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1

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

2

Cosmic very high-energy gamma rays  

Microsoft Academic Search

The article gives a brief overview, aimed at nonspecialists, about the goals and selected recent results of the detection of very-high energy gamma-rays (energies above 100 GeV) with ground based detectors. The stress is on the physics questions, especially the origin of Galactic Cosmic Rays and the emission of TeV gamma-radiation from active galaxies. Moreover some particle-physics questions which are

R. Plaga

1998-01-01

3

Terrestrial effects of high energy cosmic rays  

NASA Astrophysics Data System (ADS)

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 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. The muon flux dominates the radiation dose from cosmic rays causing damage to DNA and an increase in mutation rates and cancer, which can have serious biological implications for surface and sub-surface life. Using CORSIKA, we perform massive computer simulations and construct lookup tables for 10 GeV - 1 PeV primaries, which can be used to quantify these effects from enhanced cosmic ray exposure to any astrophysical source. These tables are freely available to the community and can be used for other studies. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. Increased radiation dose from muons could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

Atri, Dimitra

4

Active Galactic Nuclei:. Sources for Ultra High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Ultra high energy cosmic ray events presently show a spectrum, which we interpret here as galactic cosmic rays due to a starburst, in the radio galaxy Cen A which is pushed up in energy by the shock of a relativistic jet. The knee feature and the particles with energy immediately higher in galactic cosmic rays then turn into the bulk of ultra high energy cosmic rays. This entails that all ultra high energy cosmic rays are heavy nuclei. This picture is viable if the majority of the observed ultra high energy events come from the radio galaxy Cen A, and are scattered by intergalactic magnetic fields across much of the sky.

Biermann, P. L.; Becker, J. K.; Caramete, L.; Gergely, L.; Mari?, I. C.; Meli, A.; de Souza, V.; Stanev, T.

5

Terrestrial Effects of High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

On geological timescales, the Earth is likely to be exposed to an increased 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 charged secondary particles. Increased ionization could lead to changes in atmospheric chemistry, resulting in ozone depletion. This could increase the flux of solar UVB radiation at the surface, which is potentially harmful to living organisms. Increased ionization affects the global electrical circuit can could possibly enhance the low-altitude cloud formation rate. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the biological radiation dose. The muon flux dominates radiation dose from cosmic rays causing DNA damage and increase in the mutation rates, which can have serious biological implications for terrestrial and sub-terrestrial life. This radiation dose is an important constraint on the habitability of a planet. Using CORSIKA, we perform massive computer simulations and construct lookup tables from 10 GeV - 1 PeV primaries (1 PeV - 0.1 ZeV in progress), which can be used to quantify these effects. These tables are freely available to the community and can be used for other studies, not necessarily relevant to Astrobiology. We use these tables to study the terrestrial implications of galactic shock generated by the infall of our galaxy toward the Virgo cluster. This could be a possible mechanism explaining the observed periodicity in biodiversity in paleobiology databases.

Atri, Dimitra

2011-01-01

6

High energy physics in cosmic rays  

NASA Astrophysics Data System (ADS)

In the first half-century of cosmic ray physics, the primary research focus was on elementary particles; the positron, pi-mesons, mu-mesons, and hyperons were discovered in cosmic rays. Much of this research was carried out at mountain elevations; Pic du Midi in the Pyrenees, Mt. Chacaltaya in Bolivia, and Mt. Evans/Echo Lake in Colorado, among other sites. In the 1960s, claims of the observation of free quarks, and satellite measurements of a significant rise in p-p cross sections, plus the delay in initiating accelerator construction programs for energies above 100 GeV, motivated the Michigan-Wisconsin group to undertake a serious cosmic ray program at Echo Lake. Subsequently, with the succession of higher energy accelerators and colliders at CERN and Fermilab, cosmic ray research has increasingly focused on cosmology and astrophysics, although some groups continue to study cosmic ray particle interactions in emulsion chambers.

Jones, Lawrence W.

2013-02-01

7

High energy physics in cosmic rays  

SciTech Connect

In the first half-century of cosmic ray physics, the primary research focus was on elementary particles; the positron, pi-mesons, mu-mesons, and hyperons were discovered in cosmic rays. Much of this research was carried out at mountain elevations; Pic du Midi in the Pyrenees, Mt. Chacaltaya in Bolivia, and Mt. Evans/Echo Lake in Colorado, among other sites. In the 1960s, claims of the observation of free quarks, and satellite measurements of a significant rise in p-p cross sections, plus the delay in initiating accelerator construction programs for energies above 100 GeV, motivated the Michigan-Wisconsin group to undertake a serious cosmic ray program at Echo Lake. Subsequently, with the succession of higher energy accelerators and colliders at CERN and Fermilab, cosmic ray research has increasingly focused on cosmology and astrophysics, although some groups continue to study cosmic ray particle interactions in emulsion chambers.

Jones, Lawrence W. [University of Michigan, Ann Arbor, Michigan (United States)

2013-02-07

8

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

9

Very High Energy Cosmic Rays and Their Interactions  

NASA Astrophysics Data System (ADS)

The investigation of high energy cosmic rays and their interactions is a very active field of research. This article summarizes the progress made during the last years as reflected by the contributions to the XIII International Symposium on Very High Energy Cosmic Ray Interactions held in Pylos, Greece.

Engel, Ralph

2006-01-01

10

Origin and propagation of extremely high-energy cosmic rays  

Microsoft Academic Search

Cosmic-ray particles with energies in excess of 1020eV have been detected. The sources as well as the physical mechanism(s) responsible for endowing cosmic-ray particles with such enormous energies are unknown. This report gives a review of the physics and astrophysics associated with the questions of origin and propagation of these extremely high-energy (EHE) cosmic-rays in the Universe. After a brief

Pijushpani Bhattacharjee; Guenter Sigl

2000-01-01

11

High energy cosmic ray iron spectrum experiment  

NASA Technical Reports Server (NTRS)

An instrument containing a gas Cerenkov counter and an iron ionization spectrometer was constructed in order to measure the cosmic-ray iron spectrum to 300 GeV/nucleon. Trajectories of particles were determined by entopistic or position-determining scintillator systems. The geometric factors with and without the gas Cerenkov counter were 0.3 and 0.6 sq m-ster, respectively. The instrument was successfully flown in June 1976 without the spectrometer and in October 1976 with the spectrometer from Palestine, Texas. The June flight yielded 14.5 h of data; the October flight, 25 h.

Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Schmidt, W. K. H.; Simon, M.; Spiegelhauer, H.

1978-01-01

12

High Energy Cosmic Electrons: Messengers from Nearby Cosmic Ray Sources or Dark Matter?  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the recent discoveries by the Large Area Telescope (LAT) and the Gamma-ray Burst Monitor (GBM) on board the Fermi Gamma-Ray Telescope in reference to high energy cosmic electrons, and whether their source is cosmic rays or dark matter. Specific interest is devoted to Cosmic Ray electrons anisotropy,

Moiseev, Alexander

2011-01-01

13

Some methods in high energy cosmic ray measurement  

NASA Technical Reports Server (NTRS)

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.

1980-01-01

14

Ionization of High Energy Cosmic-Ray Electrons  

Microsoft Academic Search

The ionization produced by high energy cosmic-ray electrons has been measured in a cloud chamber in order to determine whether the probable ionization produced by a high velocity particle continues to rise logarithmically with the energy, or whether it takes on a constant value as has been predicted theoretically. A lateral clearing field was arranged so that the ionization could

Evans Hayward

1947-01-01

15

Topological defects and ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

The observation of ultra-high-energy cosmic rays (UHECR) with energies above 1011 GeV poses a serious challenge to the particle acceleration mechanisms so far proposed. This fact has motivated the search for non-acceleration models, in which the high energy cosmic rays are produced by the decay of a very heavy particle. Topological defects are attractive candidates for this scenario. Due to their topological stability these objects can retain their energy for very long times and release quanta of their constituents, typically with GUT scale masses, which in turn decay to produce the UHECR. In the present thesis we study in detail several scenarios involving different topological defects. The first part of the thesis is devoted to ordinary cosmic string scenarios, in particular, cusp evaporation and direct particle emission. We analyze these models by using numerical simulations and conclude that they are not able to account for the flux of ultra-high energy cosmic ray observed. We then consider superconducting string models, especially in connection with cusp-like regions with chiral (null) currents. We calculate the electromagnetic radiation emitted from these regions and the formation of stable loops by self-intersection of the string near the cusp. This process could have interesting consequences for cosmic ray production. Finally, we present a different scenario in which very massive monopoles (m ~ 1014 GeV) are bound by a light string formed at approximately 300 GeV. These monopoles do not have the usual magnetic charge, or in fact any unconfined flux. Gravitational radiation is the only significant energy-loss mechanism for the bound systems. Their lifetimes can then be comparable with the age of the universe, and their final annihilation will then contribute to the high energy end of the cosmic ray spectrum.

Blanco-Pillado, Jose Juan

2001-08-01

16

Cosmic strings and ultra-high energy cosmic rays  

NASA Technical Reports Server (NTRS)

The flux is calculated of ultrahigh energy protons due to the process of cusp evaporation from cosmic string loops. For the standard value of the dimensionless cosmic string parameter epsilon is identical to G(sub mu) approx. = 10(exp -6), the flux is several orders of magnitude below the observed cosmic ray flux of ultrahigh energy protons. However, the flux at any energy initially increases as the value of epsilon is decreased. This at first suggests that there may be a lower limit on the value of epsilon, which would imply a lower limit on the temperature of a cosmic string forming phase transition in the early universe. However, the calculation shows that this is not the case -- the particle flux at any energy reaches its highest value at epsilon approx. = 10(exp -15) and it then decreases for further decrease of the value of epsilon. This is due to the fact that for too small values of epsilon (less than 10(exp -15)), the energy loss of the loops through the cusp evaporation process itself (rather than gravitational energy loss of the loops) becomes the dominant factor that controls the behavior of the number density of the loops at the relevant times of emission of the particles. The highest flux at any energy remains at least four orders of magnitude below the observed flux. There is thus no lower limit on epsilon.

Bhattacharjee, Pijushpani

1989-01-01

17

Ultra-high energy cosmic rays: Setting the stage  

NASA Astrophysics Data System (ADS)

The history of ultra-high energy cosmic ray physics is reviewed from the post-war era of arrays such as Volcano Ranch, Haverah Park and Akeno to the development of air-fluorescence and current hybrid arrays. The aim of this paper is to present the background information needed for a better understanding of the current issues in this field that are discussed in much greater depth in the rest of this conference.

Sokolsky, P.

2013-06-01

18

TESTING THE ORIGIN OF HIGH-ENERGY COSMIC RAYS  

SciTech Connect

Recent accurate measurements of cosmic-ray (CR) protons and nuclei by ATIC-2, CREAM, and PAMELA reveal (1) unexpected spectral hardening in the spectra of CR species above a few hundred GeV per nucleon, (2) a harder spectrum of He compared to protons, and (3) softening of the CR spectra just below the break energy. These newly discovered features may offer a clue to the origin of the observed high-energy Galactic CRs. We discuss possible interpretations of these spectral features and make predictions for the secondary CR fluxes and secondary-to-primary ratios, anisotropy of CRs, and diffuse Galactic {gamma}-ray emission in different phenomenological scenarios. Our predictions can be tested by currently running or near-future high-energy astrophysics experiments.

Vladimirov, A. E.; Moskalenko, I. V.; Porter, T. A. [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States); Johannesson, G. [Science Institute, University of Iceland, Dunhaga 5, IS-107 Reykjavik (Iceland)

2012-06-10

19

Testing the Origin of High-energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Recent accurate measurements of cosmic-ray (CR) protons and nuclei by ATIC-2, CREAM, and PAMELA reveal (1) unexpected spectral hardening in the spectra of CR species above a few hundred GeV per nucleon, (2) a harder spectrum of He compared to protons, and (3) softening of the CR spectra just below the break energy. These newly discovered features may offer a clue to the origin of the observed high-energy Galactic CRs. We discuss possible interpretations of these spectral features and make predictions for the secondary CR fluxes and secondary-to-primary ratios, anisotropy of CRs, and diffuse Galactic ?-ray emission in different phenomenological scenarios. Our predictions can be tested by currently running or near-future high-energy astrophysics experiments.

Vladimirov, A. E.; Jóhannesson, G.; Moskalenko, I. V.; Porter, T. A.

2012-06-01

20

Ultra-high energy cosmic rays: Observational results  

NASA Astrophysics Data System (ADS)

The study of ultra-high energy cosmic rays has experienced a jump in statistics as well as improved instrumentation. The number of detected cosmic rays has increased by more than a factor of ten over the past decade, and measurements are checked using multiple detection techniques. The energy spectrum clearly has a spectral hardening known as "the ankle" and also a "GZK-like" downturn above 1019.5 eV. Evidence of trans-GZK arrival directions correlating with AGNs and/or the large-scale matter distribution within the GZK sphere has not been confirmed so far. More data are needed to verify and understand that anisotropy. A search for neutron fluxes from discrete sources in the Galaxy has yielded no detection, and the neutron flux upper limits constrain models for EeV proton production. Additional constraint has come from measuring the first harmonic in right ascension of the cosmic ray arrival directions, which has yielded upper limits below 2% at energies up to 2 EeV.

Sommers, Paul

2012-12-01

21

Active Galactic Nuclei: Sources for ultra high energy cosmic rays?  

NASA Astrophysics Data System (ADS)

>The origin of ultra high energy cosmic rays promises to lead us to a deeper understanding of the structure of matter. This is possible through the study of particle collisions at center-of-mass energies in interactions far larger than anything possible with the Large Hadron Collider, albeit at the substantial cost of no control over the sources and interaction sites. For the extreme energies we have to identify and understand the sources first, before trying to use them as physics laboratories. Here we describe the current stage of this exploration. The most promising contenders as sources are radio galaxies and gamma ray bursts. The sky distribution of observed events yields a hint favoring radio galaxies. Key in this quest are the intergalactic and galactic magnetic fields, whose strength and structure are not yet fully understood. Current data and statistics do not yet allow a final judgement. We outline how we may progress in the near future.

Biermann, Peter L.; Becker, Julia K.; Caramete, Lauren?iu; Curu?iu, Alex; Engel, Ralph; Falcke, Heino; Gergely, László Á.; Isar, P. Gina; Mari?, Ioana C.; Meli, Athina; Kampert, Karl-Heinz; Stanev, Todor; Ta?c?u, Oana; Zier, Christian

2009-05-01

22

Development of Ultra High-Energy Cosmic Ray Research  

NASA Astrophysics Data System (ADS)

The discovery of extensive air showers by Rossi, Schmeiser, Bothe, Kolhörster and Auger at the end of the 1930s, facilitated by the coincidence technique of Bothe and Rossi, led to fundamental contributions in the field of cosmic ray physics and laid the foundation for high-energy particle physics. Soon after World War II a cosmic ray group at MIT in the USA pioneered detailed investigations of air shower phenomena and their experimental skill laid the foundation for many of the methods and much of the instrumentation used today. Soon interests focused to the highest energies requiring much larger detectors to be operated. The first detection of air fluorescence light by Japanese and US groups in the early 1970s marked an important experimental breakthrough towards this end as it allowed huge volumes of atmosphere to be monitored by optical telescopes. Radio observations of air showers, pioneered in the 1960s, are presently experiencing a renaissance and may revolutionise the field again. In the last 7 decades the research has seen many ups but also a few downs. However, the example of the Cygnus X-3 story demonstrated that even non-confirmable observations can have a huge impact by boosting new instrumentation to make discoveries and shape an entire scientific community.

Kampert, Karl-Heinz; Watson, Alan A.

23

High-Energy cosmic rays and neutrinos from gamma-ray bursts  

NASA Astrophysics Data System (ADS)

A complete model for the origin of high-energy ( 1014 eV) cosmic rays from gamma-ray bursts (GRBs) and implications of this hypothesis are described. Detection of high-energy neutrinos from GRBs provide an unambiguous test of the model. Evidence for cosmic-ray acceleration in GRBs is suggested by the detection of anomalous ?-ray components such as that observed from GRB 941017. Neutron ?-decay halos around star-forming galaxies such as the Milky Way are formed as a consequence of this model. Cosmic rays from GRBs in the Galaxy are unlikely to account for the ˜ 1018 eV cosmic-ray excess reported by the Sydney University Giant Air Shower Recorder (SUGAR), but could contribute to past extinction events.

Dermer, C.

2005-07-01

24

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

25

The high energy cosmic ray detector for Spacelab II  

NASA Technical Reports Server (NTRS)

A large cosmic ray detector to be flown on Spacelab II is presently under construction at the University of Chicago. The instrument, with a geometric factor of 5 sq m-ster, is designed to measure the elemental composition and the energy spectra of individual cosmic ray nuclei (Li to Fe) from 50 GeV/nucleon to several TeV/nucleon. Plastic scintillators are used for charge determination, and gas Cerenkov and transition radiation detectors for energy measurements. The instrument and its functions are described, and several test results that are important for an optimum design are discussed.

Lamport, J. E.; Lheureux, J.; Meyer, P.; Muller, D.

1980-01-01

26

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

27

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

28

High-energy cosmic rays and neutrinos from semirelativistic hypernovae  

Microsoft Academic Search

The origin of the ultrahigh-energy (UHE) cosmic rays (CRs) from the second knee (˜6×1017eV) 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

Xiang-Yu Wang; Soebur Razzaque; Peter Mészáros; Zi-Gao Dai

2007-01-01

29

Electron calibration of a high energy cosmic ray detector  

NASA Technical Reports Server (NTRS)

The spectrum of cosmic ray electrons above 10 GeV was studied extensively. The spectrum is predicted to steepen at an energy which is related to the lifetime of electrons in the interstellar medium against losses due to inverse Compton collisions with photons and to synchrotron radiation in galactic magnetic fields. The experimental results diverge widely; the lack of agreement between the various measurements is due to a variety of experimental problems.

Simnett, G. M.; Silverberg, R. F.; Crannell, C. J.; Gearhart, R. A.; Hagen, F. A.; Jones, W. V.; Kurz, R. J.; Ormes, J. F.; Price, R. D.

1972-01-01

30

Possible cosmological origin of the ultra high energy cosmic rays  

SciTech Connect

Using improved spectrum evolution results for nucleons propagation through the 3/sup 0/K microwave background we present a model of the UHE cosmic rays, above 10/sup 18/ eV, assuming a universal cosmological component associated with bright phase activity and a semi-local component associated with the Virgo cluster. The results for the spectrum and anisotropy are in good agreement with the Haverah Park EAS observations. An unambiguous and potentially detectable electron neutrino spectrum is derived.

Hill, C.T.

1984-04-01

31

Relativistic waves raised by explosions in space as sources of ultra-high-energy cosmic rays  

Microsoft Academic Search

The paper discusses the possibility of particle acceleration up to high energies in relativistic waves generated by various explosive processes in the interstellar medium. We propose to use the surfatron mechanism of acceleration (surfing) of charged particles trapped in the front of relativistic waves as a generator of high-energy cosmic rays (CRs). Conditions under which surfing in the waves under

G. N. Kichigin

32

Cosmic ray composition measurements and high energy ionization spectrometers  

NASA Technical Reports Server (NTRS)

Element abundances of cosmic rays Li through Si with energy above 0.8 GeV/amu were measured on a balloon borne instrument containing a total absorption ionization spectrometer. Statistical techniques were used to analyze the five measurements of each particle to determine its charge and energy. The technique allows a determination of systematic errors to be made. Corrections for Landau fluctuations, spark chamber inefficiency, and background particles were included. Comparison with other published results is made. Differences in the shape of the spectrum determined from measurements of different workers indicate that the absolute intensity is still known to only plus or minus 15% between 2 and 10 GV/c rigidity.

Arens, J. F.; Ormes, J. F.

1974-01-01

33

Contribution from individual nearby sources to the spectrum of high-energy cosmic-ray electrons  

NASA Astrophysics Data System (ADS)

In the last few years, very important data on high-energy cosmic-ray electrons and positrons from high-precision space-born and ground-based experiments have attracted a great deal of interest. These particles represent a unique probe for studying local comic-ray accelerators because they lose energy very rapidly. These energy losses reduce the lifetime so drastically that high-energy cosmic-ray electrons can attain the Earth only from rather local astrophysical sources. This work aims at calculating, by means of Monte Carlo simulation, the contribution from some known nearby astrophysical sources to the cosmic-ray electron/positron spectra at high energy (?10 GeV). The background to the electron energy spectrum from distant sources is determined with the help of the GALPROP code. The obtained numerical results are compared with a set of experimental data.

Sedrati, R.; Attallah, R.

2014-04-01

34

Superluminal Particles and High-energy Cosmic Rays  

Microsoft Academic Search

Lorentz symmetry has been tested at low energy with great accuracy, but its extrapolation to very high-energy phenomena is much less well established. We expect a possible breaking of Lorentz symmetry to be a very high energy and very short distance phenomenon, compatible with existing data. If textbook special relativity is only an approximate property of the equations describing a

Luis Gonzalez-Mestres

1997-01-01

35

Plasma Effects on Extragalactic Ultra-high-energy Cosmic Ray Hadron Beams in Cosmic Voids  

NASA Astrophysics Data System (ADS)

The linear instability of an ultrarelativistic hadron beam (? b ? 106) in the unmagnetized intergalactic medium (IGM) is investigated with respect to the excitation of collective electrostatic and aperiodic electromagnetic fluctuations. This analysis is important for the propagation of extragalactic ultrarelativistic cosmic rays (E > 1015 eV) from their distant sources to Earth. We calculate minimum instability growth times that are orders of magnitude shorter than the cosmic ray propagation time in the IGM. Due to nonlinear effects, especially the modulation instability, the cosmic ray beam stabilizes and can propagate with nearly no energy loss through the IGM.

Krakau, S.; Schlickeiser, R.

2014-07-01

36

High-energy galactic gamma radiation from cosmic rays concentrated in spiral arms  

NASA Technical Reports Server (NTRS)

A model for the emission of high-energy (exceeding 100 Mev) gamma-rays from the galactic disk has been developed and compared with recent SAS-2 observations. In the calculation, it is assumed that (1) the high energy galactic gamma-rays result primarily from the interaction of cosmic rays with galactic matter, (2) the cosmic-ray density is proportional to the matter density on the scale of galactic arms, and (3) the matter in the Galaxy is distributed in a spiral pattern consistent with density-wave theory and experimental data on the matter distribution that is available, including the 21-cm H I line emission, continuum emission from H II regions, and data currently being used to estimate the H2 density. The calculated galactic-longitude distribution of gamma rays is in good agreement with the SAS-2 observations in relative shape and absolute flux. As a corollary, the nonuniform cosmic-ray distribution of this model tends to support the galactic origin of the fraction of cosmic rays which is important in the production of high-energy photons. Modifications of the basic model show that the gamma-ray flux is relatively sensitive to large variations of the assumed distribution of molecular hydrogen in the Galaxy.

Bignami, G. F.; Fichtel, C. E.; Kniffen, D. A.; Thompson, D. J.

1975-01-01

37

On the Excess of Ultra-high Energy Cosmic Rays in the Direction of Centaurus A  

NASA Astrophysics Data System (ADS)

A posteriori anisotropy study of ultra-high energy cosmic rays (UHECRs) with the Pierre Auger Observatory (PAO) has shown evidence of an excess of cosmic-ray particles above 55 EeV within 18° of the direction of the radio galaxy Centaurus A. However, the origin of the excess remains elusive. We simulate the propagation of different species of particles coming from the direction of Centaurus A in the Galactic magnetic fields and find that only particles of nuclear charge Z <~ 10 can avoid being deflected outside of the 18° window of Centaurus A. On the other hand, considering the increasingly heavy composition of UHECRs at the highest energies measured by PAO, a plausible scenario for cosmic rays from the direction of Centaurus A can be found if they consist of intermediate-mass nuclei. The chemical composition of cosmic rays can be further constrained by lower-energy cosmic rays of the same rigidity. We find that cosmic-ray acceleration in the lobes of Centaurus A is not favored, while acceleration in the stellar winds that are rich in intermediate-mass nuclei could meet the requirement. This suggests that the observed excess may originate from cosmic-ray accelerators induced by stellar explosions in the star-forming regions of Centaurus A and/or the Centaurus cluster located behind Centaurus A.

Liu, Ruo-Yu; Wang, Xiang-Yu; Wang, Wei; Taylor, Andrew M.

2012-08-01

38

The Most Likely Sources of High-Energy Cosmic-Ray Electrons in Supernova Remnants  

Microsoft Academic Search

Evidence of nonthermal X-ray emission and TeV gamma rays from supernova remnants (SNRs) have strengthened the hypothesis that primary Galactic cosmic-ray electrons are accelerated in SNRs. High-energy electrons lose energy via synchrotron and inverse Compton processes during propagation in the Galaxy. Because of these radiative losses, TeV electrons liberated from SNRs at distances larger than ~1 kpc, or times older

T. Kobayashi; Y. Komori; K. Yoshida; J. Nishimura

2004-01-01

39

Cerenkov light collection in the high energy astronomical observatory - A cosmic ray experiment.  

NASA Technical Reports Server (NTRS)

Review of some of the problems encountered in the development of an improved Cerenkov counter for high energy cosmic ray experiments, and discussion of the approaches used or contemplated for the solution of these problems. The solution is felt to be contingent upon a better UV-reflecting paint and an improved radiator and photomultiplier positioning.

Arens, J. F.; Balasubrahmanyan, V. K.; Ormes, J. F.; Schutt, J. B.; Shai, C. M.; Silverberg, R.; Crannell, C. J.

1972-01-01

40

On Acceleration and Propagation of Ultra-High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

This paper discusses the correlation reported in 2008 by the Pierre Auger Observatory (PAO) of the arrival directions of the highest energy cosmic rays with active galactic nuclei (AGN). It is argued that these correlating AGN do not have the power required to be the sources of ultra-high energy protons. This current PAO dataset is further shown to disfavor giant radio-galaxies (both Fanaroff-Riley type I and II) as sources of ultra-high energy protons. The current data thus likely point to the local large scale structure, in which the actual sources of ultra-high energy cosmic rays camouflage. Finally, it is shown that the last gamma-ray burst in Centaurus A could explain, through rescattering on the Cen A lobes, the apparent cluster of events in this direction.

Lemoine, Martin

41

Ultra-high energy cosmic rays and the extragalactic gamma ray flux  

NASA Astrophysics Data System (ADS)

Ultra-high energy cosmic rays interacting with the radiation fields in the universe cause electromagnetic cascades resulting in a flux of extragalactic gamma rays, detectable to some 100 GeV. Recent precise measurements of the extragalactic gamma ray flux by Fermi-LAT, coupled with estimates of the background from active galactic nuclei of various types, allows limits to be set on the cascade component. By comparison with prediction and, making various assumptions, i.e. taking a particular model, limits can be set on the maximum energy to which ultra-high energy particles can be accelerated. If our model is correct, it is unlikely that the maximum energy is above 100 EeV, in turn, the apparent ‘GZK’ cut-off in the measured ultra-high energy spectrum could instead be due to a fall-off in the intrinsic emergent particle spectrum. However, it is not possible to be dogmatic at the present time because of uncertainty in many of the parameters involved. We have used recent estimates of the range of parameters and have found that although our model has parameters in the allowable ranges the uncertainties are so large that our result is not unique, although the method is satisfactory. The result must thus, so far, be taken as an indication only.

Erlykin, A. D.; Wolfendale, A. W.

2014-07-01

42

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

43

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

44

Cosmic ray physics, high energy physics and space sciences, an Indian story with international flavour.  

NASA Astrophysics Data System (ADS)

Centenary of discovery of cosmic rays by Viktor Hess a century back provides a unique opportunity to look back and examine the role of this important area of research that led to some of the most fundamental discoveries in science besides giving birth to high energy physics and space sciences. Scientists trained in cosmic rays with their broad and deep understanding of different facets of science, technology and management have played a critical role in the development of science in the post independent India. International collaboration during the past seven decades was an important catalyst in this process. Here we will discuss these issues from a historical perspective.

Menon, Mgk

2012-07-01

45

Intensities of high-energy cosmic rays at Mount Kanbala  

NASA Astrophysics Data System (ADS)

General features of family events with Summary Egamma 200 TeV, observed by the emulsion chambers at Mt. Kanbala, are presented in comparison with the Monte Carlo simulation. The lateral and cluster structure, and the energy spectra of constituent gamma-rays and hadrons are shown to be consistent with the Monte Carlo results calculated under the assumption of heavy-enriched primary, scaling, QCD jets and increasing cross-section.

Ren, J. R.; Kuang, H. H.; Huo, A. X.; Lu, S. L.; Su, S.; Wang, Y. X.; Xue, Y. G.; Wang, C. R.; He, M.; Zhang, N. J.

1985-08-01

46

Possible Association of Ultra--High-Energy Cosmic-Ray Events with Strong Gamma-Ray Bursts  

NASA Astrophysics Data System (ADS)

We point out that each of the error boxes of the two highest energy cosmic-ray shower events known overlaps with that of a strong gamma-ray burst (GRB). The GRBs precede the cosmic rays by 5.5 and 11 months, respectively. In one case the strongest known cosmic ray is paired with the strongest gamma-ray burst in the BATSE catalog. The probability of this occurring by chance seems rather small. Without building on post factum statistics, we think the above is remarkable enough to suggest that the cosmic-ray and gamma-ray burst were produced by the same outburst. A time delay, and a small positional disparity, are expected, since the trajectory of a charged cosmic-ray particle is wriggled by intervening magnetic fields. We estimate that the Galaxy's field alone may produce a delay of the order observed. With similar energies going into gamma rays and cosmic rays, we expect only a few times 10% of the strongest GRBs to be followed by a detection of an ultra--high-energy (E > 1020 eV) cosmic ray in existing experiments. We discuss some of the implications that follow if such an association is confirmed. For example, the upper limit on the distance of the cosmic-ray source, combined with a much better determined position of the gamma-ray burst source, reduces greatly the volume in which to look for an optical counterpart. The need to produce ultra--high-energy cosmic rays in the GRB source imposes additional constraints on the physical conditions in it. There is also useful information in the time delay regarding, e.g., intergalactic magnetic fields.

Milgrom, Mordehai; Usov, Vladimir

1995-08-01

47

Detection of High Energy Cosmic Ray with the Advanced Thin Ionization Calorimeter (ATIC)  

NASA Technical Reports Server (NTRS)

ATIC is a balloon-borne investigation of cosmic ray spectra, from below 50 GeV to near 100 TeV total energy, using a fully active Bismuth Gemmate (BGO) calorimeter. It is equipped with the first large area mosaic of small fully depleted silicon detector pixels capable of charge identification in cosmic rays from H to Fe. As a redundancy check for the charge identification and a coarse particle tracking system, three projective layers of x-y scintillator hodoscopes were employed, above, in the center and below a Carbon interaction 'target'. Very high energy gamma-rays and their energy spectrum may provide insight to the flux of extremely high energy neutrinos which will be investigated in detail with several proposed cubic kilometer scale neutrino observatories in the next decade.

Adams, J. H.; Ahn, E. J.; Bashindzhagyan, G.; Case, G.; Chang, J.; Christl, M.; Ellison, S.; Fazely, Ali R.; Ganel, O.; Gould, R.

2003-01-01

48

Modeling high-energy cosmic ray induced terrestrial muon flux: A lookup table  

NASA Astrophysics Data System (ADS)

On geological timescales, the Earth is likely to be exposed to an increased flux of high-energy cosmic rays (HECRs) from astrophysical sources such as nearby supernovae, gamma-ray bursts or by galactic shocks. Typical cosmic ray energies may be much higher than the ?1GeV flux which normally dominates. 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. Secondary particles such as muons and thermal neutrons produced as a result of nuclear interactions are able to reach the ground, enhancing the radiation dose. Muons contribute 85% to the radiation dose from cosmic rays. This enhanced dose could be potentially harmful to the biosphere. This mechanism has been discussed extensively in literature but has never been quantified. Here, we have developed a lookup table that can be used to quantify this effect by modeling terrestrial muon flux from any arbitrary cosmic ray spectra with 10 GeV to 1 PeV primaries. This will enable us to compute the radiation dose on terrestrial planetary surfaces from a number of astrophysical sources.

Atri, Dimitra; Melott, Adrian L.

2011-06-01

49

Super high energy cosmic ray events and properties of hadronic interactions  

SciTech Connect

This review summarizes the results from large scale emulsion chamber experiments carried out to study super high energy interactions using the cosmic ray beam. These events have a total visible energy greater than 100 TeV or a center of mass energy greater than 700 GeV. Over 1000 events have been observed at mountain laboratories around the world. These experiments provide evidence for continued increase of QCD jet production above SPS P-barP collider energies, a possible breakdown of scaling in the fragmentation region and a continuing increase in the total cross section. In addition, the results strongly suggest a dominance of nuclei with atomic mass between 20less than or equal toAless than or equal to56 in the primary cosmic ray beam at 10/sup 6/-10/sup 7/ GeV per nucleus, in the region of the 'bend' of the all-particle cosmic ray spectrum.

Yodh, G.B.

1984-11-15

50

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

51

The Need for Direct High-Energy Cosmic-Ray Measurements  

NASA Technical Reports Server (NTRS)

Measuring the chemical composition of the cosmic rays in the energy region of greater than or equal to 10(exp 12)eV would be highly useful in settling several nagging questions concerning the propagation of cosmic rays in the galaxy. In particular an accurate measurement of secondary to primary ratios such as Boron to Carbon would gibe clear evidence as to whether the propagation of cosmic rays is determined by a diffusion coefficient that varies with the particle's energy as E(sup 0.5) or E(sup 0.3). This would go a long ways in helping us to understand the anistropy (or lack thereof) of the highest energy cosmic rays and the power requirements for producing those particles at approximately equal to 10(exp 18) eV which are believed to be highest energy particles produced in the Galaxy. This would be only one of the benefits of a mission such as ACCESS to perform direct particle measurements on very high energy cosmic rays.

Jones, Frank C.; Streitmatter, Robert

2004-01-01

52

A C++ code to solve the DGLAP equations applied to Ultra High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

We solve numerically the Dokshitzer-Gribov-Lipatov-Altarelli-Parisi (DGLAP) equations for the evolution of fragmentation functions using the Laguerre method. We extend this method to include supersymmetric evolution. The solution to the DGLAP equations is particularly interesting to calculate the expected spectra of Ultra High Energy Cosmic Rays in models where they are produced by the decay of a massive particle /X, MX>1012 GeV.

Toldrà, Ramon

2002-03-01

53

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

54

Observations of High Energy Cosmic Ray Electrons by the ATIC Balloon Experiment  

NASA Technical Reports Server (NTRS)

Recently the Advanced Thin Ionization Calorimeter (ATIC) balloon experiment reported observations of high energy cosmic ray electrons over the energy range 300 to 800 GeV, indicating a feature or "bump" in the otherwise smoothly decreasing energy spectrum. The severe energy losses that occur as these high energy particles traverse the galaxy render the cosmic ray electron spectrum sensitive to local (a few kiloparsecs) sources and hence very interesting. The ATIC results are the first time that such a cosmic ray spectrum anomaly has been observed at high energy. Potential sources of this electron excess include pulsars, microquasars, supernovae remnants as well as the annihilation of exotic dark matter candidate particles. ATIC has had three successful high altitude flights over the continent of Antarctica 2000-2001, 2002-2003 and 2007-2008. Only results from the first two flights have been reported so far. During this talk we will discuss the ATIC experiment, the electron observations (including preliminary results from the most recent ATIC flight), examine the merits of the various source models and compare the ATIC observations with other recent measurements.

Guzik, T. G.; Chang, J.; Adams, J. H., Jr.; Ahn, H. S.; Bashindzhagyan, G. L.; Christl, M.; Isbert, J.; Kim, K. C.; Kuznetsov, E. N.; Panasyuk, M. I.; Panov, A. D.; Schmidt, W. K. H.; Seo, E. S.; Sokolskaya N. V.; Watts, J. W.; Wefel, J. P.; Wu, J.; Zatsepin, V. I.

2009-01-01

55

High Energy Cosmic Ray Electron Spectra measured from the ATIC Balloon Experiment  

NASA Technical Reports Server (NTRS)

The Advanced Thin Ionization Calorimeter Balloon Experiment (ATIC) is specifically designed for high energy cosmic ray ion detection. From simulation and a CERN beam test exposure we find that the design consisting of a graphite target and an energy detection device, a totally active calorimeter of BGO scintillator, gives us sufficient information to distinguish electrons from protons up to the TeV energy range. Balloon observations were successfully carried out over Antarctica in both 2000/2001 and 2002/2003 for a total of more than 35 days. This paper presents preliminary results on the spectrum of high energy electrons observed in the first ATIC flight.

