WorldWideScience

Sample records for cosmic ray diffusion

  1. Global diffusion of cosmic rays

    CERN Document Server

    Snodin, A P; Sarson, G R; Bushby, P J; Rodrigues, L F S

    2015-01-01

    The propagation of charged particles, including cosmic rays, in a partially ordered magnetic field is characterized by a diffusion tensor whose components depend on the particle's Larmor radius $R_L$ and the degree of order in the magnetic field. This prescription relies explicitly on the assumption of a scale separation between random and mean magnetic fields, which usually applies in laboratory plasmas, but not in most astrophysical environments such as the interstellar medium (ISM). Direct estimates of the cosmic-ray diffusion tensor from test particle simulations have explored the range of particle energies corresponding to $10^{-2} \\lesssim R_L/l_c \\lesssim 10^{3}$, where $l_c$ is the magnetic correlation length. Modern simulations of the ISM have numerical resolution of order 1 pc, so the Larmor radius of the cosmic ray particles that dominate in their energy density is at least $10^{6}$ times smaller than the numerically resolved scales of the random magnetic field. Large-scale simulations of cosmic ra...

  2. Cosmic ray penetration in diffuse clouds

    CERN Document Server

    Morlino, G

    2015-01-01

    Cosmic rays are a fundamental source of ionization for molecular and diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of cosmic rays inside a cloud also determines the $\\gamma$-ray flux produced by hadronic collisions between cosmic rays and cloud material. We study the spectrum of cosmic rays inside and outside of a diffuse cloud, by solving the stationary transport equation for cosmic rays including diffusion, advection and energy losses due to ionization of neutral hydrogen atoms. We found that the cosmic ray spectrum inside a diffuse cloud differs from the one in the interstellar medium for energies smaller than $E_{br}\\approx 100$ MeV, irrespective of the model details. Below $E_{br}$, the spectrum is harder (softer) than that in the interstellar medium if the latter is a power law $\\propto p^{-s}$ with $s$ larger (smaller) than $\\sim0.42$.

  3. Cosmic ray penetration in diffuse clouds

    CERN Document Server

    Morlino, G; Krause, J

    2015-01-01

    Cosmic rays are a fundamental source of ionization for molecular and diffuse clouds, influencing their chemical, thermal, and dynamical evolution. The amount of cosmic rays inside a cloud also determines the $\\gamma$-ray flux produced by hadronic collisions between cosmic rays and cloud material. We study the spectrum of cosmic rays inside and outside of a diffuse cloud, by solving the stationary transport equation for cosmic rays including diffusion, advection and energy losses due to ionization of neutral hydrogen atoms. We found that the cosmic ray spectrum inside a diffuse cloud differs from the one in the interstellar medium (ISM) for energies smaller than $E_{br}\\approx 100$ MeV, irrespective of the model details. Below $E_{br}$, the spectrum is harder (softer) than that in the ISM if the latter is a power law $\\propto p^{-s}$ with $s$ larger (smaller) than $\\sim0.42$. As a consequence also the ionization rate due to CRs is strongly affected. Assuming an average Galactic spectrum similar to the one infe...

  4. Cosmic-ray diffusion in magnetized turbulence

    CERN Document Server

    Tautz, R C

    2015-01-01

    The problem of cosmic-ray scattering in the turbulent electromagnetic fields of the interstellar medium and the solar wind is of great importance due to the variety of applications of the resulting diffusion coefficients. Examples are diffusive shock acceleration, cosmic-ray observations, and, in the solar system, the propagation of coronal mass ejections. In recent years, it was found that the simple diffusive motion that had been assumed for decades is often in disagreement both with numerical and observational results. Here, an overview is given of the interaction processes of cosmic rays and turbulent electromagnetic fields. First, the formation of turbulent fields due to plasma instabilities is treated, where especially the non-linear behavior of the resulting unstable wave modes is discussed. Second, the analytical and the numerical side of high-energy particle propagation will be reviewed by presenting non-linear analytical theories and Monte-Carlo simulations. For the example of the solar wind, the im...

