNRs) remain the most plausible sources of CRs up to rigidity ˜106-107GV. This confidence somehow resulted in the construction of a paradigm, the so-called SNR paradigm: CRs are accelerated through diffusive shock acceleration in SNRs and propagate diffusively in the Galaxy in an energy dependent way. Qualitative confirmation of the SNR acceleration scenario has recently been provided by gamma ray and X-ray observations. Diffusive propagation in the Galaxy is probed observationally through measurement of the secondary to primary nuclei flux ratios (such as B/C). There are however some weak points in the paradigm, which suggest that we are probably missing some physical ingredients in our models. The theory of diffusive shock acceleration at SNR shocks predicts spectra of accelerated particles which are systematically too hard compared with the ones inferred from gamma ray observations. Moreover, hard injection spectra indirectly imply a steep energy dependence of the diffusion coefficient in the Galaxy, which in turn leads to anisotropy larger than the observed one. Moreover recent measurements of the flux of nuclei suggest that the spectra have a break at rigidity ˜200GV, which does not sit well with the common wisdom in acceleration and propagation. In this paper I will review these new developments and suggest some possible implications.

Blasi, Pasquale

2013-06-01

347

Cosmic-Ray Modulation Equations  

NASA Astrophysics Data System (ADS)

The temporal variation of the cosmic-ray intensity in the heliosphere is called cosmic-ray modulation. The main periodicity is the response to the 11-year solar activity cycle. Other variations include a 27-day solar rotation variation, a diurnal variation, and irregular variations such as Forbush decreases. General awareness of the importance of this cosmic-ray modulation has greatly increased in the last two decades, mainly in communities studying cosmogenic nuclides, upper atmospheric physics and climate, helio-climatology, and space weather, where corrections need to be made for these modulation effects. Parameterized descriptions of the modulation are even used in archeology and in planning the flight paths of commercial passenger jets. The qualitative, physical part of the modulation is generally well-understood in these communities. The mathematical formalism that is most often used to quantify it is the so-called Force-Field approach, but the origins of this approach are somewhat obscure and it is not always used correct. This is mainly because the theory was developed over more than 40 years, and all its aspects are not collated in a single document. This paper contains a formal mathematical description intended for these wider communities. It consists of four parts: (1) a description of the relations between four indicators of "energy", namely energy, speed, momentum and rigidity, (2) the various ways of how to count particles, (3) the description of particle motion with transport equations, and (4) the solution of such equations, and what these solutions mean. Part (4) was previously described in Caballero-Lopez and Moraal (J. Geophys. Res, 109: A05105, doi: 10.1029/2003JA010358, 2004). Therefore, the details are not all repeated here. The style of this paper is not to be rigorous. It rather tries to capture the relevant tools to do modulation studies, to show how seemingly unrelated results are, in fact, related to one another, and to point out the historical context of some of the results. The paper adds no new knowledge. The summary contains advice on how to use the theory most effectively.

Moraal, H.

2013-06-01

348

Probing neutrino dark energy with extremely high energy cosmic neutrinos  

Microsoft Academic Search

Recently, a new non-standard-model neutrino interaction mediated by a light scalar field was proposed, which renders the big bang relic neutrinos of the cosmic neutrino background a natural dark energy candidate, the so-called neutrino dark energy. As a further consequence of this interaction, the neutrino masses become functions of the neutrino energy densities and are thus promoted to dynamical, time\\/redshift

Andreas Ringwald; Lily Schrempp

2006-01-01

349

Characteristics of high energy interactions II. Production spectra of Gamma-rays in graphite  

Microsoft Academic Search

Twenty high energy nuclear interactions produced in the graphite units of an emulsion chamber were recorded. The emulsion\\u000a chamber was exposed to cosmic rays at an atmospheric depth of 10 g cm?2 for about 7 hr over Hyderabad, India. Fourteen interactions which radiated energy? E\\u000a r?1000 GeV in the form of?-rays were analysed in detail. The median energy ?? E

A K Agrawal; R Hasan; M S Swami

1979-01-01

350

Acceleration of Cosmic Rays at Large Scale Cosmic Shocks in the Universe  

NASA Astrophysics Data System (ADS)

Cosmological hydrodynamic simulations of large scale structure in the universe have shown that accretion shocks and merger shocks form due to flow motions associated with the gravitational collapse of nonlinear structures. Estimated speed and curvature radius of these shocks could be as large as a few 1000 km/s and several Mpc, respectively. According to the diffusive shock acceleration theory, populations of cosmic-ray particles can be injected and accelerated to very high energy by astrophysical shocks in tenuous plasmas. In order to explore the cosmic ray acceleration at the cosmic shocks, we have performed nonlinear numerical simulations of cosmic ray (CR) modified shocks with the newly developed CRASH (Cosmic Ray Amr SHock) numerical code. We adopted the Bohm diffusion model for CRs, based on the hypothesis that strong Alfvén waves are self-generated by streaming CRs. The shock formation simulation includes a plasma-physics-based ``injection'' model that transfers a small proportion of the thermal proton flux through the shock into low energy CRs for acceleration there. We found that, for strong accretion shocks, CRs can absorb most of shock kinetic energy and the accretion shock speed is reduced up to 20 %, compared to pure gas dynamic shocks. For merger shocks with small Mach numbers, however, the energy transfer to CRs is only about 10-20 % with an associated CR particle fraction of 10(-3) . Nonlinear feedback due to the CR pressure is insignificant in the latter shocks. Although detailed results depend on models for the particle diffusion and injection, these calculations show that cosmic shocks in large scale structure could provide acceleration sites of extragalactic cosmic rays of the highest energy.

Kang, Hyesung; Jones, T. W.

2002-12-01

351

SLAC Cosmic Ray Telescope Facility  

SciTech Connect

SLAC does not have a test beam for the HEP detector development at present. We have therefore created a cosmic ray telescope (CRT) facility, which is presently being used to test the FDIRC prototype. We have used it in the past to debug this prototype with the original SLAC electronics before going to the ESA test beam. Presently, it is used to test a new waveform digitizing electronics developed by the University of Hawaii, and we are also planning to incorporate the new Orsay TDC/ADC electronics. As a next step, we plan to put in a full size DIRC bar box with a new focusing optics, and test it together with a final SuberB electronics. The CRT is located in building 121 at SLAC. We anticipate more users to join in the future. This purpose of this note is to provide an introductory manual for newcomers.

Va'vra, J.

2010-02-15

352

A Bayesian Approach to Comparing Cosmic Ray Energy Spectra  

NASA Astrophysics Data System (ADS)

A common problem in ultra-high energy cosmic ray physics is the comparison of energy spectra. The question is whether the spectra from two experiments or two regions of the sky agree within their statistical and systematic uncertainties. We develop a method to directly compare energy spectra for ultra-high energy cosmic rays from two different regions of the sky in the same experiment without reliance on agreement with a theoretical model of the energy spectra. The consistency between the two spectra is expressed in terms of a Bayes factor, defined here as the ratio of the likelihood of the two-parent source hypothesis to the likelihood of the one-parent source hypothesis. Unlike other methods, for example ?2 tests, the Bayes factor allows for the calculation of the posterior odds ratio and correctly accounts for non-Gaussian uncertainties. The latter is particularly important at the highest energies, where the number of events is very small.

BenZvi, S. Y.; Connolly, B. M.; Pfendner, C. G.; Westerhoff, S.