Chang, J.; Schmidt, W. K. H.; Adams, J. H.; Ahn, H. S.; Bashindzhagyan, G.; Batkov, K. E.; Christl, M.; Fazely, A. R.; Ganel, O.; Gunasingha, R. M.

2003-01-01

56

Gravitational radiation from ultra high energy cosmic rays in models with large extra dimensions  

NASA Astrophysics Data System (ADS)

The effects of classical gravitational radiation in models with large extra dimensions are investigated for ultra high energy cosmic rays (CRs). The cross sections are implemented into a simulation package (SENECA) for high energy hadron induced CR air showers. We predict that gravitational radiation from quasi-elastic scattering could be observed at incident CR energies above 10 9 GeV for a setting with more than two extra dimensions. It is further shown that this gravitational energy loss can alter the energy reconstruction for CR energies ECR ? 5 × 10 9 GeV.

Koch, Ben; Drescher, Hans-Joachim; Bleicher, Marcus

2006-06-01

57

High energy neutrinos from primary cosmic rays accelerated in the cores of active galaxies  

NASA Technical Reports Server (NTRS)

The spectra and high-energy neutrino fluxes are calculated from photomeson production in active galactic nuclei (AGN) such as quasars and Seyfert galaxies using recent UV and X-ray observations to define the photon fields and an accretion-disk shock-acceleration model for producing ultrahigh-energy cosmic rays in the AGN. Collectively AGN should produce the dominant isotropic neutrino background between 10 exp 4 and 10 exp 10 GeV. Measurement of this background could be critical in determining the energy-generation mechanism, evolution, and distribution of AGN. High-energy background spectra and spectra from bright AGN such as NGC4151 and 3C273 are predicted which should be observable with present detectors. High energy AGN nus should produce a sphere of stellar disruption around their cores which could explain their observed broad-line emission regions.

Stecker, F. W.; Done, C.; Salamon, M. H.; Sommers, P.

1991-01-01

58

Active Galactic Nuclei, Gamma Ray Bursts and ultra high energy cosmic rays  

NASA Astrophysics Data System (ADS)

The importance of explaining and achieving the highest observed cosmic ray energies by the first order Fermi acceleration mechanism in a given astrophysical environment, is a recurring theme in astroparticle physics. We discuss the acceleration of cosmic rays in relativistic shock formations, focusing on numerical studies concerning proton acceleration efficiency by subluminal and superluminal shocks, emphasising on the dependence of the scattering model, shock Lorentz factor and the angle between the magnetic field and the shock front. We present a diffuse cosmic ray prediction model, where results are compared with the measured flux of cosmic rays at the highest energies. We show that while steeper Active Galactic Nuclei spectra provide an excellent fit, Gamma Ray Burst spectra being flatter can hardly explain the highest energy observed flux. Our model explains well the first evidence of a correlation between the cosmic ray flux above 5.7 x 10^10 GeV and the distribution of Active Galactic Nuclei provided by AUGER. Gamma Ray Bursts seem not to account for the origin of the highest cosmic ray energies, nevertheless, neutrino production is expected in these sources either in mildly or highly relativistic shocks. It is interesting to note that superluminal shocks in relativistic astrophysical environments may be observable via neutrino and photon fluxes, rather than as proton contributors. For this purpose observations from current gamma-ray and neutrino observatories is important.

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

59

Origin of Ultra-High Energy Cosmic Rays: Nuclear Composition of Gamma-Ray Burst Jets  

NASA Astrophysics Data System (ADS)

Ultra-high energy cosmic rays (UHECRs) are the most energetic particles flying from space and their source is not clarified yet. Recently, the Pierre Auger Observatory (PAO) suggests that UHECRs involve heavy nuclei. The PAO results require that a considerable fraction of metal nuclei must exist in the accelerating site, which can be realized only in the stellar interior. This puts strong constraints on the origin of UHECRs. In order to definitize the constraints from PAO results, we investigate the fraction of metal nuclei in a relativistic jet in gamma-ray burst associated with core-collapse supernova. If the jet is initially dominated by radiation field, quasi-statistical equilibrium (QSE) is established and heavy nuclei are dissociated to light particles such as 4He during the acceleration and expansion. On the other hand, if the jet is mainly accelerated by magnetic field heavy or intermediate mass nuclei can survive. The criterion to contain the metal nuclei is that the temperature at the launch site is below 4.5 × 109K. Therefore, if the composition of UHECRs is dominated by metal nuclei, a GRB with the magnetized jet is the most plausible candidate of the accelerating site.

Shibata, Sanshiro; Tominaga, Nozomu

2012-09-01

60

Origin of Ultra-High Energy Cosmic Rays: Nuclear Composition of Gamma-ray Burst Jets  

NASA Astrophysics Data System (ADS)

Recent results from the Pierre Auger Observatory (PAO) suggest that ultra-high energy cosmic rays (UHECRs) involve heavy or intermediate mass nuclei. This indicates that a considerable fraction of heavy nuclei must exist in the accelerating sites. Here, we focus on relativistic jets in gamma-ray bursts associated with core-collapse supernovae, which could contain large amount of metal. We investegate the dependence of nuclear composition on the outflow parameters. We show that when ratio of thermal to total energy density at initial radius of the outflow is high, heavy nuclei are dissociated to light particles such as ?-particles during the expansion, even if the outflow initially consists of heavy and intermediate nuclei. This result demonstrates that nuclear composition of the outflow in standard fireball model is dominated by light particles after the acceleration. However, we suggest that if the jets are accelerated by magnetic field, fraction of thermal energy in the jets is not necessarily high and metal nuclei could survive in the jets.

Shibata, Sanshiro; Tominaga, Nozomu

2011-09-01

61

New Results on High Energy Cosmic Ray Electrons Observed with Fermi LAT and Their Implications on the Models of Pulsars  

NASA Technical Reports Server (NTRS)

This viewgraph presentation describes, in detail, the Fermi Large Area Telescope (LAT) and GLAST Burst Monitor (GBM). Observations made from the June 11, 2008 launch and a discussion of observations made of high energy cosmic ray electrons is also presented.

Moiseev, Alexander

2010-01-01

62

Evaluation of the cosmic-ray induced background in coded aperture high energy gamma-ray telescopes  

NASA Technical Reports Server (NTRS)

While the application of coded-aperture techniques to high-energy gamma-ray astronomy offers potential arc-second angular resolution, concerns were raised about the level of secondary radiation produced in a thick high-z mask. A series of Monte-Carlo calculations are conducted to evaluate and quantify the cosmic-ray induced neutral particle background produced in a coded-aperture mask. It is shown that this component may be neglected, being at least a factor of 50 lower in intensity than the cosmic diffuse gamma-rays.

Owens, Alan; Barbier, Loius M.; Frye, Glenn M.; Jenkins, Thomas L.

1991-01-01

63

Relativistic waves raised by explosions in space as sources of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

The paper discusses the possibility of particle acceleration up to high energies in relativistic waves generated by various explosive processes in the interstellar medium. We propose to use the surfatron mechanism of acceleration (surfing) of charged particles trapped in the front of relativistic waves as a generator of high-energy cosmic rays (CRs). Conditions under which surfing in the waves under consideration can be made are studied thoroughly. Ultra-high-energy CRs (up to 1020 eV) are shown to be obtained due to the surfing in relativistic plane and spherical waves. Surfing is supposed to take place in nonlinear Langmuir waves excited by powerful electromagnetic radiation or relativistic beams of charged particles, as well as in strong shock waves generated by relativistic jets or spherical formations that expand fast (fireballs).

Kichigin, G. N.

2013-01-01

64

On the possibility of observing cosmic ray sources in high energy gamma rays  

NASA Technical Reports Server (NTRS)

If cosmic rays are accelerated by strong shocks, then cosmic ray sources should be characterized by spectra, dN/dE alpha E exp -(2.0-2.2), reflecting the strength of those shocks. This is expected from the 'standard leaky box' model of cosmic ray propagation in which the source spectra are harder than the observed spectra because higher energy particles have shorter residence times in the galactic magnetic fields. Furthermore, data on cosmic ray nucleons suggest that these sources might be surrounded by material. If the latter is true, such sources should be observable in gamma rays at energies beyond 1 GeV where the angular resolution of gamma-ray telescopes is optimized and the background is significantly reduced. For identified sources, the source location accuracy can be shown to improve with increasing energy in spite of the decreasing statistics, as long as the gamma-ray spectrum is harder than dN/dE alpha E exp -gamma. A Monte Carlo model is used to predict the photon spectra which would be expected from cosmic ray sources under varying assumptions about the strength of the shocks in the acceleration region.

Ormes, J. F.

1987-01-01

65

Relations Between High Energy Astroparticle Physics, Cosmic Ray Physics and Space Situational Awareness  

NASA Astrophysics Data System (ADS)

The paper overviews high energy galactic and solar cosmic ray data respectively models, which contributes to the physics behind space situational awareness (SSA) activities. The European SSA programme was signed during the ESA Ministerial Conference in November 2008. SSA activities related to Near Earth Objects (NEOs) and space weather (SW) will be explained in detail. Technological, societal economic impacts due to SW will be highlighted. In addition European and international endeavors for the forecast of SW storms and protection of critical infrastructures against SW will be sketched. New technologies and scientific inputs from microphysics detector developments like Medipix will significant contribute - by means of monitoring galactic, solar cosmic ray particles and imaging CMEs (Coronal Mass Ejections) on their propagation from the Sun towards Earth - to SW related nowcast and to applications of a new generation of highly miniaturized active space radiation and imaging monitors.

Jansen, Frank; Behrens, Jörg

2010-04-01

66

Numerical Simulation of the Anomalous Transport of High-Energy Cosmic Rays in Galactic Superbubble  

NASA Technical Reports Server (NTRS)

A continuous-time random-walk (CTRW) model to simulate the transport and acceleration of high-energy cosmic rays in galactic superbubbles has recently been put forward (Barghouty & Schnee 2102). The new model has been developed to simulate and highlight signatures of anomalous transport on particles' evolution and their spectra in a multi-shock, collective acceleration context. The superbubble is idealized as a heterogeneous region of particle sources and sinks bounded by a random surface. This work concentrates on the effects of the bubble's assumed astrophysical characteristics (cf. geometry and roughness) on the particles' spectra.

Barghouty, A. F.; Price, E. M.; MeWaldt, R. A.

2013-01-01

67

Clustering of ultra-high energy cosmic ray arrival directions on medium scales  

NASA Astrophysics Data System (ADS)

The two-point autocorrelation function of ultra-high energy cosmic ray (UHECR) arrival directions has a broad maximum around 25°, combining the data with energies above 4 × 10 19 eV (in the HiRes energy scale) of the HiRes stereo, AGASA, Yakutsk and SUGAR experiments. This signal is not or only marginally present analyzing events of a single experiment, but becomes significant when data from several experiments are added. Both the energy dependence of the signal and its angular scale might be interpreted as first signatures of the large-scale structure of UHECR sources and of intervening magnetic fields.

Kachelrieß, M.; Semikoz, D. V.

2006-08-01

68

CRT: A Numerical Tool for Propagating UltraHigh Energy Cosmic Rays Through Galactic Magnetic Field Models  

Microsoft Academic Search

The deflection of ultra high energy cosmic rays (UHECRs) by cosmic magnetic fields, particularly the Galactic magnetic field (GMF), may be sufficiently large to confuse identification of their sources. Here we present a publicly available numerical tool CRT, which can forward- or back-track particles of any type through multiple magnetic field configurations. Trajectories are determined by numerically integrating the relativistic

Michael Sutherland; Brian Baughman; James Beatty

2011-01-01

69

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

70

Modeling the Galactic Magnetic Field and its Application in verifying a Pulsar Origin of Very High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Deflection of Cosmic Ray charged particles under the influence of magnetic fields (Galactic and Extragalactic) causes a nearly isotropic distribution of their observed fluxes especially in lower energy ranges. Anyhow, as very high energy cosmic rays experience less deflections in their paths, they may point out the direction of their sources within a few degrees. We used a Galactic magnetic field model to study the possible Galactic sources of these cosmic rays. The propagation of cosmic rays in this Galactic magnetic field is simulated to estimate average deflection angles into their straight-line paths from their sources. Pulsars with suitable characteristics are selected and deflection regions around them are defined. Compared with the observational data (i.e. detected directions of observed CRs), the possibility of a Galactic origin of ultra high energy cosmic rays is examined. We defined deflection angles in terms of energies for sources in a distance d into center and anti-center directions. The probability of observing cosmic rays of di?erent energies from the direction of a source in a distance d is studied and the possibility of a pulsar origin of very high energy cosmic rays due to some recent models, is discussed.

Davoudifar, Pantea; Rowshan Tabari, Keihanak

2014-03-01

71

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

NASA Astrophysics Data System (ADS)

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.

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

2011-02-01

72

High energy galactic gamma radiation from cosmic rays concentrated in spiral arms. [using SAS-B satellite  

NASA Technical Reports Server (NTRS)

A model for the emission of high energy ( 100 MeV) gamma rays from the galactic disk was developed and compared to recent SAS-2 observations. In the calculation, it is assumed that (1) the high energy galactic gamma rays result primarily from the interaction of cosmic rays with galactic matter; (2) on the basis of theoretical and experimental arguments the cosmic ray density is proportional to the matter density on the scale of galactic arms; and (3) the matter in the galaxy, atomic and molecular, is distributed in a spiral pattern consistent with density wave theory and the experimental data on the matter distribution.

Bignami, G. F.; Fichtel, C. E.; Thompson, D. J.; Kniffen, D. A.

1974-01-01

73

Ultra high energy cosmic ray energy spectrum and composition using hybrid analysis with telescope array  

NASA Astrophysics Data System (ADS)

Cosmic radiation was discovered in 1912. This year, the 100 th anniversary of the discovery, marks not only the major progress that has been made in understanding these particles, but also the remaining questions about them. Questions about their sources, acceleration mechanisms, propagation and composition are still unanswered. There are only two experiments currently running that have the ability to study cosmic rays in the Ultra High Energy (E > 1018.0 eV) regime. The Telescope Array studies Ultra High Energy Cosmic Rays (UHECRs) 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 (HiRes) experiment, providing a direct link back to the HiRes experiment and data. The surface array is comprised of 507 Scintillator Detectors (SD) of a similar design as was used by the Akeno Giant Air Shower Array (AGASA), providing a link to that experiment as well. Studying TA hybrid events (events observed by both the FD and SD), makes the analysis presented in this work the lynchpin that connects the HiRes experiment to the AGASA experiment. This uniquely allows for a direct comparison between the two detection types and allows us to answer questions about the differences in the energy spectrum measurements shown by the two previous experiments. Furthermore, the hybrid analysis improves the geometrical reconstruction of the showers significantly. This provides a more accurate measurement of the energy of the primary particle and makes it possible to make an accurate prediction regarding the chemical composition of the cosmic ray particle. Historically, only the HiRes experiment and the Pierre Auger Observatory (PAO) have made significant composition measurements of UHECRs, and they report conflicting measurements. The hybrid composition measurement done in this work can be directly compared to the hybrid PAO result.

Allen, Monica Gene

74

New detection technologies for ultra-high energy cosmic rays and neutrinos  

NASA Astrophysics Data System (ADS)

Even with an accumulated data set from an integrated six years of lifetime from the Auger experiment, no point sources of charged cosmic rays have be identified at the highest energies. Significantly increased apertures such as promised by the JEMEUSO mission will be required to identify these sources from the cosmic ray signatures themselves. However, in employing water-cherenkov surface detectors as well as fluorescence telescopes, Auger has demonstrated the power provided by the hybrid technology approach. New detection technologies thus provide a valuable tool, in particular for the study of systematic effects. Over the past decade, in particular radio detection of cosmic ray air-showers has become a viable future detection technology to enhance and complement existing air-shower experiments. Following the proof-of-principle provided by the Lopes experiment, this technology is now being pursued in all major air-shower detectors. In the MHz regime, the radio signal is dominated by geomagnetic emission from the electrons deflected in the earth magnetic field, with secondary contributions from a global charge excess. As the majority of the energy in the shower is carried by these electron and the radio signal traverses the atmosphere basically unattenuated, this approach not only promises superior energy resolution but may also provide an independent handle on the longitudinal shower development and hence the primary composition. Theoretical signal predictions provided by detailed Monte-Carlo simulations as well as analytic shower parametrizations are in good agreement with measurements provided by the AERA and Codalema experiments. Recent efforts also include studies of the radio emission in the GHz regime, where the ambient noise is significantly reduced, yet the emission mechanism in this regime has not been firmly established yet. As neutrinos are not deflected in the intergalactic magnetic fields, the detection of neutrino-induced cascades in dense media provides another promising approachfor the identification of the sources of cosmic rays. The low event rates and large required target volumes limit the experimental methods to far-ranging signatures .from the cascade, such as acoustic emission from the quasi-instantaneous energy deposit or Cherenkov emission from the charged particles in the cascade. Searching for optical Cherenkov photons in a cubic-kilometer of Antarctic ice, the IceCube experiment has recently found an excess of high-energy neutrinos in the TeV-PeV range.Yet its effective volume is too small to detect the GZK flux predicted from interaction of the highest-energy cosmic rays with the ambient cosmic microwave background. Seeking to increase the observed target volume, radio observations of the rim of the moon have energy thresholds well beyond the EeV scale and thus are more likely to find interactions of charged cosmic rays than GZK neutrinos. The currently best sensitivity to this flux is provided from searches for GHz radio emission of neutrino-induced cascades in the antarctic ice from the ANITA ballon experiment. While no high-energy neutrinos have been found, a geomagnetic emission component from air-showers

Böser, Sebastian

2013-06-01

75

On the Origin and Survival of Ultra-High-Energy Cosmic-Ray Nuclei in Gamma-Ray Bursts and Hypernovae  

Microsoft Academic Search

The chemical composition of the ultra-high-energy (UHE) cosmic rays serves as an important clue to their origin. Recent measurements of the elongation rates by the Pierre Auger Observatory hint at the possible presence of heavy or intermediate-mass nuclei in the UHE cosmic rays. Gamma-ray bursts (GRBs) and hypernovae have been suggested as possible sources of the UHE cosmic rays. Here

Xiang-Yu Wang; Soebur Razzaque; Peter Mészáros

2008-01-01

76

Enhancement of high-energy cosmic-ray spectrum by type-II supernovae  

NASA Technical Reports Server (NTRS)

The cosmic-ray spectrum has an intensity enhancement in the energy range 10 to the 14th to 10 to the 16th eV per nucleus. Recent observations of heavy cosmic rays in this energy range indicate that the Ca/Fe ratio may be as large as 10 times the solar value. It is suggested that pulsars in type-II supernova remnants are the origin of this component of the cosmic-ray spectrum.

Takahashi, Y.; Miyaji, S.; Parnell, T. A.; Weisskopf, M. C.; Hayashi, T.

1986-01-01

77

Observing ultra high energy cosmic rays with the Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

The Pierre Auger Observatory was designed to measure ultra-high energy cosmic rays above 1018eV with high accuracy using a hybrid air shower detection technique. A Surface Detector (SD) with 1600 water-Cherenkov stations on a 1500 m triangular grid covers an area of 3000 km2. The atmosphere above the array is viewed by a Fluorescence Detector (FD) with 24 telescopes at 4 sites in the periphery of the SD. As an enhancement to this baseline design, in order to reach a lower energy threshold below 1017eV, the Collaboration has implemented extensions to the Observatory. The SD extension is AMIGA (Auger Muons and Infill for the Ground Array), an infilled area with detectors at a smaller spacing than in the main array and with buried scintillator counters. The FD is complemented by HEAT (High Elevation Auger Telescopes), with 3 additional telescopes that are tilted upwards to extend the elevation range. A review of the status and the main results from the observatory is presented with the emphasis given to the measurement of energy spectrum above 1018 eV where we observe a suppression for energies larger than 3×1019 eV, chemical composition, arrival directions, the search for photons and neutrinos as primary particles and finally the importance of the extensions of the Auger Observatory due that they allow to study the energy range where the transition from a Galactic to an extra-Galactic origin of cosmic rays may occur.

Salazar, I. Humberto; Varela, C. Enrique; Pierre Auger Collaboration

2013-06-01

78

Extensive air showers and ultra high-energy cosmic rays: a historical review  

NASA Astrophysics Data System (ADS)

The discovery of extensive air showers by Rossi, Schmeiser, Bothe, Kohlhörster and Auger at the end of the 1930s, facilitated by the coincidence technique of Bothe and Rossi, led to fundamental contributions in the field of cosmic ray physics and laid the foundation for high-energy particle physics. Soon after World War II a cosmic ray group at MIT in the USA pioneered detailed investigations of air shower phenomena and their experimental skill laid the foundation for many of the methods and much of the instrumentation used today. Soon interests focussed on the highest energies requiring much larger detectors to be operated. The first detection of air fluorescence light by Japanese and US groups in the early 1970s marked an important experimental breakthrough towards this end as it allowed huge volumes of atmosphere to be monitored by optical telescopes. Radio observations of air showers, pioneered in the 1960s, are presently experiencing a renaissance and may revolutionise the field again. In the last 7 decades the research has seen many ups but also a few downs. However, the example of the Cygnus X-3 story demonstrated that even non-confirmable observations can have a huge impact by boosting new instrumentation to make discoveries and shape an entire scientific community.

Kampert, Karl-Heinz; Watson, Alan A.

2012-08-01

79

On the heavy chemical composition of the ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

The Pierre Auger Observatory's (PAO) shower profile measurements can be used to constrain the chemical composition of the ultra-high energy cosmic ray (UHECR) spectrum. In particular, the PAO's measurements of the average depth of shower maximum and the fluctuations of the depth of shower maximum indicate that the cosmic ray spectrum is dominated by a fairly narrow distribution (in charge) of heavy or intermediate mass nuclei at the highest measured energies (E?1019eV), and contains mostly lighter nuclei or protons at lower energies (E˜1018eV). In this article, we study the propagation of UHECR nuclei with the goal of using these measurements, along with those of the shape of the spectrum, to constrain the chemical composition of the particles accelerated by the sources of the UHECRs. We find that with modest intergalactic magnetic fields, 0.3 nG in strength with 1 Mpc coherent lengths, good fits to the combined PAO data can be found for the case in which the sources accelerate primarily intermediate mass nuclei (such as nitrogen or silicon). Without intergalactic magnetic fields, we do not find any composition scenarios that can accommodate the PAO data. For a spectrum dominated by heavy or intermediate mass nuclei, the Galactic (and intergalactic) magnetic fields are expected to erase any significant angular correlation between the sources and arrival directions of UHECRs.

Hooper, Dan; Taylor, Andrew M.

2010-04-01

80

Towards unravelling the structural distribution of ultra-high-energy cosmic ray sources  

NASA Astrophysics Data System (ADS)

We investigate the possibility that observations of ultra-high-energy cosmic-rays (UHE-CRs) in the near future may be able to unveil their local source distribution. In order to discuss this possibility, we simulate the arrival distribution of UHE protons taking into account their propagation process in intergalactic space with a realistic model of extragalactic magnetic field (EGMF) and investigate the similarity of the spatial patterns of the arrival distribution and the source distribution. We find that UHE protons above 1019.8 eV are the best indicators for unravelling the source distribution within 100 Mpc, and the detection of about 500 events on the whole sky would allow us to unveil the local structure of the UHE universe for plausible EGMF strength and source number density. This number of events could be detected by 5 years observation by the Pierre Auger Observatory (PAO). We also discuss the deflection of the trajectories of UHE protons by Galactic magnetic field. On the GMF models which are preferred by many observations, the deflection angles are consistent with the angular scale of the positional correlation reported by the PAO, and cosmic-ray observation in the northern hemisphere is preferred to that in the southern hemisphere due to the smaller deflections of UHE protons.

Takami, Hajime; Sato, Katsuhiko

2008-08-01

81

A model-based clustering approach for mass composition analysis of high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We consider multivariate skew-t distributions for modeling composition data of high energy cosmic rays. The model has been validated with simulated data for different primary nuclei and hadronic models focusing on the depth of maximum Xmax and number of muons N? observables. Further, we consider mixtures of multivariate skew-t distributions in the framework of model-based clustering for the determination of the cosmic ray mass composition and for event-by-event classification. With respect to other approaches in the field, the method is based on analytical calculations and allows to incorporate different sets of constraints provided by the present hadronic models. We present some applications to simulated data sets generated with different assumptions on the nuclear abundances. As it does not fully rely on the hadronic model predictions, the method is particularly suited to the current experimental scenario in which evidences of discrepancies of the measured data with respect to the models have been reported for some shower observables, such as the number of muons at ground level.

Riggi, S.; Ingrassia, S.

2013-08-01

82

Geometry Study of Ultra High Energy Cosmic Ray Showers Using Hybrid Analysis from Telescope Array  

NASA Astrophysics Data System (ADS)

The Telescope Array experiment studies ultra high energy cosmic rays at energies >10^18 eV using a hybrid detector. Fluorescence telescopes measure the longitudinal development of the extensive air shower generated by a primary cosmic ray particle. Meanwhile, scintillator surface detectors measure the lateral distribution of secondary particles that hit the ground, the ``footprint'' of the shower. Combining the information from both detectors, a more precise measurement of the shower geometry can be obtained, and hence, a more accurate understanding of the energy and composition of the primary particle. The Middle Drum (MD) fluorescence observatory is located at the northwest corner of the Telescope Array and consists of 14 telescopes. It is one of three fluorescence observatories which observe the sky above the 507 scintillator surface detectors of the Telescope Array. I will discuss the MD hybrid data and resolution. I will show that in comparison with using MD information alone, the hybrid method improves the geometrical resolution of the shower by a factor of five in shower-detector plane angle, and by an order of magnitude in the shower core distance.

Allen, Monica

2010-10-01

83

The UCSD high energy X-ray timing experiment cosmic ray particle anticoincidence detector  

NASA Technical Reports Server (NTRS)

The HEXTE, part of the X-Ray Timing Explorer (XTE), is designed to make high sensitivity temporal and spectral measurements of X-rays with energies between 15 and 250 keV using NaI/CsI phoswich scintillation counters. To achieve the required sensitivity it is necessary to provide anticoincidence of charged cosmic ray particles incident upon the instrument, some of which interact to produce background X-rays. The proposed cosmic ray particle anticoincidence shield detector for HEXTE uses a novel design based on plastic scintillators and wavelength-shifter bars. It consists of five segments, each with a 7 mm thick plastic scintillator, roughly 50 cm x 50 cm in size, coupled to two wavelength-shifter bars viewed by 1/2 inch photomultiplier tubes. These segments are configured into a five-sided, box-like structure around the main detector system. Results of laboratory testing of a model segment, and calculations of the expected performance of the flight segments and particle anticoincidence detector system are presented to demonstrate that the above anticoincidence detector system satisfies its scientific requirements.

Hink, P. L.; Rothschild, R. E.; Pelling, M. R.; Macdonald, D. R.; Gruber, D. E.

1991-01-01

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

Isotropy of ultra-high-energy cosmic rays and multiple supernova I galactic source  

SciTech Connect

Ultra-high-energy cosmic rays are usually associated with an extragalactic origin. Active galactic nuclei are an unlikely source because of photon drag. Here the possibility of supernova events are considered. The time spread of arrival of 10/sup 20/ eV protons is 100 to 400 years at 10 to 20 kpc and the angular spread is +-15 to +-30/sup 0/ depending upon the Galactic field configuration. The time spread is sufficient to include several to a dozen type I SN. This is enough events and angular spread to include the observed data. The concentration of the observed events at the galactic poles is contradictory. The flux is reasonable if the observed flux and slope at 10/sup 12/ to 10/sup 15/ eV is characteristic of the source(s) and confined at this energy for roughly 100 traversals of the Galaxy, or 3 x 10/sup 6/ years.

Colgate, S.A.

1983-04-07

86

Results on high-energy cosmic rays by EAS-TOP at Gran Sasso.  

NASA Astrophysics Data System (ADS)

Very high-energy cosmic rays have to be studied through the ground-based detectors of the extensive air showers (EAS) that they produce in the atmosphere. The main measurements to be performed are of: primary energy spectra, composition, anisotropies, "neutral primary" astronomy, and interaction properties. This requires complete detectors of all the EAS components, and for this purpose the EAS-TOP array has been constructed at Campo Imperatore (2000 m a.s.l.) on top of the Gran Sasso underground laboratories. The array has been progressively going into operation since 1988. The authors present the status and performances of the different detectors, and the results obtained up to now on the different items under discussion.

Aglietta, M.; Alessandro, B.; Antonioli, P.; Arneodo, F.; Bergamasco, L.; Bertaina, M.; Fauth, A. C.; Castagnoli, C.; Castellina, A.; Chiavassa, A.; Castagnoli, G. C.; D'Ettorre Piazzoli, B.; di Sciascio, G.; Fulgione, W.; Galeotti, P.; Ghia, P. L.; Iacovacci, M.; Mannocchi, G.; Melagrana, C.; Morello, C.; Navarra, G.; Riccati, L.; Saavedra, O.; Trinchero, G. C.; Vallania, P.; Vernetto, S.

1997-12-01

87

Ultra high energy neutrino nucleon cross section from cosmic ray experiments and neutrino telescopes  

NASA Astrophysics Data System (ADS)

We deduce the cosmogenic neutrino flux by jointly analysing ultra high energy cosmic ray data from HiRes-I and II, AGASA and the Pierre Auger Observatory. We make two determinations of the neutrino flux by using a model-dependent method and a model-independent method. The former is well-known, and involves the use of a power-law injection spectrum. The latter is a regularized unfolding procedure. We then use neutrino flux bounds obtained by the RICE experiment to constrain the neutrino nucleon inelastic cross section at energies inaccessible at colliders. The cross section bounds obtained using the cosmogenic fluxes derived by unfolding are the most model-independent bounds to date.

Barger, V.; Huber, Patrick; Marfatia, Danny

2006-11-01

88

Characteristics of cesium iodide for use as a particle discriminator for high energy cosmic rays  

NASA Technical Reports Server (NTRS)

The possible use of CsI to discriminate between high energy cosmic ray electrons and interacting protons has been investigated. The pulse-shape properties as a function of ionization density, temperature, and spectral response are presented for thallium-activated CsI and as a function of ionization density for sodium-activated CsI. The results are based on previously published data and on corroborative measurements from the present work. Experimental results on the response of CsI to electron-induced electromagnetic cascades and to interacting hadrons are described. Bibliographies of publications dealing with the properties of CsI and with pulse-shape discrimination techniques are presented.

Crannell, C. J.; Kurz, R. J.; Viehmann, W.

1973-01-01

89

The Isotropy Problem of Ultra-High Energy Cosmic Rays: The Effects of Anisotropic Transport  

NASA Astrophysics Data System (ADS)

Time dependent anisotropic transport of ultra-high energy cosmic rays (UHECRs) from point-like sources in the Galaxy is calculated in various ways. To fully account for the discreteness of UHECR sources in space and time, the Monte Carlo method is used to randomly place sources in the Galaxy and calculate the anisotropy of UHECR flux, given specific realisations of source distribution. We show that reduction in the rate of cross-field transport reduces the anisotropy. However, if the crossfield transport is very small, drift of UHECRs in the Galactic magnetic field (GMF) becomes the dominant contributor to the anisotropy. Test particle simulations further illustrate the effect of drift and verify our analytical calculation. The surprisingly low anisotropy measured by Auger can be interpreted as intermittency of UHECR sources, without invoking a flat source distribution and/or a high source rate. Frequent events that follow star formation, such as hypernovae, imply an anisotropy that exceeds the Auger limit.

Kumar, Rahul; Eichler, David

2013-04-01

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

Japanese-American Cooperative Emulsion Experiment /JACEE/. [high energy cosmic ray studies  

NASA Technical Reports Server (NTRS)

The instrumentation and results of long duration balloon flights carried out jointly by U.S. and Japan researchers to examine high energy cosmic rays are reported. Basic detector geometries are 2.5 sq m sr with operation at altitudes with 3-4 g/sq cm pressure, with observations thus far of over 100 hr. Energies from 2-100 TeV are recorded for nucleus-nucleus and hadron-nucleus interactions, and searches are made for new particle or interactions. The detector is an emulsion chamber which comprises doubly-coated nuclear emulsions on 800 micron thick methacryl substrates, X-ray films, etchable detectors, low density spacers, and lead sheets. Segmentation of the instrument into a primary charge module, a target section, a spacer section, and a lead-emulsion calorimeter allows accurate charge measurement for primary nuclei, reliable energy resolution, and a large geometrical factor for collecting high energy events. A primary Ca nucleus of 300 TeV has been observed.

Huggett, R. W.; Hunter, S. D.; Jones, W. V.; Takahashi, Y.; Ogata, T.; Saito, T.; Holynski, R.; Jurak, A.; Wolter, W.; Parnell, T. A.

1981-01-01

92

Nearby supernova remnants and the cosmic ray spectral hardening at high energies  

NASA Astrophysics Data System (ADS)

Recent measurements of cosmic ray spectra of several individual nuclear species by the CREAM, TRACER and ATIC experiments indicate a change in the spectral index of the power laws at TeV energies. Possible explanations among others include non-linear diffusive shock acceleration of cosmic rays, different cosmic ray propagation properties at higher and lower energies in the Galaxy and the presence of nearby sources. In this paper, we show that if supernova remnants are the main sources of cosmic rays in our Galaxy, the effect of the nearby remnants can be responsible for the observed spectral changes. Using a rigidity-dependent escape of cosmic rays from the supernova remnants, we explain the apparent observed property that the hardening of the helium spectrum occurs at relatively lower energies as compared to the protons and also that the spectral hardening does not persist beyond ˜(20-30) TeV energies.

Thoudam, Satyendra; Hörandel, Jörg R.

2012-04-01

93

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

94

Composition Studies of Ultra-High Energy Cosmic Rays using Xmax by the High-Resolution Fly's Eye Observatory  

NASA Astrophysics Data System (ADS)

Both the mean value of airshower maximum Xmax and the width of the Xmax distribution are known to be sensitive to the chemical composition of cosmic rays initiating a set of extensive airshowers. Thus, studies of Xmax are an important part of efforts to understand the nature and origin of Ultra-High Energy Cosmic Rays, the most energetic elementary particles known in the universe. With the Northern Hemisphere's largest exposure to date to cosmic rays above 10^18 eV, the two fluorescence detectors of the High-Resolution Fly's Eye (HiRes) Observatory are uniquely positioned to study this phenomenon. Here, we report the results of recent studies of the depth of airshower maximum Xmax in cosmic-ray induced extensive airshowers observed in stereo by HiRes.

Belz, John

2009-05-01

95

Optimized trigger for ultra-high-energy cosmic-ray and neutrino observations with the low frequency radio array  

Microsoft Academic Search

When an ultra-high energy neutrino or cosmic-ray strikes the Lunar surface a radio-frequency pulse is emitted. We plan to use the LOFAR radio telescope to detect these pulses. In this work we propose an efficient trigger implementation for LOFAR optimized for the observation of short radio pulses.