  5. Propagation of cosmic rays into diffuse clouds

    CERN Document Server

    Morlino, Giovanni

    2014-01-01

    We study the capability of low-energy cosmic rays (CR) to penetrate into diffuse clouds when they move from the hot ionized plasma to a cool cloud embedded in that plasma. The spectrum of CR inside a cloud can be remarkably different from the the one present in the hot interstellar medium because when CRs pass through a dense cloud of matter, they suffer energy losses due to ionization and nuclear interactions. Hence there is a net flux of CRs towards the cloud that can excite Alfv\\'en waves. In turn, self-excited Alfv\\'en waves enhances the diffusion of CRs near the edge of the cloud, forcing CRs to spend more time in this layer and increasing the amount of energy losses. The final effect is that the flux of CR entering into the cloud is strongly suppressed below an energy threshold whose value depends on ambient parameters. For the first time we use the full kinetic theory to describe this problem, coupling CRs and Alfv\\'en waves through the streaming instability, and including the damping of the waves due ...

  6. Numerical study of Cosmic Ray Diffusion in MHD turbulence

    OpenAIRE

    Beresnyak, A.; Yan, H.; Lazarian, A.

    2010-01-01

    We study diffusion of Cosmic Rays (CRs) in turbulent magnetic fields using test particle simulations. Electromagnetic fields are produced in direct numerical MHD simulations of turbulence and used as an input for particle tracing, particle feedback on turbulence being ignored. Statistical transport coefficients from the test particle runs are compared with earlier analytical predictions. We find qualitative correspondence between them in various aspects of CR diffusion. In the incompressible ...

  7. On the diffusivity of cosmic ray transport

    NARCIS (Netherlands)

    Tautz, R.C.; Shalchi, A.

    2010-01-01

    A common assumption in particle transport theory is the assumption of diffusive propagation, corresponding to a linear increase of the mean square displacement of particle orbits with time. In recent years, however, several authors have discovered nondiffusive transport in observations and in test p

  8. On the diffusivity of cosmic ray transport

    OpenAIRE

    Tautz, R. C.; Shalchi, A.

    2010-01-01

    A common assumption in particle transport theory is the assumption of diffusive propagation, corresponding to a linear increase of the mean square displacement of particle orbits with time. In recent years, however, several authors have discovered nondiffusive transport in observations and in test particle simulations. Some analytical theories also predict subdiffusion or superdiffusion of charged particles. In this article, a recently developed test particle code is employed to explore diffu...

  9. Diffusive Origin of the Cosmic-Ray Spectral Hardening

    CERN Document Server

    Tomassetti, N

    2012-01-01

    Recent data from ATIC, CREAM and PAMELA revealed that the energy spectra of cosmic ray (CR) nuclei above 100 GeV/nucleon experience a remarkable hardening with increasing energy. This effect cannot be recovered by the conventional descriptions of CR acceleration and diffusive propagation processes. Using analytical calculations, I show that the hardening effect can be consequence of a spatial change of the CR diffusion properties in different regions of the Galaxy. I discuss the implications of this scenario for the main CR observables and its connections with the open issues of the CR physics.

  10. Diffusive Shock Acceleration of High Energy Cosmic Rays

    CERN Document Server

    Baring, M G

    2004-01-01

    The process of diffusive acceleration of charged particles in shocked plasmas is widely invoked in astrophysics to account for the ubiquitous presence of signatures of non-thermal relativistic electrons and ions in the universe. A key characteristic of this statistical energization mechanism is the absence of a momentum scale; astrophysical systems generally only impose scales at the injection (low energy) and loss (high energy) ends of the particle spectrum. The existence of structure in the cosmic ray spectrum (the "knee") at around 3000 TeV has promoted contentions that there are at least two origins for cosmic rays, a galactic one supplying those up to the knee, and even beyond, and perhaps an extragalactic one that can explain even the ultra-high energy cosmic rays (UHECRs) seen at 1-300 EeV. Accounting for the UHECRs with familiar astrophysical sites of acceleration has historically proven difficult due to the need to assume high magnetic fields in order to reduce the shortest diffusive acceleration tim...

  11. Cosmic ray diffusion in the galaxy and diffuse gamma emission

    Energy Technology Data Exchange (ETDEWEB)

    Gaggero, Daniele [Instituto Nazionale di Fisica Nucleare, Pisa (Italy)

    2012-11-01

    The original work presented in this thesis constitutes an important contribution to modern Cosmic Ray (CR) physics, and comes during one of the most exciting periods of this field. The first part introduces a new numerical code (DRAGON) to model the CR propagation in our Galaxy. The code is then used to perform a combined analysis of CR data, making it possible to determine their propagation properties with unprecedented accuracy. The second part is dedicated to a theoretical interpretation of the recent crucial experimental results on cosmic electron and positron spectra (PAMELA, Fermi-LAT experiments). Using the tools developed in the first part of the thesis, the author convincingly argues for the existence of a new spectral component, which could arise either from local astrophysical sources, such as pulsars, or from Dark Matter annihilation or decay. This thesis is a highly advanced work; the methods, analysis and results are clearly and carefully presented. This work is set to become an important reference document for any future work in this area.