2011-09-01

353

Search for very high energy gamma ray emission from Cygnus X-3  

SciTech Connect

The Haleakala Gamma Ray Telescope is designed to detect very high energy gamma rays by the atmospheric Cherenkov technique, with an energy threshold of approximately 300 GeV. During 1985, approximately 113 hours of observations were conducted on Cygnus X-3. These data were analyzed to search for pulsar-like periodicity and periodicity correlated with the 4.8 hour period seen in x-ray and infrared data. While no periodic structure was detected at any of the aforementioned time scales, long-term averaging indicates gamma ray emission from Cygnus X-3 is present, and is 2-3% of the ambient cosmic ray background.

Szentgyorgyi, A.H.

1986-01-01

354

Sulphur mountain: Cosmic ray intensity records  

SciTech Connect

This book deals with the comic ray intensity registrations at the Sulphur Mountain Cosmic Ray Laboratory. The time series of intensity form a valuable data-set, for studying cosmic ray intensity variations and their dependence on solar activity. The IGY neutron monitor started operating from July 1, 1957 and continued through 1963. Daily mean values are tabulated for the period and these are also represented in plots. This monitor was set up by the National Research Council of Canada.

Venkatesan, D.; Mathews, T.

1985-01-01

355

Radiographic Images Produced by Cosmic-Ray Muons  

SciTech Connect

An application of high energy physics instrumentation is to look for structure or different densities (materials) hidden in a matrix (tons) of material. By tracing muons produced by primary Cosmic Rays, it has been possible to generate a kind of radiographs which shows the inner structure of dense containers, monuments or mountains. In this paper I review the basics principles of such techniques with emphasis in the Sun Pyramid project, carried out by IFUNAM in collaboration with Instituto Nacioanal de Antropologia e Historia.

Alfaro, Ruben [Instituto de Fisica, Universidad Nacional Autonoma de Mexico, Apartado Postal 20-364, 01000, Mexico D.F. (Mexico)

2006-09-25

356

Search for ultra-high-energy cosmic neutrinos with the IceCube neutrino observatory  

NASA Astrophysics Data System (ADS)

A search for extremely-high-energy (EHE) neutrinos with energies greater than 106 GeV has been performed using the data taken with the IceCube detector at the South Pole between May 2010 and May 2012. Two neutrino-induced cascade events are observed passing all the signal search criteria over an expected background of 0.06 events. Energies of the observed two events are estimated to be in the range of 106 ~ 107 GeV. We find no events with energies above 109 GeV in the sample of accumulated effective all-flavor-sum neutrino detection exposure of >= 4.8 × 1016 cm2 sec sr. An upper limit on the neutrino flux in the energy range above 106 GeV is obtained from the observations. The present IceCube data disfavors strong cosmological evolutions of ultra-high-energy cosmic-ray sources such as AGNs associated with radio-loud jets.

Yoshida, Shigeru

2013-05-01

357

Crest - A Balloon-borne Instrument To Measure Cosmic-ray Electrons Above TeV Energies  

Microsoft Academic Search

The observation of high energy (E > 1 TeV) electrons in the cosmic radiation provides important information on the distribution and energetics of local cosmic-ray sources. Galactic cosmic-ray electrons are thought to be shock accelerated in supernova remnants as evident from observations of non-thermal X-rays and TeV gamma rays. Their locally observed energy spectrum above 1 TeV is expected to

Michael Schubnell; T. Anderson; C. Bower; S. Coutu; M. Geske; D. Müller; J. Musser; S. Nutter; G. Tarlé; S. Wakely; A. Yagi

2009-01-01

358

6Li and Gamma Rays: Complementary Constraints on Cosmic-Ray History  

NASA Astrophysics Data System (ADS)

The rare isotope 6Li is made only by cosmic rays, predominantly in ??-->6Li fusion reactions with interstellar medium (ISM) helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays in our Galaxy. The same hadronic cosmic-ray interactions also produce high-energy ?-rays (mostly via pp-->?0-->??). Thus, hadronic ?-rays and 6Li are intimately linked. Specifically, 6Li directly encodes the local cosmic-ray fluence over cosmic time, while extragalactic hadronic ?-rays encode an average cosmic-ray fluence over lines of sight out to the horizon. We examine this link and show how 6Li and ?-rays can be used together to place important model-independent limits on the cosmic-ray history of our Galaxy and the universe. We first constrain ?-ray production from ordinary Galactic cosmic rays, using the local 6Li abundance. We find that the solar 6Li abundance demands an accompanying extragalactic pionic ?-ray intensity that exceeds that of the entire observed extragalactic ?-ray background (EGRB) by a factor of 2-6. Possible explanations for this discrepancy are discussed. We then constrain Li production using recent determinations of the EGRB. We note that cosmic rays created during cosmic structure formation would lead to pre-Galactic Li production, which would act as a ``contaminant'' to the primordial 7Li content of metal-poor halo stars; the EGRB can place an upper limit on this contamination if we attribute the entire EGRB pionic contribution to structure-forming cosmic rays. Unfortunately, the uncertainties in the determination of the EGRB are so large that the present ?-ray data cannot guarantee that the pre-Galactic Li contribution is small compared to primordial 7Li; thus, an improved determination of the EGRB will shed important new light on this issue. Our limits and their more model-dependent extensions will improve significantly with additional observations of 6Li in halo stars and with improved measurements of the EGRB spectrum by GLAST.

Fields, Brian D.; Prodanovi?, Tijana

2005-04-01

359

Cosmic Rays Variations and Human Physiological State  

NASA Astrophysics Data System (ADS)

It was obtained in our previous investigations that geomagnetic activity as an indirect indicator of solar activity correlates with some human physiological and psycho-physiological parameters. A lot of studies indicate that other parameters of space weather like cosmic rays Forbush decreases affect myocardial infarction, brain stroke, car accidents, etc. The purpose of that work was to study the effect of cosmic rays variations on human physiological status. It was established that the decrease in cosmic rays intensity was related to an increase in systolic and diastolic blood pressure and reported subjective psycho-physiological complaints in healthy volunteers.

Dimitrova, S.

2009-12-01

360

Cosmic-Ray Spectra in Interstellar Space  

SciTech Connect

At energies below {approx}300 MeV/nuc our knowledge of cosmic-ray spectra outside the heliosphere is obscured by the energy loss that cosmic rays experience during transport through the heliosphere into the inner solar system. This paper compares measurements of secondary electron-capture isotope abundances and cosmic-ray spectra from ACE with a simple model of interstellar propagation and solar modulation in order to place limits on the range of interstellar spectra that are compatible with both sets of data.

Mewaldt, R.A.; Cummings, A.C.; Davis, A.J.; Leske, R.A.; Stone, E.C. [California Institute of Technology, Pasadena, CA 91126 (United States); Wiedenbeck, M.E. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena CA 91190 (United States); Scott, L.M.; Binns, W.R.; Israel, M.H. [Department of Physics, Washington University, St. Louis MO. 63105 (United States); Rosenvinge, T.T. von [NASA/Goddard Space Flight Center, Greenbelt MD 20771 (United States)

2004-09-15

361

Hard X-Ray and Gamma-Ray Emission Induced by Ultra-High-Energy Protons in Cluster Accretion Shocks  

Microsoft Academic Search

All sufficiently massive clusters of galaxies are expected to be surrounded by strong accretion shocks, where protons can be accelerated to ~1018-1019 eV under plausible conditions. Such protons interact with the cosmic microwave background and efficiently produce very high energy electron-positron pairs, which then radiate synchrotron and inverse Compton emission, peaking respectively at hard X-ray and TeV gamma-ray energies. Characterized

Susumu Inoue; Felix A. Aharonian; Naoshi Sugiyama

2005-01-01

362

Cosmic-ray positrons: are there primary sources?  