K. Singh; M. Mevius; O. Scholten; J. M. Anderson; A. van Ardenne; M. Arts; M. Avruch; A. Asgekar; M. Bell; P. Bennema; M. Bentum; G. Bernadi; P. Best; A.-J. Boonstra; J. Bregman; R. van de Brink; C. Broekema; W. Brouw; M. Brueggen; S. Buitink; H. Butcher; W. van Cappellen; B. Ciardi; A. Coolen; S. Damstra; R. Dettmar; G. van Diepen; K. Dijkstra; P. Donker; A. Doorduin; M. Drost; A. van Duin; J. Eisloeffel; H. Falcke; M. Garrett; M. Gerbers; J. Griessmeier; T. Grit; P. Gruppen; A. Gunst; M. van Haarlem; M. Hoeft; H. Holties; J. H orandel; L. A. Horneffer; A. Huijgen; C. James; A. de Jong; D. Kant; E. Kooistra; Y. Koopman; L. Koopmans; G. Kuper; P. Lambropoulos; J. van Leeuwen; M. Loose; P. Maat; C. Mallary; R. McFadden; H. Meulman; J.-D. Mol; J. Morawietz; E. Mulder; H. Munk; L. Nieuwenhuis; R. Nijboer; M. J. Norden; J. Noordam; R. Overeem; H. Paas; V. N. Pandey; M. Pandey-Pommier; R. Pizzo; A. Polatidis; W. Reich; J. de Reijer; A. Renting; P. Riemers; H. Roettgering; J. Romein; J. Roosjen; M. Ruiter; A. Schoenmakers; G. Schoonderbeek; J. Sluman; O. Smirnov; B. Stappers; M. Steinmetz; H. Stiepel; K. Stuurwold; M. Tagger; Y. Tang; S. ter Veen; R. Vermeulen; M. de Vos; C. Vogt; E. van der Wal; H. Weggemans; S. Wijnholds; M. Wise; O. Wucknitz; S. Yattawatta; J. van Zwieten

2011-01-01

96

Future use of silicon photomultipliers for the fluorescence detection of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

A sophisticated technique to measure extensive air showers initiated by ultra-high-energy cosmic rays is by means of fluorescence telescopes. Secondary particles of the air shower excite nitrogen molecules of the atmosphere, which emit fluorescence light when they de-excite. Due to their high photon detection efficiency (PDE) silicon photomultipliers (SiPMs) promise to increase the sensitivity of todays fluorescence telescopes which use photomultiplier tubes - for example the fluorescence detector of the Pierre Auger Observatory. On the other hand drawbacks like a small sensitive area, a strong temperature dependency and a high noise rate have to be managed. We present plans for a prototype fluorescence telescope using SiPMs and a special light collecting optical system of Winston cones to increase the sensitive area. In this context we made measurements of the relative PDE of SiPMs depending on the incident angle of light. The results agree with calculations based on the Fresnel equations. Furthermore, measurements of the brightness of the night sky are presented since this photon flux is the main background to the fluorescence signals of the extensive air showers. To compensate the temperature dependency of the SiPM, frontend electronics make use of temperature sensors and microcontrollers to directly adjust the bias-voltage according to the thermal conditions. To reduce the noise rate we study the coincidence of several SiPMs signals triggered by cosmic ray events. By summing up these signals the SiPMs will constitute a single pixel of the fluorescence telescope.

Stephan, Maurice; Hebbeker, Thomas; Lauscher, Markus; Meurer, Christine; Niggemann, Tim; Schumacher, Johannes

2011-09-01

97

Statistical analysis of the correlation between active galactic nuclei and ultra-high energy cosmic rays  

NASA Astrophysics Data System (ADS)

We develop the statistical methods for comparing two sets of arrival directions of cosmic rays in which the two-dimensional distribution of arrival directions is reduced to the one-dimensional distributions so that the standard one-dimensional Kolmogorov-Smirnov test can be applied. Then we apply them to the analysis of correlation between the ultra-high energy cosmic rays (UHECR) with energies above 5.7 × 1019 eV, observed by Pierre Auger Observatory (PAO) and Akeno Giant Air Shower Array (AGASA), and the active galactic nuclei (AGN) within the distance 100 Mpc. For statistical test, we set up the simple AGN model for UHECR sources in which a certain fraction of observed UHECR are originated from AGN within a chosen distance, assuming that all AGN have equal UHECR luminosity and smearing angle, and the remaining fraction are from the isotropic background contribution. For the PAO data, our methods exclude not only a hypothesis that the observed UHECR are simply isotropically distributed but also a hypothesis that they are completely originated from the selected AGN. But, the addition of appropriate amount of isotropic component either through the background contribution or through the large smearing effect improves the correlation greatly and makes the AGN hypothesis for UHECR sources a viable one. We also point out that restricting AGN within the distance bin of 40-60 Mpc happens to yield a good correlation without appreciable isotropic component and large smearing effect. For the AGASA data, we don't find any significant correlation with AGN.

Kim, Hang Bae; Kim, Jihyun

2011-03-01

98

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

99

Gradients and Anisotropies of High Energy Cosmic Rays in the Outer Heliosphere.  

National Technical Information Service (NTIS)

Two cosmic rays which pass through the same point going in opposite directions will, in the absence of scattering and inhomogeneities in the magnetic field, trace helices about adjacent flux tubes, whose centerlines are separated by one gyrodiameter. A di...

W. Fillius E. C. Roelof E. J. Smith D. Wood W. H. Ip

1985-01-01

100

Gradients and Anisotropies of High Energy Cosmic Rays in Outer Heliosphere,  

National Technical Information Service (NTIS)

Two cosmic rays which pass through the same point going in opposite directions will, in the absence of scattering and inhomogeneities in the magnetic field, trace helices about adjacent flux tubes, whose centerlines are separated by one gyrodiameter. A di...

F. Walker E. C. Roelof E. J. Smith D. Wood W. H. Ip

1985-01-01

101

Detecting filaments in the ultra-high energy cosmic ray distribution  

NASA Astrophysics Data System (ADS)

We propose and test new statistical tools to study the distribution of cosmic rays based on the use of the minimal spanning tree. The method described is particularly sensitive to filamentary structures, as those expected to arise from strong sources of charged cosmic rays which get deflected by intervening magnetic fields. We also test the method with data available from the AGASA and SUGAR surface detector arrays.

Harari, Diego; Mollerach, Silvia; Roulet, Esteban

2006-07-01

102

Diffuse fluxes of cosmic high energy neutrinos  

NASA Technical Reports Server (NTRS)

Production spectra of high-energy neutrinos from galactic cosmic ray interactions with interstellar gas and extragalactic ultrahigh energy cosmic-ray interactions with microwave black-body photons are presented and discussed. These production processes involve the decay of charged pions and are thus related to the production of cosmic gamma-rays from the decay of neutral pions. Estimates of the neutrino fluxes from various diffuse cosmic sources are then made and the reasons fro significant differences with previous estimates are discussed. Predicted event rates for a DUMAND type detection system are significantly lower than early estimates indicated.

Stecker, F. W.

1978-01-01

103

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

NASA Astrophysics Data System (ADS)

Data collected by the Pierre Auger Observatory (Auger) provide evidence for anisotropy in the arrival directions of cosmic rays (CRs) with energies higher than 57 EeV, which suggests a correlation with the positions of active galactic nuclei (AGNs) located within ~ 75 Mpc and 3fdg2 of the arrival directions. This analysis, however, does not take into account AGN morphology. A detailed study of the sample of AGNs whose positions are located within 3fdg2 of the CR events (and extending our analysis out to ~ 150 Mpc) shows that most of them are classified as Seyfert 2 and low-ionization nuclear emission-line region galaxies whose properties do not differ substantially from other local AGNs of the same type. Therefore, if the production of the highest energy CRs is persistent in nature, i.e., operates in a single object on long (gsim Myr) timescales, the claimed correlation between the CR events observed by Auger and the local active galaxies should be considered as resulting from a chance coincidence. In addition, most of the selected sources do not show significant jet activity, and hence, in most conservative scenarios, there are no reasons for expecting them to accelerate CRs up to the highest energies, ~1020 eV. 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 the nearby radio galaxy NGC 5128 (Cen A) alone could be associated with at least four events due to its large radio extent, and PKS 1343-60 (Cen B), another nearby radio galaxy, can be associated with more than one 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 to the Earth. 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 (e.g., Fermi Gamma-ray Space Telescope formerly Gamma-Ray Large Area Space Telescope, and High Energy Stereoscopic System in the Southern hemisphere) 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.

2009-03-01

104

Analysis of the mass composition of high-energy cosmic ray  

NASA Astrophysics Data System (ADS)

This paper analyses mass composition of high-energy cosmic ray, comparing simulation and experimental results. Using the nuclear interaction models QGSJET-II and Sibyll, we simulate EAS initiated by the primary nuclei representing all mass groups (p, He, O, Si, Fe). EAS is simulated for several energy levels between 1.1018 and 5.1019 eV. For such generated simulation data, we compute X-max distributions, mean X-max and RMS and compare these values with the experimental data from the Auger Experiment. The results show that for the 2-sigma confidence level, mass composition including nuclei from the CNO group and heavier can be fitted for Sibyll model only. For any combination of 3 and 4 primary particles, no model fits the experimental data at the 1-sigma confidence level. For the p + Fe bi-particle composition, or other combination of two particles, also no model fitting the experimental data can be found for the analysed energy interval.

Malinowski, Jan

2013-02-01

105

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

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

The spectrum of high energy cosmic-ray electrons - Results and interpretation  

NASA Technical Reports Server (NTRS)

Results of a measurement of high energy cosmic-ray electrons that was performed with a balloon-borne transition radiation/shower detector telescope are presented. The data cover the energy range from 5 to 300 GeV. The interstellar spectrum below 10 GeV, which is affected by solar modulation, is derived through analysis of the nonthermal galactic radio emission, and extended to lower energies (about 300 MeV). The interstellar differential spectrum is described by a power law dependence on E with an index of -1.4 below 2 GeV, but attaining a slope of -2.6 at 2-10 GeV, and steepening further to almost -3.6 at 30-300 GeV. The features of this spectrum are interpreted in the context of galactic propagation models, assuming that the spectrum at the acceleration site has the form of a single power law. It is concluded that: (1) regions outside the galactic disk contribute to the confinement volume of electrons, (2) the containment time of electrons is of the order 10 to the 7th years and is independent of energy, (3) the spectrum at the acceleration site has a power law exponent equal to -2.65, and (4) a specific mechanism is responsible for the apparent flattening of the electron spectrum below 2 GeV.

Muller, D.; Tang, J.

1983-01-01

108

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

109

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

110

Anisotropy expectations for ultra-high-energy cosmic rays with future high-statistics experiments  

NASA Astrophysics Data System (ADS)

Context. Ultra-high-energy cosmic rays (UHECRs) have attracted a lot of attention in astroparticle physics and high-energy astrophysics, due to their challengingly high energies, and to their ability to constrain the physical processes and astrophysical parameters in the most energetic sources of the universe. Despite their very large acceptance, current detectors have failed to detect significant anisotropies in their arrival directions, which had been expected to lead to the long-sought identification of their sources. Some indications about the composition of the UHECRs, which may become heavier at the highest energies, have even called into question the possibility that such a goal could be achieved in the foreseeable future. Aims: We investigate the potential value of a new-generation detector, with an exposure increased by one order of magnitude, to overcome the current situation and make notable progress in detecting anisotropies and thus in the study of UHECRs. We take as an example the expected performances of the JEM-EUSO detector, assuming a uniform full-sky coverage with a total exposure of 300 000 km2 sr yr. Methods: We simulated realistic UHECR sky maps for a wide range of possible astrophysical scenarios allowed by the current constraints, taking the energy losses and photo-dissociation of the UHE protons and nuclei into account, as well as their deflections by intervening magnetic fields. These sky maps, built for both the expected statistics of JEM-EUSO and the current Pierre Auger Observatory statistics, as a reference, were analysed from the point of view of their intrinsic anisotropies, using the two-point correlation function. A statistical study of the resulting anisotropies was performed for each astrophysical scenario, varying the UHECR source composition and spectrum and the source density and exploring a set of five hundred independent realizations for each choice of a parameter set. Results: We find that significant anisotropies are expected to be detected by a next-generation UHECR detector, for essentially all the astrophysical scenarios studied, and give precise, quantitative meaning to this statement. Conclusions: Our results show that a gain of one order of magnitude in the total exposure of UHECR detectors would make a significant difference compared to the existing experiments, and would allow considerable progress in the study of these mysterious particles and their sources.

Rouillé d'Orfeuil, B.; Allard, D.; Lachaud, C.; Parizot, E.; Blaksley, C.; Nagataki, S.

2014-07-01

111

Cosmic Rays  

NSDL National Science Digital Library

This series of web pages 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.

Stern, David

2005-04-27

112

Measuring the Ultra-High Energy Cosmic Ray Energy Spectrum with the Telescope Array  

NASA Astrophysics Data System (ADS)

The Telescope Array experiment (TA) is the largest cosmic ray observatory in the northern hemisphere. TA consists of an array of 507 scintillation counter surface detectors (SD) augmented by three optical fluorescence telescope observatories (FD). In analyzing the data collected by the TA SD, a novel technique is employed which consists of generating a very detailed simulation that can be directly compared against actual observations. This method enables a very careful analysis with a thoroughgoing understanding of the resolution constraints in the data. The method above will be described and the most recent SD, FD, and hybrid measurements of the cosmic ray energy spectrum will be presented.

Stokes, Benjamin; Ivanov, Dmitri; Thomson, Gordon

2012-03-01

113

Measurement of the Ultra-High Energy Cosmic Ray Spectrum by the Telescope Array Surface Detector  

NASA Astrophysics Data System (ADS)

The Telescope Array experiment is the largest cosmic ray observatory in the northern hemisphere. Telescope Array consists of an array of 507 scintillation counter surface detectors (TASD) augmented by three optical fluorescence telescope observatories. In analyzing the data collected by the TASD, a novel technique is employed which consists of generating a very detailed simulation that can be directly compared against actual observations. This enables a very careful analysis with a thoroughgoing understanding of the resolution constraints in the data. This method will be described and the most recent TASD measurement of the cosmic ray energy spectrum will be presented.

Stokes, Benjamin

2013-04-01

114

New Results on High Energy Cosmic Ray Electrons Observed with Fermi LAT and Their Implications on the Origin of Cosmic Rays  

NASA Technical Reports Server (NTRS)

The Large Area Telescope on-board the Fermi Gamma-Ray Space Telescope has collected more than 10 million cosmic ray electrons with energy above 7 GeV since its science operation on orbit. High energy electrons rapidly lose their energy by synchrotron radiation on Galactic magnetic fields and by inverse Compton scattering on the interstellar radiation field. The typical distance over which a 1 TeV electron loses half its total energy is estimated to be 300-400 pc.This makes them a unique tool for probing nearby Galactic space. Observed spectrum has a harder spectral index than was previously reported and suggests the presence of nearby sources of high energy electrons. One of viable candidates are nearby pulsars, possibly some of recently discovered by Fermi. At the same time the dark matter origin of such sources cannot be ruled out. I will also report our current upper limits on cosmic ray electrons anisotropy which helps to set constraints on their local sources.

Moiseev, Alexander

2010-01-01

115

Anomalous Transport of High-energy Cosmic Rays in Galactic Superbubbles. I. Numerical Simulations  

NASA Astrophysics Data System (ADS)

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 ?1015 eV for protons and ?3 × 1015 eV for alphas. Our simulations are consistent with a bubble's mean magnetic field strength of ?1 ?G and a shock separation distance ~0.1 × the characteristic radius of the bubble. The simulations imply that the diffusion coefficient (for the elementary shock acceleration process) is <~ 1027 cm2 s-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.; Schnee, D. A.

2012-04-01

116

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

117

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 Technical Reports Server (NTRS)

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. (editor); Wefel, J. P. (editor)

1985-01-01

118

Detection of High Energy Cosmic Rays with Advanced Thin Ionization Calorimeter, ATIC  

NASA Technical Reports Server (NTRS)

The author presents preliminary results of the first flight of the Advanced Thin Ionization Calorimeter (ATIC). ATIC is a multiple, long duration balloon flight, investigation for the study of cosmic ray spectra from below 50 GeV to near 100 TeV total energy, using a fully active Bismuth Germanate (BGO) calorimeter. It is equipped with the first large area mosaic of small fully depleted silicon detector pads capable of charge identification of cosmic rays from H to Fe. As a redundancy check for the charge identification and a coarse particle tracking system, three projective layers of x-y scintillator hodoscopes were employed, above, in the center and below a Carbon interaction 'target'.

Adams, J. H.; Ahn, E. J.; Ahn, H. S.; Bashindzhagyan, G.; Case, G.; Chang, J.; Christl, M.; Ellison, S.; Fazely, A. R.; Ganel, O.

2002-01-01

119

Propagation of ultra-high-energy cosmic ray nuclei in cosmic magnetic fields and implications for anisotropy measurements  

NASA Astrophysics Data System (ADS)

Recent results from the Pierre Auger Observatory (PAO) indicate that the composition of ultra-high-energy cosmic rays (UHECRs) with energies above 1019 eV may be dominated by heavy nuclei. An important question is whether the distribution of arrival directions for such UHECR nuclei can exhibit observable anisotropy or positional correlations with their astrophysical source objects despite the expected strong deflections by intervening magnetic fields. For this purpose, we have simulated the propagation of UHECR nuclei including models for both the extragalactic magnetic field (EGMF) and the Galactic magnetic field (GMF). We find that the GMF is particularly crucial for suppressing the anisotropy as well as source correlations. Assuming that only iron nuclei are injected steadily from sources with equal luminosity and spatially distributed according to the observed large scale structure in the local Universe, at the number of events published by the PAO so far (69 events above 5.5 × 1019 eV), the arrival distribution of UHECRs would be consistent with no auto-correlation at 95% confidence if the mean number density of UHECR sources ns ? 10-6 Mpc-3, and consistent with no cross-correlation with sources within 95% errors for ns ? 10-5 Mpc-3. On the other hand, with 1000 events above 5.5 × 1019 eV in the whole sky, next generation experiments can reveal auto-correlation with more than 99% probability even for ns ? 10-3 Mpc-3, and cross-correlation with sources with more than 99% probability for ns ? 10-4 Mpc-3. In addition, we find that the contribution of Centaurus A is required to reproduce the currently observed UHECR excess in the Centaurus region. Secondary protons generated by photodisintegration of primary heavy nuclei during propagation play a crucial role in all cases, and the resulting anisotropy at small angular scales should provide a strong hint of the source location if the maximum energies of the heavy nuclei are sufficiently high.

Takami, Hajime; Inoue, Susumu; Yamamoto, Tokonatsu

2012-07-01

120

A ring imaging Cherenkov telescope for observations of high energy cosmic rays  

Microsoft Academic Search

We describe a ring imaging Cherenkov counter for high altitude balloon flights designed to measure the energy spectra of cosmic ray nuclei above 40 GeV\\/amu. The instrument has a 3 m long nitrogen gas radiator at 1 atm, a spherical and planar mirror system, and ~ 2.2 m2 of TMAE\\/ethane photon detecting drift chambers with fused silica windows in the

J. Buckley; J. Dwyer; D. Müller; S. Swordy; K. K. Tang

1992-01-01

121

A new measurement of the flux of the light cosmic-ray nuclei at high energies  

NASA Technical Reports Server (NTRS)

A new cosmic-ray detector utilizing a ring-imaging Cerenkov counter to determine the energy of light cosmic-ray nuclei was flown on high-altitude balloon from Fort Sumner, NM, in 1991 September. We describe the design and performance of this instrument and discuss the data analysis procedures. The measurement provides a new determination of the absolute flux and differential energy spectrum of the primary cosmic-ray species helium between 40 and 320 GeV/nucleon. The experiment also yields the spectra of carbon and oxygen and some information on the intensities of the secondary nuclei Li, Be, and B. A comparison between our results and previous measurements of heavier nuclei (Z greater than or equal to 4) from HEAO 3 and Spacelab 2 indicates good consistency between these measurements. The data set is compared with the results of a leaky box propagation model. We find good agreement with this model if the abundance of helium relative to oxygen at the source is taken to be 25 +/- 6 and if the source spectrum is given by a power law in energy proportional to E(exp -2.15).

Buckley, J.; Dwyer, J.; Mueller, D.; Swordy, S.; Tang, K. K.

1994-01-01

122

Gradients and anisotropies of high energy cosmic rays in the outer heliosphere  

NASA Technical Reports Server (NTRS)

Two cosmic rays which pass through the same point going in opposite directions will, in the absence of scattering and inhomogeneities in the magnetic field, trace helices about adjacent flux tubes, whose centerlines are separated by one gyrodiameter. A directional anisotropy at the point suggests a difference in the number of cosmic rays loading the two flux tubes; that is, a density gradient over the baseline of a gyrodiameter. Previous studies at lower energies have shown that the cosmic ray density gradients vary in time and space. It is suggested that the radial gradient associated with solar cycle modulation is supported largely by narrow barriers which encircle the sun and propagate outward with the solar wind. If so, the anisotropy is a desirable way to detect spatial gradients, because it can be associated with the local solar wind and magnetic field conditions. Anisotropic measurements made by Cerenkov detectors on Pioneers 10 and 11 were studied. It was found that local anisotropy varies greatly, but that the long term average is consistent with the global radial gradient measured between two spacecraft over a baseline of many AU.

Fillius, W.; Roelof, E. C.; Smith, E. J.; Wood, D.; Ip, W. H.

1985-01-01

123

High-energy cosmic rays and tests of basic principles of Physics. Looking at the Planck scale and beyond  

NASA Astrophysics Data System (ADS)

With the present understanding of data, the observed flux suppression for ultra-high energy cosmic rays (UHECR) at energies above 4.1019 eV can be a signature of the Greisen-Zatsepin-Kuzmin (GZK) cutoff or be related to a similar mechanism. But it may also correspond, for instance, to the maximum energies available at the relevant sources. In both cases, violations of special relativity modifying cosmic-ray propagation or acceleration at very high energy can potentially play a role. Other violations of fundamental principles of standard particle physics (quantum mechanics, energy and momentum conservation, vacuum homogeneity and "static" properties, effective space dimensions, quark confinement…) can also be relevant at these energies. In particular, UHECR data would in principle allow to set bounds on Lorentz symmetry violation (LSV) in patterns incorporating a privileged local reference frame (the "vacuum rest frame", VRF). But the precise analysis is far from trivial, and other effects can also be present. The effective parameters can be related to Planckscale physics, or even to physics beyond Planck scale, as well as to the dynamics and effective symmetries of LSV for nucleons, quarks, leptons and the photon. LSV can also be at the origin of GZK-like effects. In the presence of a VRF, and contrary to a "grand unification" view, LSV and other violations of standard principles can modify the internal structure of particles at very high energy and conventional symmetries may cease to be valid at energies close to the Planck scale. We present an updated discussion of these topics, including experimental prospects, new potentialities for high-energy cosmic ray phenomenology and the possible link with unconventional pre-Big Bang scenarios, superbradyon (superluminal preon) patterns… The subject of a possible superluminal propagation of neutrinos at accelerator energies is also dealt with.

Gonzalez-Mestres, L.

2014-04-01

124

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

125

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

126

Large area ion chambers for a high energy cosmic ray experiment  

NASA Technical Reports Server (NTRS)

High resolution measurement of the iron group nuclei was performed with the intention of determining individual abundances in the cosmic ray flux at the earth of particles with z = 22 to 30. Of the three types of dE/dx detectors used in the experiment, pulse ion chambers, Cerenkov radiators and scintillators, the first has the best z resolution over a wide range of particle z and energy. The plastic scintillators define the particle acceptance cone of the telescope while the Cerenkov detector aids in rejection of low energy particle background and measurement of particle velocity.

1976-01-01

127

Full-Sky Search for Ultra High Energy Cosmic Ray Anisotropies  

NASA Astrophysics Data System (ADS)

Using data from the SUGAR and the AGASA experiments taken during a 10 yr period with nearly uniform exposure to the entire sky, we search for anisotropy patterns in the arrival directions of cosmic rays with energies > 1019.6 eV. We determine the angular power spectrum from an expansion in spherical harmonics for modes out to = 5. Based on available statistics, we find no significant deviation from isotropy. We compare the rather modest results which can be extracted from existing data samples with the results that should be forthcoming as new full-sky observatories begin operation.

Anchordoqui, L. A.; Hojvat, C.; McCauley, T. P.; Paul, T. C.; Reucroft, S.; Swain, J. D.; Widom, Allan

2003-07-01

128

Cosmic-ray composition measurements with high-energy ionization spectrometers  

NASA Technical Reports Server (NTRS)

Element abundances of cosmic rays for elements Li through Si with energy above 0.8 GeV/amu were measured on a balloon-borne instrument containing a total absorption ionization spectrometer. Statistical techniques were used to analyze the five measurements of each particle to determine its charge and energy. The technique allows a determination of systematic errors to be made. Corrections for Landau fluctuations, spark-chamber inefficiency, and background particles were included. Comparison with other published results is made. There are differences in the shapes of the differential spectra determined from measurements using different techniques, and our intensities still lie somewhat below those of other workers.

Arens, J. F.; Ormes, J. F.

1975-01-01

129

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. Program summaryProgram title: TIERRAS for AIRES 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 10 eV shower with statistical sampling (thinning) below 10 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

130

A balloon-borne ionization spectrometer with very large aperture for the detection of high energy cosmic rays  

NASA Technical Reports Server (NTRS)

A balloon experiment which was used to determine the chemical composition of very high-energy cosmic rays up to and beyond 100 GeV/nucleon is described. The detector had a geometric factor of 1 sq m sr and a total weight on the balloon of 2100 kg. The apparatus consisted of an ionization spectrometer, spark chambers, and plastic scintillation and Cherenkov counters. It was calibrated at CERN up to 24 GeV/c protons and at DESY up to 7 GeV/c electrons. In October 1972 it was flown successfully on a stratospheric balloon.

Atallah, K.; Modlinger, A.; Schmidt, W. K. H.; Cleghorn, T. F.

1975-01-01

131

High-energy galactic cosmic rays in the magnetospheres of terrestrial exoplanets  

NASA Astrophysics Data System (ADS)

Theoretical arguments indicate that close-in terrestial exoplanets may have weak magnetic fields, especially in the case of planets more massive than Earth ("super- Earths"). Planetary magnetic fields, however, constitute one of the shielding layers which protect the planet against cosmic ray particles. In particular, a weak magnetic field results in a high particle flux to the top of the planetary atmosphere. For the case of cosmic ray protons, we numerically analyze the propagation of the particles through planetary magnetospheres. We evaluate the efficiency of magnetospheric shielding as a function of the particle energy (in the range 64 MeV ? E ? 500 GeV) and of the planetary magnetic field strength (in the range 0.05ME ?M? 3ME). In order to illustrate possible effects of weak magnetic fields, we show the dependency of the penetration energy on the planetary magnetic field strength. We discuss implications of increased particle fluxes, including the modification of atmospheric chemistry, destruction of atmospheric biomarker molecules, and potential biological implications.

Grießmeier, J.-M.; Stadelmann, A.; Grenfell, J. L.; Patzer, A. B. C.; von Paris, P.; Lammer, H.

2012-09-01

132

Engine-driven Relativistic Supernovae as Sources of Ultra High Energy Cosmic Rays  

NASA Astrophysics Data System (ADS)

Understanding the origin of the highest energy cosmic rays is a crucial step in probing new physics at energies unattainable by terrestrial accelerators. Their sources remain an enigma half a century after their discovery. 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 work we measure 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.

Ray, Alak; Chakraborti, Sayan

2011-08-01

133

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

134

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

135

Fermi LAT Results and Perspectives in Measurements of High Energy Galactic Cosmic Rays  

NASA Technical Reports Server (NTRS)

Real breakthrough during last 1-1.5 years in cosmic ray electrons: ATIC, HESS, Pamela, and finally Fermi-LAT. New quality data have made it possible to start quantitative modeling. With the new data more puzzles than before on CR electrons origin. Need "multi-messenger" campaign: electrons, positrons, gammas, X-ray, radio, neutrino... It is viable that we are dealing with at least two distinct mechanisms of "primary" electron (both signs) production: a softer spectrum of negative electrons, and a harder spectrum of both e(+)+e(-). Exotic (e.g. DM) origin is not ruled out. Upper limits on CR electrons anisotropy are set. Good perspectives to have the Fermi LAT results on proton spectrum and positron fraction.

Moiseev, Alexander

2010-01-01

136

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

SciTech Connect

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 Veron-Cetty Veron 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 51 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.

Abreu, P.

2012-01-01

137

Probing the origin of cosmic rays with extremely high energy neutrinos using the IceCube Observatory  

NASA Astrophysics Data System (ADS)

We have searched for extremely high energy neutrinos using data taken with the IceCube detector between May 2010 and May 2012. Two neutrino-induced particle shower events with energies around 1 PeV were observed, as reported previously. In this work, we investigate whether these events could originate from cosmogenic neutrinos produced in the interactions of ultrahigh energy cosmic rays with ambient photons while propagating through intergalactic space. Exploiting IceCube’s large exposure for extremely high energy neutrinos and the lack of observed events above 100 PeV, we can rule out the corresponding models at more than 90% confidence level. The model-independent quasidifferential 90% C.L. upper limit, which amounts to E2??e+??+??=1.2×10-7GeVcm-2s-1sr-1 at 1 EeV, provides the most stringent constraint in the energy range from 10 PeV to 10 EeV. Our observation disfavors strong cosmological evolution of the highest energy cosmic-ray sources such as the Fanaroff-Riley type II class of radio galaxies.

Aartsen, M. G.; Abbasi, R.; Ackermann, M.; Adams, J.; Aguilar, J. A.; Ahlers, M.; Altmann, D.; Arguelles, C.; Auffenberg, J.; Bai, X.; Baker, M.; Barwick, S. W.; Baum, V.; Bay, R.; Beatty, J. J.; Becker Tjus, J.; Becker, K.-H.; BenZvi, S.; Berghaus, P.; Berley, D.; Bernardini, E.; Bernhard, A.; Besson, D. Z.; Binder, G.; Bindig, D.; Bissok, M.; Blaufuss, E.; Blumenthal, J.; Boersma, D. J.; Bohm, C.; Bose, D.; Böser, S.; Botner, O.; Brayeur, L.; Bretz, H.-P.; Brown, A. M.; Bruijn, R.; Casey, J.; Casier, M.; Chirkin, D.; Christov, A.; Christy, B.; Clark, K.; Clevermann, F.; Coenders, S.; Cohen, S.; Cowen, D. F.; Cruz Silva, A. H.; Danninger, M.; Daughhetee, J.; Davis, J. C.; Day, M.; De Clercq, C.; De Ridder, S.; Desiati, P.; de Vries, K. D.; de With, M.; DeYoung, T.; Díaz-Vélez, J. C.; Dunkman, M.; Eagan, R.; Eberhardt, B.; Eisch, J.; 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.; Frantzen, K.; Fuchs, T.; Gaisser, T. K.; Gallagher, J.; Gerhardt, L.; Gladstone, L.; Glüsenkamp, T.; Goldschmidt, A.; Golup, G.; Gonzalez, J. G.; Goodman, J. A.; Góra, D.; Grandmont, D. T.; Grant, D.; Gretskov, P.; Groh, J. C.; Groß, A.; Ha, C.; Haj Ismail, A.; Hallen, P.; Hallgren, A.; Halzen, F.; Hanson, K.; Heereman, D.; Heinen, D.; Helbing, K.; Hellauer, R.; Hickford, S.; Hill, G. C.; Hoffman, K. D.; Hoffmann, R.; Homeier, A.; Hoshina, K.; Huelsnitz, W.; Hulth, P. O.; Hultqvist, K.; Hussain, S.; Ishihara, A.; Jacobi, E.; Jacobsen, J.; Jagielski, K.; Japaridze, G. S.; Jero, K.; Jlelati, O.; Kaminsky, B.; Kappes, A.; Karg, T.; Karle, A.; Kauer, M.; Kelley, J. L.; Kiryluk, J.; Kläs, J.; Klein, S. R.; Köhne, J.-H.; Kohnen, G.; Kolanoski, H.; Köpke, L.; Kopper, C.; Kopper, S.; Koskinen, D. J.; Kowalski, M.; Krasberg, M.; Kriesten, A.; Krings, K.; Kroll, G.; Kunnen, J.; Kurahashi, N.; Kuwabara, T.; Labare, M.; Landsman, H.; Larson, M. J.; Lesiak-Bzdak, M.; Leuermann, M.; Leute, J.; Lünemann, J.; Macías, O.; Madsen, J.; Maggi, G.; Maruyama, R.; Mase, K.; Matis, H. S.; McNally, F.; Meagher, K.; Merck, M.; Meures, T.; Miarecki, S.; Middell, E.; Milke, N.; Miller, J.; Mohrmann, L.; Montaruli, T.; Morse, R.; Nahnhauer, R.; Naumann, U.; Niederhausen, H.; Nowicki, S. C.; Nygren, D. R.; Obertacke, A.; Odrowski, S.; Olivas, A.; Omairat, A.; O'Murchadha, A.; Paul, L.; Pepper, J. A.; Pérez de los Heros, C.; Pfendner, C.; Pieloth, D.; Pinat, E.; Posselt, J.; Price, P. B.; Przybylski, G. T.; Rädel, L.; Rameez, M.; Rawlins, K.; Redl, P.; Reimann, R.; Resconi, E.; Rhode, W.; Ribordy, M.; Richman, M.; Riedel, B.; Rodrigues, J. P.; Rott, C.; Ruhe, T.; Ruzybayev, B.; Ryckbosch, D.; Saba, S. M.; Sander, H.-G.; Santander, M.; Sarkar, S.; Schatto, K.; Scheriau, F.; Schmidt, T.; Schmitz, M.; Schoenen, S.; Schöneberg, S.; Schönwald, A.; Schukraft, A.; Schulte, L.; Schulz, O.; Seckel, D.; Sestayo, Y.; Seunarine, S.; Shanidze, R.; Sheremata, C.; Smith, M. W. E.; Soldin, D.; Spiczak, G. M.; Spiering, C.; Stamatikos, M.; Stanev, T.; Stanisha, N. A.; Stasik, A.; Stezelberger, T.; Stokstad, R. G.; Stößl, A.; Strahler, E. A.; Ström, R.; Sullivan, G. W.; Taavola, H.; Taboada, I.; Tamburro, A.; Tepe, A.; Ter-Antonyan, S.; Teši?, G.; Tilav, S.; Toale, P. A.; Tobin, M. N.; Toscano, S.; Unger, E.; Usner, M.; Vallecorsa, S.; van Eijndhoven, N.; Van Overloop, A.; van Santen, J.; Vehring, M.; Voge, M.; Vraeghe, M.; Walck, C.; Waldenmaier, T.; Wallraff, M.; Weaver, Ch.; Wellons, M.; Wendt, C.; Westerhoff, S.; Whitehorn, N.; Wiebe, K.; Wiebusch, C. H.; Williams, D. R.; Wissing, H.; Wolf, M.; Wood, T. R.; Woschnagg, K.; Xu, D. L.; Xu, X. W.; Yanez, J. P.; Yodh, G.; Yoshida, S.; Zarzhitsky, P.; Ziemann, J.; Zierke, S.; Zoll, M.

2013-12-01

138

From high energy gamma sources to cosmic rays, one century after their discovery. Summary of the SciNeGHE2012 workshop  

NASA Astrophysics Data System (ADS)

The interplay between studies and measurements concerning high energy gamma ray sources and cosmic rays was the main focus of the 2012 edition of the Science with the New Generation of High Energy Gamma-ray Experiments (SciNeGHE) workshop. The workshop started with a special session devoted to the history of the cosmic radiation research in the centenary of its discovery, with a special attention also to the history of very high energy gamma-ray astronomy. The main results and the current status from space-borne and ground-based gamma and cosmic ray experiments were presented, together with the state of the art theoretical scenarios. The future of the field was studied through the presentation of many new experiment concepts, as well as through the analysis of new observational techniques and R&D programs.

Longo, Francesco

2013-06-01

139

First Mass-resolved Measurement of High-Energy Cosmic-Ray Antiprotons.  

PubMed

We report new results for the cosmic-ray antiproton-to-proton ratio from 3 to 50 GeV at the top of the atmosphere. These results represent the first measurements, on an event-by-event basis, of mass-resolved antiprotons above 18 GeV. The results were obtained with the NMSU-WIZARD/CAPRICE98 balloon-borne magnet spectrometer equipped with a gas-RICH (Ring-Imaging Cerenkov) counter and a silicon-tungsten imaging calorimeter. The RICH detector was the first ever flown that is capable of identifying charge-one particles at energies above 5 GeV. The spectrometer was flown on 1998 May 28-29 from Fort Sumner, New Mexico. The measured p&d1;/p ratio is in agreement with a pure secondary interstellar production. PMID:10813676

Bergström; Boezio; Carlson; Francke; Grinstein; Khalchukov; Suffert; Hof; Kremer; Menn; Simon; Stephens; Ambriola; Bellotti; Cafagna; Ciacio; Circella; De Marzo C; Finetti; Papini; Piccardi; Spillantini; Bartalucci; Ricci; Casolino; De Pascale MP; Morselli; Picozza; Sparvoli; Bonvicini; Schiavon; Vacchi; Zampa; Mitchell; Ormes; Streitmatter; Bravar; Stochaj

2000-05-10

140

Can multistate dark matter annihilation explain the high-energy cosmic ray lepton anomalies?  