  12. Cosmic-ray induced diffusion in interstellar ices

    CERN Document Server

    Kalvans, Juris

    2014-01-01

    Cosmic rays are able to heat interstellar dust grains. This may enhance molecule mobility in icy mantles that have accumulated on the grains in dark cloud cores. A three-phase astrochemical model was used to investigate the molecule mobility in interstellar ices. Specifically, diffusion through pores in ice between the subsurface mantle and outer surface, assisted by whole-grain heating, was considered. It was found that the pores can serve as an efficient transport route for light species. The diffusion of chemical radicals from the mantle to the outer surface are most effective. These species accumulate in the mantle because of photodissociation by the cosmic-ray induced photons. The faster diffusion of hydrogen within the warm ice enhances the hydrogenation of radicals on pore surfaces. The overall result of the whole grain heating-induced radial diffusion in ice are higher abundances of the ice species whose synthesis involve light radicals. Examples of stable species synthesized this way include the comp...

  13. Cosmic ray-driven galactic winds: streaming or diffusion?

    CERN Document Server

    Wiener, Joshua; Oh, Peng

    2016-01-01

    Cosmic rays (CRs) have recently re-emerged as attractive candidates for mediating feedback in galaxies. They can have energy densities comparable to the thermal gas, but do not suffer catastrophic cooling losses. Recent simulations have shown that the momentum and energy deposited by CRs moving with respect to the ambient medium can drive galactic winds. However, simulations are hampered by our ignorance of the details of CR transport. Two key limits previously considered model CR transport as a purely diffusive process (with a constant diffusion coefficient) and as an advective streaming process. With a series of GADGET simulations, we compare and contrast the results of these different assumptions. In idealised three-dimensional galaxy formation models, we show that these two cases result in significant differences for the galactic wind mass loss rates and star formation suppression in dwarf galaxies with halo masses $M\\approx10^{10}\\,\\textrm{M}_\\odot$: diffusive CR transport results in more than ten times ...

  14. Diffuse Synchrotron Emission from Galactic Cosmic Ray Electrons

    CERN Document Server

    Di Bernardo, Giuseppe; Evoli, Carmelo; Gaggero, Daniele

    2015-01-01

    Synchrotron diffuse radiation (SDR) emission is one of the major Galactic components, in the 100 MHz up to 100 GHz frequency range. Its spectrum and sky map provide valuable measure of the galactic cosmic ray electrons (GCRE) in the relevant energy range, as well as of the strength and structure of the Galactic magnetic fields (GMF), both regular and random ones. This emission is an astrophysical sky foreground for the study of the Cosmic Microwave Background (CMB), and the extragalactic microwave measurements, and it needs to be modelled as better as possible. In this regard, in order to get an accurate description of the SDR in the Galaxy, we use - for the first time in this context - 3-dimensional GCRE models obtained by running the DRAGON code. This allows us to account for a realistic spiral arm pattern of the source distribution, demanded to get a self-consistent treatment of all relevant energy losses influencing the final synchrotron spectrum.

  15. Cosmic ray-driven galactic winds: streaming or diffusion?

    Science.gov (United States)

    Wiener, Joshua; Pfrommer, Christoph; Peng Oh, S.

    2017-01-01

    Cosmic rays (CRs) have recently re-emerged as attractive candidates for mediating feedback in galaxies because of their long cooling timescales. Simulations have shown that the momentum and energy deposited by CRs moving with respect to the ambient medium can drive galactic winds. However, simulations are hampered by our ignorance of the details of CR transport. Two key limits previously considered model CR transport as a purely diffusive process (with constant diffusion coefficient) and as an advective streaming process. With a series of GADGET simulations, we compare the results of these different assumptions. In idealised three-dimensional galaxy formation models, we show that these two cases result in significant differences for the galactic wind mass loss rates and star formation suppression in dwarf galaxies with halo masses M ≈ 1010 M⊙: diffusive CR transport results in more than ten times larger mass loss rates compared to CR streaming models. We demonstrate that this is largely due to the excitation of Alfvén waves during the CR streaming process that drains energy from the CR population to the thermal gas, which is subsequently radiated away. By contrast, CR diffusion conserves the CR energy in the absence of adiabatic changes and if CRs are efficiently scattered by Alfvén waves that are propagating up the CR gradient. Moreover, because pressure gradients are preserved by CR streaming, but not diffusion, the two can have a significantly different dynamical evolution regardless of this energy exchange. In particular, the constant diffusion coefficients usually assumed can lead to unphysically high CR fluxes.