Microsoft Academic Search

Galactic cosmic rays consist of primary and secondary particles. Primary cosmic rays are thought to be energized by first order Fermi acceleration processes at supernova shock fronts within our Galaxy. The cosmic rays that eventually reach the Earth from this source are mainly protons and atomic nuclei, but also include electrons. Secondary cosmic rays are created in collisions of primary

Stéphane Coutu; Steven W. Barwick; James J. Beatty; Amit Bhattacharyya; Chuck R. Bower; Christopher J. Chaput; Georgia A. de Nolfo; Michael A. DuVernois; Allan Labrador; Shawn P. McKee; Dietrich Müller; James A. Musser; Scott L. Nutter; Eric Schneider; Simon P. Swordy; Gregory Tarlé; Andrew D. Tomasch; Eric Torbet

1999-01-01

363

Strongly Interacting Neutrinos as the Highest Energy Cosmic Rays: A Quantitative Analysis  

Microsoft Academic Search

Scattering processes in the cosmic microwave background limit the propagation of ultra high energy charged particles in our Universe. For extragalactic proton sources resonant photopion production results in the famous Greisen-Zatsepin-Kuzmin (GZK) cutoff at about 4x10^10 GeV expected in the spectrum observed on Earth. The faint flux of ultra high energy cosmic rays of less than one event per year

Markus Ahlers; Andreas Ringwald; Huitzu Tu

2005-01-01

364

Extraterrestrial High Energy Neutrino Fluxes.  

National Technical Information Service (NTIS)

Using the most recent cosmic ray spectra up to 2x10 to the 20th power eV, production spectra of high energy neutrinos from cosmic ray interactions with interstellar gas and extragalactic interactions of ultrahigh energy cosmic rays with 3K universal backg...

F. W. Stecker

1979-01-01

365

Cosmic rays, supernova, and the origin of ultrahigh energy particles  

SciTech Connect

The acceleration of ultrahigh energy cosmic rays, greater than or equal to10/sup 15 -20/ eV, is still an unsolved problem in high-energy astrophysics. The now classical mechanism of stochastic acceleration of cosmic rays in a strong shock in the interstellar or intergalactic medium is limited in time and dimension for all likely acceleration sites, particularly for the highest energies. Acceleration of cosmic rays across a plasma shock of velocity, ..beta../sub s/ (..beta../sub s/ = v/sub shock//c), requires 1/..beta../sub s/ number of crossings and therefore (1/..beta../sub s/)/sup 2/ number of scatterings for doubling the energy of a particle. This requires a space of the order of 1/..beta../sub s/ x the scattering length, or a multiple of the Larmor radius and hence, the space requirements to cosmic ray acceleration are very many Larmor orbits in dimension, as well as times that are larger by (1/..beta../sub s/)/sup 2/ x t/sub Larmor/. The acceleration of cosmic rays by the shock in the envelope of a Type 1 supernova is reviewed, and the interaction of the accelerated matter with the nearby ISM is considered. The spectrum of relativistic ejected matter is preferentially trapped in the ISM. Further acceleration of each energy group should take place in both the near relativistic shock wave and the compression by the following matter. The possible acceleration of ultrahigh energy cosmic rays in the accretion disk of a near-stationery magnetic neutron star such as Cyg-X3 is another strong possibility. Here the diffusion of magnetic flux radially outwards opposite to the viscous diffusion of mass radially inwards is considered as a likely topology for a unipolar generator acceleration of ultrahigh energy particles.

Colgate, S.A.

1985-01-01

366

Cosmic Rays in the Earth'S Magnetic Field.  

National Technical Information Service (NTIS)

Studies are presented of the behavior of cosmic rays in the earth's magnetic field. It discusses the theory of motion of charged particles in an idealized field model and presents results of trajectory calculations of asymptotic directions and cutoff rigi...

L. I. Dorman V. S. Smirnov M. I. Tyasto

1973-01-01

367

Cosmic ray gradients in the outer heliosphere.  

NASA Astrophysics Data System (ADS)

Pioneer 10 and 11 spacecraft are now probing the outer heliosphere. The authors have used the UCSD instruments on board to study the gradient, and to look at the time and spatial variations of the cosmic ray intensities.

Fillius, W.; Wake, B.; Ip, W.-H.; Axford, I.

1983-08-01

368

Cosmic ray test of INO RPC stack  

NASA Astrophysics Data System (ADS)

The India-based Neutrino Observatory (INO) collaboration is planning to build a 50 kt magnetised iron calorimeter (ICAL) detector using glass Resistive Plate Chambers (RPCs) as active detector elements. A stack of 12 such glass RPCs of 1 m ×1 m in area is tracking cosmic ray muons for over three years. In this paper, we will review the constructional aspects of the stack and discuss the performance of the RPCs using this cosmic ray data.

Bhuyan, M.; Datar, V. M.; Kalmani, S. D.; Lahamge, S. M.; Mondal, N. K.; Nagaraj, P.; Pal, S.; Reddy, L. V.; Redij, A.; Samuel, D.; Saraf, M. N.; Satyanarayana, B.; Shinde, R. R.; Verma, P.

2012-01-01

369

Galactic Cosmic Rays and the Environment  

Microsoft Academic Search

SH.3.6.14 Galactic Cosmic Rays and the Environment G. Cini Castagnoli, G. Bonino, P. Della Monica, C. Taricco Istituto di Cosmogeofisica, CNR, Corso Fiume 4, 10133 Torino, Italy and Dipartimento di Fisica Generale, Università di Torino, Via P. Giuria 1, 10125 Torino Recently Svensmark and Friis-Christensen (1997) reported an indication that the Galactic Cosmic Rays (GCR) modulated by the solar wind

G. Cini Castagnoli

1999-01-01

370

First Search for Point Sources of High Energy Cosmic Neutrinos with the ANTARES Neutrino Telescope  

Microsoft Academic Search

Results are presented of a search for cosmic sources of high energy neutrinos with the ANTARES neutrino telescope. The data were collected during 2007 and 2008 using detector configurations containing between 5 and 12 detection lines. The integrated live time of the analyzed data is 304 days. Muon tracks are reconstructed using a likelihood-based algorithm. Studies of the detector timing