SciTech Connect

Multistate dark matter (DM) models with small mass splittings and couplings to light hidden sector bosons have been proposed as an explanation for the PAMELA/Fermi/H.E.S.S. high-energy lepton excesses. We investigate this proposal over a wide range of DM density profiles, in the framework of concrete models with doublet or triplet dark matter and a hidden SU(2) gauge sector that mixes with standard model hypercharge. The gauge coupling is bounded from below by the DM relic density, and the Sommerfeld enhancement factor is explicitly computable for given values of the DM and gauge boson masses M, {mu} and the (largest) dark matter mass splitting {delta}M{sub 12}. Sommerfeld enhancement is stronger at the galactic center than near the Sun because of the radial dependence of the DM velocity profile, which strengthens the inverse Compton (IC) gamma ray constraints relative to usual assumptions. We find that the PAMELA/Fermi/H.E.S.S. lepton excesses are marginally compatible with the model predictions, and with CMB and Fermi gamma ray constraints, for M congruent with 800 GeV, {mu} < or approx. 200 MeV, and a dark matter profile with noncuspy Einasto parameters {alpha} > or approx. 0.20, r{sub s{approx}}30 kpc. We also find that the annihilating DM must provide only a subdominant (< or approx. 0.4) component of the total DM mass density, since otherwise the boost factor due to Sommerfeld enhancement is too large.

Cirelli, Marco [CERN Theory Division, CERN, Case C01600, CH-1211 Geneve (Switzerland); Insitut de Physique Theorique, CNRS URA 2306 and CEA/Saclay, F-91191 Gif-sur-Yvette (France); Cline, James M. [CERN Theory Division, CERN, Case C01600, CH-1211 Geneve (Switzerland); Physics Department, McGill University, 3600 University Street, Montreal, Quebec, H3A 2T8 (Canada)

2010-07-15

141

Abundances and energy spectra of high energy heavy cosmic-ray nuclei  

SciTech Connect

We have measured the relative abundances of the cosmic rays in the iron group region at energies from a few GeV/amu to approximately 70 GeV/amu. This is done using a balloon-borne instrument consisting of gas ionization chambers, a plastic scintillator, a plastic Cherenkov counter, and a CO/sub 2/ gas Cherenkov counter. The instrument was flown from Palestine, Texas in the fall of 1982 for a total exposure of 62 m/sup 2/-ster-hr at an average atmospheric depth of 4 g/cm/sup 2/. The elemental charge was determined for a combination of the scintillator and plastic Cherenkov detector. Results are reported on the /sub 22/Ti//sub 26/Fe, /sub 24/Cr//sub 26/Fe, /sub 20/Ca//sub 26/Fe, and /sub 28/Ni//sub 28/Fe abundance ratios from 2 to 70 GeV/amu. Within this work results on the previously unused method of relativistic rise in gas ionization chambers is detailed as well as results on the return to nonsaturation of plastic scintillators.

Barthelmy, S.D.

1985-01-01

142

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

143

Germ cell mutagenesis in medaka fish after exposures to high-energy cosmic ray nuclei: A human model  

NASA Astrophysics Data System (ADS)

Astronauts beyond the Earth's orbit are exposed to high-energy cosmic-ray nuclei with high values of linear energy transfer (LET), resulting in much more biological damage than from x-rays or -rays and may result in mutations and cancer induction. The relative biological effectiveness of these nuclei depends on the LET, rising to as high as 50 at LET values of 100-200 keV/µm. An endpoint of concern is germ cell mutations passed on to offspring, arising from exposure to these nuclei. A vertebrate model for germ cell mutation is Medaka fish (Oryzias latipes). We exposed wild type males to doses of 1 GeV per nucleon Fe nuclei or to 290 MeV per nucleon C nuclei. They were mated to females with recessive mutations at five-color loci. The transparent embryos from >100 days of mating (representing exposed sperm, spermatids, or spermatogonia) were observed so as to detect dominant lethal mutations and total color mutations, even though the embryos might not hatch. The relative number of mutant embryos as a function of dose were compared with those induced by -rays. The relative biological effectiveness values for dominant lethal mutations and total color mutations for exposed sperm and spermatids were 1.3-2.1 for exposure to C nuclei and 1.5-3.0 for exposure to Fe nuclei. (The spermatogonial data were uncertain.) These low values, and the negligible number of viable mutations, compared with those for mutations in somatic cells and for neoplastic transformation, indicate that germ cell mutations arising from exposures to cosmic ray nuclei are not a significant hazard to astronauts. astronaut hazards | linear energy transfer | relative biological effect

Shimada, Atsuko; Shima, Akihiro; Nojima, Kumie; Seino, Yo; Setlow, Richard B.

2005-04-01

144

Germ cell mutagenesis in medaka fish after exposures to high-energy cosmic ray nuclei: A human model  

PubMed Central

Astronauts beyond the Earth's orbit are exposed to high-energy cosmic-ray nuclei with high values of linear energy transfer (LET), resulting in much more biological damage than from x-rays or ?-rays and may result in mutations and cancer induction. The relative biological effectiveness of these nuclei depends on the LET, rising to as high as ?50 at LET values of ?100-200 keV/?m. An endpoint of concern is germ cell mutations passed on to offspring, arising from exposure to these nuclei. A vertebrate model for germ cell mutation is Medaka fish (Oryzias latipes). We exposed wild type males to doses of 1 GeV per nucleon Fe nuclei or to 290 MeV per nucleon C nuclei. They were mated to females with recessive mutations at five-color loci. The transparent embryos from >100 days of mating (representing exposed sperm, spermatids, or spermatogonia) were observed so as to detect dominant lethal mutations and total color mutations, even though the embryos might not hatch. The relative number of mutant embryos as a function of dose were compared with those induced by ?-rays. The relative biological effectiveness values for dominant lethal mutations and total color mutations for exposed sperm and spermatids were 1.3-2.1 for exposure to C nuclei and 1.5-3.0 for exposure to Fe nuclei. (The spermatogonial data were uncertain.) These low values, and the negligible number of viable mutations, compared with those for mutations in somatic cells and for neoplastic transformation, indicate that germ cell mutations arising from exposures to cosmic ray nuclei are not a significant hazard to astronauts.

Shimada, Atsuko; Shima, Akihiro; Nojima, Kumie; Seino, Yo; Setlow, Richard B.

2005-01-01

145

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

146

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

147

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

148

First observation of high-energy cosmic ray events obtained in coincidence between EAS-TOP and LVD at Gran Sasso.  

NASA Astrophysics Data System (ADS)

The authors present the first results of the combined measurements of the EAS-TOP (at the surface) and LVD (deep underground) detectors operating as a combined telescope in the study of UHE cosmic rays and their interactions. Examples of different classes of events and their significance in different high-energy and astrophysical studies are discussed.

Aglietta, M.; Alpat, B.; Alyea, E. D.

1992-12-01

149

On Measuring the Ultra High Energy Cosmic Ray Spectrum above 3 x 10^18 eV by Pierre Auger Observatory  

NASA Astrophysics Data System (ADS)

We report the Ultra High Energy Cosmic Ray (UHECR) spectrum above 3 x 10^18 eV measured by Pierre Auger Observatory (PAO). PAO uses both the Fluorescence detector (FD) and the water cerenkov tank surface detectors (SD). PAO offers an exciting opportunity to compare the systematics of and cross-calibrate FD and SD for the first time.

Lee, Joong

2006-04-01

150

Can multistate dark matter annihilation explain the high-energy cosmic ray lepton anomalies?  

Microsoft Academic Search

Multistate dark matter (DM) models with small mass splittings and couplings to light hidden sector bosons have been proposed as an explanation for the PAMELA\\/Fermi\\/H.E.S.S. high-energy lepton excesses. We investigate this proposal over a wide range of DM density profiles, in the framework of concrete models with doublet or triplet dark matter and a hidden SU(2) gauge sector that mixes

Marco Cirelli; James M. Cline

2010-01-01

151

Evolution of the ultra high energy cosmic ray spectrum by transport equation  

SciTech Connect

Ultra-high energy proton primaries interacting with the 3/sup 0/K photon background are treated as a transport phenomenon. Baryon number is explicitly conserved and the evolved spectrum develops a bump at a scale of order 5x10/sup 19/ eV, below the cutoff, due to the pile-up of energy degraded protons. This may correspond in part to the observed ankle structure in the CR spectrum.

Hill, C.T.; Schramm, D.N.

1983-04-01

152

The Dynamics of High-energy Cosmic Rays In Near Earth Space and Earthquake Prediction  

NASA Astrophysics Data System (ADS)

The existence of correlation between short-term variations of high energy charged par- ticle fluxes in the near Earth space and seismic activity was discovered at the end of 1980s in MARIA experiment on board SALYUT-7 orbital station. Basing on 15 years investigations of high energy charged particles fluxes dynamics in magnetosphere by means of instruments installed on spacecraft it was found the correlation between the variations of particle intensities and earthquakes as temporal and spatial as well. It dis- plays as the sudden increases of counting rate of charged particles several hours before active phase of earthquakes with magnitudes more then 4 (Richter scale) The detailed study of electron and proton flux variations under the radiation belt was continued by means of MARIA-2 magnetic spectrometer on board MIR orbital station, and by in- strument ELECTRON on board INTERCOSMOS-BULGARIA-1300 and METEOR- 3 satellites. The results of analysis of bursts of high-energy charged particle fluxes on the base of these experiments and data of GAMMA and SAMPEX satellites as well are presented. All these experiments confirmed the existence of correlation between short-term sharp increases of particle intensities and seismic phenomena. The possi- ble nature of this correlation is discussed. The phenomenon is explained by resonance interaction of VLF electromagnetic emission of seismic origin with charged particles trapped in radiation belt above an epicentre and following drift of disturbance along the longitude in the same L-shell as epicentre has. The fact of spatial correlation of epicentre position and place of registration of intensity variation gives the possibility to obtain the coordinates of future earthquake some hours before its beginning with accuracy up to 100 km in real time and so use this precursor in practice.

Alexandrin, S.; Galper, A.; Grishantseva, L.; Koldashov, S.; Maslennikov, L.; Murashov, A.; Picozza, P.; Voronov, S.

153

New Estimation of the Spectral Index of High-Energy Cosmic Rays as Determined by the Compton-Getting Anisotropy  

Microsoft Academic Search

The amplitude of the Compton-Getting (CG) anisotropy contains the power-law index of the cosmic-ray energy spectrum. Based on this relation and using the Tibet air shower array data, we measure the cosmic-ray spectral index to be -3.03 +\\/- 0.55stat +\\/- <0.62syst between 6 and 40 TeV, consistent with -2.7 from direct energy spectrum measurements. Potentially, this CG anisotropy analysis can

M. Amenomori; X. J. Bi; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Zhaoyang Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; A. F. Li; J. Y. Li; Y.-Q. Lou; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; S. Ozawa; J. R. Ren; T. Saito; M. Sakata; T. K. Sako; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; S. Torii; H. Tsuchiya; S. Udo; B. Wang; H. Wang; X. Wang; Y. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou

2008-01-01

154

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

155

Ultra-High-Energy Cosmic-Ray Acceleration by Magnetic Reconnection in Newborn Accretion-induced Collapse Pulsars  

NASA Astrophysics Data System (ADS)

We here investigate the possibility that the ultra-high-energy cosmic-ray (UHECR) events observed above the Greisen-Zatsepin-Kuzmin (GZK) limit are mostly protons accelerated in reconnection sites just above the magnetosphere of newborn millisecond pulsars that are originated by accretion-induced collapse (AIC). We formulate the requirements for the acceleration mechanism and show that AIC pulsars with surface magnetic fields 1012 G=1020 eV. Because the expected rate of AIC sources in our Galaxy is very small (~10-5 yr-1), the corresponding contribution to the flux of UHECRs is negligible and the total flux is given by the integrated contribution from AIC sources produced by the distribution of galaxies located within the distance that is unaffected by the GZK cutoff (~50 Mpc). We find that reconnection should convert a fraction ?>~0.1 of magnetic energy into UHECRs in order to reproduce the observed flux.

de Gouveia Dal Pino, Elisabete M.; Lazarian, Alex

2000-06-01

156

Measurement of the Flux of Ultra-High Energy Cosmic Rays by the Telescope Array FADC Fluorescence Detectors  

NASA Astrophysics Data System (ADS)

Ultra-high energy cosmic rays (UHECRs) produce the most powerful collisions between single particles and atmospheric matter. They have been studied since the early 20th century yet, to this date, there is no clear answer as to the acceleration process responsible for their production. The Telescope Array Project is an experiment designed to observe the showers of particles produced as by-products of the interactions between UHECRs and the atmosphere. As a hybrid experiment, it currently utilizes 38 fluorescence detectors (FDs) divided between three sites overlooking an array of 507 surface detectors (SDs). The project's mission is to study the energy, composition and origin of UHECRs using a variety of techniques which may include some or all of the experiment's apparatus. This document, in particular, is a presentation of the UHECR energy spectrum measured at Telescope Array using the fluorescence detection technique in monocular mode. Only data from the 24 FDs at Black Rock Mesa (BR) and Long Ridge (LR) stations are used here.

Stratton, Sean R.

157

Ultra-high energy cosmic ray acceleration by accretion-induced collapse pulsars in the local universe  

NASA Astrophysics Data System (ADS)

We discuss the possibility that the ultra-high energy cosmic rays (UHECRs) observed above the GZK limit could be mostly protons accelerated in magnetic reconnection sites just above the magnetosphere of newborn millisecond pulsars originated by accretion-induced-collapse (AICpulsars). We find that the observed total flux of UHECRs can be produced by the integrated contribution from all AICpulsars of the local distribution of galaxies within a distance which is unaffected by the GZK cutoff (< 50 Mpc) (de Gouveia Dal Pino & Lazarian 2000). We also examine the potential acceleration mechanisms in the reconnection site and find that first-order Fermi acceleration cannot provide either sufficient efficiency (due to synchrotron losses) or the expected spectral index for the UHECR particle spectrum. This leaves the one-shot acceleration via an induced electric field within the reconnection region as the only viable process for UHECR acceleration. We find that AIC-pulsars with surface magnetic fields 1012 - 1015 G, and spin periods ˜ 1 - 60 ms, are able to accelerate particles to energies > 1020 eV, but the magnetic field just above the Alfv´en surface must be predominantly toroidal for the particles to be allowed to escape from the acceleration zone without being deflected. Synchrotron losses impose important constraints on the magnetic field topology of any UHECR accelerators involving compact sources with strong magnetic fields.

de Gouveia dal Pino, E. M.; Lazarian, A.

2001-08-01

158

Design of a wireless sensor network with nanosecond time resolution for mapping of high-energy cosmic ray shower events  

NASA Astrophysics Data System (ADS)

We describe a low-cost, low-power wireless sensor network we are developing for high time-resolution (ns-scale) characterization of particle showers produced by ultra-high-energy (UHE) cosmic rays, to infer shower direction at sites where hard-wired data connections may be inconvenient to install. The front-end particle detector is a scintillator block monitored by a photomultiplier tube (PMT). We keep the sensor nodes synchronized to within 1 ns using periodic highintensity optical pulses from a light-emitting-diode (LED) overdriven at very high current (~30 A) in short (4 ns) bursts. With minimal optics, this signal is resolvable under free-space transmission in ambient light conditions at multi-meter distances using a high-speed avalanche photodiode (APD) receiver at each node. PMT pulse waveforms are digitized relative to this precise time reference on a Field Programmable Gate Array (FPGA) using a Time-over-Threshold (ToT)/Time-to-Digital Converter (TDC) digitizer developed at BNL. A central server receives timestamped, digitized PMT pulse waveforms from the sensor nodes via Wi-Fi and performs real-time data visualization & analysis. Total cost per sensor node is a few thousand dollars, with total power consumption per sensor node under 1 Watt, suitable for, e.g., solar-powered installations at remote field locations.

Frank, Michael P.; Junnarkar, Sachin S.; Fagan, Triesha; O'Neal, Ray H.; Takai, Helio

2010-04-01

159

The Tunka - Multi-component EAS detector for high energy cosmic ray studies  

NASA Astrophysics Data System (ADS)

The EAS Cherenkov array Tunka-133, with about 3 km2 sensitive area, has been installed in the Tunka Valley, Siberia. The accessible energy range is 1015-1018 eV. In this contribution, a description of the array and main results obtained so far are presented. A current update of the array includes the deployment of scintillation stations, radio antennas, as well as optical stations. The deployments of these optical stations are the first step towards Tunka-HiSCORE, a wide-angle, large field-of-view gamma-ray telescope.

Berezhnev, S. F.; Besson, D.; Budnev, N. M.; Büker, M.; Brüeckner, M.; Chiavassa, A.; Chvalaev, O. A.; Gress, O. A.; Dyachok, A. N.; Epimakhov, S. N.; Hampf, D.; Haungs, A.; Hiller, R.; Horns, D.; Ivanova, A.; Karpov, N. I.; Kalmykov, N. N.; Kazarina, Yu.; Konstantinov, E. N.; Kostunin, D.; Korobchenko, A. V.; Korosteleva, E. E.; Kozhin, V. A.; Kunnas, M.; Kuzmichev, L. A.; Lubsandorzhiev, B. K.; Lubsandorzhiev, N. B.; Mirgazov, R. R.; Monhoev, R.; Nachtigall, R.; Panasyuk, M. I.; Pankov, L. V.; Pankov, A. L.; Pokhorukov, A.; Popova, E. G.; Porelli, A.; Prosin, V. V.; Ptuskin, V. S.; Rowell, G. P.; Schröder, F. G.; Semeney, Yu. A.; Shaibonov, B. A.; Silaev, A. A.; Silaev, A. A.; Skurikhin, A. V.; Spiering, C.; Spitschan, D.; Sveshnikova, L. G.; Wischnewski, R.; Yashin, I. V.; Zagorodnikov, A. V.

2013-12-01

160

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

161

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

162

Constraints on the Acceleration of Ultra-High-Energy Cosmic Rays in Accretion-induced Collapse Pulsars  

NASA Astrophysics Data System (ADS)

We have recently proposed that ultra-high-energy cosmic rays (UHECRs) observed above the Greisen-Zatsepin-Kuzmin (GZK) limit could be mostly protons accelerated in reconnection sites just above the magnetosphere of newborn millisecond pulsars originated by accretion-induced collapse (AIC). Although the expected rate of AIC sources in our own Galaxy is very small (~10-5 yr-1), our estimates have shown that the observed total flux of UHECRs could be obtained from the integrated contribution of AIC pulsars in the whole distribution of galaxies located within the distance that is unaffected by the GZK cutoff (~50 Mpc). We examine the potential acceleration mechanisms in the magnetic reconnection site and find that first-order Fermi acceleration cannot provide sufficient efficiency. To prevent synchrotron losses, only very small deflection angles of the UHECRs would be allowed in the strong magnetic fields of a pulsar, which is contrary to the requirements for efficient Fermi acceleration. This leaves one-shot acceleration via an induced electric field within the reconnection region as the only viable process for UHECR acceleration. We formulate the constraints on both the magnetic field topology and strength in order to accelerate the particles and allow them to freely escape from the system. Under fast reconnection conditions, we find that AIC pulsars with surface magnetic fields 1012=1020 eV, but the magnetic field just above the Alfvén surface must be predominantly toroidal for the particles to be allowed to escape from the acceleration zone without being deflected. Synchrotron losses bring potentially important constraints on the magnetic field geometry of any UHECR accelerators involving compact sources with strong magnetic fields.

de Gouveia Dal Pino, Elisabete M.; Lazarian, A.

2001-10-01

163

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

164

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

165

Investigating cosmic ray coincidences  

NASA Astrophysics Data System (ADS)

Every laboratory has its own supply of high energy particles. Secondary cosmic rays provide a sea level flux of muons at a rate of about 1 cm-2 min-1. This article describes an extracurricular A-level investigation that indicates muon-electron collisions in the roof of the laboratory.

Dunne, Peter; Miller, Alex

2001-07-01

166

On the Possibility of Radar Detection of Ultra-high Energy Cosmic Ray- and Neutrino-induced Air Showers  

NASA Technical Reports Server (NTRS)

We show that cosmic rays air showers resulting from primaries with energies above 10(sup 19) eV should be straightforward to detect with radar ranging techniques, where the radar echoes are produced by scattering from the column of ionized air produced by the shower.

Gorham, P.

1999-01-01

167

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

168

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...

169

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

170

High-Energy Cutoff for Solar Cosmic Rays by the Data of Large Non-Standard Detectors  

NASA Astrophysics Data System (ADS)

A problem of the upper energy limit for solar cosmic rays (SCR) is studied. Formerly, this limit has been estimated mostly by the data of world network of standard detectors of cosmic rays — neutron monitors, muon telescopes and ionization chambers. Recently, it became possible to use for this purpose also the data of some large non-standard detectors (Baksan Underground Scintillation telescope BUST, Extensive Air Shower (EAS) Arrays like Carp et and Andyrchy, project GRAND Array and others). Even though those detectors have been designed for resolving quite different nuclear and astrophysical problems, nevertheless, they proved to be sensible to the effects caused by powerful sporadic manifestations of the solar activity. These observations allow to advance into the energy range above 100 GeV and understand more distinctly the extreme potentialities of solar accelerators.

Miroshnichenko, Leonty I.

2003-07-01

171

ANALYSIS OF LARGE-SCALE ANISOTROPY OF ULTRA-HIGH ENERGY COSMIC RAYS IN HiRes DATA  

SciTech Connect

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 {theta} {sub 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 {theta} {sub s} > 10 deg. 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.; 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.; Gray, R. C.; Hanlon, W. F. [Department of Physics and High Energy Astrophysics Institute, University of Utah, Salt Lake City, UT 84112 (United States); Amann, J. F.; Hoffman, C. M. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Finley, C. B. [Department of Physics and Nevis Laboratories, Columbia University, New York, NY 10027 (United States)] (and others)

2010-04-10

172

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

173

Ultra-High Energy Cosmic Neutrinos  

NASA Astrophysics Data System (ADS)

Astrophysical processes appear to produce particles with energies of at least 10^19-20 eV. Yet extra-galactic astronomy appears to be limited for photons with energies above 10^14 eV due to absorption. Neutrino astronomy offers the possibility to perform extra-galactic astronomy to these energies and beyond without an absorption cutoff. In addition, the interactions of ultra-high energy (UHE) neutrinos of cosmic origin with local matter may reveal exotic new physics processes that are unavailable to modern accelerators. UHE neutrino telescopes based on optical detection techniques that are currently operating and under construction will soon have apertures on the scale of 10 km^3-sr with excellent thresholds. Radio and acoustic detection techniques have been demonstrated in laboratory experiments and are being used to instrument apertures from 10 to to 10,000 km^3-sr for neutrinos with energies above 10^16 eV. Neutrino telescopes based on radio detection include the RICE detectors placed on the Amanda strings at the South Pole. The GLUE antennas pointed at the Moon have set limits on the neutrino intensity at higher energies. The best sensitivity at the highest energies comes from the FORTE satellite which looked for interactions in Greenland ice. The upcoming ANITA long-duration balloon flights over Antarctica will be sensitive to neutrinos produced by the interactions of cosmic rays with the cosmic microwave background radiation. Using the acoustic technique, the SAUND collaboration recently performed a UHE neutrino search using hydrophones in the deep sea near the Bahamas. Investigations for even larger apertures include several other detection possibilities, including placing radio and acoustic sensors in large underground salt formations. The acoustic technique may find promise in solid media currently under investigation. The neutrino sensitivity of current and proposed telescopes based on optical, radio, acoustic techniques will be compared for both specific models and in a model-independent fashion.

Saltzberg, David

2006-04-01

174

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

NASA Astrophysics Data System (ADS)

We have measured the cosmic ray spectrum at energies above $10^{17}$ eV 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 observation of a feature known as the ``ankle'' near $3\\times 10^{18}$ eV, and strong evidence for a suppression near $6\\times 10^{19}$ eV.

Abbasi, R.; Abuzayyad, T.; Amman, J.; Archbold, G.; Atkins, R.; Bellido, J.; Belov, K.; Belz, J.; Benzvi, S.; Bergman, D.

2005-07-01

175

Gamma rays, cosmic rays, and galactic structure  

NASA Technical Reports Server (NTRS)

Observations of cosmic and gamma radiation by SAS-2 satellite are summarized and analyzed to determine processes responsible for producing observed galactic radiation. In addition to the production of gamma rays in discrete galactic objects such as pulsars, there are three main mechanisms by which high-energy (greater than 100 MeV) radiation is produced by high-energy interactions involving cosmic rays in interstellar space. These processes, which produce what may be called diffuse galactic gamma-rays, are: (1) the decay of pi mesons produced by interactions of cosmic ray nucleons with interstellar gas nuclei; (2) the bremsstrahlung radiation produced by cosmic ray electrons interacting in the Coulomb fields of nuclei of interstellar gas atoms; and (3) Compton interactions between cosmic ray electrons and low-energy photons in interstellar space.

Stecker, F. W.

1977-01-01

176

Correlation of the ultra high energy cosmic rays with different classes of extragalactic objects: contribution of the nearest and brightest members of sample  

NASA Astrophysics Data System (ADS)

The correlations of ultra high energy cosmic rays (UHECR) arrival directions, detected in the experiments AGASA and SUGAR, with sky distribution of extragalactic objects of different classes (potential cosmic ray sources) are investigated. Contrary to previous investigations of various authors with the use of significant number of objects of different classes (about hundreds in a samples), we investigated the correlation with the brightest and nearest objects of each class, as the possibility to detect cosmic rays (CR) from them increases owing to a greater expected flow of CR and less energy losses during CR propagation. Using the Monte-Carlo method, we investigated correlation of UHECRs with first 3, 5, 10 and 20 objects among the nearest and brightest of Abell clusters, radio galaxies, ultra luminous infrared galaxies, BL Lacs, and also with 10 closest superclusters of galaxies. The correlation of AGASA CR with five brightest radio galaxies (owing to coincidence of the radio galaxy 3C123 with a CR doublet) and with ten brightest infrared galaxies (9 pairs of a galaxy -- CR for six galaxies), with probability of a random realization of 0.004 and 0.0007, respectively, is found to be significant. From the calculated generation energy of CR in potential sources, the nature of particles (protons or nuclei of iron) is determined. For events of the detector SUGAR, an appreciable clusterisation and correlation with extragalactic objects under consideration are not revealed.

Elyiv, A. A.; Hnatyk, B. I.

2006-07-01

177

Cosmic Necklaces and Ultrahigh Energy Cosmic Rays  

SciTech Connect

Cosmic necklaces are hybrid topological defects consisting of monopoles and strings, with two strings attached to each monopole. We argue that the cosmological evolution of necklaces may significantly differ from that of cosmic strings. The typical velocity of necklaces can be much smaller than the speed of light, and the characteristic scale of the network much smaller than the horizon. We estimate the flux of high-energy protons produced by monopole annihilation in the decaying closed loops. For some reasonable values of the parameters it is comparable to the observed flux of ultrahigh-energy cosmic rays. {copyright} {ital 1997} {ital The American Physical Society}

Berezinsky, V. [INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi (Antarctica) (Italy)] [INFN, Laboratori Nazionali del Gran Sasso, 67010 Assergi (Antarctica) (Italy); Vilenkin, A. [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)] [Institute of Cosmology, Department of Physics and Astronomy, Tufts University, Medford, Massachusetts 02155 (United States)

1997-12-01

178

Diffuse fluxes of cosmic high-energy neutrinos  

NASA Technical Reports Server (NTRS)

Production spectra of high-energy neutrinos from galactic cosmic-ray interactions with interstellar gas and extragalactic ultrahigh-energy cosmic-ray interactions with microwave blackbody photons are presented and discussed. These production processes involve the decay of charged pions and are thus related to the production of cosmic gamma rays from the decay of neutral pions. Estimates of the neutrino fluxes from various diffuse cosmic sources are then made, and the reasons for significant differences with previous estimates are discussed. Small predicted event rates for a DUMAND (deep underwater muon and neutrino detector) type detection system, combined with a possible significant flux of prompt neutrinos from the atmosphere above 50 TeV, may make the study of diffuse extraterrestrial neutrinos more difficult than previously thought.

Stecker, F. W.

1979-01-01

179

A new method of ionization-neutron calorimeter for direct investigation of high-energy electrons and primary nuclei of cosmic-rays up to the ``knee'' region  

NASA Astrophysics Data System (ADS)

A new technique of the Ionization Neutron Calorimeter (INCA) to be installed aboard a satellite or a space station is capable of opening new horizons for cosmic-ray physics. The main goal of the experiment proposed is studying local nearby sources of high-energy cosmic rays by measuring the spectrum and composition of the nuclear component with the energy resolution of better than 30% that is sufficient for solution of these problems in the energy range 0.1-10 PeV, i.e., in the so-called "knee" region, and the spectrum of primary electrons in the energy range 0.1-10 TeV with the proton-background suppression factor up to 10 7. In addition, this experiment can provide new information on the cosmic-ray gamma-radiation in the energy interval 30 GeV-1 TeV, neutrons and gamma-rays from solar flares, and the existence of very massive exotic charged particles in cosmic radiation. The INCA is a calorimeter combining properties of conventional ionization calorimeters and classical neutron monitors. It can measure both the ionization produced by charged particles and evaporation neutrons arising as a result of excitation of heavy-absorber nuclei by cascade particles. The advantages of the INCA are not only excellent electron-proton separation but a high geometry factor of about 2 m2sr/ ton owing to the INCA optimized composition and shape, whereas conventional ionization calorimeters are usually limited by geometry factor on the order of 0.1 m2sr/ ton. To verify the INCA concept, a prototype was constructed and exposed to pion and proton accelerator beams with energies of 4 and 70 GeV, respectively, and to an electron beam with an energy of 200-550 MeV. The experimental data obtained agree well with the results of a Monte Carlo simulation by the SHIELD code.

Alexandrov, K. V.; Ambrosio, M.; Ammosov, V. V.; Antonova, V. P.; Aramo, C.; Bonvicini, V.; Chechin, V. A.; Chubenko, A. P.; Drobzhev, V. I.; Erlykin, A. D.; Fujii, M.; Hatano, Y.; Kryukov, S. V.; Ladygin, E. A.; Lomonosov, B. N.; Merzon, G. I.; Mukhamedshin, R. A.; Murashov, V. N.; Pavlyuchenko, V. P.; Panasyuk, M. I.; Roganova, T. M.; Roussetski, A. S.; Ryabov, V. A.; Ryazhskaya, O. G.; Saito, T.; Sasaki, H.; Shchepetov, A. L.; Sobolevskii, N. M.; Starkov, N. I.; Sveshnikova, L. G.; Trostin, I. S.; Tsarev, V. A.; Vacchi, A.; Wolfendale, A.; Yanagita, T.; Zatsepin, G. T.; Zhdanov, G. B.; Zhukov, A. P.

2001-02-01

180

Reexamination of the cosmic-ray helium spectrum and the He-3/He-4 ratio at high energies  

SciTech Connect

Cosmic ray He spectral data collected by satellites in earth orbit were used to examine a recent measurement of He-3 of about 6 GeV/nucleon, an overabundance compared to predictions made with a leaky box approach. The spectral rigidity index at the time of the measurement was no more than 2.55, indicating a near-earth He-3/He-4 ratio of 0.17, although an index in the range 10-20 GV and a ratio of close to 0.24 is the usual value. New magnetic spectrometer data, however, show that a single spectral rigidity value for the near-earth He-3/He-4 ratio cannot be correct. The Fokker-Planck equation is used to demonstrate that solar modulation of the He flux yields an energy/abundance distribution close to observational data. 31 references.

Webber, W.R.; Golden, R.L.; Mewaldt, R.A.

1987-01-01

181

A reexamination of the cosmic-ray helium spectrum and the He-3/He-4 ratio at high energies  

NASA Technical Reports Server (NTRS)

Cosmic ray He spectral data collected by satellites in earth orbit were used to examine a recent measurement of He-3 of about 6 GeV/nucleon, an overabundance compared to predictions made with a leaky box approach. The spectral rigidity index at the time of the measurement was no more than 2.55, indicating a near-earth He-3/He-4 ratio of 0.17, although an index in the range 10-20 GV and a ratio of close to 0.24 is the usual value. New magnetic spectrometer data, however, show that a single spectral rigidity value for the near-earth He-3/He-4 ratio cannot be correct. The Fokker-Planck equation is used to demonstrate that solar modulation of the He flux yields an energy/abundance distribution close to observational data.

Webber, W. R.; Golden, R. L.; Mewaldt, R. A.

1987-01-01

182

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

183

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

184

Constraints on dark matter models from a Fermi LAT search for high-energy cosmic-ray electrons from the Sun  

NASA Astrophysics Data System (ADS)

During its first year of data taking, the Large Area Telescope (LAT) onboard the Fermi Gamma-Ray Space Telescope has collected a large sample of high-energy cosmic-ray electrons and positrons (CREs). We present the results of a directional analysis of the CRE events, in which we searched for a flux excess correlated with the direction of the Sun. Two different and complementary analysis approaches were implemented, and neither yielded evidence of a significant CRE flux excess from the Sun. We derive upper limits on the CRE flux from the Sun’s direction, and use these bounds to constrain two classes of dark matter models which predict a solar CRE flux: (1) models in which dark matter annihilates to CREs via a light intermediate state, and (2) inelastic dark matter models in which dark matter annihilates to CREs.

Ajello, M.; Atwood, W. B.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Bouvier, A.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Cecchi, C.; Charles, E.; Chekhtman, A.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Cutini, S.; de Angelis, A.; de Palma, F.; Dermer, C. D.; Digel, S. W.; Do Couto E Silva, E.; Drell, P. S.; Favuzzi, C.; Fegan, S. J.; Focke, W. B.; Fukazawa, Y.; Fusco, P.; Gargano, F.; Gehrels, N.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Guiriec, S.; Gustafsson, M.; Hadasch, D.; Iafrate, G.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, J.; Kuss, M.; Latronico, L.; Lionetto, A. M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Mazziotta, M. N.; McEnery, J. E.; Michelson, P. F.; Mizuno, T.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Norris, J. P.; Nuss, E.; Ohsugi, T.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Ritz, S.; Schalk, T. L.; Sgrò, C.; Siegal-Gaskins, J.; Siskind, E. J.; Smith, P. D.; Spandre, G.; Spinelli, P.; Suson, D. J.; Takahashi, H.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Tibaldo, L.; Tosti, G.; Troja, E.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vilchez, N.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yang, Z.; Zimmer, S.

2011-08-01

185

The Origin of Cosmic Rays  

ScienceCinema

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 to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the “end” of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform “cosmic ray astronomy”, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

186

The Origin of Cosmic Rays  

ScienceCinema

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 to fit together to provide us with a global picture of the origin of cosmic rays of unprecedented clarity. Here we will describe what we learned from recent observations of astrophysical sources (such as supernova remnants and active galaxies) and we will illustrate what these observations tell us about the physics of particle acceleration and transport. We will also discuss the ?end? of the Galactic cosmic ray spectrum, which bridges out attention towards the so called ultra high energy cosmic rays (UHECRs). At ~1020 eV the gyration scale of cosmic rays in cosmic magnetic fields becomes large enough to allow us to point back to their sources, thereby allowing us to perform ?cosmic ray astronomy?, as confirmed by the recent results obtained with the Pierre Auger Observatory. We will discuss the implications of these observations for the understanding of UHECRs, as well as some questions which will likely remain unanswered and will be the target of the next generation of cosmic ray experiments.

Pasquale Blasi

2010-01-08

187

Images of very high energy cosmic ray sources in the Galaxy: I. A source towards the galactic centre  

NASA Astrophysics Data System (ADS)

Recent analyses of the anisotropy of cosmic rays at 1018 eV (the AGASA and SUGAR data) show significant excesses from regions close to the galactic centre and Cygnus. Our aim is to check whether such anisotropies can be caused by single sources of charged particles. We investigate propagation of protons in two models of the galactic regular magnetic field (with the irregular component included) assuming that the particles are injected by a short-lived discrete source lying in the direction of the galactic centre. We show that apart from a prompt image of the source, the regular magnetic field may cause delayed images at quite large angular distances from the actual source direction. The image is strongly dependent on the time elapsed after ejection of particles and it is also very sensitive to their energy. For the most favourable conditions for particle acceleration by a young pulsar, the predicted fluxes are two to four orders of magnitude higher than those observed. The particular numbers strongly depend on the galactic magnetic field model adopted but it seems that a single pulsar in the galactic centre could be responsible for the observed excess.