  16. Antiproton Flux in Cosmic Ray Propagation Models with Anisotropic Diffusion

    CERN Document Server

    Grajek, Phillip

    2010-01-01

    Recently a cosmic ray propagation model has been introduced, where anisotropic diffusion is used as a mechanism to allow for $\\mathcal{O}(100)$ km/s galactic winds. This model predicts a reduced antiproton background flux, suggesting an excess is being observed. We implement this model in GALPROP v50.1 and perform a $\\chi^2$ analysis for B/C, $^{10}$Be/$^{9}$Be, and the recent PAMELA $\\bar{p}/p$ datasets. By introducing a power-index parameter $\\alpha$ that dictates the dependence of the diffusion coefficient $D_{xx}$ on height $|z|$ away from the galactic plane, we confirm that isotropic diffusion models with $\\alpha=0$ cannot accommodate high velocity convective winds suggested by ROSAT, while models with $\\alpha=1$ ($D_{xx}\\propto |z|$) can give a very good fit. A fit to B/C and $^{10}$Be/$^{9}$Be data predicts a lower $\\bar{p}/p$ flux ratio than the PAMELA measurement at energies between approximately 2 GeV to 20 GeV. A combined fit including in addition the $\\bar{p}/p$ data is marginal, suggesting only a...

  17. Diffusion coefficient and radial gradient of galactic cosmic rays

    CERN Document Server

    Modzelewska, Renata

    2015-01-01

    We present the temporal changes of the diffusion coefficient K of galactic cosmic rays (GCRs) at the Earth orbit calculated based on the experimental data using two different methods. The first approach is based on the Parker convection-diffusion approximation of GCR modulation [1]: i.e. K~Vr=dI where dI is the variation of the GCR intensity measured by neutron monitors (NM),V is the solar wind velocity and r is the radial distance. The second approach is based on the interplanetary magnetic field (IMF) data. It was suggested that parallel mean free path can be expressed in terms of B as in [2]-[4]. Using data of the product of the parallel mean free path and radial gradient of GCR calculated based on the GCR anisotropy data (Ahluwalia et al., this conference ICRC 2013, poster ID: 487 [5]), we estimate the temporal changes of the radial gradient of GCR at the Earth orbit. We show that the radial gradient exhibits a strong solar cycle dependence (11-year variation) and a weak solar magnetic cycle dependence (2...

  18. Pinpointing the knee of cosmic rays with diffuse PeV γ-rays and neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Y. Q.; Hu, H. B.; Yuan, Q.; Tian, Z.; Gao, X. J. [Key Laboratory of Particle Astrophysics, Institute of High Energy Physics, Chinese Academy of Science, Beijing 100049 (China)

    2014-11-01

    The origin of the knee in the cosmic ray spectrum remains to be an unsolved fundamental problem. There are various kinds of models that predict different break positions and the compositions of the knee. In this work, we suggest the use of diffuse γ-rays and neutrinos as probes to test these models. Based on several typical types of composition models, the diffuse γ-ray and neutrino spectra are calculated and show distinctive cutoff behaviors at energies from tens of TeV to multi-PeV. The expected flux will be observable by the newly upgraded Tibet-ASγ+MD (muon detector) experiment as well as more sensitive future projects, such as LHAASO and HiSCORE. By comparing the neutrino spectrum with the recent observations by the IceCube experiment, we find that the diffuse neutrinos from interactions between the cosmic rays and the interstellar medium may not be responsible to the majority of the IceCube events. Future measurements of the neutrinos may be able to identify the Galactic diffuse component and shed further light on the problem of the knee of cosmic rays.