S. Adrián-Martínez; J. A. Aguilar; I. Al Samarai; A. Albert; M. André; M. Anghinolfi; G. Anton; S. Anvar; M. Ardid; A. C. Assis Jesus; T. Astraatmadja; J. J. Aubert; B. Baret; S. Basa; V. Bertin; S. Biagi; A. Bigi; C. Bigongiari; C. Bogazzi; M. Bou-Cabo; B. Bouhou; M. C. Bouwhuis; J. Brunner; J. Busto; F. Camarena; A. Capone; C. Carloganu; G. Carminati; J. Carr; S. Cecchini; Z. Charif; Ph. Charvis; T. Chiarusi; M. Circella; R. Coniglione; H. Costantini; P. Coyle; C. Curtil; M. P. Decowski; I. Dekeyser; A. Deschamps; C. Distefano; C. Donzaud; D. Dornic; Q. Dorosti; D. Drouhin; T. Eberl; U. Emanuele; A. Enzenhöfer; J. P. Ernenwein; S. Escoffier; P. Fermani; M. Ferri; V. Flaminio; F. Folger; U. Fritsch; J. L. Fuda; S. Galatà; P. Gay; G. Giacomelli; V. Giordano; J. P. Gómez-González; K. Graf; G. Guillard; G. Halladjian; G. Hallewell; H. van Haren; J. Hartman; A. J. Heijboer; Y. Hello; J. J. Hernández-Rey; B. Herold; J. Hößl; C. C. Hsu; M. de Jong; M. Kadler; O. Kalekin; A. Kappes; U. Katz; O. Kavatsyuk; P. Kooijman; C. Kopper; A. Kouchner; I. Kreykenbohm; V. Kulikovskiy; R. Lahmann; P. Lamare; G. Larosa; D. Lattuada; D. Lefèvre; G. Lim; D. Lo Presti; H. Loehner; S. Loucatos; S. Mangano; M. Marcelin; A. Margiotta; J. A. Martínez-Mora; A. Meli; T. Montaruli; L. Moscoso; H. Motz; M. Neff; E. Nezri; D. Palioselitis; G. E. Pavalas; K. Payet; P. Payre; J. Petrovic; P. Piattelli; N. Picot-Clemente; V. Popa; T. Pradier; E. Presani; C. Racca; C. Reed; C. Richardt; R. Richter; C. Rivière; A. Robert; K. Roensch; A. Rostovtsev; J. Ruiz-Rivas; M. Rujoiu; G. V. Russo; F. Salesa; D. F. E. Samtleben; P. Sapienza; F. Schöck; J. P. Schuller; F. Schüssler; T. Seitz; R. Shanidze; F. Simeone; A. Spies; M. Spurio; J. J. M. Steijger; Th. Stolarczyk; A. Sánchez-Losa; M. Taiuti; C. Tamburini; S. Toscano; B. Vallage; V. Van Elewyck; G. Vannoni; M. Vecchi; P. Vernin; S. Wagner; G. Wijnker; J. Wilms; E. de Wolf; H. Yepes; D. Zaborov; J. D. Zornoza; J. Zúñiga

2011-01-01

371

Multi-spectra Cosmic Ray Flux Measurement  

NASA Astrophysics Data System (ADS)

The Earth's upper atmosphere is constantly bombarded by rain of charged particles known as primary cosmic rays. These primary cosmic rays will collide with the atmospheric molecules and create extensive secondary particles which shower downward to the surface of the Earth. In recent years, a few studies have been done regarding to the applications of the cosmic ray measurements and the correlations between the Earth's climate conditions and the cosmic ray fluxes [1,2,3]. Most of the particles, which reach to the surface of the Earth, are muons together with a small percentage of electrons, gammas, neutrons, etc. At Georgia State University, multiple cosmic ray particle detectors have been constructed to measure the fluxes and energy distributions of the secondary cosmic ray particles. In this presentation, we will briefly describe these prototype detectors and show the preliminary test results. Reference: [1] K.Borozdin, G.Hogan, C.Morris, W.Priedhorsky, A.Saunders, L.Shultz, M.Teasdale, Nature, Vol.422, 277 (2003). [2] L.V. Egorova, V. Ya Vovk, O.A. Troshichev, Journal of Atmospheric and Terrestrial Physics 62, 955-966 (2000). [3] Henrik Svensmark, Phy. Rev. Lett. 81, 5027 (1998). )

He, Xiaochun; Dayananda, Mathes

2010-02-01

372

Magnetic Experiments on the Cosmic Rays  

Microsoft Academic Search

BOTHE and Kolhörster1 wore the first to show that the cosmic rays manifest themselves to us as highly penetrating corpuscular rays. Direct experimental data on the nature as well as on the energy of these rays are still lacking; they might be obtained by experiments on the magnetic deflection if a sufficiently large and intense magnetic field could bo reached.

Bruno Rossi

1931-01-01

373

Cosmic-ray Helium Hardening  

NASA Astrophysics Data System (ADS)

Recent observations by the CREAM and ATIC-2 experiments suggest that (1) the spectrum of cosmic-ray (CR) helium is harder than that of CR protons below the knee energy, 1015eV, and (2) all CR spectra become hard at gsim1011eV nucleon-1. We propose a new idea, that higher energy CRs are generated in a more helium-rich region, to explain the hardening without introducing different sources for CR helium. The helium-to-proton ratio at ~100 TeV exceeds the Big Bang abundance Y = 0.25 by several times, and the different spectrum is not reproduced within the diffusive shock acceleration theory. We argue that CRs are produced in a chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium if CRs escape from the supernova remnant shock in an energy-dependent way. We provide a simple analytical spectrum that also fits well the hardening due to the decreasing Mach number in the hot superbubble with ~106 K. Our model predicts hard and concave spectra for heavier CR elements.

Ohira, Yutaka; Ioka, Kunihito

2011-03-01

374

Cosmic Rays and Space Weather  

NASA Astrophysics Data System (ADS)

In this review-paper we consider following problems. 1. Cosmic rays (CR) as element of space weather 1.1. Influence of CR on the Earth's atmosphere and global climate change 1.2. Radia-tion hazard from galactic CR 1.3. Radiation hazard from solar CR 1.4. Radiation hazard from energetic particle precipitation from radiation belts 2. CR as tool for space weather forecasting 2.1. Forecasting of the part of global climate change caused by CR intensity variations 2.2. Forecasting of radiation hazard for aircrafts and spacecrafts caused by variations of galactic CR intensity 2.3. Forecasting of the radiation hazard from solar CR events by using on-line one-min ground neutron monitors network and satellite data 2.4. Forecasting of great magnetic storms hazard by using on-line one hour CR intensity data from ground based world-wide network of neutron monitors and muon telescopes 3. CR, space weather, and satellite anomalies 4. CR, space weather, and people health

Dorman, Lev

375

CTA - A New Observatory for Very High Energy Gamma-Ray Observations  

NASA Astrophysics Data System (ADS)

The Cherenkov Telescope Array (CTA) will be a new observatory for the study of very high energy (VHE) gamma-ray sources. It seeks to achieve an order of magnitude improvement in sensitivity in the ~30 GeV to ~100 TeV energy band over currently operating instruments (VERITAS, MAGIC, HESS). CTA will shed new light on the high energy extension of the spectra of Fermi sources, probe the known VHE sources with unprecedented sensitivity and angular resolution, and detect hundreds of new sources. The plans for CTA are presented. The presentation focuses on how CTA will be able to address key science topics such as the indirect detection of dark matter, cosmic ray acceleration, and very high-energy gamma-ray production in blazar jets.

Williams, David A.; Telescope Array, Cherenkov

2013-04-01

376

Record neutron monitor counting rates from galactic cosmic rays  

NASA Astrophysics Data System (ADS)

Neutron monitors have recorded the flux of high-energy Galactic cosmic rays for more than half a century. During the recent, prolonged, deep minimum in solar activity, many sources indicate that modulated Galactic cosmic rays have attained new Space Age highs. However, reported neutron monitor rates are ambiguous; some record new highs while others do not. This work examines the record of 15 long-running neutron monitors to evaluate cosmic ray fluxes during the recent extraordinary solar minimum in a long-term context. We show that ground-level neutron rates did reach a historic high during the recent solar minimum, and we present a new analysis of the cosmic ray energy spectrum in the year 2009 versus year 1987. To do this, we define a reference as the average of eight high-latitude neutron monitors, four in the Northern Hemisphere (Apatity, Inuvik, Oulu, Thule) and four in the Southern Hemisphere (Kerguelen, McMurdo, Sanae, Terre Adelie). Most stations display changes in sensitivity, which we characterize by a simple linear trend. After correcting for the change in sensitivity, a consistent picture emerges. With our correction, all stations considered display new highs at the recent solar minimum, approximately 3% above the previous record high. These increases are shown to be consistent with spacecraft observations.