Bednarek, W.; Giller, M.; Zielinska, M.

2002-08-01

188

Direct cosmic-ray detection  

NASA Astrophysics Data System (ADS)

One century after the discovery of cosmic rays, many questions remain open on their origin, nature, and transport. Experiments to detect them directly have constantly improved, and are today of highly diversified designs. Indeed, precise measurements of cosmic rays in an energy range from ˜104 to ˜1015eV allow one to study the mechanism of acceleration of primary cosmic rays up to very high energy, to characterise their possible sources, and to clarify their interactions with the interstellar medium. Such measurements of elemental cosmic-ray spectra require complementary and redundant charge- and energy-identification detectors, such as the balloon-borne Cosmic-Ray Energetics And Mass (CREAM) experiment, which measures cosmic rays from 1012 to 1015 eV for all elements up to and including iron. Here I present the current status of direct cosmic-ray measurements, with the focus on the latest CREAM results. Finally, I briefly discuss the cosmic-ray identification above the knee.

Putze, Antje

2012-01-01

189

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

190

A 100,000 pulse height analyzer for use in High Energy Cosmic Ray Experiments (HECRE) on high altitude balloon flights  

NASA Technical Reports Server (NTRS)

A description is given of a wide dynamic range pulse height analyzer system developed for use on High Energy Cosmic Ray Experiment (HECRE) Balloon Flights. A wide dynamic range of 100,000 is obtained by extending the range of a basic 1024 channel analyzer through the use of multiple ranges and range selection. The system described here contains four 100,000 pulse height analyzers. Each 100,000 pulse height analyzer consists of a group of cordwood welded modules mounted and interconnected on a printed circuit card. Four of these card assemblies, the required clock drive circuitry (discrete components mounted and interconnected on a separate card) and three input-output connectors are interconnected and mounted on the system board.

Cancro, C. A.; Garrahan, N. M.; Mcgowan, R. G.

1971-01-01

191

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

192

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

193

Propagation of high-energy particles inside solid matter - Cosmic-ray-induced spallation in iron meteorites  

NASA Astrophysics Data System (ADS)

A model for evaluating the variations with depth of high-energy particle fluxes propagating inside spherical solid bodies is proposed for use in calculating the production rates of spallogenic nuclides in meteorites. It is shown that the production by secondary particles is the major process determining the abundances of the produced nuclides. The angular distribution of these particles is of little incidence. The model is restricted to energies above 300 MeV. Results are presented from application of the model to the products of high-energy reactions induced in iron meteorites.

Zanda, B.; Malinie, G.; Audouze, J.

1989-09-01

194

Charge composition of high energy heavy primary cosmic ray nuclei. Ph.D. Thesis - Catholic Univ. of Am.  

NASA Technical Reports Server (NTRS)

A detailed study of the charge composition of primary cosmic radiation for about 5000 charged nuclei from neon to iron with energies greater than 1.16 GeV/nucleon is presented. Values are obtained after corrections were made for detector dependences, atmospheric attenuation, and solar modulation. New values of 38.5, 32.4, 23.7, and 16.8 g/sq cm for the attenuation mean free paths in air for the same charge groups are presented.

Price, R. D.

1974-01-01

195

Observations of Cosmic Rays and Solar Energetic Particles from the Ulysses COSPIN High Energy Telescope Following Completion of the Solar Maximum Solar Polar Passes.*  

NASA Astrophysics Data System (ADS)

At the end of 2002, following its second pass over the Sun's north polar region, Ulysses had reached a radial distance of about 4.5 AU at a heliographic latitude of 24°N. While solar activity remained high, the modulated intensity of cosmic rays observed by Ulysses’ COSPIN High Energy Telescope had increased significantly from the levels observed early in 2001, which most likely represented the maximum modulation for this solar cycle. Despite continuing solar activity, the new qA<0 magnetic polarity of the Sun's dipole field was fully established for both poles since the change in the North Pole polarity in 2000. Although the current sheet tilt was still large (>40° as reported by the Wilcox Solar Observatory) and the solar wind was still frequently disturbed by solar activity, it is worthwhile to examine the recent increase in the quiet-time cosmic ray fluxes for evidence of the change in latitudinal gradients expected upon change of magnetic polarity. A difficulty is the lack of a well-matched 1 AU base-line to help distinguish spatial from temporal variations following the termination of IMP-8 operations in late 2001. We will summarize Ulysses observations of energetic (>~30 MeV/n) protons and helium through the most recent available data, and will discuss available options for determining baseline fluxes at 1 AU for studies of the radial and latitudinal gradients. **This work was supported in part by NASA/JPL Contract 955432, by NASA Grant NASA 5-28516 and by NSF grant ATM 99-12341.

McKibben, R. B.; Lopate, C.; Connell, J. J.; Posner, A.

2003-04-01

196

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

197

High-Energy Particles from ?-Ray Bursts  

NASA Astrophysics Data System (ADS)

The widely accepted interpretation of the phenomenology of ?-ray bursts (GRBs), bursts of 0.1 MeV-1 MeV photons lasting for a few seconds (see [1] for a review), is that the observable effects are due to the dissipation of the kinetic energy of a relativistically expanding wind, a "fireball", whose primal cause is not yet known (see [2,3] for reviews). The recent detection of "afterglows", delayed low energy (X-ray to radio) emission of GRBs (see [4] for review), confirmed the cosmological origin of the bursts, through the redshift determination of several GRB host-galaxies, and confirmed standard model predictions of afterglows that result from the collision of an expanding fireball with its surrounding medium (see [5] for review). In this review, the production in GRB fireballs of ?-rays, high-energy cosmic-rays and neutrinos is discussed in the light of recent GRB and ultra-high-energy cosmic-ray observations.Based on lectures given at the ICTP Summer School on Astroparticle Physics and Cosmology (ICTP, Trieste Italy, June 2000), and at the VI Gleb Wataghin School on High Energy Phenomenology (UNICAMP, Campinas Brazil, July 2000).

Waxman, Eli

198

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

199

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

The annual progress report on Cosmic X Ray Physics for the period 1 Jan. to 31 Dec. 1990 is presented. Topics studied include: soft x ray background, new sounding rocket payload: x ray calorimeter, and theoretical studies.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1991-01-01

200

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

The annual progress report on Cosmic X Ray Physics is presented. Topics studied include: the soft x ray background, proportional counter and filter calibrations, the new sounding rocket payload: X Ray Calorimeter, and theoretical studies.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1990-01-01

201

Cosmic-ray detectors on the Moon  

NASA Technical Reports Server (NTRS)

The state of cosmic ray physics is reviewed. It is concluded that the nonexistent lunar magnetic field, the low lunar radiation background, and the lack of an atmosphere on the Moon provide an excellent environment for the study of high energy primary cosmic rays.

Linsley, John

1988-01-01

202

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

203

How Cosmic Rays Affect Humans  

NSDL National Science Digital Library

In this lesson about cosmic rays, students will describe why cosmic rays are dangerous to astronauts. Includes information about student preconceptions. This is activity 3 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

204

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

205

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

206

OBSERVATIONS OF HIGH-ENERGY COSMIC-RAY ELECTRONS FROM 30 GeV TO 3 TeV WITH EMULSION CHAMBERS  

SciTech Connect

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 m{sup 2} sr day at altitudes of 4.0-9.4 g cm{sup -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 {approx}1 kpc and times within {approx}1 Multiplication-Sign 10{sup 5} yr ago.

Kobayashi, T. [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara 252-5258 (Japan); Komori, Y. [Faculty of Health and Social Services, Kanagawa University of Human Services, Yokosuka 238-0013 (Japan); Yoshida, K.; Yanagisawa, K. [College of Systems Engineering and Science, Shibaura Institute of Technology, Saitama 337-8570 (Japan); Nishimura, J.; Yamagami, T.; Saito, Y. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara 229-8510 (Japan); Tateyama, N. [Faculty of Engineering, Kanagawa University, Yokohama 221-8686 (Japan); Yuda, T. [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa 277-8582 (Japan); Wilkes, R. J., E-mail: tadasik-112850@jasper.dti.ne.jp, E-mail: komori-y@kuhs.ac.jp, E-mail: yoshida@shibaura-it.ac.jp, E-mail: nisimura@icrr.u-tokyo.ac.jp, E-mail: tateyama@n.kanagawa-u.ac.jp, E-mail: yuda@icrr.u-tokyo.ac.jp, E-mail: wilkes@u.washington.edu [Department of Physics, University of Washington, Seattle, WA 98195-1560 (United States)

2012-12-01

207

Cosmic Ray Impact on Extrasolar Earth-Like Planets in Close-in Habitable Zones  

Microsoft Academic Search

Because of their different origins, cosmic rays can be subdivided into galactic cosmic rays and solar\\/stellar cosmic rays. The flux of cosmic rays to planetary surfaces is mainly determined by two planetary parameters: the atmospheric density and the strength of the internal magnetic moment. If a planet exhibits an extended magnetosphere, its surface will be protected from high-energy cosmic ray

J.-M. Grießmeier; A. Stadelmann; U. Motschmann; N. K. Belisheva; H. Lammer; H. K. Biernat

2005-01-01

208

Cascaded Gamma Rays as a Probe of Cosmic Rays  

NASA Astrophysics Data System (ADS)

Very-high-energy (VHE) and ultra-high-energy (UHE) gamma rays from extragalactic sources experience electromagnetic cascades during their propagation in intergalactic space. Recent gamma-ray data on TeV blazars and the diffuse gamma-ray background may have hints of the cascade emission, which are especially interesting if it comes from UHE cosmic rays. I show that cosmic-ray-induced cascades can be discriminated from gamma-ray-induced cascades with detailed gamma-ray spectra. I also discuss roles of structured magnetic fields, which suppress inverse-Compton pair halos/echoes but lead to guaranteed signals - synchrotron pair halos/echoes.

Murase, Kohta

2014-06-01

209

Very high energy gamma ray astronomy  

NASA Technical Reports Server (NTRS)

Recent results in ground based very high energy gamma ray astronomy are reviewed. The various modes of the atmospheric Cerenkov technique are described, and the importance of cosmic ray rejection methods is stressed. The positive detections of the Crab pulsar that suggest a very flat spectrum and time-variable pulse phase are discussed. Observations of other pulsars (particularly Vela) suggest these features may be general. Evidence that a 4.8 hr modulated effect was detected from Cyg X-3 is strengthened in that the exact period originally proposed agrees well with a recent determination of the X-ray period. The southern sky observations are reviewed, and the significance of the detection of an active galaxy (NGC 5128) is considered for source models and future observations.

Grindlay, J. E.

1976-01-01

210

THE NuSTAR EXTRAGALACTIC SURVEY: A FIRST SENSITIVE LOOK AT THE HIGH-ENERGY COSMIC X-RAY BACKGROUND POPULATION  

SciTech Connect

We report on the first 10 identifications of sources serendipitously detected by the Nuclear Spectroscopic Telescope Array (NuSTAR) to provide the first sensitive census of the cosmic X-ray background source population at {approx}> 10 keV. We find that these NuSTAR-detected sources are Almost-Equal-To 100 times fainter than those previously detected at {approx}> 10 keV and have a broad range in redshift and luminosity (z = 0.020-2.923 and L{sub 10-40{sub keV}} Almost-Equal-To 4 Multiplication-Sign 10{sup 41}-5 Multiplication-Sign 10{sup 45} erg s{sup -1}); the median redshift and luminosity are z Almost-Equal-To 0.7 and L{sub 10-40{sub keV}} Almost-Equal-To 3 Multiplication-Sign 10{sup 44} erg s{sup -1}, respectively. We characterize these sources on the basis of broad-band Almost-Equal-To 0.5-32 keV spectroscopy, optical spectroscopy, and broad-band ultraviolet-to-mid-infrared spectral energy distribution analyses. We find that the dominant source population is quasars with L{sub 10-40{sub keV}} > 10{sup 44} erg s{sup -1}, of which Almost-Equal-To 50% are obscured with N{sub H} {approx}> 10{sup 22} cm{sup -2}. However, none of the 10 NuSTAR sources are Compton thick (N{sub H} {approx}> 10{sup 24} cm{sup -2}) and we place a 90% confidence upper limit on the fraction of Compton-thick quasars (L{sub 10-40{sub keV}} > 10{sup 44} erg s{sup -1}) selected at {approx}> 10 keV of {approx}< 33% over the redshift range z = 0.5-1.1. We jointly fitted the rest-frame Almost-Equal-To 10-40 keV data for all of the non-beamed sources with L{sub 10-40{sub keV}} > 10{sup 43} erg s{sup -1} to constrain the average strength of reflection; we find R < 1.4 for {Gamma} = 1.8, broadly consistent with that found for local active galactic nuclei (AGNs) observed at {approx}> 10 keV. We also constrain the host-galaxy masses and find a median stellar mass of Almost-Equal-To 10{sup 11} M{sub Sun }, a factor Almost-Equal-To 5 times higher than the median stellar mass of nearby high-energy selected AGNs, which may be at least partially driven by the order of magnitude higher X-ray luminosities of the NuSTAR sources. Within the low source-statistic limitations of our study, our results suggest that the overall properties of the NuSTAR sources are broadly similar to those of nearby high-energy selected AGNs but scaled up in luminosity and mass.

Alexander, D. M.; Del Moro, A.; Lansbury, G. B.; Aird, J. [Department of Physics, Durham University, Durham DH1 3LE (United Kingdom); Stern, D.; Assef, R. J. [Jet Propulsion Laboratory, California Institute of Technology, 4800 Oak Grove Drive, Mail Stop 169-221, Pasadena, CA 91109 (United States); Ajello, M.; Boggs, S. E. [Space Sciences Laboratory, University of California, Berkeley, CA 94720 (United States); Ballantyne, D. R. [Center for Relativistic Astrophysics, School of Physics, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Bauer, F. E. [Departamento de Astronomia y Astrofisica, Pontificia Universidad Catolica de Chile, Casilla 306, Santiago 22 (Chile); Brandt, W. N. [Department of Astronomy and Astrophysics, 525 Davey Lab, The Pennsylvania State University, University Park, PA 16802 (United States); Christensen, F. E.; Craig, W. W. [DTU Space-National Space Institute, Technical University of Denmark, Elektrovej 327, DK-2800 Lyngby (Denmark); Civano, F.; Hickox, R. C. [Department of Physics and Astronomy, Dartmouth College, 6127 Wilder Laboratory, Hanover, NH 03755 (United States); Comastri, A. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Elvis, M. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Grefenstette, B. W.; Harrison, F. A. [Cahill Center for Astrophysics, 1216 East California Boulevard, California Institute of Technology, Pasadena, CA 91125 (United States); Hailey, C. J. [Columbia Astrophysics Laboratory, 550 W 120th Street, Columbia University, NY 10027 (United States); and others

2013-08-20

211

Measuring the ultra-high energy comic ray flux with the Telescope Array Middle Drum detector  

Microsoft Academic Search

The Telescope Array (TA) Experiment, located 200 kilometers southwest of Salt Lake City, Utah, is the largest Ultra-High Energy cosmic ray detector in the northern hemisphere. TA is a follow up to the High Resolution Fly's Eye (HiRes) and AGASA experiments, and seeks to gain insight into cosmic ray acceleration by measuring the flux of cosmic rays with energies over

Thomas Sonley

2009-01-01

212

Spectral index of high-energy cosmic rays by the Compton-Getting effect at solar time frame with the Tibet air shower array  

Microsoft Academic Search

We report on the spectral index of cosmic rays around 10 TeV energy region obtained by observation of the Compton-Getting anisotropy due to the terrestrial orbital motion around the Sun with the Tibet III air shower array during the period from 1999 to 2005. The spectral index has turned out to be 2.99±0.54, which is consistent with 2.74 by the

S. Ayabe; X. J. Bi; D. Chen; S. W. Cui; Danzengluobu; L. K. Ding; X. H. Ding; C. F. Feng; Zhaoyang Feng; Z. Y. Feng; X. Y. Gao; Q. X. Geng; H. W. Guo; H. H. He; M. He; K. Hibino; N. Hotta; Haibing Hu; H. B. Hu; J. Huang; Q. Huang; H. Y. Jia; F. Kajino; K. Kasahara; Y. Katayose; C. Kato; K. Kawata; Labaciren; G. M. Le; A. F. Li; J. Y. Li; Y.-Q. Lou; H. Lu; S. L. Lu; X. R. Meng; K. Mizutani; J. Mu; K. Munakata; A. Nagai; H. Nanjo; M. Nishizawa; M. Ohnishi; I. Ohta; H. Onuma; T. Ouchi; S. Ozawa; J. R. Ren; T. Saito; M. Sakata; T. Sasaki; M. Shibata; A. Shiomi; T. Shirai; H. Sugimoto; M. Takita; Y. H. Tan; N. Tateyama; T. K. Sako; S. Torii; H. Tsuchiya; S. Udo; B. Wang; H. Wang; X. Wang; Y. G. Wang; H. R. Wu; L. Xue; Y. Yamamoto; C. T. Yan; X. C. Yang; S. Yasue; Z. H. Ye; G. C. Yu; A. F. Yuan; T. Yuda; H. M. Zhang; J. L. Zhang; N. J. Zhang; X. Y. Zhang; Y. Zhang; Yi Zhang; Zhaxisangzhu; X. X. Zhou

2008-01-01

213

Cosmic rays and hadronic interactions  

SciTech Connect

The cosmic ray spectrum extends to particles with energy E{approx} 10{sup 20} eV, that corresponds (assuming that the primary particle is a proton) to a nucleon-nucleon c.m. energy {radical}(s) Asymptotically-Equal-To 430TeV, 50 times higher than the current LHC energy. These very high energy particles can be studied via the observation of the showers they generate in the atmosphere. The interpretation of the data requires therefore the modeling of hadronic interactions in an energy range beyond what can be studied in accelerator experiments. The theoretical problem of estimating the relevant properties of hadronic interactions in this energy range is therefore of central importance for the interpretation of the cosmic ray data. Viceversa, it is in principle possible to obtain information about hadronic interactions from the cosmic ray observations, but this program has to confront the fact that the (freely available) cosmic ray beam has an unknown energy spectrum and an unknown mass composition.

Lipari, Paolo [INFN sez. Roma, and Dipartimento di Fisica, Universita di Roma Sapienza (Italy)

2013-03-25

214

The ALTA cosmic ray experiment electronics system  

NASA Astrophysics Data System (ADS)

Understanding the origin and propagation of high-energy cosmic rays is a fundamental area of astroparticle physics with major unanswered questions. The study of cosmic rays with energy more than 1014 eV, probed only by ground-based experiments, has been restricted by the low particle flux. The Alberta Large-area Time-coincidence Array (ALTA) uses a sparse array of cosmic ray detection stations located in high schools across a large geographical area to search for non-random high-energy cosmic ray phenomena. Custom-built ALTA electronics is based on a modular board design. Its function is to control the detectors at each ALTA site allowing precise measurements of event timing and energy in the local detectors as well as time synchronization of all of the sites in the array using the global positioning system.

Brouwer, W.; Burris, W. J.; Caron, B.; Hewlett, J.; Holm, L.; Hamilton, A.; McDonald, W. J.; Pinfold, J. L.; Price, P.; Schaapman, J. R.; Sibley, L.; Soluk, R. A.; Wampler, L. J.

2005-03-01

215

Cosmic ray propagation in the local superbubble  

NASA Technical Reports Server (NTRS)

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.

1984-01-01

216

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

217

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

218

Educational Cosmic Ray Arrays  

SciTech Connect

In the last decade a great deal of interest has arisen in using sparse arrays of cosmic ray detectors located at schools as a means of doing both outreach and physics research. This approach has the unique advantage of involving grade school students in an actual ongoing experiment, rather then a simple teaching exercise, while at the same time providing researchers with the basic infrastructure for installation of cosmic ray detectors. A survey is made of projects in North America and Europe and in particular the ALTA experiment at the University of Alberta which was the first experiment operating under this paradigm.

Soluk, R. A. [Centre for Subatomic Research, University of Alberta, Edmonton, Alberta, T6G 2N5 (Canada)

2006-04-11

219

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

220

High Energy Electron and Gamma - Ray Detection with ATIC  

NASA Technical Reports Server (NTRS)

The Advanced Thin Ionization Calorimeter (ATIC) balloon borne ionization calorimeter is well suited to record and identify high energy cosmic ray electrons, and at very high energies gamma-ray photons as well. We have simulated the performance of the instrument, and compare the simulations with actual high energy electron exposures at the CERN accelerator. Simulations and measurements do not compare exactly, in detail, but overall the simulations have predicted actual measured behavior quite well. ATIC has had its first 16 day balloon flight at the turn of the year over Antarctica, and first results obtained using the analysis methods derived from simulations and calibrations will be reported.

Chang, J.; Schmidt, W. K. H.; Whitaker, Ann F. (Technical Monitor)

2001-01-01

221

Discovery of cosmic rays  

NASA Astrophysics Data System (ADS)

The mysterious invisible radiation that ionized air was studied a century ago by many scientists. Finally, on 7 August 1912, Victor Hess in his seventh balloon flight that year, reached an altitude of about 5000 m. With his electroscopes on board the hydrogen-filled balloon he observed that the ionization instead of decreasing with altitude increased significantly. Hess had discovered cosmic rays, a discovery that gave him the 1936 Nobel Prize in physics. When research resumed after World War I focus was on understanding the nature of the cosmic radiation. Particles or radiation? Positive or negative? Electrons, positrons or protons? Progress came using new instruments like the Geiger-Muller tube and around 1940 it was clear that cosmic rays were mostly protons.

Carlson, Per

2013-02-01

222

Cosmic Ray Energetics And Mass  

NASA Astrophysics Data System (ADS)

The balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment was flown for ~161 days in six flights over Antarctica. High energy cosmic-ray data were collected over a wide energy range from ~ 10^10 to > 10^14 eV at an average altitude of ~38.5 km with ~3.9 g/cm2 atmospheric overburden. Cosmic-ray elements from protons (Z = 1) to iron nuclei (Z = 26) are separated with excellent charge resolution. Building on success of the balloon flights, the payload is being reconfigured for exposure on the International Space Station (ISS). This ISS-CREAM instrument is configured with the CREAM calorimeter for energy measurements, and four finely segmented Silicon Charge Detector layers for precise charge measurements. In addition, the Top and Bottom Counting Detectors (TCD and BCD) and Boronated Scintillator Detector (BSD) have been newly developed. The TCD and BCD are scintillator based segmented detectors to separate electrons from nuclei using the shower profile differences, while BSD distinguishes electrons from nuclei by detecting thermal neutrons that are dominant in nuclei induced showers. An order of magnitude increase in data collecting power is possible by utilizing the ISS to reach the highest energies practical with direct measurements. The project status including results from on-going analysis of existing data and future plans will be discussed.

Seo, Eun-Suk

2014-08-01

223

Anisotropy Studies of Ultra-High Energy Cosmic Rays Using Monocular Data Collected by the High-Resolution Fly's Eye (HiRes)  

NASA Astrophysics Data System (ADS)

While the existence of cosmic rays with energies exceeding 1018 electronvolts has been well established, attempts to correlate these particles with sources have yielded results which are ambiguous at best. Even the highest energy events, whose energies render them largely immune to bending by galactic magnetic fields, have eluded identification with particular sources. We present here the results of new searches for anisotropy within the HiRes mono cular dataset, which contains events ranging from 1018 to over 1020 eV. Using various skymap analysis techniques, we search for event excesses from a priori pointlike sources (Cygnus X-3, M87, and the AGASA "triplet"), extended sources (the galactic and supergalactic planes) and evidence for dip ole moments in the full sky survey. We place upper limits on the existence of both pointlike and extended sources within HiRes' Northern Hemisphere field of view.

Bellido, J.; Belz, John W.; Dawson, B.; Jui, C.; Schindel, M.; Stokes, B. T.; HIRES Collaboration

2003-07-01

224

Very High Energy gamma Ray Astrophysics. Progress Report, August 1, 1980-July 31, 1981.  

National Technical Information Service (NTIS)

Very high energy (VHE) gamma ray astronomy gives insight into fundamental questions regarding the origins of cosmic rays and the types of particle acceleration mechanisms which operate in nature. VHE photons are detected by means of the Cerenkov light the...

R. C. Lamb

1981-01-01

225

On Cosmic Ray Propagation  

NASA Astrophysics Data System (ADS)

Cosmic ray propagation is diffusive because of pitch angle scattering by waves. We demonstrate that if the high-amplitude magnetic turbulence with (delta B)/B ~ 1 is present on top of the mean field gradient, the diffusion becomes asymmetric. As an example, we solve this diffusion problem in one dimension analytically with a Markov chain analysis. The cosmic ray density markedly differs from the standard diffusion prediction. The equation for the continuous limit is also derived, which shows limitations of the convection-diffusion equation. There is an interesting connection of this problem to laboratory experimental studies of particle transport in multi-mirror machines. The implications of the results are discussed. Supported by grant DOE grant DE-FG02-07ER54940 and NSF grant AST-1209665.

Medvedev, Mikhail

2014-06-01

226

Origin of cosmic rays  

NASA Astrophysics Data System (ADS)

It is argued that there are three 'origins' of cosmic rays; the origin of the particles, the origin of the energy, and the site of the acceleration. The evidence for each origin is discussed and a plausible synthesis outlined for the particles of Galactic origin where the energy comes mainly (but not exclusively) from supernova explosions, the site of the acceleration is at strong collisionless shock waves, and the accelerated particles come from the interstellar and circumstellar material swept over by these shocks. If these shocks are capable (as indicated by recent observations and theoretical work) of significantly amplifying magnetic fields this picture appears capable of explaining the cosmic ray particles at all energies below the 'ankle' at 3 × 1018 eV. The particles above this energy are generally taken to be of extra-galactic origin and possible acceleration sites for these UHE particles are briefly discussed.

Drury, Luke O.'C.

2012-12-01

227

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

228

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

229

Jupiter as a Giant Cosmic Ray Detector  

NASA Astrophysics Data System (ADS)

We explore the feasibility of using the atmosphere of Jupiter to detect ultra-high-energy cosmic rays (UHECRs). The large surface area of Jupiter allows us to probe cosmic rays of higher energies than previously accessible. Cosmic ray extensive air showers in Jupiter's atmosphere could in principle be detected by the Large Area Telescope (LAT) on the Fermi observatory. In order to be observed, these air showers would need to be oriented toward the Earth, and would need to occur sufficiently high in the atmosphere that the gamma rays can penetrate. We demonstrate that, under these assumptions, Jupiter provides an effective cosmic ray "detector" area of 3.3 × 107 km2. We predict that Fermi-LAT should be able to detect events of energy >1021 eV with fluence 10-7 erg cm-2 at a rate of about one per month. The observed number of air showers may provide an indirect measure of the flux of cosmic rays >~ 1020 eV. Extensive air showers also produce a synchrotron signature that may be measurable by Atacama Large Millimeter/submillimeter Array (ALMA). Simultaneous observations of Jupiter with ALMA and Fermi-LAT could be used to provide broad constraints on the energies of the initiating cosmic rays.

Rimmer, P. B.; Stark, C. R.; Helling, Ch.

2014-06-01

230

Maximum cosmic ray energies and the shock acceleration mechanism  

NASA Astrophysics Data System (ADS)

The Ultra High Energy Cosmic Rays have a flux which is about one particle per square km per century, at an energy of ~=1020 eV. Shocks in astrophysical environments, such as in jets of Active Galactic Nuclei, seem to be the sources of these cosmic rays. In this selected talk I will briefly present and discuss the efficiency of the first order Fermi acceleration mechanism in extragalactic astrophysical shocks, focusing at the highest cosmic ray energies.

Meli, A.

2010-06-01

231

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

232

A Cerenkov-delta E-Cerenkov detector for high energy cosmic ray isotopes and an accelerator study of Ar-40 and Fe-56 fragmentation. Ph.D. Thesis  

NASA Technical Reports Server (NTRS)

A high energy cosmic ray detector--the High Energy Isotope Spectrometer Telescope (HEIST) is described. It is a large area (0.25 m(swp 2) SR) balloon borne isotope spectrometer designed to make high resolution measurements of isotopes in the element range from neon to nickel (10 Z 28) at energies of about 2 GeV/nucleon. HEIST determines the mass of individual nuclei by measuring both the change in the Lorentz factor (delta gamma) that results from traversing the NaI stack, and the energy loss (delta E) in the stack. Since the total energy of an isotope is given by E = (gamma M), the mass M can be determined by M = delta E/delta, gamma. The instrument is designed to achieve a typical mass resolution of 0.2 amu. The isotopic composition of the fragments from the breakup of high energy An-40 and Fe-56 nuclei are measured experimentally. Isotope yields are compared with calculated yields based on semi-empirical cross-section formulae.

Lau, K. H.

1985-01-01

233

How to Detect Cosmic Rays  

NSDL National Science Digital Library

In this lesson on cosmic rays, students will explain two examples of a cosmic ray detector. Includes information about student preconceptions and a demonstration that requires a geiger counter and optional access to a small radioactive source that emits energetic helium nuclei (alpha particles), e.g., the mineral the mineral autunite, which contains uranium. This is activity two of four from The Cosmic Ray Telescope for the Effects of Radiation (CRaTER).

234

Modulation of Cosmic Ray Precipitation Related to Climate  

NASA Technical Reports Server (NTRS)

High energy cosmic rays may influence the formation of clouds, and thus can have an impact on weather and climate. Cosmic rays in the solar wind are incident on the magnetosphere boundary and are then transmitted through the magnetosphere and atmosphere to reach the upper troposphere.

Feynman, J.; Ruzmaikin, A.

1998-01-01

235

Real-time cosmic ray monitoring system for space weather  

Microsoft Academic Search

We have developed a real-time system to monitor high-energy cosmic rays for use in space weather forecasting and specification. Neutron monitors and muon detectors are used for our system, making it possible to observe cosmic rays with dual energy range observations. In large solar energetic particle (SEP) events, the ground level enhancement (GLE) can provide the earliest alert for the

T. Kuwabara; J. W. Bieber; J. Clem; P. Evenson; R. Pyle; K. Munakata; S. Yasue; C. Kato; S. Akahane; M. Koyama; Z. Fujii; M. L. Duldig; J. E. Humble; M. R. Silva; N. B. Trivedi; W. D. Gonzalez; N. J. Schuch

2006-01-01

236

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

237

Cosmic Rays of Extreme Energies  

NASA Astrophysics Data System (ADS)

The origin of the highest energy cosmic rays is a challenging mystery defying decades of observations. The sources of these extremely energetic particles should be among the most powerful extragalactic sources. Extremely energetic cosmic rays (EECRs) reach interaction energies orders of magnitude beyond the LHC probing the frontiers of particle physics. Possible explanations for their origin have narrowed down with the confirmation of a GZK-like spectral feature. Hints of anisotropies in the distribution of arrival directions raise hopes for observing source images directly, however, composition measurements reported by Auger suggest a surprising interpretation. A clear resolution of this mystery calls for much larger statistics at extremely high energies beyond the reach of current observatories. A future space program can achieve several orders of magnitude in additional exposure to EECRs. The first step in such a program is the Extreme Universe Space Observatory at the Japanese Experiment Module (JEM-EUSO). JEM-EUSO is a large field of view ultraviolet telescope to be deployed at the International Space Station. JEM-EUSO can increase the annual exposure to EECRs by an order of magnitude.

Olinto, Angela V.

2013-10-01

238

Antiprotons in cosmic rays  

NASA Technical Reports Server (NTRS)

Recent experimental observations and results are discussed. It was found that the approximately 50 antiprotons collected in balloon experiments to date have generated considerable theoretical interest. Clearly, confirmatory experiments and measurements over an extended energy range are required before definite conclusions are drawn. Antiproton measurements have a bearing on astrophysical problems ranging from cosmic ray propagation to issues of cosmological import. The next generation of balloon experiments and the Particle Astrophysics Magnet Facility being discussed for operation on NASA's space station should provide data and insights of highest interest.

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

1987-01-01

239

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

240

The HEAO-3 Cosmic Ray Isotope spectrometer  

NASA Technical Reports Server (NTRS)

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.

1982-01-01

241

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

242

Heavy Electrons in Cosmic Rays  

Microsoft Academic Search

Neddermeyer and Anderson1, on the basis of their experiments on the loss of energy by cosmic ray particles, have suggested that there are present in cosmic rays `new' particles of mass greater than that of an electron and less than that of a proton. In this note we give additional evidence for such a particle (some of which has previously

E. J. Williams; E. Pickup

1938-01-01

243

Cosmic ray propagation and containment  

NASA Technical Reports Server (NTRS)

The cosmic rays, an active gaseous component of the disk of the galaxy, are considered along with their propagation and containment as a part of the general dynamics of the disk. The sources of cosmic rays are a matter of speculation. The disk is inflated by the cosmic ray gas pressure comparable to the magnetic pressure, but the rate of inflation is unknown. The time spent by the individual cosmic ray particles in the disk is inversely proportional to the cosmic ray production rate. It is evident from the decay of Be(1c) that the cosmic rays circulate through a volume of space perhaps ten times the thickness of the gaseous disk, suggesting a magnetic halo extending out approximately 1 kpc from either face of the disk. The cosmic rays may be responsible for the halo by inflating the magnetic fields of the disk. Extension of the fields to 1 kpc would imply a high production rate and short life of cosmic rays in the dense gaseous disk of the galaxy.

Parker, E. N.

1976-01-01

244

High-energy emission in gamma-ray bursts  

NASA Technical Reports Server (NTRS)

Between February 1980 and August 1983 the Gamma-Ray Spectrometer on the Solar Maximum Mission Satellite (SMM) detected 72 events identified as being of cosmic origin. These events are an essentially unbiased subset of all gamma-ray bursts. The measured spectra of these events show that high energy (greater than 1 MeV) emission is a common and energetically important feature. There is no evidence for a general high-energy cut-off or a distribution of cut-offs below about 6 MeV. These observations imply a limit on the preferential beaming of high energy emission. This constraint, combined with the assumption of isotropic low energy emission, implies that the typical magnetic field strength at burst radiation sites is less than 1 x 10 to the 12th gauss.

Matz, S. M.; Forrest, D. J.; Vestrand, W. T.; Chupp, E. L.; Share, G. H.; Rieger, E.

1985-01-01

245

Modulation of cosmic ray precipitation related to climate  

NASA Astrophysics Data System (ADS)

High energy cosmic rays may influence the formation of clouds and thus impact weather and climate. Due to systematic solar wind changes, the intensity of cosmic rays incident on the magnetopause has decreased markedly during this century. The pattern of cosmic ray precipitation through the magnetosphere to the upper troposphere has also changed. Early in the century, the part of the troposphere open to cosmic rays of all energies was typically confined to a relatively small high-latitude region. As the century progressed the size of this region increased by over 25% and there was a 6.5° equatorward shift in the yearly averaged latitudinal position of the subauroral region in which cloud cover has been shown to be cosmic ray flux dependent. We suggest these changes in cosmic ray intensity and latitude distribution may have influenced climate change during the last 100 years.

Feynman, J.; Ruzmaikin, A.

1999-07-01

246

A study of very high energy hadron interactions through observation of cosmic-ray families with visible energy not less than 500 TeV, 3  

NASA Astrophysics Data System (ADS)

This report presents the clean and/or quasi-clean examples which show characteristics of extremely large pt(gamma) particle production among 75 families of the highest energy range--those with visible energy sum greater than 500 TeV. It is possible to select clean and/or quasi-clean families by looking for the events which show an absent or very minor contribution of lower energy showers over the family area, since such lower energy showers near the threshold energy must come from secondary and/or tertiary effects during the passage through the atmosphere. Examples are given of such quasi-clean families with extreme large lateral spread and where the interaction must occur near the chambers. This indicates abnormal large pt particle production. The studies have been continuously made on the nature of high energy secondaries from 'Centauro-species' in Chacaltaya two-story chambers. Striking characteristics have been noticed on the nature of high energy secondaries from Chiron-type families. They are the existence of penetrating 'mini-clusters' of small pt(gamma) particle productions and the short collision mean free path of high energy secondaries in not only in atmosphere but also in the chamber material. The results of a systematic study on interaction mean free path of high energy secondaries from Chiron-type interactions by measuring the distribution of shower starting position in Chacaltaya two-story chambers are outlined.

Baradzei, L. T.; Borisov, A. S.; Cherdyntseva, K. V.; Guseva, Z. M.; Denisova, V. G.; Dobrotin, N. A.; Dunaevsky, A. M.; Kanevskaya, E. A.; Karpova, S. A.; Maximenko, V. M.