  19. Fluxes of diffuse gamma rays and neutrinos from cosmic-ray interactions with circumgalactic gas

    CERN Document Server

    Kalashev, Oleg

    2016-01-01

    The Milky Way is surrounded by a gravitationally bound gas corona extending up to the Galaxy's virial radius. Interactions of cosmic-ray particles with this gas give rise to energetic secondary gamma rays and neutrinos. We present a quantitative analysis of the neutrino and gamma-ray fluxes from the corona of the Milky Way together with a combined contribution of coronae of other galaxies. The high-energy neutrino flux is insufficient to explain the IceCube results, while the contribution to the FERMI-LAT diffuse gamma-ray flux is not negligible.

  20. Expectations for high energy diffuse galactic neutrinos for different cosmic ray distributions

    CERN Document Server

    Pagliaroli, G; Villante, F L

    2016-01-01

    The interaction of cosmic rays with the gas contained in our Galaxy is a guaranteed source of diffuse high energy neutrinos. We provide expectations for this component by considering different assumptions for the cosmic ray distribution in the Galaxy which are intended to cover the large uncertainty in cosmic ray propagation models. We calculate the angular dependence of the diffuse galactic neutrino flux and the corresponding rate of High Energy Starting Events in IceCube by including the effect of detector angular resolution. Moreover we discuss the possibility to discriminate the galactic component from an isotropic astrophysical flux. We show that a statistically significant excess of events from the galactic plane in present IceCube data would favour models in which the cosmic ray density in the inner galactic region is much larger than its local value, thus bringing relevant information on the cosmic ray radial distribution.

  1. Fermi bubble $\\gamma$-rays as a result of diffusive injection of Galactic cosmic rays

    CERN Document Server

    Thoudam, Satyendra

    2013-01-01

    Recently, the {\\it{Fermi}} space telescope has discovered two large $\\gamma$-ray emission regions, the so-called "Fermi bubbles", that extend up to $\\sim 50^\\circ$ above and below the Galactic center. The $\\gamma$-ray emission from the bubbles are found to follow a hard spectrum with no significant spatial variation in intensity and spectral shape. The origin of the emission is still not clearly understood. Suggested explanations include injection of cosmic-ray nuclei from the Galactic center by high-speed Galactic winds, electron acceleration by multiple shocks and stochastic electron acceleration inside the bubbles. In this letter, it is proposed that the $\\gamma$-rays can be the result of diffusive injection of Galactic cosmic-ray protons during their propagation through the Galaxy. Considering that cosmic rays undergo much slower diffusion inside the bubbles than in the averaged Galaxy and at the same time suffer from inelastic collisions with the bubble plasma, this model can explain the observed intensi...

  2. Pinpointing the knee of cosmic rays with diffuse PeV gamma-rays and neutrinos

    CERN Document Server

    Guo, Y Q; Yuan, Q; Tian, Z; Gao, X J

    2013-01-01

    The origin of the knee in cosmic ray spectrum remains to be an unsolved fundamental problem. There are various kinds of models which predict different break positions and the compositions of the knee. In this work, we suggest to use diffuse $\\gamma$-rays and neutrinos as probes to test these models. Based on several typical types of the composition models, the diffuse $\\gamma$-ray and neutrino spectra are calculated, which show distinctive cutoff behaviours at energies from tens of TeV to multi-PeV. The expected flux will be observable by the newly upgraded Tibet-AS$\\gamma$+MD (muon detector) experiment as well as more sensitive future projects, such as LHAASO and HiSCORE. By comparing the neutrino spectrum with the recent observations by IceCube experiment, we find that the diffuse neutrinos from interactions between the cosmic rays and the interstellar medium may not be responsible to the majority of the IceCube events. Future measurements of the neutrinos may be able to identify the Galactic diffuse compon...

  3. Cosmic-ray diffusion in a sectored magnetic field in the distant heliosheath

    CERN Document Server

    Florinski, V; Kota, J; Guo, X; 10.1088/0004-637X/754/1/31

    2013-01-01

    Very high intensities of galactic cosmic rays measured by Voyager 1 in the heliosheath appear to be incompatible with the presence of a modulation "wall" near the heliopause produced by a pile up of the heliospheric magnetic field. We propose that the modulation wall is a structure permeable to cosmic rays as a result of a sectored magnetic field topology compressed by plasma slowdown on approach to the heliopause and stretched to high latitudes by latitudinal flows in the heliosheath. The tightly folded warped current sheet permits efficient cosmic-ray transport in the radial direction via a drift-like mechanism. We show that when stochastic variations in the sector widths are taken into account, particle transport becomes predominantly diffusive both along and across the magnetic sectors. Using a test-particle model for cosmic rays in the heliosheath we investigate the dependence of the diffusion coefficients on the properties of the sector structure and on particle energy.