Oh, Suyeon; Bieber, John W.; Evenson, Paul; Clem, John; Yi, Yu; Kim, Yongkyun

2013-09-01

377

High energy astrophysics  

NASA Astrophysics Data System (ADS)

The origin of cosmic rays is considered along with the interaction of high energy particles with matter. The interactions of high energy photons and electron-photon cascades are discussed, taking into account photoelectric absorption, Compton scattering, pair production, and electron-photon cascades or electromagnetic showers. Attention is given to nuclear interactions, detectors for X-rays and gamma-rays, X-ray and gamma-ray telescopes, plastics and meteorites, cosmic rays at the top of the atmosphere, extensive air showers, the influence of the earth's magnetic field, the solar wind and its influence upon the local flux of cosmic rays, and the dynamics of cosmic rays in the solar wind. Observational optical and radio astronomy is considered along with the Milky Way Galaxy, the large-scale structure of the universe, the evolution of stars, the interstellar gas and magnetic field, synchrotron radiation and the radio emission from the Galaxy, the energy losses and diffusion of cosmic ray electrons under cosmic conditions, cosmic ray protons and nuclei, and the diffusion and confinement of cosmic rays in the Galaxy. Other topics are related to extragalactic sources of cosmic rays and the acceleration of cosmic rays.

Longair, M. S.

378

Determination and study of the cosmic-ray composition above 100 TeV  

SciTech Connect

This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The goal of this project was to develop a new technique using ground-based measurements to determine the cosmic-ray composition at energies around 10{sup 15} eV (the knee in the cosmic-ray spectrum). Cosmic rays are high-energy nuclei that continuously bombard the earth. Though cosmic rays were first detected in the 1870s it wasn`t until 1915 that their cosmic origin was established. At present, the authors still do not know the source of cosmic rays. At energies above 50 TeV (1 TeV = 1 trillion electron-volts) they do not know the composition of the cosmic rays. At about 5 PeV (1PeV = 10{sup 15} eV) the cosmic ray spectrum steepens. Knowledge of the composition above and below this point can help determine the origin of cosmic rays.

Sinnis, G.; Haines, T.J.; Hoffman, C.M. [and others

1998-11-01

379

Astrophysics of Galactic Charged Cosmic Rays  

NASA Astrophysics Data System (ADS)

A review is given of the main properties of the charged component of galactic cosmic rays, particles detected at Earth with an energy spanning from tens of MeV up to about 1019 eV. After a short introduction to the topic and a historical overview, the properties of cosmic rays are discussed with respect to different energy ranges. The origin and the propagation of nuclei in the Galaxy are dealt with from a theoretical point of view. The mechanisms leading to the acceleration of nuclei by supernova remnants and to their subsequent diffusion through the inhomogeneities of the galactic magnetic field are discussed, and some clue is given on the predictions and observations of fluxes of antimatter, both from astrophysical sources and from dark matter annihilation in the galactic halo.The experimental techniques and instrumentations employed for the detection of cosmic rays at Earth are described. Direct methods are viable up to ? 1014 eV, by means of experiments flown on balloons or satellites, while above that energy, due to their very low flux, cosmic rays can be studied only indirectly by exploiting the particle cascades they produce in the atmosphere.The possible physical interpretation of the peculiar features observed in the energy spectrum of galactic cosmic rays, and in particular the so-called "knee" at about 4 ×1015 eV, is discussed. A section is devoted to the region between about 1018 and 1019 eV, which is believed to host the transition between galactic and extragalactic cosmic rays. The conclusion gives some perspectives on the cosmic ray astrophysics field. Thanks to a wealth of different experiments, this research area is living a very flourishing era. The activity is exciting both from the theoretical and the instrumental sides, and its interconnection with astronomy, astrophysics, and particle physics experiences nonstop growth.

Castellina, Antonella; Donato, Fiorenza

380

Cosmic ray neutron induced upsets as a major contributor to the soft error rate of current and future generation DRAMs  

Microsoft Academic Search

The system soft error rate (SSER) of 4M\\/16M DRAMs has been shown to be dependent on the cosmic ray neutron flux. A simple model and accelerated soft error rate (ASER) measurements made with an intense, high energy neutron beam support this result. The model predicts that cosmic ray neutron induced soft errors will become important at the 64M DRAM generation

W. R. McKee; H. P. McAdams; E. B. Smith; J. W. McPherson; J. W. Janzen; J. C. Ondrusek; A. E. Hyslop; D. E. Russell; R. A. Coy; D. W. Bergman; N. Q. Nguyen; T. J. Aton; L. W. Block; V. C. Huynh

1996-01-01

381

THE INTERACTION OF COSMIC RAYS WITH DIFFUSE CLOUDS  

SciTech Connect

We study the change in cosmic-ray pressure, the change in cosmic-ray density, and the level of cosmic-ray-induced heating via Alfven-wave damping when cosmic rays move from a hot ionized plasma to a cool cloud embedded in that plasma. The general analysis method outlined here can apply to diffuse clouds in either the ionized interstellar medium or in galactic winds. We introduce a general-purpose model of cosmic-ray diffusion building upon the hydrodynamic approximation for cosmic rays (from McKenzie and Voelk and Breitschwerdt and collaborators). Our improved method self-consistently derives the cosmic-ray flux and diffusivity under the assumption that the streaming instability is the dominant mechanism for setting the cosmic-ray flux and diffusion. We find that, as expected, cosmic rays do not couple to gas within cool clouds (cosmic rays exert no forces inside of cool clouds), that the cosmic-ray density does not increase within clouds (it may decrease slightly in general, and decrease by an order of magnitude in some cases), and that cosmic-ray heating (via Alfven-wave damping and not collisional effects as for {approx}10 MeV cosmic rays) is only important under the conditions of relatively strong (10 {mu}G) magnetic fields or high cosmic-ray pressure ({approx}10{sup -11} erg cm{sup -3}).

Everett, John E.; Zweibel, Ellen G., E-mail: everett@physics.wisc.edu [Department of Astronomy, University of Wisconsin-Madison, Madison, WI 53706 (United States)

2011-10-01

382

Positron fraction in cosmic rays and models of cosmic-ray propagation  

SciTech Connect

The positron fraction observed by PAMELA and other experiments up to {approx}100 GeV is analyzed in terms of models of cosmic-ray propagation. It is shown that generically we expect the positron fraction to reach {approx}0.6 at energies of several TeV, and its energy dependence bears an intimate but subtle connection with that of the boron to carbon ratio in cosmic rays. The observed positron fraction can be fit in a model that assumes a significant fraction of the boron below {approx}10 GeV is generated through spallation of cosmic-ray nuclei in a cocoonlike region surrounding the sources, and the positrons of energy higher than a few GeV are almost exclusively generated through cosmic-ray interactions in the general interstellar medium. Such a model is consistent with the bounds on cosmic-ray anisotropies and other observations.

Cowsik, R.; Burch, B. [Physics Department and McDonnell Center for the Space Sciences, Washington University, St. Louis, Missouri 63130 (United States)

2010-07-15

383

Diffuse Galactic gamma rays from shock-accelerated cosmic rays.  