1993-06-01

247

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.

248

Very high energy gamma-ray spectroscopy  

Microsoft Academic Search

The cosmic gamma-ray spectrum in the relatively unexplored energy range 1 ⪅ E? ⪅ 103GeV may have several interesting features. It may contain the gamma-ray lines from photino annihilation in the galactic halo, if photinos indeed comprise the unidentified dark matter in typical galaxies. There could also be a detectable diffuse background at E? > 30 GeV. These and other

David Eichler; James H. Adams Jr.

1987-01-01

249

Performance of the AMS02 Experiment for High Energy Gamma Ray Astrophysics  

Microsoft Academic Search

AMS is a particle detector designed to perform high precision measurements of the cosmic rays fluxes with the main goals of searching for anti-nuclei, as remnants of primordial anti-matter, and of measuring the faintest components of the cosmic flux, anti- protons, positrons and high energy photons. To fulfill the requirements of large acceptance, long exposure time and excellent particle identification

Sonia Natale; Martin Pohl

2007-01-01

250

Very High Energy Gamma-Ray Astronomy  

Microsoft Academic Search

We present a review of the current status of very high energy gamma-ray astronomy. The development of the atmospheric Cerenkov imaging technique for ground-based gamma-ray astronomy has led to a rapid growth in the number of observatories. The detection of TeV gamma-rays from active galactic nuclei was unexpected and is providing new insights into the emission mechanisms in the jets.

Michael Catanese; Trevor C. Weekes

1999-01-01

251

Detecting Gamma-Ray Bursts with Ultra-High Energy Neutrinos  

NASA Astrophysics Data System (ADS)

Gamma-ray bursts are candidate sources of ultra-high energy cosmic rays and neutrinos. While cosmic rays are scattered in the intervening magnetic field, neutrinos point back to their sources being charge neutral and make neutrino astronomy possible. Detection of ultrahigh energy neutrinos by future experiments such as ANITA, ANTARES, Ice-Cube and RICE can provide useful information such as particle acceleration, radiation mechanism and magnetic field about the sources and their progenitors. Detection of ultrahigh energy neutrinos which point back to their sources may establish gamma-ray bursts as the sources of GZK cosmic rays.

Razzaque, Soebur; Mészáros, Peter; Waxman, Eli

252

Life extinctions by cosmic ray jets.  

NASA Astrophysics Data System (ADS)

High energy cosmic ray jets from nearby mergers or accretion induced collapse (AIC) of neutron stars (NS) 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 most of the massive life extinctions on planet Earth in the past 600 My. Biological mutations due to ionizing radiations could have caused the fast appearance of new species after the massive extinctions. An early warning of future extinctions due to NS mergers may be obtained by identifying, mapping and timing all the nearby binary neutron stars systems. A warning of an approaching cosmic ray burst from a nearby NS merger/AIC may be provided by a very intense gamma ray burst which precedes it.

Dar, A.

253

Development of TUS pinhole cameras for observing transient luminous events from space and establishing role of those events as a background for ultra-high-energy cosmic-ray measurements  

NASA Astrophysics Data System (ADS)

The TUS (tracking ultraviolet setup) experiment is intended for the observation from space of ultraviolet (UV) fluorescence induced both by ultra-high-energy cosmic rays (UHECRs) with energies above 5 × 1019 eV and by transient luminous events (TLEs) occurring in the upper atmosphere. These two types of events are very different in terms of duration, lateral shape, and intensity; thus, each behaves as a background for the other. The TUS is equipped with two conventional pinhole cameras as auxiliary instrumentation to detect and efficiently distinguish TLEs from UHECRs. Each pinhole camera contains a MAPMT (multi-anode photo-multiplier tube) and its associated analog and digital electronics. The R11265-03-M64 MAPMT has been custom-made for space applications by Hamamatsu Photonics, particularly for the future EUSO (Extreme Universe Space Observatory) UHECR space mission. Thus, the TUS pinhole system will be the test bench for the deployment in space of a large number, ˜5000, of MAPMTs. In this study, we present the design and fabrication of the pinhole cameras, and we estimate the detectability of TLEs with respect to atmospheric light background.

Kim, Ji Eun; Lee, Jik; Park, A. H.; Park, I. H.; Garipov, G. K.; Khrenov, B. A.; Klimov, P. A.; Panasyuk, M. I.

2014-03-01

254

Pulsars, supernovae, and ultrahigh energy cosmic rays  

NASA Astrophysics Data System (ADS)

The acceleration of ultrahigh energy nuclei in fast spinning newborn pulsars can explain the observed spectrum of ultrahigh energy cosmic rays and the trend towards heavier nuclei for energies above 10^{19} eV as indicated by air shower studies reported by the Auger Observatory. By assuming a normal distribution of pulsar birth periods centered at 300 ms, we show that the contribution of extragalactic pulsar births to the ultrahigh energy cosmic ray spectrum naturally gives rise to a contribution to very high energy cosmic rays (VHECRs, between 10^{16} and 10^{18} eV) by Galactic pulsar births. The required injected composition to fit the observed spectrum depends on the absolute energy scale, differing considerably between the energy scale used by Auger and that used by the Telescope Array. Depending on the composition of the cosmic rays that escape the supernova remnant and the diffusion behavior of VHECRs in the Galaxy, the contribution of Galactic pulsar births can also bridge the gap between predictions for cosmic ray acceleration in supernova remnants and the observed spectrum below the ankle. Fast spinning newborn pulsars that could produce UHECRs would be born in supernovae that could present interesting specific radiative features, due to the interaction of the pulsar wind with the surrounding ejecta. The resulting supernova lightcurves could present a high luminosity plateau over a few years, and a bright X-ray and gamma-ray peak around one or two years after the onset of the explosion. If such signatures were observed, they could have important implications both for UHECR astrophysics and for the understanding of core-collapse supernovae.

Kotera, K.; Fang, K.; Olinto, A. V.; Phinney, E. S.

2012-12-01

255

Calculation of cosmic ray induced single event upsets: Program CRUP (Cosmic Ray Upset Program)  

NASA Astrophysics Data System (ADS)

This report documents PROGRAM CRUP, COSMIC RAY UPSET PROGRAM. The computer program calculates cosmic ray induced single-event error rates in microelectronic circuits exposed to several representative cosmic-ray environments.

Shapiro, P.

1983-09-01

256

Recent high energy gamma-ray results from SAS-2  

NASA Technical Reports Server (NTRS)

Recent developments in gamma-ray astronomy due to the results from SAS-2 have focused on two areas. First, the emission from the plane of the Galaxy is the dominant feature in the gamma-ray sky. The galactic latitude and longitude distributions are consistent with the concept that the high-energy radiation originates from cosmic rays interacting with interstellar matter, and the measurements support a galactic origin for cosmic rays. Second, searches of the SAS-2 data for emission from localized sources have shown three strong discrete gamma-ray sources: the Crab nebula and PSR 0531 + 21, the Vela supernova remnant and PSR 0833-45, and a source near galactic coordinates 193 deg longitude, +3 deg latitude, which does not appear to be associated with other known celestial objects. Evidence has also been found for pulsed gamma-ray emission from two other radio pulsars, PSR 1818-04 and PSR 1747-46. A localized source near longitudes 76-80 deg may be associated with the X-ray source Cyg X-3.

Thompson, D. J.; Fichtel, C. E.; Hartman, R. C.; Kniffen, D. A.; Bignami, G. F.; Ogelman, H. B.; Ozel, M. E.; Tumer, T.; Lamb, R. C.

1977-01-01

257

Cosmic X-ray physics  

Microsoft Academic Search

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument

D. McCammon; D. P. Cox; W. L. Kraushaar; W. T. Sanders

1985-01-01

258

Cosmic ray acceleration at modified shocks  

NASA Astrophysics Data System (ADS)

The non-linear back reaction of accelerated cosmic rays at a non-relativistic shock front leads to the formation of a smooth precursor with a length scale corresponding to the diffusive scale of the energetic particles. The instabilities present in these modified shocks may play a crucial role as past theoretical work has shown. First, it was claimed that shocklets that could be created in the precursor region of a specific width might energize few thermal particles to sufficient acceleration and second, some precursor regions may act as confining large angle scatterers for very high energy cosmic rays. Our aim here is to investigate numerically these claims by constructing a Monte Carlo code simulating the above conditions which could throw further light to the exact mechanism of efficiency, particularly in the case of highly oblique shocks as these appear in nature much more often.

Meli, A.; Biermann, P. L.; Dimitrakoudis, S.

259

Cosmic X-Ray Physics.  

National Technical Information Service (NTIS)

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaning...

D. Mccammon D. P. Cox W. L. Kraushaar W. T. Sanders

1985-01-01

260

THE STUDY OF COSMIC ? RAYS  

Microsoft Academic Search

CONTENTS 1. Introduction 630 2. Main Cosmic ?-ray (CGR) Production Processes. Interaction of CGR with Interstellar and Intergalactic Matter 631 3. Methods of Study of CGR 632 4. Comparability of Experimental Results. Calibration of ? Detectors 634 5. Conditions of CGR Study. Atmospheric and Local Backgrounds 635 6. Results of Diffuse CGR Measurement in Balloons. The ?-ray Flux Extrapolated to

A M Galper; V G Kirillov-Ugryumov; B I Luchkov; O F Prilutski?

1972-01-01

261

The survival of heavy nuclei in cosmic ray source environments  

NASA Technical Reports Server (NTRS)

The results are discussed that were obtained from the Goddard balloon spectrometer experiment to study the composition and energy distribution of high energy cosmic rays. The significant findings indicate that: (1) On a total energy scale, protons constitute only a minor proportion of the cosmic rays. They account for only 20 percent; the rest of the cosmic rays are complex nuclei. (2) All the nuclei have the same power low spectrum in total energy and so the composition appears to be independent of energy.

Balasubrahmanyan, V. K.

1972-01-01

262

Cosmic rays X. The cosmic ray knee and beyond: diffusive acceleration at oblique shocks  

NASA Astrophysics Data System (ADS)

Our purpose is to evaluate the rate of the maximum energy and the acceleration rate that cosmic rays acquire in the non-relativistic diffusive shock acceleration as it could apply during their lifetime in various astrophysical sites, where highly oblique shocks exist. We examine numerically (using Monte-Carlo simulations) the effect of the diffusion coefficients on the energy gain and the acceleration rate, by testing the role between the obliquity of the magnetic field to the shock normal, and the significance of both perpendicular cross-field diffusion and parallel diffusion coefficients to the acceleration rate. We find (and justify previous analytical work - Jokipii 1987, ApJ, 313, 842) that in highly oblique shocks the smaller the perpendicular diffusion gets compared to the parallel diffusion coefficient values, the greater the energy gain of the cosmic rays to be obtained. An explanation of the cosmic ray spectrum in high energies, between 1015 eV and about 1018 eV is claimed, as we estimate the upper limit of energy that cosmic rays could gain in plausible astrophysical regimes; interpreted by the scenario of cosmic rays which are injected by three different kind of sources, (a) supernovae which explode into the interstellar medium, (b) Red Supergiants, and (c) Wolf-Rayet stars, where the two latter explode into their pre-supernovae winds.

Meli, A.; Biermann, P. L.

2006-08-01

263

Ultrahigh energy cosmic rays from topological defects--cosmic strings, monopoles, necklaces, and all that  

SciTech Connect

The topological defect scenario of origin of the observed highest energy cosmic rays is reviewed. Under a variety of circumstances, topological defects formed in the early Universe can be sources of very massive particles in the Universe today. The decay products of these massive particles may be responsible for the observed highest energy cosmic ray particles above 10{sup 20} eV. Some massive particle production processes involving cosmic strings and magnetic monopoles are discussed. We also discuss the implications of results of certain recent numerical simulations of evolution of cosmic strings. These results (which remain to be confirmed by independent simulations) seem to show that massive particle production may be a generic feature of cosmic strings, which would make cosmic strings an inevitable source of extremely high energy cosmic rays with potentially detectable flux. At the same time, cosmic strings are severely constrained by the observed cosmic ray flux above 10{sup 20} eV, if massive particle radiation is the dominant energy loss mechanism for cosmic strings.

Bhattacharjee, Pijushpani [Laboratory for High Energy Astrophysics, NASA/Goddard Space Flight Center, Code 661, Greenbelt, Maryland 20771 (United States); Indian Institute of Astrophysics, Bangalore-560 034 (India)

1998-06-15

264

Gamma-ray bursters as sources of cosmic rays  

NASA Astrophysics Data System (ADS)

From the little we know of the physical conditions in ?-ray bursters, it seems that they are potentially effective in the acceleration of high-energy cosmic rays (CRs), especially if the bursters are at cosmological distances. We find that, with the observed statistics and fluxes of ?-ray bursts, cosmological bursters may be an important source of cosmic rays in two regions of the observed spectrum: (1) At the very-high-energy end ( E > 10 19 eV), where CRs must be of extragalactic origin. (2) Around and above the spectral feature that has been described as a bump and/or a knee, which occurs around 10 15 eV. The occasional bursters that occur inside the Galaxy — about once in a few hundred thousand years if burst emission is isotropic; more often, if it is beamed — could maintain the density of galactic cosmic rays at the observed level in this range. These two energy ranges might correspond to two typical CR energy scales characteristic of bursters: one pertinent to CR acceleration due to interaction of a magnetized-fireball front with an ambient medium; the other to acceleration in the fireball itself (e.g. shock acceleration).

Milgrom, Mordehai; Usov, Vladimir

1996-04-01

265

Fermi LAT Observations of Cosmic-Ray Electrons.  

National Technical Information Service (NTIS)

Designed as a gamma-ray instrument, the LAT is a capable detector of high energy cosmic ray electrons. The LAT is composed of a 4x4 array of identical towers. Each tower has a Tracker and a Calorimeter module. Entire LAT is covered by segmented Anti-Coinc...

A. Moiseev

2011-01-01

266

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

267

The microphysics and macrophysics of cosmic rays  

SciTech Connect

This review paper commemorates a century of cosmic ray research, with emphasis on the plasma physics aspects. Cosmic rays comprise only ?10{sup ?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. [Departments of Astronomy and Physics and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)] [Departments of Astronomy and Physics and Center for Magnetic Self-Organization, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

2013-05-15

268

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

269

Cosmic rays at fluid discontinuities  

NASA Technical Reports Server (NTRS)

Cosmic-ray transport near discontinuities in the background fluid velocity is considered. Matching conditions for the cosmic-ray distribution are derived for both shear and compressive (shock) discontinuities, keeping terms to second order in the ratio of fluid speed to energetic-particle speed. Acceleration is found at shear discontinuities, which is not present in the first-order theory, and a modification of the matching condition at shocks. If there is no particle source concentrated at a shock, the new condition reduces to that obtained from first-order theory. Monte Carlo simulations show good agreement with the theory.

Jokipii, J. R.; Kota, J.; Morfill, G.

1989-01-01

270

Tensor anisotropy of cosmic rays  

NASA Astrophysics Data System (ADS)

Long-termobservations of the muon intensity of galactic cosmic rays at the Nagoya (35°10' N, 136°58' E) and Yakutsk (62°01' N, 129°43' E) stations have revealed amplitude-phase annual and semiannual oscillations of the semidiurnal variation. These oscillations are attributable to the properties of the cosmic-ray anisotropy tensor that result from shielding by the interplanetary magnetic field and solar-wind shear flow. The mentioned tensor is also shown to have a north-south asymmetry.

Krymsky, G. F.; Krivoshapkin, P. A.; Gerasimova, S. K.; Gololobov, P. Yu.

2014-04-01

271

The source abundances of galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The galactic cosmic ray source abundances have been determined from two complete datasets, one at low and the other at high energy. For both exponential and truncated exponential pathlength distributions (PLD), the two sets of source abundances show significant differences for the primary elements, i.e., the Fe/O ratio. An energy dependent PLD reduces but does not eliminate the discrepancy, and this may indicate an energy dependence in the source composition. New source abundances for Na, P, Cl, Ca, and Mn are derived.

Dwyer, R. D.; Garcia-Munoz, M.; Guzik, T. G.; Meyer, P.; Simpson, J. A.; Wefel, J. P.

1982-01-01

272

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

273

Evaluation of Galactic Cosmic Ray Models  

NASA Technical Reports Server (NTRS)

Models of the galactic cosmic ray spectra have been tested by comparing their predictions to an evaluated database containing more than 380 measured cosmic ray spectra extending from 1960 to the present.

Adams, James H., Jr.; Heiblim, Samuel; Malott, Christopher

2009-01-01

274

Effect of re-acceleration on cosmic ray components  

NASA Technical Reports Server (NTRS)

Reacceleration of cosmic rays in interstellar space has been studied in detail in order to examine the behavior of the ratios of secondary to primary nuclei in cosmic radiation. It is found that modest acceleration in a confinement region, where particles escape more freely at high energies, provides a better fit to the observed data. The effect of reacceleration on the spectral shape of proton and helium components of cosmic rays has been studied. The examination of two different models has shown that reacceleration provides a poor fit to the observed proton data.

Stephens, S. A.; Golden, R. L.

1989-01-01

275

The Cosmic Ray Electron Excess  

NASA Technical Reports Server (NTRS)

This slide presentation reviews the possible sources for the apparent excess of Cosmic Ray Electrons. The presentation reviews the Advanced Thin Ionization Calorimeter (ATIC) instrument, the various parts, how cosmic ray electrons are measured, and shows graphs that review the results of the ATIC instrument measurement. A review of Cosmic Ray Electrons models is explored, along with the source candidates. Scenarios for the excess are reviewed: Supernova remnants (SNR) Pulsar Wind nebulae, or Microquasars. Each of these has some problem that mitigates the argument. The last possibility discussed is Dark Matter. The Anti-Matter Exploration and Light-nuclei Astrophysics (PAMELA) mission is to search for evidence of annihilations of dark matter particles, to search for anti-nuclei, to test cosmic-ray propagation models, and to measure electron and positron spectra. There are slides explaining the results of Pamela and how to compare these with those of the ATIC experiment. Dark matter annihilation is then reviewed, which represent two types of dark matter: Neutralinos, and kaluza-Kline (KK) particles, which are next explained. The future astrophysical measurements, those from GLAST LAT, the Alpha Magnetic Spectrometer (AMS), and HEPCAT are reviewed, in light of assisting in finding an explanation for the observed excess. Also the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) could help by revealing if there are extra dimensions.

Chang, J.; Adams, J. H.; Ahn, H. S.; Bashindzhagyan, G. L.; Christl, M.; Ganel, O.; Guzik, T. G.; Isbert, J.; Kim, K. C.; Kuznetsov, E. N.; Panasyuk, M. I.; Panov, A. D.; Schmidt, W. K. H.; Seo, E. S.; Sokolskaya, N. V.; Watts, J. W.; Wefel, J. P.; Wu, J.; Zatsepin, V. I.

2008-01-01

276

The Stability of Cosmic Ray Precursors  

NASA Astrophysics Data System (ADS)

I consider the stability of cosmic ray precursors near shocks propagating in a high-? plasma. It is shown that the interplay between cosmic ray effects and the classical firehose and mirror instabilities lead to a more vigorous instability. Consequences for cosmic ray acceleration are discussed.

Achterberg, A.

2013-01-01

277

Research in cosmic and gamma ray astrophysics  

NASA Technical Reports Server (NTRS)

Discussed here is research in cosmic ray and gamma ray astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology. The primary activities discussed involve the development of new instrumentation and techniques for future space flight. In many cases these instrumentation developments were tested in balloon flight instruments designed to conduct new investigations in cosmic ray and gamma ray astrophysics. The results of these investigations are briefly summarized. Specific topics include a quantitative investigation of the solar modulation of cosmic ray protons and helium nuclei, a study of cosmic ray positron and electron spectra in interplanetary and interstellar space, the solar modulation of cosmic rays, an investigation of techniques for the measurement and interpretation of cosmic ray isotopic abundances, and a balloon measurement of the isotopic composition of galactic cosmic ray boron, carbon, and nitrogen.

Stone, Edward C.; Mewaldt, Richard A.; Prince, Thomas A.

1992-01-01

278

Significance of medium energy gamma ray astronomy in the study of cosmic rays  

NASA Technical Reports Server (NTRS)

Medium energy (about 10 to 30 MeV) gamma ray astronomy provides information on the product of the galactic electron cosmic ray intensity and the galactic matter to which the electrons are dynamically coupled by the magnetic field. Because high energy (greater than 100 MeV) gamma ray astronomy provides analogous information for the nucleonic cosmic rays and the relevant matter, a comparison between high energy and medium energy gamma ray intensities provides a direct ratio of the cosmic ray electrons and nucleons throughout the galaxy. A calculation of gamma ray production by electron bremsstrahlung shows that: bremsstrahlung energy loss is probably not negligible over the lifetime of the electrons in the galaxy; and the approximate bremsstrahlung calculation often used previously overestimates the gamma ray intensity by about a factor of two. As a specific example, expected medium energy gamma ray intensities are calculated for the speral arm model.

Fichtel, C. E.; Kniffen, D. A.; Thompson, D. J.; Bignami, G. F.; Cheung, C. Y.

1975-01-01

279

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

280

The highest energy cosmic rays: Observations  

NASA Astrophysics Data System (ADS)

Observations of cosmic ray air showers with energies above 0.1 EeV (1017 eV) are key to understanding where the highest energy cosmic rays originate, how they acquire their energy, what types of particles they are, and also the nature of their ultra-high-energy hadronic interactions at the top of the atmosphere. Prominent features of the energy spectrum have now been established, although some difference remains in energy normalization between results from different observatories. A distinct ankle is present near 4 EeV, and a GZK-like downturn is evident above about 30 EeV. Well above that GZK threshold, there have been tantalizing indications of clustering of arrival directions and correlation with catalogs of local matter, but no anisotropy has been independently confirmed so far at any energy above 0.1 EeV. With 99% confidence, the dipole anisotropy is less than 2% for energies just below 1 EeV, as measured in right ascension from the southern hemisphere. Moreover, no discrete source of neutral particles has been discovered and astrophysically interesting upper limits have been derived. Although the present upper limits on the diffuse intensities of photons and neutrinos do not constrain typical models of GZK production, they have eliminated most top-down models in which cosmic rays originate through the annihilation or decay of supermassive particles. The vast majority of cosmic rays must be protons and other charged nuclei. Data from different observatories have led to inconsistent inferences about the relative abundances of primary mass groups and the dependence of the composition on energy. The effective proton-air interaction cross section has been measured at EeV energies and is in agreement with conventional extrapolations obtained from measurements at collider energies.

Sommers, Paul

2013-02-01

281

Measuring Cosmic Rays at 1 PeV and Above  

NASA Astrophysics Data System (ADS)

High energy cosmic rays arrive at Earth's upper atmosphere from all directions with a remarkably smooth power-law spectrum. Structures in this otherwise smooth spectrum (such as changes in slope or in chemical composition) give clues as to the sources, acceleration, and propagation of these particles. At energies beyond 1 PeV, as cosmic rays become too rare for direct measurements to be practical, large ground-based experiments make indirect measurements of cosmic ray air showers. They employ a wide range of detection technologies and techniques, exploring known features in the spectrum such as the "knee" and the "ankle", as well as searching for new clues in the energy spectrum, chemical composition, and anisotropy in arrival directions of these particles. This talk will overview the broad landscape of ground-based cosmic ray detector arrays, and will focus on the IceCube Observatory at the South Pole.

Rawlins, Katherine

2012-05-01

282

An Empirical Model for Determination of the Cosmic Ray Spectra  

NASA Astrophysics Data System (ADS)

The high-energy charged particles entering the Earth's environment from interplanetary space have the significant effect on the space weather. We propose an improved model, which generalizes the differential D(E) and integral D(>E) spectra of galactic (GCR) and anomalous cosmic ray (ACR) protons and heavier elements during the 11-year solar cycle. The model takes into account the cosmic ray (CR) modulation by the solar wind and numerous solar and heliospheric events during different levels of solar activity. Modulated energy spectrum of galactic cosmic rays is compared with force field approximation. The difference is in the order of 1.5 %. The model solutions are compared with IMAX-92, CAPRICE-94 and AMS-98 measurements. This computed analytical model gives practical possibility for investigation of experimental data from measurements of galactic cosmic rays and their anomalous component. The obtained parameters are used for determination the profiles of the ionization in the ionosphere and middle atmosphere.

Buchvarova, M.; Velinov, P.

2006-12-01

283

Cosmic rays from ground level to space: South African perspective  

NASA Astrophysics Data System (ADS)

In South Africa, cosmic rays have been observed since the late 1950's. At present four cos-mic ray detectors, called neutron monitors, are been operated, with one in Antarctica and one in Namibia. These relative high energy measurements contribute significantly to the under-standing of the propagation of cosmic rays from the galaxy, through the heliosphere to Earth, and then through its magnetosphere and atmosphere. They therefore also contribute to the study of space weather and space climate. Since cosmic rays of lower energies are cut-off by the magnetosphere and atmosphere as protective barriers, they must be observed in space. In this context, South Africa has given the first steps with a newly created Space Agency, and subsequent proposals for future micro-satellites. A progress report on this challenge will be presented.

Potgieter, Marius

284

Modelling ground and space based cosmic ray observations  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are high energy charged particles that permeate the interstellar envi-ronment. They are subjected to a variety of highly time dependent physical processes when they enter the heliosphere. These processes cause the cosmic ray spectrum and intensities to change as a function of position, time and energy, referred to as heliospheric modulation. This modulation of cosmic rays manifests in observations, both ground and space based. In order to interpret these observations, much effort is put into modelling these modulation processes. This leads to a deeper understanding, not only of the physical processes that shape cosmic ray modulation, but also the heliospheric medium itself. With the emphasis on developing countries with limited funding and resources, it is also shown that numerical modelling studies offer a relatively cost-effective way to make a considerable contribution to space physics, and that modelling studies provide a valuable tool in interpreting both ground and space based observations.

Toit Strauss, Du; Potgieter, Marius; Ferreira, Stefan

285

Cosmic x ray physics  

NASA Technical Reports Server (NTRS)

This final report covers the period 1 January 1985 - 31 March 1992. It is divided into the following sections: the soft x-ray background; proportional counter and filter calibrations; sounding rocket flight preparations; new sounding rocket payload: x-ray calorimeter; and theoretical studies. Staff, publications, conference proceedings, invited talks, contributed talks, colloquia and seminars, public service lectures, and Ph. D. theses are listed.

Mccammon, Dan; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1992-01-01

286

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

287

Cosmic ray variations during PCA type absorption  

NASA Technical Reports Server (NTRS)

It is shown based on data on the cosmic-ray neutron component, ionospheric soundings, and measurements of cosmic radio-emission absorption at Vostok station (Antarctica) that the ionization of the lower ionosphere increases during low intensity of Forbush-type cosmic rays. This is manifested in increased absorption and the appearance of strong sporadic layers in the E-region.

Kozin, I. D.

1972-01-01

288

Gamma ray bursts and extreme energy cosmic rays  

NASA Astrophysics Data System (ADS)

Extreme Energy Cosmic Ray particles (EECR) with E>1020 eV arriving on Earth with very low flux (~1 particle/Km2-1000yr) require for their investigation very large detecting areas, exceeding values of 1000 km2 sr. Projects with these dimensions are now being proposed: Ground Arrays (``Auger'' with 2×3500 km2 sr) or exploiting the Earth Atmosphere as seen from space (``AIR WATCH'' and OWL,'' with effective area reaching 1 million km2 sr). In this last case, by using as a target the 1013 tons of air viewed, also the high energy neutrino flux can be investigated conveniently. Gamma Rays Bursts are suggested as a possible source for EECR and the associated High Energy neutrino flux.

Scarsi, Livio

1998-06-01

289

Neutron Transport Associated with the Galactic Cosmic Ray Cascade  

Microsoft Academic Search

Transport of low energy neutrons associated with the galactic cosmic ray cascade is analyzed in this dissertation. A benchmark quality analytical algorithm is demonstrated for use with B scRYNTRN, a computer program written by the High Energy Physics Division of N scASA Langley Research Center, which is used to design and analyze shielding against the radiation created by the cascade.

Robert Clay Singleterry Jr.; R. C. Jr

1993-01-01

290

Observations of Very High Energy Gamma-Ray Emission from Supernova Remnants with VERITAS  

NASA Astrophysics Data System (ADS)

The nature and source of cosmic rays has been at the core of particle astrophysics since their discovery almost a century ago. The cosmic ray spectrum is best described by a broken power law, and can be better understood as three distinct parts. Theory holds that cosmic rays up to ˜­10^15 eV - those below the "knee" or steepening in the spectrum - are produced in the shocks of supernova remnants. Direct detection of cosmic rays produced in supernova remnant shocks is impossible, however, as cosmic rays below ˜­10^18 eV are deflected by the Galactic magnetic field and cannot be traced back to their origins. If high energy hadrons are produced within the immediate environment of a supernova remnant, collisions will occur within the surrounding medium. As a result, pion production and subsequent decay will give rise to very high energy gamma rays (E>100 GeV). Since these gamma rays will not interact with any magnetic field, they can be traced back to their point of origin. Thus, Atmospheric Cherenkov Detectors like VERITAS, which have the capability to detect very high energy gamma rays via their interaction with our atmosphere, provide us the means of directly testing the theory of the origin of cosmic rays in supernova remnants. Observations of 13 supernovae made with the VERITAS instrument are presented herein, including 5 individually targeted remnants and 8 remnants within the VERITAS Cygnus region Sky Survey. The observations provide detections of two known VHE remnants (Cassiopeia A and the Crab Nebula), and meaningful flux limits on the remainder. Comparison of these results to both hadronic- and leptonic-origin emission models is carried out.

Theiling, Mark

291

?\\/hadron separation in very-high-energy ? -ray astronomy using a multivariate analysis method  

Microsoft Academic Search

In recent years, Imaging Atmospheric Cherenkov Telescopes (IACTs) have discovered a rich diversity of very high energy (VHE, >100GeV) ?-ray emitters in the sky. These instruments image Cherenkov light emitted by ?-ray induced particle cascades in the atmosphere. Background from the much more numerous cosmic-ray cascades is efficiently reduced by considering the shape of the shower images, and the capability

S. Ohm; C. van Eldik; K. Egberts

2009-01-01

292

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

293

Ionisation as indicator for cosmic ray acceleration  

NASA Astrophysics Data System (ADS)

Astrospheres and wind bubbles of massive stars are believed to be sources of cosmic rays with energies E ≲ 1 TeV. These particles are not directly detectable, but their impact on surrounding matter, in particular ionisation of atomic and molecular hydrogen, can lead to observable signatures. A correlation study of both gamma ray emission, induced by proton-proton interactions of cosmic ray protons with kinetic energies Ep ? 280 MeV with ambient hydrogen, and ionisation induced by cosmic ray protons of kinetic energies Ep < 280 MeV can be performed in order to study potential sources of (sub)TeV cosmic rays.

Schuppan, F.; Röken, C.; Fedrau, N.; Becker Tjus, J.

2014-06-01

294

Cosmic-ray-modified supernova remnant shocks  

NASA Technical Reports Server (NTRS)

The evolution of cosmic-ray-modified SNRs during the early Sedov phase is investigated using the time-dependent, two-fluid model for diffusive shock acceleration. Consideration is given to the sensitivity of net acceleration efficiency to model assumptions regarding density structure of the external medium as well as time dependence in the diffusion coefficient and the cosmic-ray adiabatic index. Of the model assumptions explored, the greatest sensitivity was found to time variations in the specific heat ratio to cosmic rays. It was found that if tau is greater than or approximately equal to few times 100, dynamically significant cosmic-ray pressures are produced early in the Sedov inefficient cosmic-ray accelerators. For the SNR models under consideration, the total energy channeled into the cosmic rays can be of order 10 percent of the initial blast energy for both the uniform density and inverse-square density interstellar medium models.

Jones, T. W.; Kang, Hyesung

1992-01-01

295

Galactic cosmic ray composition and energy spectra  

NASA Technical Reports Server (NTRS)

Galactic cosmic ray nuclei represent a significant risk to long-duration spaceflight outside the magnetosphere. We review briefly existing measurements of the composition and energy spectra of heavy cosmic ray nuclei, pointing out which species and energy ranges are most critical to assessing cosmic ray risks for spaceflight. Key data sets are identified and a table of cosmic ray abundances is presented for elements from H to Ni (Z = 1 to 28). Because of the 22-year nature of the solar modulation cycle, data from the approaching 1998 solar minimum is especially important to reducing uncertainties in the cosmic ray radiation hazard. It is recommended that efforts to model this hazard take advantage of approaches that have been developed to model the astrophysical aspects of cosmic rays.

Mewaldt, R. A.

1994-01-01

296

Possible Contribution of Mature gamma-ray Pulsars to Cosmic-ray Positrons  

Microsoft Academic Search

We restudy the possible contribution of mature gamma-ray pulsars to cosmic ray positrons based on the new version of outer gap model. In this model, the inclination angle and average properties of the outer gap are taken into account, and more mature pulsars can have the outer gap and emit high energy photons. Half of the primary particles in the

Quan-Gui Gao; Ze-Jun Jiang; Li Zhang

2008-01-01

297

Cloud chamber visualization of primary cosmic rays  

SciTech Connect

From 1948 until 1963, cloud chambers were carried to the top of the atmosphere by balloons. From these flights, which were begun by Edward P. Ney at the University of Minnesota, came the following results: discovery of heavy cosmic ray nuclei, development of scintillation and cherenkov detectors, discovery of cosmic ray electrons, and studies of solar proton events. The history of that era is illustrated here by cloud chamber photographs of primary cosmic rays.

Earl, James A. [Department of Astronomy, University of Maryland, College Park MD (United States)

2013-02-07

298

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

299

Propagation of cosmic rays in the galaxy  

NASA Technical Reports Server (NTRS)

The characteristics of a model for analyzing the propagation of cosmic rays are discussed. The requirements for analyzing the relevant observational data on cosmic rays are defines as: (1) the chemical and isotopic composition of cosmic rays as a function of energy, (2) the flux and energy spectrum of the individual nucleonic components, (3) the flux and energy spectrum of the electronic component, (4) the cosmic ray prehistory, and (5) the degree of isotropy in their arrival directions as a function of energy. It is stated that the model which has been able to bring to pass the greatest measure of success is the galactic confinement model.

Daniel, R. R.; Stephens, S. A.

1974-01-01

300

A hysteresis effect in cosmic ray modulation  

NASA Technical Reports Server (NTRS)

The rigidity dependence is investigated in the modulation of cosmic ray protons and alphas at intermediate (2-13 Gv) rigidities during the declines and recoveries of the cosmic ray flux near cosmic ray minimum. The results include the finding that sudden changes in the modulation of the primary cosmic rays are initiated by large solar particle outflow and begin as type I Forbush decreases. Typically, the modulation spectrum becomes flatter at intermediate rigidity below 13 Gv and steeper at rigidities above 13 Gv during early recovery.

Verschell, H. J.; Mendell, R. B.; Korff, S. A.

1974-01-01

301

Cosmic ray studies with the MINOS detectors  

NASA Astrophysics Data System (ADS)

The MINOS experiment uses two layered scintillator and steel detectors along with a muon neutrino beam to search for ?? disappearance, and thus neutrino oscillations. The Far Detector ('FD') is situated in a former iron mine in the Soudan Underground Mine State Park in Northeastern MN, 700 m (2070 mwe) below the surface. This 5.4 kt steel/scintillator calorimeter measures the neutrino flux after they have traveled the 735 km baseline. It also detects atmospheric neutrinos at a rate of several per week, and is the first magnetized atmospheric neutrino detector, able to discriminate between ?? and ?? on an event-by-event basis. The similar 1 kt Near Detector ('ND') is 100 m (220 mwe) underground at Fermilab. This poster discusses the science being done with the high energy cosmic ray muons which penetrate the rock overburden and are seen by the detectors. The typical surface energy of those seen at the FD are ~1 TeV (coming from ~8 TeV primary cosmic rays) and ~110 GeV at the ND (~900 GeV primaries).

Habig, Alec; Minos Collaboration

2008-11-01

302

Cosmic ray diffusion: Report of the Workshop in Cosmic Ray Diffusion Theory  

NASA Technical Reports Server (NTRS)

A workshop in cosmic ray diffusion theory was held at Goddard Space Flight Center on May 16-17, 1974. Topics discussed and summarized are: (1) cosmic ray measurements as related to diffusion theory; (2) quasi-linear theory, nonlinear theory, and computer simulation of cosmic ray pitch-angle diffusion; and (3) magnetic field fluctuation measurements as related to diffusion theory.