  4. COSMIC-RAY DIFFUSION IN A SECTORED MAGNETIC FIELD IN THE DISTANT HELIOSHEATH

    Energy Technology Data Exchange (ETDEWEB)

    Florinski, V. [Department of Physics, University of Alabama, Huntsville, AL 35899 (United States); Alouani-Bibi, F.; Guo, X. [Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721 (United States)

    2012-07-20

    Very high intensities of galactic cosmic rays measured by Voyager 1 in the heliosheath appear to be incompatible with the presence of a modulation 'wall' near the heliopause produced by a pile up of the heliospheric magnetic field. We propose that the modulation wall is a structure permeable to cosmic rays as a result of a sectored magnetic field topology compressed by plasma slowdown on approach to the heliopause and stretched to high latitudes by latitudinal flows in the heliosheath. The tightly folded warped current sheet permits efficient cosmic-ray transport in the radial direction via a drift-like mechanism. We show that when stochastic variations in the sector widths are taken into account, particle transport becomes predominantly diffusive both along and across the magnetic sectors. Using a test-particle model for cosmic rays in the heliosheath we investigate the dependence of the diffusion coefficients on the properties of the sector structure and on particle energy.

  5. Ultrahigh Energy Cosmic Rays, The Diffuse High Energy Gamma Ray Background and Anti-protons

    CERN Document Server

    Eichler, David; Gavish, Eyal

    2016-01-01

    Theories for the origin of ultrahigh energy cosmic rays (UHECR) may imply a significant diffuse background in secondary $\\gamma$-rays from the pair cascads the UHECR initiate when interacting with background light. It is shown that, because the spectrum of these secondary $\\gamma$-rays is softer than the measured diffuse $\\gamma$-ray background in the 10-1000 GeV range, the addition of a hard component from the decay of TeV dark matter particles, subject to the implied constraints on its parameters, improves the fit. It is further argued that any compact astrophysical source of $\\bar p$s is unlikely to be as strong as decay of TeV dark matter particles, given bounds set by neutrino observations. The diffuse $\\gamma$-ray background presently sets the strongest lower bound on the lifetime of TeV dark matter particles, and hence on attendant anti-proton production, and further identification of other contributors to this background will further tighten these constraints.

  6. FERMI-LAT OBSERVATIONS OF THE DIFFUSE {gamma}-RAY EMISSION: IMPLICATIONS FOR COSMIC RAYS AND THE INTERSTELLAR MEDIUM

    Energy Technology Data Exchange (ETDEWEB)

    Ackermann, M. [Deutsches Elektronen Synchrotron DESY, D-15738 Zeuthen (Germany); Ajello, M.; Bechtol, K.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Borgland, A. W.; Buehler, R. [W. W. Hansen Experimental Physics Laboratory, Kavli Institute for Particle Astrophysics and Cosmology, Department of Physics and SLAC National Accelerator Laboratory, Stanford University, Stanford, CA 94305 (United States); Atwood, W. B. [Santa Cruz Institute for Particle Physics, Department of Physics and Department of Astronomy and Astrophysics, University of California at Santa Cruz, Santa Cruz, CA 95064 (United States); Baldini, L.; Bellazzini, R.; Bregeon, J. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Ballet, J. [Laboratoire AIM, CEA-IRFU/CNRS/Universite Paris Diderot, Service d' Astrophysique, CEA Saclay, F-91191 Gif sur Yvette (France); Barbiellini, G. [Istituto Nazionale di Fisica Nucleare, Sezione di Trieste, I-34127 Trieste (Italy); Bastieri, D.; Buson, S. [Istituto Nazionale di Fisica Nucleare, Sezione di Padova, I-35131 Padova (Italy); Bonamente, E. [Istituto Nazionale di Fisica Nucleare, Sezione di Perugia, I-06123 Perugia (Italy); Brandt, T. J. [CNRS, IRAP, F-31028 Toulouse cedex 4 (France); Brigida, M. [Dipartimento di Fisica ' M. Merlin' dell' Universita e del Politecnico di Bari, I-70126 Bari (Italy); Bruel, P., E-mail: tporter@stanford.edu, E-mail: gudlaugu@glast2.stanford.edu, E-mail: aws@mpe.mpg.de [Laboratoire Leprince-Ringuet, Ecole polytechnique, CNRS/IN2P3, Palaiseau (France); and others