PubMed

A shock-accelerated particle flux is proportional to p(-s), where p is the particle momentum, follows from simple theoretical considerations of cosmic-ray acceleration at nonrelativistic shocks followed by rigidity-dependent escape into the Galactic halo. A flux of shock-accelerated cosmic-ray protons with s?2.8 provides an adequate fit to the Fermi Large Area Telescope ?-ray emission spectra of high-latitude and molecular cloud gas when uncertainties in nuclear production models are considered. A break in the spectrum of cosmic-ray protons claimed by Neronov, Semikoz, and Taylor [Phys. Rev. Lett. 108, 051105 (2012)] when fitting the ?-ray spectra of high-latitude molecular clouds is a consequence of using a cosmic-ray proton flux described by a power law in kinetic energy. PMID:23002818

Dermer, Charles D

2012-08-29

384

Shock-Wave and Plasma-Pinch Mechanisms of Galactic Cosmic-Ray Production  

SciTech Connect

Based on recent discoveries, we show that it is appropriate to complement the standard shock-wave model for the production of galactic cosmic rays by a plasma-pinch model. The latter describes well the production of high-energy cosmic rays, yields a simple formula for their intensity, and allows the threshold pattern of the knee-type kink in the secondary particle spectrum and a number of unusual phenomena observed above the threshold to be explained.

Trubnikov, B.A. [Russian Research Centre Kurchatov Institute, pl. Kurchatova 1, Moscow, 123182 (Russian Federation)

2005-07-01

385

Cosmic-ray ionization and chemistry: observations.  

NASA Astrophysics Data System (ADS)

The interaction between cosmic-rays and the dense regions of the ISM has important consequences on the physical and chemical state of the ISM. A major consequence is the ionisation of the ISM. I review here how the cosmic rays ionisation rate zeta is measured in the ISM and the values so far measured in ``average'' galactic clouds. I then discuss new observations in the direction of clouds spatially associated with bright gamma -rays TeV sources. The TeV emission is believed to be caused by the decay of pi 0 pions created by the irradiation of molecular clouds by large fluxes of cosmic rays just produced in SNRs. The measured zeta , enhanced by a factor 100 in at least one case, confirms this hypothesis. In addition, the high zeta causes a peculiar chemistry with the cloud possessing regions in Low and High Ionisation Phases (called LIP and HIP, in the literature), also briefly reviewed in this contribution.

Ceccarelli, C.

386

Quantum field theories, nuclear forces, and the cosmic rays (1934--1938)  

SciTech Connect

During the 1930s, cosmic rays were the most important source of data on the high-energy behavior of both quantum electrodynamics and nuclear forces. In the period 1934--1938, with which this article is concerned, the dominant fundamental theory of nuclear forces was that of the Fermi field. In sorting out the various cosmic-ray phenomena in the atmosphere, it was found that the less penetrating components were associated with electromagnetic cascade showers, and that the more penetrating component contained a new elementary'' particle, the mesotron. However, there remained puzzling features of the cosmic rays that left adequate room for other interpretations.

Brown, L.M. (Northwestern University, Evanston, Illinois 60208 (USA)); Rechenberg, H. (Max-Planck-Institut fuer Physik und Astrophysik and Werner-Heisenberg-Institut fuer Physik, P.O. Box 40 12 12, D-8000, Muenchen 40 (Germany))

1991-07-01

387

School Cosmic Ray Outreach Detector (SCROD)  

NASA Astrophysics Data System (ADS)

We report on our studies of applying novel detector technologies developed for LHC-era experiments to cosmic ray detection. In particular, we are investigating usage of scintillating tiles with embedded wavelength-shifting fibers and avalanche photodiode readout as part of a robust, inexpensive cosmic air shower detector. In the near future, we are planning to deploy detector stations based on this technology at area high schools and colleges as part of an outreach and education effort, known as SCROD.

Anchordoqui, L.; Cook, J.; MacLeod, J.; McCauley, T.; Moussienko, I.; Paul, T.; Reucroft, S.; Swain, J.; Terry, R.

388

Some aspects of galactic cosmic ray acceleration  

NASA Astrophysics Data System (ADS)

I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation. NOTE: figures may be found in the on-line version only: atro-ph/0309758.

Butt, Yousaf Mahmood

2005-01-01

389

Spectra of cosmic rays at TeV energies  

NASA Astrophysics Data System (ADS)

Cosmic rays were discovered 100 years ago with an experiment on a manned balloon that ascended to only ~ 5 km. Current helium-filled balloons for scientific research fly at altitudes around 40 km, carrying state-of-the-art particle detectors to measure TeV cosmic ray elemental spectra over a wide energy range. A challenge of balloon-borne and space-based experiments for high-energy measurements is that the detectors must be large enough to collect adequate statistics, yet stay within the weight limit for available space flight. Innovative approaches now promise high quality measurements over an energy range that was not previously possible. Measurement techniques, recent results and their implications are reviewed. The outlook for existing and future experiments is also discussed.

Seo, Eun-Suk

2013-02-01

390

Cosmic Ray Interactions in Shielding Materials  

SciTech Connect

This document provides a detailed study of materials used to shield against the hadronic particles from cosmic ray showers at Earth’s surface. This work was motivated by the need for a shield that minimizes activation of the enriched germanium during transport for the MAJORANA collaboration. The materials suitable for cosmic-ray shield design are materials such as lead and iron that will stop the primary protons, and materials like polyethylene, borated polyethylene, concrete and water that will stop the induced neutrons. The interaction of the different cosmic-ray components at ground level (protons, neutrons, muons) with their wide energy range (from kilo-electron volts to giga-electron volts) is a complex calculation. Monte Carlo calculations have proven to be a suitable tool for the simulation of nucleon transport, including hadron interactions and radioactive isotope production. The industry standard Monte Carlo simulation tool, Geant4, was used for this study. The result of this study is the assertion that activation at Earth’s surface is a result of the neutronic and protonic components of the cosmic-ray shower. The best material to shield against these cosmic-ray components is iron, which has the best combination of primary shielding and minimal secondary neutron production.

Aguayo Navarrete, Estanislao; Kouzes, Richard T.; Ankney, Austin S.; Orrell, John L.; Berguson, Timothy J.; Troy, Meredith D.

2011-09-08

391

Monopole annihilation and highest energy cosmic rays  

SciTech Connect

Cosmic rays with energies exceeding 10[sup 20] eV have been detected. The origin of these highest energy cosmic rays remains unknown. Established astrophysical acceleration mechanisms encounter severe difficulties in accelerating particles to these energies. Alternative scenarios where these particles are created by the decay of cosmic topological defects have been suggested in the literature. In this paper we study the possibility of producing the highest energy cosmic rays through a process that involves the formation of metastable magnetic monopole-antimonopole bound states and their subsequent collapse. The annihilation of the heavy monopole-antimonopole pairs constituting the monopolonia can produce energetic nucleons, [gamma] rays, and neutrinos whose expected flux we estimate and discuss in relation to experimental data so far available. The monopoles we consider are the ones that could be produced in the early Universe during a phase transition at the grand unification energy scale. We find that observable cosmic ray fluxes can be produced with monopole abundances compatible with present bounds.