Birmingham, T. J.; Jones, F. C.

1975-01-01

303

Transport and acceleration of anomalous cosmic rays  

NASA Astrophysics Data System (ADS)

Anomalous cosmic rays are produced from interstellar pickup ions by heliospheric plasma processes. The solar wind termination shock was believed to be the source of these high-energy ions before the Voyagers' shock encounter. Because ACR spectra were observed to be modulated at the shock, several different acceleration cites and mechanisms were proposed. These included termination shock locations not visited by the Voyagers, the inner helioshgeath, and regions near the heliopause. I will review and compare the current generation of ACR transport models, including an update on the Huntsville model. A need to accommodate a physically realistic geometry of the termination shock and heliosheath for ACR modeling is emphasized. I also discuss recent ACR flux decreases as a sign of Voyager's proximity to the heliopause.

Florinski, Vladimir; Senanayake, Udara

2012-07-01

304

Cosmic X-ray physics  

NASA Astrophysics Data System (ADS)

A progress report of research activities carried out in the area of cosmic X-ray physics is presented. The Diffuse X-ray Spectrometer DXS which has been flown twice as a rocket payload is described. The observation times proved to be too small for meaningful X-ray data to be obtained. Data collection and reduction activities from the Ultra-Soft X-ray background (UXT) instrument are described. UXT consists of three mechanically-collimated X-ray gas proportional counters with window/filter combinations which allow measurements in three energy bands, Be (80-110 eV), B (90-187 eV), and O (e84-532 eV). The Be band measurements provide an important constraint on local absorption of X-rays from the hot component of the local interstellar medium. Work has also continued on the development of a calorimetric detector for high-resolution spectroscopy in the 0.1 keV - 8keV energy range.

McCammon, D.; Cox, D. P.; Kraushaar, W. L.; Sanders, W. T.

1985-06-01

305

Cosmic rays and terrestrial life: A brief review  

NASA Astrophysics Data System (ADS)

“The investigation into the possible effects of cosmic rays on living organisms will also offer great interest.” - Victor F. Hess, Nobel Lecture, December 12, 1936 High-energy radiation bursts are commonplace in our Universe. From nearby solar flares to distant gamma ray bursts, a variety of physical processes accelerate charged particles to a wide range of energies, which subsequently reach the Earth. Such particles contribute to a number of physical processes occurring in the Earth system. A large fraction of the energy of charged particles gets deposited in the atmosphere, ionizing it, causing changes in its chemistry and affecting the global electric circuit. Remaining secondary particles contribute to the background dose of cosmic rays on the surface and parts of the subsurface region. Life has evolved over the past ?3 billion years in presence of this background radiation, which itself has varied considerably during the period [1-3]. As demonstrated by the Miller-Urey experiment, lightning plays a very important role in the formation of complex organic molecules, which are the building blocks of more complex structures forming life. There is growing evidence of increase in the lightning rate with increasing flux of charged particles. Is there a connection between enhanced rate of cosmic rays and the origin of life? Cosmic ray secondaries are also known to damage DNA and cause mutations, leading to cancer and other diseases. It is now possible to compute radiation doses from secondary particles, in particular muons and neutrons. Have the variations in cosmic ray flux affected the evolution of life on earth? We describe the mechanisms of cosmic rays affecting terrestrial life and review the potential implications of the variation of high-energy astrophysical radiation on the history of life on earth.

Atri, Dimitra; Melott, Adrian L.

2014-01-01

306

Solar-cycle modulation of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

A numerical solution is described of the spherically-symmetric, time-dependent, cosmic-ray modulation equation, and compared to data taken near the ecliptic. The physical mechanisms are probed responsible for the solar-cycle variations in the cosmic-ray intensity. With a physically defensible diffusion coefficient and other reasonable parameters, the spectra of protons and electrons are simulated simultaneously over the cycle, as well as the radial intensity gradients for particles greater than about 100 MeV, the overall intensity variation during the cycle, and the time lag in the recovery of low-energy particles behind high-energy ones, known commonly as the "hysteresis". The results suggest that cosmic-ray variations near the ecliptic are dominated by turbulent scattering regions in the heliosphere, overwhelming any effects of gradient and curvature drifts.

Perko, John S.

307

Solar-cycle modulation of galactic cosmic rays  

NASA Technical Reports Server (NTRS)

This paper describes a numerical solution of the spherically-symmetric, time-dependent, cosmic-ray modulation equation, compares it to data taken near the ecliptic, and probes the physical mechanisms responsible for the solar-cycle variations in the cosmic-ray intensity. With a physically defensible diffusion coefficient and other reasonable parameters, the spectra of protons and electrons can be simulated simultaneously over the cycle, the radial intensity gradients for particles greater than about 100 MeV, the overall intensity variation during the cycle, and the time lag in the recovery of low-energy particles behind high-energy ones, known commonly as the 'hysteresis.' The results suggest that cosmic-ray variations near the ecliptic are dominated by turbulent scattering regions in the heliosphere, overwhelming any effects of gradient and curvature drifts.

Perko, John S.

1988-01-01

308

On cosmic censor in high-energy particle collisions  

NASA Astrophysics Data System (ADS)

In the context of large extra-dimension or TeV-scale gravity scenarios, miniature black holes might be produced in collider experiments. In many works the validity of the cosmic censorship hypothesis has been assumed, which means that there is no chance to observe trans-Planckian phenomena in the experiments since such phenomena are veiled behind the horizons. Here, we argue that "visible borders of spacetime" (as effective naked singularities) would be produced, even dominantly over the black holes, in the collider experiments. Such phenomena will provide us an arena of quantum gravity.

Miyamoto, Umpei

2011-09-01

309

Phantom Cosmic Ray Decreases and their Extraterrestrial Origins  

NASA Astrophysics Data System (ADS)

Galactic cosmic rays are extremely high energy charged particles accelerated at extra-solar sources such as supernovae, active galactic nuclei, quasars, and gamma-ray bursts. Upon arrival at Earth's atmosphere, they collide with air molecules to produce a shower of secondary particles. One product of this air shower is energetic neutrons, which can be detected at the Earth's surface. Neutron monitors have been routinely operating for more than half a century and have shown that the cosmic ray flux at the top of the atmosphere is modulated by the heliospheric magnetic field (HMF), both at solar cycle time scales and due to shorter-term HMF variations, such as result from coronal mass ejections (CMEs). When a CME passes over the Earth, the neutron monitor counts are reduced sharply and suddenly (in a matter of hours) due to the modulation of cosmic rays by the enhancement in the heliospheric magnetic field (HMF). Such a drop in neutron counts is known as a Forbush Decrease. We present examples of unusual Forbush Decreases where there is no disturbance in the HMF at Earth at the time, which we name 'Phantom Cosmic Ray Decreases' (PCRDs). For recent PCRD events, we examine STEREO in-situ data and in each case, we find a large CME in either STEREO-A or -B. We also study neutron counts for each event from a number of neutron monitors at different longitudes. Differences between the size of the cosmic ray decreases at different longitudes are shown to give information on the location of the cosmic ray modulation source. We thus propose that these PCRDs are caused by CMEs which have missed Earth but which are large and intense enough to block out galactic cosmic rays on trajectories toward Earth.

Thomas, Simon; Owens, Mathew; Lockwood, Mike; Scott, Chris

2014-05-01

310

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

311

The Discovery and Nature of Cosmic Rays  

NSDL National Science Digital Library

In this lesson, students will learn how cosmic rays were discovered and what they are - including their size and speed. Includes background information for the teacher, questions, activities and information about student preconceptions. This is lesson 1 of 4 from "The Cosmic Ray Telescope for the Effects of Radiation (CRaTER)."

312

Cosmic-ray propagation and containment  

NASA Technical Reports Server (NTRS)

The cosmic rays are an active gaseous component of the disk of the galaxy, and their propagation and containment is a part of the general dynamics of the disk. The sources of cosmic rays are a matter of speculation. The disk is inflated by the cosmic-ray gas pressure, P, comparable to the magnetic pressure B super 2/ 8 pi, but the rate of inflation is unknown. The time spent by the individual cosmic-ray particles in the disk is inversely proportional to the cosmic-ray production rate and may be anything from 100,000 to more than 10 million years. It is evident from the decay of Be(10) that the cosmic rays circulate through a volume of space perhaps ten times the thickness of the gaseous disk, suggesting a magnetic halo extending out approximately 1 kpc from either face of the disk. The cosmic rays may be responsible for the halo by inflating the magnetic fields of the disk. Extension of the fields to 1 kpc would imply a high production rate and short life of cosmic rays in the dense gaseous disk of the galaxy.

Parker, E. N.

1977-01-01

313

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

314

History of cosmic ray research in Finland  

NASA Astrophysics Data System (ADS)

The history of cosmic ray research in Finland can be traced back to the end of 1950s, when first ground-based cosmic ray measurements started in Turku. The first cosmic ray station was founded in Oulu in 1964 performing measurements of cosmic rays by a muon telescope, which was later complemented by a neutron monitor. Since the 1990s, several research centers and universities, such as The Finnish Meteorological Institute, Helsinki University of Technology, University of Oulu, University of Turku and University of Helsinki have been involved in space science projects, such as SOHO, AMS, Cluster, Cassini, BepiColombo, etc. At the same time, ground-based cosmic ray measurements have reached a new level, including a fully automatic on-line database in Oulu and a new muon measuring underground site in Pyhäsalmi. Research groups in Helsinki, Oulu and Turku have also extensive experience in theoretical investigations of different aspects of cosmic ray physics. Cosmic ray research has a 50-year long history in Finland, covering a wide range from basic long-running ground-based observations to high-technology space-borne instrumentation and sophisticated theoretical studies. Several generations of researchers have been involved in the study ensuring transfer of experience and building the recognized Finnish research school of cosmic ray studies.

Usoskin, I. G.; Valtonen, E.; Vainio, R.; Tanskanen, P. J.; Aurela, A. M.

2009-11-01

315

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

316

Thermal Emission from Cosmic Ray Modified Shocks  

NASA Astrophysics Data System (ADS)

Efficient cosmic ray acceleration in supernova remnants results in both higher shock compression and lower post shock temperatures compared to cases where cosmic ray production is ignored. These changes in the properties of the shocked plasma will translate into changes in the thermal X-ray emission in the interaction region between the forward and reverse shocks. Furthermore, the relativistic cosmic ray electrons produced in the diffusive shock acceleration process generate nonthermal X-ray synchrotron emission which is self-consistently determined with the thermal emission through the nonlinear shock acceleration mechanism. We present results from simulations where the remnant hydrodynamics are coupled to efficient cosmic ray acceleration and to a nonequilibrium ionization calculation of thermal X-ray emission. By varying the particle injection efficiency, ambient density, and the electron heating mechanism, we produce a grid of models which show variations in the resultant X-ray spectra where the thermal and nonthermal contributions are determined self-consistently.

Patnaude, Daniel

2007-05-01

317

IceCube and the Discovery of High-Energy Cosmic Neutrinos  

NASA Astrophysics Data System (ADS)

The IceCube project has transformed one cubic kilometer of natural Antarctic ice into a neutrino detector. The instrument detects 100,000 neutrinos per year in the GeV to PeV energy range. Among those, we have recently isolated a flux of high-energy cosmic neutrinos. I will discuss the instrument, the analysis of the data, and the significance of the discovery of cosmic neutrinos.

Halzen, Francis

2014-08-01

318

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

319

Cosmic ray fluxes and atmospheric electricity  

NASA Astrophysics Data System (ADS)

Cosmic rays are the main source of ions in the lower part of the middle atmosphere at the altitudes up to 50-60 km. So, they play very important role in the atmospheric electrical processes. The following questions are discussed: 1). Cosmic ray ion production and ion recombination. It is shown that the equation of ion balance has linear form rather than quadratic one (in the case of ion production by cosmic rays). The rate of ion production and the coefficient of the linear recomb ination of light ions vs. altitude are calculated. 2). The role of cosmic rays in the processes of thundercloud electricity formation and lightning discharges. 3). The cosmic ray variations and their influence of on thunderstorm activity and the global electric circuit operation.

Stozhkov, Y.; Ermakov, V.

320

A Portable Classroom Cosmic Ray Detector  

NASA Astrophysics Data System (ADS)

Normally, one has to work at an accelerator to demonstrate the principles of particle physics. We have developed a portable cosmic ray detector, the Berkeley Lab Detector, that can bring high energy physics experimentation into the classroom. The detector, which is powered by either batteries or AC power, consists of two scintillator paddles with a printed circuit board. The printed circuit board takes the analog signals from the paddles, compares them, and determines whether the pulses arrived at the same time. It has a visual display and a computer output. The output is compatible with commonly found probes in high schools and colleges. A bright high school student can assemble it. Teachers and students have used a working detector on six of the world's continents. These activities have included cross country trips, science projects, and classroom demonstrations. A complete description can be found at the web site: cosmic.lbl.gov. Besides, basic particle physics, the detector can be used to teach statistics and also to provide an opportunity where students have to determine how much data are taken. In this presentation, we will demonstrate the detector and describe some of the projects that teachers and students have completed with it.

Matis, Howard

2012-03-01

321

Research in cosmic and gamma ray astrophysics  

NASA Technical Reports Server (NTRS)

Research activities in cosmic rays, gamma rays, and astrophysical plasmas are covered. The activities are divided into sections and described, followed by a bibliography. The astrophysical aspects of cosmic rays, gamma rays, and of the radiation and electromagnetic field environment of the Earth and other planets are investigated. These investigations are performed by means of energetic particle and photon detector systems flown on spacecraft and balloons.

Stone, E. C.; Davis, L., Jr.; Mewaldt, R. A.; Prince, T. A.

1989-01-01

322

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 ux of ultrahigh-energy cosmicrays 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

2013-12-01

323

The Voyager Cosmic Ray Experiment  

NASA Technical Reports Server (NTRS)

The Voyager Cosmic Ray Experiment includes seven dE/dx-E telescopes to measure the energy and charge of particles with atomic numbers from 1 to 26 in the energy range 1-500 MeV/nucleon and to measure electron energy in the range from 3 to 110 MeV. Isotopic composition of hydrogen through sulfur in the range up to 75 Mev/nucleon can also be resolved. The electronic systems include a dual-gain, charge sensitive preamplifier, 4096-channel pulse height analyzers for three parameter analysis of selected events, and an event type readout polling scheme to maximize the use of available telemetry space and to enhance the occurrence of rare events in the data. Details of the detector, electronic and mechanical design are presented.

Stilwell, D. E.; Davis, W. D.; Joyce, R. M.; Mcdonald, F. B.; Trainor, J. H.; Althouse, W. E.; Cummings, A. C.; Garrard, T. L.; Stone, E. C.; Vogt, R. E.

1979-01-01

324

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

325

Isotopes in galactic cosmic rays  

NASA Astrophysics Data System (ADS)

Four possible scenarios for the origin of the isotopic ratio of neon in galactic cosmic rays (GCR), (which differs from the solar system ratio), are discussed. The observed compositional effects may actually represent biases in the acceleration. Selective acceleration effects for neon exist either in the solar wind or in solar flares, and extreme variations for helium are seen in solar flares. The abundance of Ne-22 could be explained as due to small star nucleosynthesis, but the absence of N increase between the birth of the sun and now argues against this. The idea that supernovae are contributing fresh material to the GCR has little evidential support. More plausible is the notion that CGR, including the excess Ne-22, could be an outflow from OB star assemblages, including WR stars. The latter have lost their atmospheres through Roche lobe overflow, exposing the surface rich in nucleosynthetic products. These are blown away by the powerful stellar wind.

Reeves, H.

326

Cosmic ray composition investigations using ICE/ISEE-3  

NASA Technical Reports Server (NTRS)

The analysis of data from the high energy cosmic experiment on ISEE-3 and associated modeling and interpretation activities are discussed. The ISEE-3 payload included two instruments capable of measuring the composition of heavy cosmic rays. The designs of these two instruments incorporated innovations which made it possible, for the first time, to measure isotopic as well as the chemical composition for a wide range of elements. As the result of the demonstrations by these two instruments of the capability to resolve individual cosmic ray isotopes, a new generation of detectors was developed using very similar designs, but having improved reliability and increased sensitive area. The composition measurements which were obtained from the ISEE-3 experiment are summarized.

Wiedenbeck, Mark E.

1992-01-01

327

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

328

Radiographic Images Produced by Cosmic-Ray Muons  

NASA Astrophysics Data System (ADS)

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, Rubén

2006-09-01

329

Significance of medium-energy gamma-ray astronomy in the study of cosmic rays  

Microsoft Academic Search

Medium-energy (about 10--30 MeV) ..gamma..-ray astronomy can provide detailed information on the product of the galactic electron cosmic-ray intensity and the galactic matter to which the electrons are dynamically coupled by the magnetic field, since for the electrons the bremsstrahlung dominates over other radiation except possibly in a small region at the galactic center. Because high energy (>100 MeV) ..gamma..-ray

C. E. Fichtel; D. A. Kniffen; D. J. Thompson; G. F. Bignami; C. Y. Cheung

1976-01-01

330

Cosmic Ray-Air Shower Measurement from Space  

NASA Astrophysics Data System (ADS)

A feasibility study has been initiated to observe from space the highest energy cosmic rays above 1021 eV. A satellite observatory concept, the Maximum-energy Auger (Air)-Shower Satellite (MASS), is recently renamed as the Orbital Wide-angle Collector (OWL) by taking its unique feature of using a very wide field-of-view (FOV) optics. A huge array of imaging devices (about 106 pixels) is required to detect and record fluorescent light profiles of cosmic ray cascades in the atmosphere. The FOV of MASS could extend to as large as about 60 in. diameter, which views (500 - 1000 km) of earth's surface and more than 300 - 1000 cosmic ray events per year could be observed above 1020 eV. From far above the atmosphere, the MASS/OWL satellite should be capable of observing events at all angles including near horizontal tracks, and would have considerable aperture for high energy photon and neutrino observation. With a large aperture and the spatial and temporal resolution, MASS could determine the energy spectrum, the mass composition, and arrival anisotropy of cosmic rays from 1020 eV to 1022 eV; a region hitherto not explored by ground-based detectors such as the Fly's Eye and air-shower arrays. MASS/OWL's ability to identify cosmic neutrinos and gamma rays may help providing evidence for the theory which attributes the above cut-off cosmic ray flux to the decay of topological defects. Very wide FOV optics system of MASS/OWL with a large array of imaging devices is applicable to observe other atmospheric phenomena including upper atmospheric lightning. The wide FOV MASS optics being developed can also improve ground-based gamma-ray observatories by allowing simultaneous observation of many gamma ray sources located at different constellations.

Takahashi, Yoshiyuki

1997-03-01

331

Cosmic Ray-Air Shower Measurement from Space  

NASA Technical Reports Server (NTRS)

A feasibility study has been initiated to observe from space the highest energy cosmic rays above 1021 eV. A satellite observatory concept, the Maximum-energy Auger (Air)-Shower Satellite (MASS), is recently renamed as the Orbital Wide-angle Collector (OWL) by taking its unique feature of using a very wide field-of-view (FOV) optics. A huge array of imaging devices (about 10(exp 6) pixels) is required to detect and record fluorescent light profiles of cosmic ray cascades in the atmosphere. The FOV of MASS could extend to as large as about 60 in. diameter, which views (500 - 1000 km) of earth's surface and more than 300 - 1000 cosmic ray events per year could be observed above 1020 eV. From far above the atmosphere, the MASS/OWL satellite should be capable of observing events at all angles including near horizontal tracks, and would have considerable aperture for high energy photon and neutrino observation. With a large aperture and the spatial and temporal resolution, MASS could determine the energy spectrum, the mass composition, and arrival anisotropy of cosmic rays from 1020 eV to 1022 eV; a region hitherto not explored by ground-based detectors such as the Fly's Eye and air-shower arrays. MASS/OWL's ability to identify cosmic neutrinos and gamma rays may help providing evidence for the theory which attributes the above cut-off cosmic ray flux to the decay of topological defects. Very wide FOV optics system of MASS/OWL with a large array of imaging devices is applicable to observe other atmospheric phenomena including upper atmospheric lightning. The wide FOV MASS optics being developed can also improve ground-based gamma-ray observatories by allowing simultaneous observation of many gamma ray sources located at different constellations.

Takahashi, Yoshiyuki

1997-01-01

332

Primary gamma rays. [resulting from cosmic ray interaction with interstellar matter  

NASA Technical Reports Server (NTRS)

Within this galaxy, cosmic rays reveal their presence in interstellar space and probably in source regions by their interactions with interstellar matter which lead to gamma rays with a very characteristic energy spectrum. From the study of the intensity of the high energy gamma radiation as a function of galactic longitude, it is already clear that cosmic rays are almost certainly not uniformly distributed in the galaxy and are not concentrated in the center of the galaxy. The galactic cosmic rays appear to be tied to galactic structural features, presumably by the galactic magnetic fields which are in turn held by the matter in the arm segments and the clouds. On the extragalactic scale, it is now possible to say that cosmic rays are not universal at the density seen near the earth. The diffuse celestial gamma ray spectrum that is observed presents the interesting possibility of cosmological studies and possible evidence for a residual universal cosmic ray density, which is much lower than the present galactic cosmic ray density.

Fichtel, C. E.

1974-01-01

333

Galactic cosmic ray flux simulation and prediction.  

PubMed

A dynamic galactic cosmic ray model is proposed to quantitatively describe the z=1-28 ions and electrons of E=10-10(5) MeV/nucleon and their particle flux variations around the Earth's orbit and beyond the Earth's magnetosphere due to diverse large-scale variations of solar activity factors. The variations of large-scale heliospheric magnetic fields and the galactic cosmic ray flux variation time delays relative to solar activity variations are simulated. The lag characteristics and sunspot number predictions having been determined in detail, the model can be used to predict galactic cosmic ray flux levels. PMID:11540366

Nymmik, R A; Panasyuk, M I; Suslov, A A

1996-01-01

334

High energy particle astronomy.  

NASA Technical Reports Server (NTRS)

Discussion of techniques currently used in high energy particle astronomy for measuring charged and neutral cosmic rays and their isotope and momentum distribution. Derived from methods developed for accelerator experiments in particle physics, these techniques help perform important particle astronomy experiments pertaining to nuclear cosmic ray and gamma ray research, electron and position probes, and antimatter searches.

Buffington, A.; Muller, R. A.; Smith, L. H.; Smoot, G. F.

1972-01-01

335

X-ray Production By Cosmic Muons  

SciTech Connect

Muons have a small cross section for interactions and high energy, so they are very penetrating and give the significant contribution to the gamma spectra of Ge detectors, even in deep underground laboratories. One of the muon interaction effects with material is X-rays production. Having in mind that gold is often used as a detectors component, in this paper the production of X-rays in gold sample is analyzed by using an coincidence system based on plastic scintillation detector and Ge detector. The Au disc-shaped sample with mass of 40.6 g, radius 3.34 cm and 0.06 cm thickness was inside 12 cm thick lead shield of extended range HPGe detector. The plastic detector of 0.5 x 0.5 x 0.05 m dimensions was placed above the lead shield at the distance of 32 cm from detector endcap. The producing rate of K{alpha} rays per Au mass unit from coincidence gamma spectrum is determined as R {approx_equal}7.1 x 10-4 g-1s-1. Taking in account the measured muon flux of {phi}=54 s-1m-2, the muon cross section {sigma}K{alpha}{approx_equal} 43 Barn, for Au K{alpha} X-rays production is calculated. Also, the cross sections of X-ray production by cosmic muons in lead and tungsten are measured. Unexpectedly, the results obtained did not reveal Z dependence in the Z= 74-82 region.

Mrdja, D.; Bikit, I.; Veskovic, M.; Forkapic, S. [Department of Physics, Faculty of Sciences, University of Novi Sad, Trg Dositeja Obradovica 4, 21 000 Novi Sad (Serbia); Anicin, I. [Faculty of Physics, University of Belgrade, Studentski trg 12-16, 11 000 Belgrade (Serbia)

2007-04-23

336

A New View of the High Energy Gamma-Ray Sky with the Ferrni Gamma-Ray Space Telescope  

NASA Technical Reports Server (NTRS)

Following its launch in June 2008, high energy gamma-ray observations by the Fermi Gamma-ray Space Telescope have opened a new and important window on a wide variety of phenomena, including pulsars, black holes and active galactic nuclei, gamma-ray bursts, supernova remnants and the origin of cosmic rays, and searches for hypothetical new phenomena such as super symmetric dark matter annihilations. In this talk I will describe the current status of the Fermi observatory and review the science highlights from the first year of observations.

McEnery, Julie

2009-01-01

337

The cosmic ray ionization rate in the central parsec of the Galaxy  

NASA Astrophysics Data System (ADS)

Cosmic rays represent a unique crossing point of high-energy astrophysics and astrochemistry. The cosmic ray ionization rate of molecular hydrogen (?2) measured by H3 + spectroscopy in the central parsec of the Galaxy is 2 orders of magnitude higher than that in the dense clouds outside the Galactic center. However, it is still too short, by the factor of 10,000, to agree with an extremely high ?2 that accommodates the new ?-ray observations of Sgr A* and its environment.

Goto, Miwa

2014-05-01

338

Consistency of cosmic-ray source abudances with explosive nucleosynthesis  

NASA Technical Reports Server (NTRS)

A model was examined in which the cosmic ray abundances of elements from C to Fe are consistent with explosive nucleosynthesis. The observed abundance of cosmic rays near the earth, cosmic ray source abundance, and solar system abundance are discussed along with the ratios of cosmic ray sources to the solar system abundances.

Kozlovsky, B.; Ramaty, R.

1973-01-01

339

Measurement of C-12, O-16, and Fe-56 charge changing cross sections in helium at high energy, comparison with cross sections in hydrogen, and application to cosmic-ray propagation  

NASA Technical Reports Server (NTRS)

We present measurements of the spallation cross sections of carbon, oxygen, and iron in helium and hydrogen, at beam energies from 540 to 1600 MeV/nucleon, performed by exposing liquid helium, CH2, and C targets. Charge changing cross sections are reported for fragments down to Ne for Fe + alpha and Fe + p reactions, and down to B for O + alpha, O + p, C + alpha, and C + p reactions. Alpha- to p-induced cross section ratios (sigma(sub alpha)/sigma(sub p)) are determined at the same energy per nucleon. From these measurements an empirical formula for the (sigma(sub alpha)/sigma(sub p)) ratios is derived and is found in good agreement with available isotopic cross sections data from radioactivity and radiochemical techniques. These results are applied to the propagation of heavy charged cosmic rays in an interstellar medium with a helium to hydrogen abundance ratio of 0.10. It is shown that the Sc-Mn/Fe ratio prediction is decreased relative to the B/C ratio when compared to propagation calculations in a pure hydrogen interstellar medium.

Ferrando, P.; Webber, W. R.; Goret, P.; Kish, J. C.; Schrier, D. A.; Soutoul, A.; Testard, O.

1988-01-01

340

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

341

COSMIC-RAY TRANSPORT AND ANISOTROPIES  

SciTech Connect

We show that the large-scale cosmic-ray anisotropy at {approx}10 TeV can be explained by a modified Compton-Getting effect in the magnetized flow field of old supernova remnants. Cosmic rays arrive isotropically to the flow field and are then carried along with the flow to produce a large-scale anisotropy in the arrival direction. This approach suggests an optimum energy scale for detecting the anisotropy. Two key assumptions are that propagation is based on turbulence following a Kolmogorov law and that cosmic-ray interactions are dominated by transport via cosmic-ray-excited magnetic irregularities through the stellar wind of an exploding star and its shock shell. A prediction is that the amplitude is smaller at lower energies due to incomplete sampling of the velocity field and also smaller at larger energies due to smearing.

Biermann, Peter L. [MPI for Radioastronomy, Auf dem Huegel 69, D-53121 Bonn (Germany); Becker Tjus, Julia; Mandelartz, Matthias [Ruhr-Universitaet Bochum, Fakultaet fuer Physik and Astronomie, Theoretische Physik I, D-44780 Bochum (Germany); Seo, Eun-Suk [Department of Physics, University of Maryland, College Park, MD 20742 (United States)

2013-05-10

342

The origin of ultrahigh energy cosmic rays.  

NASA Astrophysics Data System (ADS)

The authors have studied cosmic rays (CR) of energy above 1019eV using data published by the World Data Centre C2 for cosmic rays. Three catalogues are available that contain information from four large CR experiments at Volcano Ranch, Haverah Park, SUGAR (Sydney), and Yakutsk, respectively. The data have been summed to study the sky as seen in the most energetic particles.

Chi, X.; Szabelski, J.; Vahia, M. N.; Wolfendale, A. W.

343

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

344

Cosmic Ray Astrophysics with AMS-02  

NASA Astrophysics Data System (ADS)

The Alpha Magnetic Spectrometer (AMS) is a cosmic ray (CR) experiment that will operate on the International Space Station for three years, measuring the particle spectra in the rigidity range from 0.2 GV to 2 TV. The AMS-02 detector will provide measurements with unprecedented statistics of the hadronic and leptonic cosmic rays, allowing for a better study of the Earth magnetosphere, of the solar system environment, of the solar system neighborhood, and of the galactic interstellar medium.

Casadei, Diego

2005-04-01

345

Apollo 17 lunar surface cosmic ray detector  

NASA Technical Reports Server (NTRS)

The objectives and selected data are presented for the Apollo 17 Lunar Surface Cosmic Ray Experiment (LSCRE) for the purpose of introducing an analysis of three of the separate detectors contained within in LSCRE package. The mica detector for measuring heavy solar wind, and the lexan stack and glass detectors for measuring energetic particles in space are discussed in terms of their deployment, exposure time, calibration, and data yield. Relevant articles on solar particles, interplanetary ions, and cosmic ray nuclei are also included.

Walker, R. M.

1974-01-01

346

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

347

The EGRET high energy gamma ray telescope  

NASA Technical Reports Server (NTRS)

The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (GRO) is sensitive in the energy range from about 20 MeV to about 30,000 MeV. Electron-positron pair production by incident gamma photons is utilized as the detection mechanism. The pair production occurs in tantalum foils interleaved with the layers of a digital spark chamber system; the spark chamber records the tracks of the electron and positron, allowing the reconstruction of the arrival direction of the gamma ray. If there is no signal from the charged particle anticoincidence detector which surrounds the upper part of the detector, the spark chamber array is triggered by two hodoscopes of plastic scintillators. A time of flight requirement is included to reject events moving backward through the telescope. The energy of the gamma ray is primarily determined by absorption of the energies of the electron and positron in a 20 cm deep NaI(Tl) scintillator.

Hartman, R. C.; Bertsch, D. L.; Fichtel, C. E.; Hunter, S. D.; Kanbach, G.; Kniffen, D. A.; Kwok, P. W.; Lin, Y. C.; Mattox, J. R.; Mayer-Hasselwander, H. A.

1992-01-01

348

The EGRET high energy gamma ray telescope  

NASA Astrophysics Data System (ADS)

The Energetic Gamma Ray Experiment Telescope (EGRET) on the Compton Gamma Ray Observatory (GRO) is sensitive in the energy range from about 20 MeV to about 30,000 MeV. Electron-positron pair production by incident gamma photons is utilized as the detection mechanism. The pair production occurs in tantalum foils interleaved with the layers of a digital spark chamber system; the spark chamber records the tracks of the electron and positron, allowing the reconstruction of the arrival direction of the gamma ray. If there is no signal from the charged particle anticoincidence detector which surrounds the upper part of the detector, the spark chamber array is triggered by two hodoscopes of plastic scintillators. A time of flight requirement is included to reject events moving backward through the telescope. The energy of the gamma ray is primarily determined by absorption of the energies of the electron and positron in a 20 cm deep NaI(Tl) scintillator.

Hartman, R. C.; Bertsch, D. L.; Fichtel, C. E.; Hunter, S. D.; Kanbach, G.; Kniffen, D. A.; Kwok, P. W.; Lin, Y. C.; Mattox, J. R.; Mayer-Hasselwander, H. A.

1992-02-01

349

The high energy X-ray universe  

PubMed Central

Since its beginning in the early 1960s, the field of X-ray astronomy has exploded, experiencing a ten-billion-fold increase in sensitivity, which brought it on par with the most advanced facilities at all wavelengths. I will briefly describe the revolutionary first discoveries prior to the launch of the Chandra and XMM-Newton X-ray observatories, present some of the current achievements, and offer some thoughts about the future of this field.

Giacconi, Riccardo

2010-01-01

350

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

351

Neutrinos associated with cosmic rays of top-down origin  

NASA Astrophysics Data System (ADS)

Top-down models of cosmic rays produce more neutrinos than photons and more photons than protons. In these models, we reevaluate the fluxes of neutrinos associated with the highest energy cosmic rays in light of mounting evidence that they are protons and not gamma rays. While proton dominance at EeV energies can possibly be achieved by efficient absorption of the dominant high-energy photon flux on universal and galactic photon and magnetic background fields, we show that the associated neutrino flux is inevitably increased to a level where it might be within reach of operating experiments such as AMANDA II, RICE and AGASA. In future neutrino telescopes, tens to a hundred, rather than a few neutrinos per kilometer squared per year, may be detected above 100 TeV.

Barbot, C.; Drees, M.; Halzen, F.; Hooper, D.

2003-02-01

352

The future of high energy gamma ray astronomy and its potential astrophysical implications  

NASA Technical Reports Server (NTRS)

Future satellites should carry instruments having over an order of magnitude greater sensitivity than those flown thus far as well as improved energy and angular resolution. The information to be obtained from these experiments should greatly enhance knowledge of: the very energetic and nuclear processes associated with compact objects; the structure of our galaxy; the origin and dynamic pressure effects of the cosmic rays; the high energy particles and energetic processes in other galaxies; and the degree of matter-antimatter symmetry of the universe. The relevant aspects of extragalactic gamma ray phenomena are emphasized along with the instruments planned. The high energy gamma ray results of forthcoming programs such as GAMMA-1 and the Gamma Ray Observatory should justify even more sophisticated telescopes. These advanced instruments might be placed on the space station currently being considered by NASA.

Fichtel, C. E.

1982-01-01

353

Pointlike gamma ray sources as signatures of distant accelerators of ultrahigh energy cosmic rays.  

PubMed

We discuss the possibility of observing distant accelerators of ultrahigh energy cosmic rays in synchrotron gamma rays. Protons propagating away from their acceleration sites produce extremely energetic electrons during photopion interactions with cosmic microwave background photons. If the accelerator is embedded in a magnetized region, these electrons will emit high energy synchrotron radiation. The resulting synchrotron source is expected to be pointlike, steady, and detectable in the GeV-TeV energy range if the magnetic field is at the nanoGauss level. PMID:16384444

Gabici, Stefano; Aharonian, Felix A

2005-12-16

354

Ground level observations of cosmic rays with neutron monitors  

NASA Astrophysics Data System (ADS)

Cosmic rays are high-energy atomic nuclei, produced mainly in the galaxy. They propagate through the heliosphere, penetrate the geomagnetic field and interact with the atmospheric nuclei to form a cascade of secondary particles. Cosmic rays can be detected by spacecraft and recorded by detectors on the earth, e.g. neutron monitors. Space experiments have the advantages above neutron monitor measurements that the primary cosmic rays are detected directly, and that their detectors measure intensities in pre-determined energy levels, from which energy spectra can be obtained. However, neutron monitors are complementary to spacecraft measurements by detecting particles in a long-term and continuous way, as well as with energies about a decade higher than possible with most spacecraft. Calibration neutron monitors were built for normalizing neutron monitors worldwide in order to obtain energy spectra. Properties of the calibrators were investigated, and at present we have started to calibrate the stationary neutron monitors. This presentation reviews the relation between ground and space based detectors of cosmic rays with emphasis on the mentioned calibration process of neutron monitors.