    2012-05-01

    The {gamma}-ray sky >100 MeV is dominated by the diffuse emissions from interactions of cosmic rays with the interstellar gas and radiation fields of the Milky Way. Observations of these diffuse emissions provide a tool to study cosmic-ray origin and propagation, and the interstellar medium. We present measurements from the first 21 months of the Fermi Large Area Telescope (Fermi-LAT) mission and compare with models of the diffuse {gamma}-ray emission generated using the GALPROP code. The models are fitted to cosmic-ray data and incorporate astrophysical input for the distribution of cosmic-ray sources, interstellar gas, and radiation fields. To assess uncertainties associated with the astrophysical input, a grid of models is created by varying within observational limits the distribution of cosmic-ray sources, the size of the cosmic-ray confinement volume (halo), and the distribution of interstellar gas. An all-sky maximum-likelihood fit is used to determine the X{sub CO} factor, the ratio between integrated CO-line intensity and H{sub 2} column density, the fluxes and spectra of the {gamma}-ray point sources from the first Fermi-LAT catalog, and the intensity and spectrum of the isotropic background including residual cosmic rays that were misclassified as {gamma}-rays, all of which have some dependency on the assumed diffuse emission model. The models are compared on the basis of their maximum-likelihood ratios as well as spectra, longitude, and latitude profiles. We also provide residual maps for the data following subtraction of the diffuse emission models. The models are consistent with the data at high and intermediate latitudes but underpredict the data in the inner Galaxy for energies above a few GeV. Possible explanations for this discrepancy are discussed, including the contribution by undetected point-source populations and spectral variations of cosmic rays throughout the Galaxy. In the outer Galaxy, we find that the data prefer models with a flatter

  7. Constraints on the cosmic ray diffusion coefficient in the W28 region from gamma-ray observations

    Science.gov (United States)

    Gabici, S.; Casanova, S.; Aharonian, F. A.; Rowell, G.

    2010-12-01

    GeV and TeV gamma rays have been detected from the supernova remnant W28 and its surroundings. Such emission correlates quite well with the position of dense and massive molecular clouds and thus it is often interpreted as the result of hadronic cosmic ray interactions in the dense gas. Constraints on the cosmic ray diffusion coefficient in the region can be obtained, under the assumption that the cosmic rays responsible for the gamma ray emission have been accelerated in the past at the supernova remnant shock, and subsequently escaped in the surrounding medium. In this scenario, gamma ray observations can be explained only if the diffusion coefficient in the region surrounding the supernova remnant is significantly suppressed with respect to the average galactic one.

  8. Diffuse galactic continuum emission measured by COMPTEL and the cosmic-ray electron spectrum

    Science.gov (United States)

    Strong, A. W.; Diehl, R.; Schoenfelder, V.; Varendorff, M.; Youssefi, G.; Bloemen, H.; Hermsen, W.; De Vries, C.; Morris, D.; Stacy, J. G.

    1994-01-01

    Diffuse galactic continuum gamma-ray emission in the 0.75-30 MeV range from the inner Galaxy has been studied using data from COMPTEL on the Compton Gamma-Ray Observatory. Observations of the inner Galaxy from the Sky Survey have been used. The imaging properties of COMPTEL enable spatial analysis of the gamma-ray distribution using model fitting. A model based on atomic and molecular gas distributions in the Galaxy has been used to derive the emissivity spectrum of the gamma-ray emission and this spectrum is compared with theoretical estimates of bremsstrahlung emission from cosmic-ray electrons.

  9. Galactic winds driven by isotropic and anisotropic cosmic ray diffusion in disk galaxies

    CERN Document Server

    Pakmor, Ruediger; Simpson, Christine M; Springel, Volker

    2016-01-01

    The physics of cosmic rays (CR) is a promising candidate for explaining the driving of galactic winds and outflows. Recent galaxy formation simulations have demonstrated the need for active CR transport either in the form of diffusion or streaming to successfully launch winds in galaxies. However, due to computational limitations, most previous simulations have modeled CR transport isotropically. Here, we discuss high resolution simulations of isolated disk galaxies in a $10^{11}\\rm{M_\\odot}$ halo with the moving mesh code {\\sc Arepo} that include injection of CRs from supernovae, advective transport, CR cooling, and CR transport through isotropic or anisotropic diffusion. We show that either mode of diffusion leads to the formation of strong bipolar outflows. However, they develop significantly later in the simulation with anisotropic diffusion compared to the simulation with isotropic diffusion. Moreover, we find that isotropic diffusion allows most of the CRs to quickly diffuse out of the disk, while in th...