Bhattacharjee, P. (Isaac Newton Institute, University of Cambridge, 20 Clarkson Road, Cambridge CB3 0EH (United Kingdom) Indian Institute of Astrophysics, Sarjapur Road, Koramangala, Bangalore 560 034 (India)); Sigl, G. (Department of Astronomy Astrophysics, Enrico Fermi Institute, The University of Chicago, Chicago, Illinois 60637-1433 (United States) NASA/Fermilab Astrophysics Center, Fermi National Accelerator Laboratory, Batavia, Illinois 60510-0500 (United States))

1995-04-15

392

Nuclear composition of 1-to 20-PeV primary cosmic rays according to lateral features of the electron-photon component of all extensive air showers and of extensive air showers accompanying high-energy gamma rays and hadrons in x-ray emulsion chambers at the Tien Shan level  

Microsoft Academic Search

Data from the Tien Shan array Adron on the dependence of the lateral distributions of the electron-photon component (age parameter\\u000a S) in extensive air showers of cosmic rays on the number of electrons, N\\u000a \\u000a e\\u000a , which is a quantity that characterizes the primary-nucleus energy E\\u000a 0, are subjected to a comparative analysis. The distributions in question are given both

N. M. Nesterova; V. P. Pavlyuchenko; A. P. Chubenko; S. B. Shaulov

2003-01-01

393

HESS High-energy astrophysics: Mapping the gamma-ray sky  

NASA Astrophysics Data System (ADS)

The very-high-energy part of the gamma-ray spectrum (energies above a few tens of GeV), is accessible from the ground, using arrays of mirrors and photomultipliers. In addition, these ground-based arrays are big enough to detect even small fluxes of gamma rays, making them sensitive instruments for mapping the gamma-ray sky. The HESS array (High Energy Stereoscopic System; also a reference to Victor Hess, awarded the Nobel Prize for Physics in 1936 for his discovery of cosmic radiation) in Namibia has been working for nearly two years now and has already begun to survey gamma-ray sources such as supernova remnants and the galactic centre, with spectacular results that we summarize here.

Chadwick, Paula

2005-12-01

394

High energy neutrinos from gamma-ray bursts  

Microsoft Academic Search

Observations suggest that ?-ray bursts (GRBs) are produced by the dissipation of the kinetic energy of a relativistic fireball. In this talk, recent work on the production of high energy neutrinos by GRB fireballs is reviewed. A significant fraction of GRB energy is expected to be converted to an accompanying burst of high energy neutrinos. Photomeson interactions produce a burst

Eli Waxman

2001-01-01

395

Muon Production in Relativistic Cosmic-Ray Interactions  

SciTech Connect

Cosmic-rays with energies up to 3x1020 eV have been observed. The nuclear composition of these cosmic rays is unknown but if the incident nuclei are protons then the corresponding center of mass energy is sqrt snn = 700 TeV. High energy muons can be used to probe the composition of these incident nuclei. The energy spectra of high-energy (> 1 TeV) cosmic ray induced muons have been measured with deep underground or under-ice detectors. These muons come from pion and kaon decays and from charm production in the atmosphere. Terrestrial experiments are most sensitive to far-forward muons so the production rates aresensitive to high-x partons in the incident nucleus and low-x partons in the nitrogen/oxygen targets. Muon measurements can complement the central-particle data collected at colliders.This paper will review muon production data and discuss some non-perturbative (soft) models that have been used to interpret the data. I will show measurements of TeV muon transverse momentum (pT) spectra in cosmic-ray air showers fromMACRO, and describe how the IceCube neutrino observatory and the proposed Km3Net detector will extend these measurements to a higher pT region where perturbative QCD should apply. With a 1 km2 surface area, the full IceCube detector should observe hundreds of muons/year with pT in the pQCD regime.

Klein, Spencer

2009-07-27

396

Very High Energy Gamma Ray Extension of GRO Observations.  

National Technical Information Service (NTIS)

This has been an exiciting year for high energy gamma-ray astronomy, both from space and from ground-based observatories. It has been a particularly active period for the Whipple Observatory gamma-ray group. In phase 1 of the Compton Gamma Ray Observatory...

T. C. Weekes

1992-01-01

397

High-energy x-ray production with pyroelectric crystals  

Microsoft Academic Search

The invention of pyroelectric x-ray generator technology has enabled researchers to develop ultraportable, low-power x-ray sources for use in imaging, materials analysis, and other applications. For many applications, the usefulness of an x-ray source is determined by its yield and endpoint energy. In x-ray fluorescence, for example, high-energy sources enable the excitation of the K-shell x-ray peaks for high-Z materials

Jeffrey A. Geuther; Yaron Danon

2005-01-01

398

Positron Abundance in Galactic Cosmic Rays  

NASA Astrophysics Data System (ADS)

On 2000 August 25 from Lynn Lake, Manitoba, we conducted a balloon flight of the LEE/AESOP (Low Energy Electrons/Anti-Electron Sub Orbital Payload) payload to measure the spectrum of cosmic-ray electrons (resolved into negatrons and positrons) from 500 MeV to 3 GeV. Analysis of the data from that flight reveals a significant decrease in the cosmic-ray positron abundance from a level that remained relatively stable throughout the decade of the 1990s. Errors on the new determination are comparatively large due to the low particle fluxes at solar maximum. Nevertheless, the magnitude of the effect is consistent with predictions based on the assumption that cosmic-ray modulation effects with 22 yr periodicity are related simply and directly to charge sign and large-scale structure of the magnetic field embedded in the solar wind.

Clem, John M.; Evenson, Paul A.

2002-03-01

399

Bruno Rossi: Cosmic Ray Research 1929 - 1953  

NASA Astrophysics Data System (ADS)

Bruno Rossi, a fresh PhD from the University of Bologna, arrived in Florence in 1928. He was appointed assistant to Antonio Garbasso, professor of experimental physics. Garbosso at that time was Mayor of Florence. His days of physics were over which gave the young Rossi a freedom to follow any line of research. After some agonizing he came upon research in cosmic rays following the discovery that a large part of the cosmic rays were charged particles. Thus began a long period of creative research. Rossi had all the talents needed, a powerful intellect and the natural ability to construct apparatus that gave clear results for his experiments. I will give some examples of his many discoveries concerning the nature of cosmic rays.

Cronin, Jim

2012-03-01

400

Structure Formation Cosmic Rays: Identifying Observational Constraints  

NASA Astrophysics Data System (ADS)

Shocks that arise from baryonic in-fall and merger events during the structure formation are believed to be a source of cosmic rays. These "structure formation cosmic rays" (SFCRs) would essentially be primordial in composition, namely, mostly made of protons and alpha particles. However, very little is known about this population of cosmic rays. One way to test the level of its presence is to look at the products of hadronic reactions between SFCRs and the ISM. A perfect probe of these reactions would be 6Li. The rare isotope 6Li is produced only by cosmic rays, dominantly in alpha alpha rightarrow 6Li fusion reactions with the ISM helium. Consequently, this nuclide provides a unique diagnostic of the history of cosmic rays. Exactly because of this unique property is 6Li affected most by the presence of an additional cosmic ray population. In turn, this could have profound consequences for the Big-Bang nucleosynthesis: cosmic rays created during cosmic structure formation would lead to pre-Galactic Li production, which would act as a "contaminant" to the primordial 7Li content of metal-poor halo stars. Given the already existing problem of establishing the concordance between 7Li observed in halo stars and primordial 7Li as predicted by the WMAP, it is crucial to set limits to the level of this "contamination". However, the history of SFCRs is not very well known. Thus we propose a few model- independent ways of testing the SFCR species and their history, as well as the existing lithium problem: 1) we establish the connection between gamma-ray and 6Li production, which enables us to place constraints on the SFCR-made lithium by using the observed Extragalactic Gamma-Ray Background (EGRB); 2) we propose a new site for testing the primordial and SFCR-made lithium, namely, low-metalicity High-Velocity Clouds (HVCs), which retain the pre-Galactic composition without any significant depletion. Although using one method alone may not give us strong constraints, using them in concert will shed a new light on the SFCR population and possibly give some answers about the pressing lithium problem.

Prodanovic, T.; Fields, B. D.