Kruger, Helena; Moraal, Harm

355

Galactic Cosmic Rays in the Outer Heliosphere: Theory and Models  

NASA Astrophysics Data System (ADS)

We review recent advances in the field of galactic cosmic ray transport in the distant heliosphere. The advent of global MHD models brought about a better understanding of the three-dimensional structure of the interface between the solar system and the surrounding interstellar space, and of the magnetic field topology in the outer heliosphere. These results stimulated a development of galactic cosmic ray transport models taking the advantage of the available detailed plasma backgrounds and of the new Voyager results from the heliosheath. It emerges that the heliosheath plays a prominent role in the process of modulation and filtration of low-energy galactic ions and electrons. The heliosheath stores particles for a duration of several years thus acting as a large reservoir of galactic cosmic rays. Cosmic-ray trajectories, transit times, and entry locations across the heliopause are discussed. When compared to observations model calculations of low energy electrons show almost no radial gradient up to the termination shock, irrespective of solar activity, but a large gradient in the inner heliosheath. Intensities are however sensitive to heliospheric conditions such as the location of the heliopause and shock. In contrast, high energy proton observations by both the Voyager spacecraft show a clear solar cycle dependence with intensities also increasing with increasing distance. By comparing these observations to model calculations we can establish whether our current understanding of long-term modulation result in computed intensities compatible to observations.

Florinski, V.; Ferreira, S. E. S.; Pogorelov, N. V.

2013-06-01

356

Contributions to the 19th International Cosmic Ray Conference  

NASA Technical Reports Server (NTRS)

Various aspects of cosmic radiation, its measurements and their patterns are presented. Measurement techniques and variations in solar cosmic ray patterns and calculations of elemental abundances are reviewed.

1985-01-01

357

Cosmic ray streaming in clusters of galaxies  

NASA Astrophysics Data System (ADS)

The observed bimodality in radio luminosity in galaxy clusters is puzzling: cosmic rays (CRs) accelerated by structure formation shocks are expected to indiscriminately produce bright radio haloes in every cluster. We investigate the possibility that CR streaming in the intracluster medium (ICM) can `switch off' hadronically induced radio and gamma-ray emission. For self-confined CRs, this depends on the source of magnetohydrodynamic wave damping: if only non-linear Landau damping operates, then CRs stream on the slow Alfvénic time-scale, but if turbulent wave damping operates, super-Alfvénic streaming is possible. As turbulence increases, it promotes outward streaming more than it enables inward turbulent advection. Curiously, the CR flux is independent of ?f (as long as it is non-zero) and depends only on plasma parameters; this enables radio haloes with flat inferred CR profiles to turn off. We perform 1D time-dependent calculations of a radio mini-halo (Perseus) and giant radio halo (Coma) and find that both diminish in radio luminosity by an order of magnitude in several hundred Myr, given plausible estimates for the magnetic field in the outskirts of the cluster. Due to the energy dependence of CR streaming, spectral curvature develops, and radio haloes turn off more slowly at low frequencies - properties consistent with observations. Similarly, CR streaming rapidly turns off gamma-ray emission at the high energies probed by Cherenkov telescopes, but not at the low energies probed by Fermi. CR mediated wave heating of the ICM is unaffected, as it is dominated by ˜GeV CRs which stream Alfvénically.

Wiener, Joshua; Oh, S. Peng; Guo, Fulai

2013-09-01

358

Relativistic cosmic rays and corotating interaction regions  

NASA Technical Reports Server (NTRS)

The relationships between relativistic galactic cosmic ray intensity variations and corotating interaction regions (CIRs) are examined. Times of CIRs overtaking the earth as indicated by Pioneer 10 and 11 plasma and field observations are compared with nucleonic intensities recorded at the Thule and McMurdo polar stations in a superposed epoch analysis, with the centers of the CIR as zero days. Results indicate a decrease in intensity around the zero days, as well as a maximum around the ninth day and a general upward trend from days -13 to 13. Further examination reveals the observed features to be present only for those CIR- associated streams in which a neutral sheet is embedded. In contrast, superposed epoch analysis of the geomagnetic Ap index with respect to CIR epochs reveals CIRs both with and without neutral sheets to produce geomagnetic storms, although the peak increase in Ap index is greater for neutral-sheet-associated CIRs. Results suggest that the CIRs modulate high-energy particle intensities by means of drifts related to neutral sheets, although diffusion effects cannot yet be ruled out.

Duggal, S. P.; Pomerantz, M. A.; Tsao, C. H.; Tsurutani, B. T.; Smith, E. J.

1981-01-01

359

High energy gamma-ray observations of SN 1987A  

NASA Technical Reports Server (NTRS)

Results are presented from observations of SN 1987A made with a combined high energy gamma ray and hard X-ray payload carried on a balloon flight over Alice Springs, Australia on April 5, 1988. The payload instrumentation is described, emphasizing the characteristics of the gamma-ray detector. The gamma-ray emission profile is illustrated and the preliminary results of the observations are summarized.

Sood, R. K.; Thomas, J. A.; Waldron, L.; Manchanda, R. K.; Rochester, G. K.

1988-01-01

360

Cosmic rays from the Geminga supernova  

NASA Astrophysics Data System (ADS)

The bright gamma-ray source Geminga has puzzled astronomers for twenty years, because of its lack of emission outside the gamma-ray regime. Recently, the nature of this object has finally been established with the discovery of a 237 ms pulsar in soft X-ray data (Halpern and Holt, 1992, Nature, 357, 222). The measurement of pulsations between 1975 and 1992 yields a steady spin-down consistent with that of an isolated pulsar, with a characteristic age of tau = 3.7 x 105 years (Bignami and Caraveo, 1992, Nature, 357, 287). From the observed gamma-ray flux, the absolute upper limit on the distance is put at R less than 380 pc, but a Vela-like gamma-ray efficiency reduces the estimate to more like R approximately 40 pc. This suggests that Geminga is one of the closest pulsars known and the existence of this neutron star implies that a supernova exploded a few 105 years ago. This explains the current soft X-ray background (Cox and Anderson, 1982, Astrophys. J., 253, 268), and it has also recently been suggested that this nearby cataclysm may be responsible for the local bubble in the Interstellar Medium (Gehrels and Chen, 1993, Nature, 361, 706; Hajivassiliou, 1992, Nature, 355, 232). Young supernova remnants are thought to be capable of efficiently accelerating cosmic rays up to 105 GeV (Lagage and Cesarsky, 1983, Astron. Astrophys., 125, 249), and if this is the case, the contribution to the ambient cosmic ray intensity from the Geminga remnant must be very important, given its proximity to Earth. Here, we assume acceleration and subsequent diffusion from the remnant, and find that both the expected cosmic ray flux and its anisotropy are close to those observed just below the 'knee' in the cosmic ray spectrum. The conventional view, of course, is that cosmic rays permeate the whole of the Galaxy, but there is evidence to suggest that the cosmic rays we obseve are of relatively local origin. This has been used (Streitmatter et al., 1985, Astron. Astrophys., 143, 249) to suggest that cosmic rays are trapped by a local magnetic supershell, and no evidence from composition or anisotropy measurements was found which precluded the production and trapping of cosmic rays in such a region.

Johnson, P. A.

1994-04-01

361

The Origin of the Spectral Intensities of Cosmic-Ray Positrons  

NASA Astrophysics Data System (ADS)

We present a straightforward model of cosmic-ray propagation in the Galaxy that can account for the observed cosmic-ray positrons entirely as secondary products of cosmic-ray interactions with the interstellar medium. In addition to accounting for the observed energy dependence of the ratio of positrons to total electrons, this model can accommodate both the observed energy dependence of secondary to primary nuclei, like boron/carbon, and the observed bounds on the anisotropy of cosmic rays. This model also predicts the energy dependence of the positron fraction at energies higher than those measured to date, with the ratio rising to ~0.7 at very high energies. The model presented in this paper arises as a natural extension of the widely used current models and allows one to include the spatial and temporal discreteness of the sources of cosmic rays.

Cowsik, R.; Burch, B.; Madziwa-Nussinov, T.

2014-05-01

362

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

363

TeV gamma-rays and the origin of cosmic rays  

NASA Astrophysics Data System (ADS)

The past decade has seen TeV gamma-ray astronomy emerge as a powerful tool for the study of high-energy astrophysical phenomena both inside and outside our galaxy. One of the central questions pursued within the field is that of the nature and origin of cosmic rays. Great strides have been made in characterizing the high-energy radiation emerging from several individual objects, but are we any closer to answering this century-old question? I will review some recent interesting TeV measurements and discuss them in this context, along with relevant multi-wavelength observations.

Wakely, Scott

2013-02-01

364

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

2012-08-31

365

The COsmic-ray Soil Moisture Interaction Code (COSMIC) for use in data assimilation  

NASA Astrophysics Data System (ADS)

Soil moisture status in land surface models (LSMs) can be updated by assimilating cosmic-ray neutron intensity measured in air above the surface. This requires a fast and accurate model to calculate the neutron intensity from the profiles of soil moisture modeled by the LSM. The existing Monte Carlo N-Particle eXtended (MCNPX) model is sufficiently accurate but too slow to be practical in the context of data assimilation. Consequently an alternative and efficient model is needed which can be calibrated accurately to reproduce the calculations made by MCNPX and used to substitute for MCNPX during data assimilation. This paper describes the construction and calibration of such a model, COsmic-ray Soil Moisture Interaction Code (COSMIC), which is simple, physically based and analytic, and which, because it runs at least 50 000 times faster than MCNPX, is appropriate in data assimilation applications. The model includes simple descriptions of (a) degradation of the incoming high-energy neutron flux with soil depth, (b) creation of fast neutrons at each depth in the soil, and (c) scattering of the resulting fast neutrons before they reach the soil surface, all of which processes may have parameterized dependency on the chemistry and moisture content of the soil. The site-to-site variability in the parameters used in COSMIC is explored for 42 sample sites in the COsmic-ray Soil Moisture Observing System (COSMOS), and the comparative performance of COSMIC relative to MCNPX when applied to represent interactions between cosmic-ray neutrons and moist soil is explored. At an example site in Arizona, fast-neutron counts calculated by COSMIC from the average soil moisture profile given by an independent network of point measurements in the COSMOS probe footprint are similar to the fast-neutron intensity measured by the COSMOS probe. It was demonstrated that, when used within a data assimilation framework to assimilate COSMOS probe counts into the Noah land surface model at the Santa Rita Experimental Range field site, the calibrated COSMIC model provided an effective mechanism for translating model-calculated soil moisture profiles into aboveground fast-neutron count when applied with two radically different approaches used to remove the bias between data and model.

Shuttleworth, J.; Rosolem, R.; Zreda, M.; Franz, T.

2013-08-01

366

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

367

EGRET Observations of High-Energy gamma Ray Pulsars  

Microsoft Academic Search

EGRET has now detected five high-energy gamma -ray pulsars: Crab, Vela, Geminga, PSR B1706-44, and most recently PSR B1055-52. The characteristics of these objects derived from EGRET data will be presented and discussed in the context of pulsar gamma -ray emission models.

J. M. Fierro; J. Chiang; Y. C. Lin; P. F. Michelson; P. L. Nolan; D. L. Bertsch; C. E. Fichtel; R. C. Hartman; S. D. Hunter; J. R. Mattox; D. J. Thompson; K. T. S. Brazier; G. Kanbach; H. A. Mayer-Hasselwander; C. von Montigny; E. Schneid; D. E. Kniffen

1993-01-01

368

High energy-resolution inelastic x-ray scattering  

SciTech Connect

A brief review is presented of various aspects of high energy-resolution inelastic x-ray scattering based on synchrotron sources. We show what kinematical advantages are provided by the photon probe and propose mirror and monochromator designs to achieve an optically efficient beam line for inelastic x-ray scattering.

Hastings, J.B.; Moncton, D.E.; Fujii

1984-01-01

369

Secondary antiprotons and propagation of cosmic rays in the Galaxy and heliosphere  

Microsoft Academic Search

High-energy collisions of cosmic-ray nuclei with interstellar gas are\\u000abelieved to be the mechanism producing the majority of cosmic ray antiprotons.\\u000aDue to the kinematics of the process they are created with a nonzero momentum;\\u000athe characteristic spectral shape with a maximum at ~2 GeV and a sharp decrease\\u000atowards lower energies makes antiprotons a unique probe of models for

Igor V. Moskalenko; Andrew W. Strong; Jonathan F. Ormes; Marius S. Potgieter

2001-01-01

370

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.

371

Detecting EHE Cosmic Rays Using Cherenkov Light  

NASA Astrophysics Data System (ADS)

Cherenkov light has been used to detect gamma rays in the TeV energy range using an imaging technique and cosmic rays in the PeV energy range using a non-imaging technique. We would like to extend the use of the non-imaging technique up to nearly 1 EeV. At these energies the technique can be used in conjunction with fluorescence detection of cosmic rays, allowing for hybrid reconstruction of shower geometries and cross calibration of energy scales. We envision using an array of Cherenkov detectors as part of the Telescope Array (TA) Low Energy extension (TALE), extending the energy range of the detector down to the Knee of the cosmic ray energy spectrum.

Bergman, Douglas

2011-04-01

372

Cosmic Ray Nuclei (CRN) detector investigation  

NASA Technical Reports Server (NTRS)

The Cosmic Ray Nuclei (CRN) detector was designed to measure elemental composition and energy spectra of cosmic radiation nuclei ranging from lithium to iron. CRN was flown as part of Spacelab 2 in 1985, and consisted of three basic components: a gas Cerenkov counter, a transition radiation detector, and plastic scintillators. The results of the experiment indicate that the relative abundance of elements in this range, traveling at near relativistic velocities, is similar to those reported at lower energy.

Meyer, Peter; Muller, Dietrich; Lheureux, Jacques; Swordy, Simon

1991-01-01

373

Cosmic-ray hydrodynamics at relativistic shocks  

NASA Technical Reports Server (NTRS)

A test particle description of first-order Fermi acceleration of cosmic rays at plane-parallel relativistic shocks is presented in which the pitch angle distribution is obtained explicitly and used to determine the pressure anisotropy or variable Eddington factor as a function of position. The Eddington factor is in turn used to find the hydrodynamical cosmic-ray sound speed, taking the anisotropy into account. For upstream flows speeds above c/sq rt 3, it is shown that the cosmic-ray sound speed exceeds the shock speed in a region just upstream of the shock and decreases montonically with distance further upstream, reaching the value c/sq rt 3 far from the shock. Thus, the shock succeeds in maintaining an anisotropy in the cosmic-ray distribution which is sufficient to keep the flow subsonic with respect to the cosmic-ray sound speed both downstream and in a finite region upstream. The astrophysical implications of these findings are discussed.

Kirk, J. G.; Webb, G. M.

1988-01-01

374

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

375

X-ray Thomson scattering in high energy density plasmas  

Microsoft Academic Search

Accurate x-ray scattering techniques to measure the physical properties of dense plasmas have been developed for applications in high energy density physics. This class of experiments produces short-lived hot dense states of matter with electron densities in the range of solid density and higher where powerful penetrating x-ray sources have become available for probing. Experiments have employed laser-based x-ray sources

Siegfried H. Glenzer; Ronald Redmer

2009-01-01

376

High energy neutrino Astronomy  

NASA Astrophysics Data System (ADS)

Astrophysical candidate sources of ultra-high energy cosmic rays inevitably produce high-energy neutrinos in and/or around them. While cosmic rays are scattered in the inter-galactic magnetic fields, neutrinos point back to their origin. Hence neutrinos can be used to probe astrophysical sources just like in usual photon astronomy. Here we present the expected neutrino signals from different astrophysical objects and discuss their possible applications to study these intriguing sources.

Razzaque, Soebur

2011-12-01

377

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

378

Cosmic rays from the galactic center  

NASA Astrophysics Data System (ADS)

We examine the possibility that recent data on cosmic ray anisotropies presented by the AGASA group may lead to the conclusion that our Galactic Center is a major source of the highest energy cosmic rays in our galaxy. We discuss how such a source would contribute to the magnitude and directional properties of the observed flux when measured against a background of extragalactic cosmic rays. We do this using the results of previous propagation calculations and our own more recent calculations which are specifically for a Galactic Center source. We find that the AGASA data can indeed be plausibly interpreted in this way and also that an argument can be made that the Galactic Center has the appropriate physical properties for acceleration to energies of the order of 10 18 eV. We show that data from the SUGAR array are compatible with the AGASA result.

Clay, R. W.; Dawson, B. R.; Bowen, J.; Debes, M.

2000-01-01

379

Ion acceleration to cosmic ray energies  

NASA Technical Reports Server (NTRS)

The acceleration and transport environment of the outer heliosphere is described schematically. Acceleration occurs where the divergence of the solar-wind flow is negative, that is at shocks, and where second-order Fermi acceleration is possible in the solar-wind turbulence. Acceleration at the solar-wind termination shock is presented by reviewing the spherically-symmetric calculation of Webb et al. (1985). Reacceleration of galactic cosmic rays at the termination shock is not expected to be important in modifying the cosmic ray spectrum, but acceleration of ions injected at the shock up to energies not greater than 300 MeV/charge is expected to occur and to create the anomalous cosmic ray component. Acceleration of energetic particles by solar wind turbulence is expected to play almost no role in the outer heliosphere. The one exception is the energization of interstellar pickup ions beyond the threshold for acceleration at the quasi-perpendicular termination shock.

Lee, Martin A.

1990-01-01

380

Anomalous isotopic composition of cosmic rays  

SciTech Connect

Recent measurements of nonsolar isotopic patterns for the elements neon and (perhaps) magnesium in cosmic rays are interpreted within current models of stellar nucleosynthesis. One possible explanation is that the stars currently responsible for cosmic-ray synthesis in the Galaxy are typically super-metal-rich by a factor of two to three. Other possibilities include the selective acceleration of certain zones or masses of supernovas or the enhancement of /sup 22/Ne in the interstellar medium by mass loss from red giant stars and planetary nebulas. Measurements of critical isotopic ratios are suggested to aid in distinguishing among the various possibilities. Some of these explanations place significant constraints on the fraction of cosmic ray nuclei that must be fresh supernova debris and the masses of the supernovas involved. 1 figure, 3 tables.

Woosley, S.E.; Weaver, T.A.

1980-06-20

381

Cosmic-ray streaming and anisotropies  

NASA Technical Reports Server (NTRS)

The paper is concerned with the differential current densities and anisotropies that exist in the interplanetary cosmic-ray gas, and in particular with a correct formulation and simple interpretation of the momentum equation that describes these on a local basis. Two examples of the use of this equation in the interpretation of previous data are given. It is demonstrated that in interplanetary space, the electric-field drifts and convective flow parallel to the magnetic field of cosmic-ray particles combine as a simple convective flow with the solar wind, and that there exist diffusive currents and transverse gradient drift currents. Thus direct reference to the interplanetary electric-field drifts is eliminated, and the study of steady-state and transient cosmic-ray anisotropies is both more systematic and simpler.

Forman, M. A.; Gleeson, L. J.

1975-01-01

382

Does electromagnetic radiation accelerate galactic cosmic rays  

NASA Technical Reports Server (NTRS)

The 'reactor' theories of Tsytovich and collaborators (1973) of cosmic-ray acceleration by electromagnetic radiation are examined in the context of galactic cosmic rays. It is shown that any isotropic synchrotron or Compton reactors with reasonable astrophysical parameters can yield particles with a maximum relativistic factor of only about 10,000. If they are to produce particles with higher relativistic factors, the losses due to inverse Compton scattering of the electromagnetic radiation in them outweigh the acceleration, and this violates the assumptions of the theory. This is a critical restriction in the context of galactic cosmic rays, which have a power-law spectrum extending up to a relativistic factor of 1 million.

Eichler, D.

1977-01-01

383

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

384

The origin of galactic cosmic rays  

NASA Astrophysics Data System (ADS)

One century ago Viktor Hess carried out several balloon flights that led him to conclude that the penetrating radiation responsible for the discharge of electroscopes was of extraterrestrial origin. One century from the discovery of this phenomenon seems to be a good time to stop and think about what we have understood about Cosmic Rays. The aim of this review is to illustrate the ideas that have been and are being explored in order to account for the observable quantities related to cosmic rays and to summarize the numerous new pieces of observation that are becoming available. In fact, despite the possible impression that development in this field is somewhat slow, the rate of new discoveries in the last decade or so has been impressive, and mainly driven by beautiful pieces of observation. At the same time scientists in this field have been able to propose new, fascinating ways to investigate particle acceleration inside the sources, making use of multifrequency observations that range from the radio, to the optical, to X-rays and gamma rays. These ideas can now be confronted with data. I will mostly focus on supernova remnants as the most plausible sources of Galactic cosmic rays, and I will review the main aspects of the modern theory of diffusive particle acceleration at supernova remnant shocks, with special attention for the dynamical reaction of accelerated particles on the shock and the phenomenon of magnetic field amplification at the shock. Cosmic-ray escape from the sources is discussed as a necessary step to determine the spectrum of cosmic rays at the Earth. The discussion of these theoretical ideas will always proceed parallel to an account of the data being collected especially in X-ray and gamma-ray astronomy. In the end of this review I will also discuss the phenomenon of cosmic-ray acceleration at shocks propagating in partially ionized media and the implications of this phenomenon in terms of width of the Balmer line emission. This field of research has recently experienced a remarkable growth, in that H? lines have been found to bear information on the cosmic-ray acceleration efficiency of supernova shocks.

Blasi, Pasquale

2013-11-01

385

High energy X-ray spectrum of Her X-1  

NASA Technical Reports Server (NTRS)

Line features in the high-energy X-ray spectrum of Her X-1 are attributed to an approximately 1% change in detector gain. The spectrum was obtained by a high-energy X-ray detector aboard OSO-8. The time-averaged spectrum of Her X-1 for the period August 31-Sept. 6, 1977 is presented; the count-rate spectrum was corrected for an average change in gain of 0.7%. The best fit power-law is reported.

Dennis, B. R.; Crannell, C. J.; Dolan, J. F.; Frost, K. J.; Orwig, L. E.; Maurer, G. S.; Cutler, E. P.

1978-01-01

386

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

387

Precursor shocks and cosmic ray acceleration  

NASA Astrophysics Data System (ADS)

Cosmic ray acceleration takes place in shocks of relativistic jets in Active Galactic Nuclei (AGN). The diffusive or stochastic acceleration are believed to be the main responsible mechanisms. Additionally, it is known that the back-reaction of accelerated cosmic rays in shock fronts in astrophysical environments, may lead to the formation of a precursor shock with a length scale which corresponds to the diffusive scale of the energetic particles. In this work we will investigate the properties of relativistic, parallel and perpendicular precursor shocks, via numerical test-particle simulations, allowing diffusive and stochastic acceleration.

Meli, A.

2013-02-01

388

Isotopic composition of heavy cosmic rays  

NASA Technical Reports Server (NTRS)

The mean isotopic composition was measured of even-charge cosmic ray elements with 14 equal to or less than 26 near 0.8 GeV/N using a balloon-borne ionization-chamber/Cerenkov-counter detector system. The experimental method makes use of the geomagnetic field as a magnetic spectrometer. Results indicate that the most abundant isotopes at the cosmic ray source are Si-28, S-32, and Ca-40, like the solar system; but Fe-54, unlike the solar system.

Maehl, R. C.; Isreal, M. H.; Klarmann, J.

1973-01-01

389

A Tale of Cosmic Rays Narrated in ? Rays by Fermi  

NASA Astrophysics Data System (ADS)

Because cosmic rays are charged particles scrambled by magnetic fields, combining direct measurements with other observations is crucial to understanding their origin and propagation. As energetic particles traverse matter and electromagnetic fields, they leave marks in the form of neutral interaction products. Among those, ? rays trace interactions of nuclei that inelastically collide with interstellar gas, as well as of leptons that undergo Bremsstrahlung and inverse-Compton scattering. Data collected by the Fermi large area telescope (LAT) are therefore telling us the story of cosmic rays along their journey from sources through their home galaxies. Supernova remnants emerge as a notable ?-ray source population, and older remnants interacting with interstellar matter finally show strong evidence of the presence of accelerated nuclei. Yet the maximum energy attained by shock accelerators is poorly constrained by observations. Cygnus X, a massive star-forming region established by the LAT as housing cosmic-ray sources, provides a test case to study the impact of wind-driven turbulence on the early propagation. Interstellar emission resulting from the large-scale propagation of cosmic rays in the Milky Way is revealed in unprecedented detail that challenges some of the simple assumptions used for the modeling. Moreover, the cosmic-ray induced ?-ray luminosities of galaxies-scale quasi-linearly with their massive-star formation rates: the overall normalization of that relation below the calorimetric limit suggests that for most systems, a substantial fraction of energy in cosmic rays escapes into the intergalactic medium. The nuclear production models and the distribution of target gas and radiation fields, not determined precisely enough yet, are key to exploiting the full potential of ?-ray data. Nevertheless, data being collected by Fermi and complementary multiwavelength/multimessenger observations are bringing us ever closer to solving the cosmic-ray mystery.

Tibaldo, Luigi

2014-05-01

390

High energy gamma-ray astronomy; Proceedings of the International Conference, ANN Arbor, MI, Oct. 2-5, 1990  

NASA Astrophysics Data System (ADS)

The present volume on high energy gamma-ray astronomy discusses the composition and properties of heavy cosmic rays greater than 10 exp 12 eV, implications of the IRAS Survey for galactic gamma-ray astronomy, gamma-ray emission from young neutron stars, and high-energy diffuse gamma rays. Attention is given to observations of TeV photons at the Whipple Observatory, TeV gamma rays from millisecond pulsars, recent data from the CYGNUS experiment, and recent results from the Woomera Telescope. Topics addressed include bounds on a possible He/VHE gamma-ray line signal of Galactic dark matter, albedo gamma rays from cosmic ray interactions on the solar surface, source studies, and the CANGAROO project. Also discussed are neural nets and other methods for maximizing the sensitivity of a low-threshold VHE gamma-ray telescope, a prototype water-Cerenkov air-shower detector, detection of point sources with spark chamber gamma-ray telescopes, and real-time image parameterization in high energy gamma-ray astronomy using transputers. (For individual items see A93-25002 to A93-25039)

Matthews, James

391

The Highest Energy Cosmic Rays and Gamma Rays  

Microsoft Academic Search

Taking advantage of the dark skies near Dugway, Utah, the University of Utah's Fly's Eye Detector has been observing cosmic rays with energies above 3x 10(16) eV by detecting light from the nitrogen fluorescence from the Extensive Air Showers produced by cosmic rays. The detection of an event measured to have 3x 10(20) eV raises the question of whether the

S. F. Taylor; T. Abu-Zayyad; K. Belov; Z. Cao; G. Chen; M. A. Huang; C. C. H. Jui; D. B. Kieda; E. C. Loh; J. N. Matthews; M. Salamon; A. Salman; J. D. Smith; P. Sokolsky; P. Sommers; S. B. Thomas; L. R. Wiencke; D. J. Bird; R. W. Clay; B. R. Dawson; K. M. Simpson; C. R. Wilkinson; J. Boyer; E. J. Mannel; Y. Ho; W. Lee; T. O'Halloran; N. Hayashida; H. Hirasawa; F. Ishikawa; H. Lafoux; M. Nagano; D. Nishikawa; T. Ouchi; H. Ohoka; M. Ohnishi; N. Sakaki; M. Sasaki; H. Shimodaira; M. Teshima; R. Torii; T. Yamamoto; S. Yoshida; T. Yuda

1998-01-01

392

Discovery of High-energy and Very High Energy ?-Ray Emission from the Blazar RBS 0413  

NASA Astrophysics Data System (ADS)

We report on the discovery of high-energy (HE; E > 0.1 GeV) and very high energy (VHE; E > 100 GeV) ?-ray emission from the high-frequency-peaked BL Lac object RBS 0413. VERITAS, a ground-based ?-ray observatory, detected VHE ? rays from RBS 0413 with a statistical significance of 5.5 standard deviations (?) and a ?-ray flux of (1.5 ± 0.6stat ± 0.7syst) × 10-8 photons m-2 s-1 (~1% of the Crab Nebula flux) above 250 GeV. The observed spectrum can be described by a power law with a photon index of 3.18 ± 0.68stat ± 0.30syst. Contemporaneous observations with the Large Area Telescope (LAT) on the Fermi Gamma-ray Space Telescope detected HE ? rays from RBS 0413 with a statistical significance of more than 9?, a power-law photon index of 1.57 ± 0.12stat +0.11 - 0.12sys, and a ?-ray flux between 300 MeV and 300 GeV of (1.64 ± 0.43stat +0.31 - 0.22sys) × 10-5 photons m-2 s-1. We present the results from Fermi-LAT and VERITAS, including a spectral energy distribution modeling of the ?-ray, quasi-simultaneous X-ray (Swift-XRT), ultraviolet (Swift-UVOT), and R-band optical (MDM) data. We find that, if conditions close to equipartition are required, both the combined synchrotron self-Compton/external-Compton and the lepto-hadronic models are preferred over a pure synchrotron self-Compton model.

Aliu, E.; Archambault, S.; Arlen, T.; Aune, T.; Beilicke, M.; Benbow, W.; Böttcher, M.; Bouvier, A.; Bradbury, S. M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cannon, A.; Cesarini, A.; Ciupik, L.; Collins-Hughes, E.; Connolly, M. P.; Coppi, P.; Cui, W.; Decerprit, G.; Dickherber, R.; Dumm, J.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Finnegan, G.; Fortson, L.; Furniss, A.; Galante, N.; Gall, D.; Godambe, S.; Griffin, S.; Grube, J.; Gyuk, G.; Hanna, D.; Hawkins, K.; Holder, J.; Huan, H.; Hughes, G.; Humensky, T. B.; Kaaret, P.; Karlsson, N.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krawczynski, H.; Krennrich, F.; Lang, M. J.; Lee, K.; Madhavan, A. S.; Maier, G.; Majumdar, P.; McArthur, S.; McCann, A.; Moriarty, P.; Mukherjee, R.; Ong, R. A.; Orr, M.; Otte, A. N.; Palma, N.; Park, N.; Perkins, J. S.; Pichel, A.; Pohl, M.; Prokoph, H.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Roache, E.; Rose, H. J.; Ruppel, J.; Saxon, D. B.; Schroedter, M.; Sembroski, G. H.; ?entürk, G. D.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Teši?, G.; Theiling, M.; Thibadeau, S.; Tsurusaki, K.; Varlotta, A.; Vivier, M.; Wakely, S. P.; Ward, J. E.; Weekes, T. C.; Weinstein, A.; Weisgarber, T.; Williams, D. A.; Zitzer, B.; Fortin, P.; Horan, D.

2012-05-01

393

Research in cosmic and gamma ray astrophysics: Cosmic physics portion  

NASA Technical Reports Server (NTRS)

Research in particle astrophysics at the Space Radiation Laboratory (SRL) of the California Institute of Technology is supported under NASA Grant NAGW-1919. A three-year proposal for continuation of support was submitted a year ago and put into effect 1 October 1992. This report is the combined progress report and continuation application called for under the Federal Demonstration Project. Gamma-ray Astrophysics at SRL is separately supported under NAGW-1919 and will be separately summarized and proposed. This report will document progress and plans for our particle spectroscopy activities and for related data analysis, calibration, and community service activities. A bibliography and a budget will be attached as appendices. The Caltech SRL research program includes a heavy emphasis on elemental and isotopic spectroscopy of energetic particles in the cosmic radiation; in solar, interplanetary, and anomalous 'cosmic' radiation; and in planetary magnetospheres as discussed.

Stone, Edward C.; Mewaldt, Richard A.; Schindler, Stephen

1993-01-01

394

Cosmic-ray positrons from mature gamma-ray pulsars  

Microsoft Academic Search

We consider a possible contribution of mature gamma -ray pulsars (with ages of >= 105 yrs) to cosmic ray positrons. Within the framework of the gamma -ray pulsar outer gap model, e+\\/- pairs in the pulsar magnetosphere are produced by the cascade of e+\\/- pairs through synchrotron radiation of the return current from the outer gap. A good fraction of

L. Zhang; K. S. Cheng

2001-01-01

395

Studies of Cosmic Rays with GeV Gamma Rays.  

National Technical Information Service (NTIS)

We describe the role of GeV gamma-ray observations with GLAST-LAT (Gamma-ray Large Area Space Telescope - Large Area Telescope) in identifying interaction sites of cosmic-ray proton (or hadrons) with interstellar medium (ISM). We expect to detect gamma ra...

H. Tajima J. Chiang J. Cohen-Tanugi S. Finazzi T. Kamae

2007-01-01

396

Cosmic Ray Composition Studies with the High Resolution Fly's Eye  

NASA Astrophysics Data System (ADS)

The depth of shower maximum or Xmax of extensive airshowers is a sensitive probe of the chemical composition of ultra-high energy cosmic rays. Both the evolution of mean Xmax with energy and the width of the Xmax distribution can provide clues as to the species of the particles initiating the airshowers. Here, we report the results of composition studies using Xmax with data collected in stereoscopic mode by the High-Resolution Fly's Eye observatory. The HiRes data are best explained by a predominantly protonic composition above 1.6 EeV.

Belz, John

2009-10-01

397

Medium scale clustering of ultrahigh energy cosmic ray arrival directions  

NASA Astrophysics Data System (ADS)

The two-point autocorrelation function of ultra-high energy cosmic ray (UHECR) arrival directions has a broad maximum around 25 degrees, combining the data with energies above 4× 1019 eV (in the HiRes energy scale) of the HiRes stereo, AGASA, Yakutsk and SUGAR experiments. This signal is not or only marginally present analyzing events of a single experiment, but becomes significant when data from several experiments are added. Both the energy dependence of the signal and its angular scale might be interpreted as first signatures of the large-scale structure of UHECR sources and of intervening magnetic fields.

Kachelriess, M.; Semikoz, D. V.

398

Treatment of foods with high-energy X rays  

NASA Astrophysics Data System (ADS)

The treatment of foods with ionizing energy in the form of gamma rays, accelerated electrons, and X rays can produce beneficial effects, such as inhibiting the sprouting in potatoes, onions, and garlic, controlling insects in fruits, vegetables, and grains, inhibiting the growth of fungi, pasteurizing fresh meat, poultry, and seafood, and sterilizing spices and food additives. After many years of research, these processes have been approved by regulatory authorities in many countries and commercial applications have been increasing. High-energy X rays are especially useful for treating large packages of food. The most attractive features are product penetration, absorbed dose uniformity, high utilization efficiency and short processing time. The ability to energize the X-ray source only when needed enhances the safety and convenience of this technique. The availability of high-energy, high-power electron accelerators, which can be used as X-ray generators, makes it feasible to process large quantities of food economically. Several industrial accelerator facilities already have X-ray conversion equipment and several more will soon be built with product conveying systems designed to take advantage of the unique characteristics of high-energy X rays. These concepts will be reviewed briefly in this paper. .

Cleland, M. R.; Meissner, J.; Herer, A. S.; Beers, E. W.

2001-07-01

399

Cosmic Ray Study with the PAMELA Experiment  

NASA Astrophysics Data System (ADS)

In six years of data collection years in space, the experiment PAMELA has discovered very interesting features in cosmic rays, namely in the fluxes of protons, helium, electrons, that might change our basic vision of the mechanisms of production, acceleration and propagation of cosmic rays in the Galaxy. In addition, PAMELA measurements of cosmic antiproton and positron fluxes are setting strong constraints to the nature of Dark Matter. The continuous particle detection is allowing a constant monitoring of the solar activity and detailed study of the solar modulation for a long period, giving important improvements to the comprehension of the heliosphere mechanisms. PAMELA is also measuring the radiation environment around the Earth, and has recently discovered an antiproton radiation belt.

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

2013-02-01

400

From cosmic ray physics to cosmic ray astronomy: Bruno Rossi and the opening of new windows on the universe  

NASA Astrophysics Data System (ADS)

Bruno Rossi is considered one of the fathers of modern physics, being also a pioneer in virtually every aspect of what is today called high-energy astrophysics. At the beginning of 1930s he was the pioneer of cosmic ray research in Italy, and, as one of the leading actors in the study of the nature and behavior of the cosmic radiation, he witnessed the birth of particle physics and was one of the main investigators in this fields for many years. While cosmic ray physics moved more and more towards astrophysics, Rossi continued to be one of the inspirers of this line of research. When outer space became a reality, he did not hesitate to leap into this new scientific dimension. Rossi's intuition on the importance of exploiting new technological windows to look at the universe with new eyes, is a fundamental key to understand the profound unity which guided his scientific research path up to its culminating moments at the beginning of 1960s, when his group at MIT performed the first in situ measurements of the density, speed and direction of the solar wind at the boundary of Earth's magnetosphere, and when he promoted the search for extra-solar sources of X rays. A visionary idea which eventually led to the breakthrough experiment which discovered Scorpius X-1 in 1962, and inaugurated X-ray astronomy.

Bonolis, Luisa

2014-01-01