2005-06-01

401

The attenuation length of the high energy nucleonic component of the cosmic radiation near sea level  

Microsoft Academic Search

Summary  From the analysis of neutron data obtained at two widely separated stations, it is shown that during 1957 the attenuation\\u000a length of the high energy nucleonic component of the cosmic radiation near sea level was (138.1±0.8) g cm?2 at high geomagnetic latitudes. Analysis of data from a number of stations shows that the amplitudes of Forbush type decreases\\u000a increase by

K. G. McCracken; D. H. Johns

1959-01-01

402

Direct observations of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

The mysterious " radiation ... entering our atmosphere from above" discovered by Hess in 1912 is now known to be dominated by relativistic charged particles, mostly with energies in the GeV-range, but extending to energies higher by many orders of magnitude. As none of these particles can penetrate the earth's atmosphere without interaction, detailed studies of their composition and energy spectra require observations with high-altitude balloons or spacecraft. This became possible only towards the middle of the 20th century. The direct measurements have now revealed much detail about the Galactic cosmic rays below 1015eV, but do not yet provide much overlap with the air-shower region of energies. A historic overview of the measurements is given, beginning with the realization that the majority of the cosmic rays are protons. The discovery and astrophysical significance of the heavier nuclei, and of the ultra-heavy nuclei beyond iron and up to the actinides, are then described, and measurements of the isotopic composition are discussed. Observations of the individual energy spectra are reviewed, and finally, the detection of electrons, positrons, and anti-protons in the cosmic rays, and the searches for exotic or unusual phenomena are summarized. Emphasis is given to the fact that all of these discoveries have become possible through the evolution of increasingly sophisticated detection techniques, a process that is continuing through the present time. The precise knowledge of the abundance distributions of the elements in the cosmic rays and of their isotopic composition permits a comparison with the "universal abundance scale" and provides strong constraints on the origin of the cosmic-ray material in the interstellar medium. "Clock-isotopes" reveal the time history of the particles. The shapes of the energy spectra of the individual cosmic-ray components are related to evolving ideas about particle acceleration and propagation in the Galaxy. In conclusion, prospects for future work are briefly discussed.

Müller, Dietrich

2012-08-01

403

Energy Spectrum of Cosmic-Ray Electrons at TeV Energies  

Microsoft Academic Search

The very large collection area of ground-based gamma-ray telescopes gives them a substantial advantage over balloon or satellite based instruments in the detection of very-high-energy (>600GeV) cosmic-ray electrons. Here we present the electron spectrum derived from data taken with the High Energy Stereoscopic System (H.E.S.S.) of imaging atmospheric Cherenkov telescopes. In this measurement, the first of this type, we are

F. Aharonian; A. G. Akhperjanian; U. Barres de Almeida; A. R. Bazer-Bachi; Y. Becherini; B. Behera; W. Benbow; K. Bernlöhr; C. Boisson; A. Bochow; V. Borrel; I. Braun; E. Brion; J. Brucker; P. Brun; R. Bühler; T. Bulik; I. Büsching; T. Boutelier; S. Carrigan; P. M. Chadwick; A. Charbonnier; R. C. G. Chaves; A. Cheesebrough; L.-M. Chounet; A. C. Clapson; G. Coignet; L. Costamante; M. Dalton; B. Degrange; C. Deil; H. J. Dickinson; A. Djannati-Ataï; W. Domainko; L. O.'C. Drury; F. Dubois; G. Dubus; J. Dyks; M. Dyrda; K. Egberts; D. Emmanoulopoulos; P. Espigat; C. Farnier; F. Feinstein; A. Fiasson; A. Förster; G. Fontaine; M. Füßling; S. Gabici; Y. A. Gallant; L. Gérard; B. Giebels; J. F. Glicenstein; B. Glück; P. Goret; C. Hadjichristidis; D. Hauser; M. Hauser; S. Heinz; G. Heinzelmann; G. Hermann; J. A. Hinton; A. Hoffmann; W. Hofmann; M. Holleran; S. Hoppe; D. Horns; A. Jacholkowska; O. C. de Jager; I. Jung; K. Katarzynski; S. Kaufmann; E. Kendziorra; M. Kerschhaggl; D. Khangulyan; B. Khélifi; D. Keogh; Nu. Komin; K. Kosack; G. Lamanna; J.-P. Lenain; T. Lohse; V. Marandon; J. M. Martin; O. Martineau-Huynh; A. Marcowith; D. Maurin; T. J. L. McComb; C. Medina; R. Moderski; E. Moulin; M. Naumann-Godo; M. de Naurois; D. Nedbal; D. Nekrassov; J. Niemiec; S. J. Nolan; S. Ohm; J.-F. Olive; E. de Oña Wilhelmi; K. J. Orford; J. L. Osborne; M. Ostrowski; M. Panter; G. Pedaletti; G. Pelletier; P.-O. Petrucci; S. Pita; G. Pühlhofer; M. Punch; A. Quirrenbach; B. C. Raubenheimer; M. Raue; S. M. Rayner; M. Renaud; F. Rieger; J. Ripken; L. Rob; S. Rosier-Lees; G. Rowell; B. Rudak; C. B. Rulten; J. Ruppel; V. Sahakian; A. Santangelo; R. Schlickeiser; F. M. Schöck; R. Schröder; U. Schwanke; S. Schwarzburg; S. Schwemmer; A. Shalchi; J. L. Skilton; H. Sol; D. Spangler; L. Stawarz; R. Steenkamp; C. Stegmann; G. Superina; P. H. Tam; J.-P. Tavernet; R. Terrier; O. Tibolla; C. van Eldik; G. Vasileiadis; C. Venter; J. P. Vialle; P. Vincent; M. Vivier; H. J. Völk; F. Volpe; S. J. Wagner; M. Ward; A. A. Zdziarski; A. Zech

2008-01-01

404

Cosmic-ray Muon Flux In Belgrade  

SciTech Connect

Two identical plastic scintillator detectors, of prismatic shape (50x23x5)cm similar to NE102, were used for continuous monitoring of cosmic-ray intensity. Muon {delta}E spectra have been taken at five minute intervals, simultaneously from the detector situated on the ground level and from the second one at the depth of 25 m.w.e in the low-level underground laboratory. Sum of all the spectra for the years 2002-2004 has been used to determine the cosmic-ray muon flux at the ground level and in the underground laboratory.

Banjanac, R.; Dragic, A.; Jokovic, D.; Udovicic, V. [Institute of Physics, University of Belgrade, Belgrade (Serbia and Montenegro); Puzovic, J.; Anicin, I. [Faculty of Physics, University of Belgrade, Belgrade (Serbia and Montenegro)

2007-04-23

405

Cosmic Ray physics with ARGO-YBJ  

NASA Astrophysics Data System (ADS)

The ARGO-YBJ experiment has been in stable data taking from November 2007 till February 2013 at the Yang-BaJing Cosmic Ray Laboratory (Tibet, P.R.China, 4300 m a.s.l.). It exploits the full coverage and the high altitude to detect air showers with an energy threshold as low as a few hundred GeV. The detector is made of a single layer of RPCs operated in streamer mode, fully instrumenting a central carpet of about 5800 m. A guard ring extends the partially instrumented area to about 11,000 m. The main results so far achieved on Cosmic Ray physics are reported.

Iacovacci, M.

2013-06-01

406

Cosmic Rays, Carbon Dioxide, and Climate  

NASA Astrophysics Data System (ADS)

Several recent papers have applied correlation analysis to climate-related time series in the hope of finding evidence for causal relationships. For a critical discussion of correlations between solar variability, cosmic rays, and cloud cover, see Laut [2003]. A prominent new example is a paper by Shaviv and Veizer [2003], which claims that fluctuations in cosmic ray flux reaching the Earth can explain 66