  10. Diffusive shock acceleration at laser driven shocks: studying cosmic-ray accelerators in the laboratory

    CERN Document Server

    Reville, B; Gregori, G

    2012-01-01

    The non-thermal particle spectra responsible for the emission from many astrophysical systems are thought to originate from shocks via a first order Fermi process otherwise known as diffusive shock acceleration. The same mechanism is also widely believed to be responsible for the production of high energy cosmic rays. With the growing interest in collisionless shock physics in laser produced plasmas, the possibility of reproducing and detecting shock acceleration in controlled laboratory experiments should be considered. The various experimental constraints that must be satisfied are reviewed. It is demonstrated that several currently operating laser facilities may fulfil the necessary criteria to confirm the occurrence of diffusive shock acceleration of electrons at laser produced shocks. Successful reproduction of Fermi acceleration in the laboratory could open a range of possibilities, providing insight into the complex plasma processes that occur near astrophysical sources of cosmic rays.

  11. Constraining Dark Matter and Ultra-High Energy Cosmic Ray Sources with Fermi-LAT Diffuse Gamma Ray Background

    CERN Document Server

    Kalashev, Oleg

    2016-01-01

    We use the recent measurement of the isotropic $\\gamma$-ray background (IGRB) by Fermi LAT and analysis of the contribution of unresolved point $\\gamma$-ray sources to IGRB to build constraints on the models of ultra-high cosmic rays (UHECR) origin. We also calculate the minimal expected diffuse $\\gamma$-ray flux produced by UHECR interactions with an interstellar photon background. Finally, for the subclass of dark matter (DM) models with decaying weakly interacting massive particles (WIMP), we build constraints on the particle decay time using minimal expected contributions to the IGRB from unresolved point $\\gamma$-ray sources and UHECR.

  12. Constraints on cosmic ray electrons and diffuse gamma rays with AMS-02 and HESS data

    CERN Document Server

    Chen, Ding; Jin, Hong-Bo

    2014-01-01

    Lately, AMS-02 and HAWC have reported their observations of cosmic rays(CRs), which promote the further exploration of CR origins. We choose some experimental data of CRs to focus the origins of CR electrons and estimate the spectrum of CR electrons. Based on the conventional diffusion model of CRs, we perform a global analysis on the spectrum feature of CR electrons with the data of AMS-02, HESS and Milagro. The results verify that the spectrum of CR electrons has the apparent structure beyond a simple power law. The difference between the power indices above and below the reference rigidity is greater than 0.2, which is near the momentum loss rate of CR electrons. The data of HESS electrons matches the TeV extension of AMS-02 electrons and the relevant spectrum of CR electrons does not have TeV breaks. By use of the difference between the CR electrons and primary electrons constrained by AMS-02 and HESS, the TeV bounds of positron excess are predicted. In the bounds, the flux relevant to the up-limit is bey...

  13. Inhomogeneous diffusion model for recent data on high-energy cosmic rays

    CERN Document Server

    Tomassetti, Nicola

    2015-01-01

    The AMS Collaboration has recently released precision data on cosmic ray (CR) leptons and protons at high energies. Interesting progresses have also been made on the measurement of CR nuclei, such as the boron-to-carbon ratio or the lithium spectrum, up to TeV/nucleon energies. In order to provide a description these data, I consider a diffusion model of CR propagation which allows for latitudinal variations of the CR diffusion properties in the Galactic halo. I discuss the role of high-precision data on light CR nuclei in resolutely testing this model and the key propagation parameters.

  14. Cosmic ray driven Galactic winds

    Science.gov (United States)

    Recchia, S.; Blasi, P.; Morlino, G.

    2016-11-01

    The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas from the Galaxy, thereby regulating several physical processes, including star formation. The dynamics of these cosmic ray driven winds is intrinsically non-linear in that the spectrum of cosmic rays determines the characteristics of the wind (velocity, pressure, magnetic field) and in turn the wind dynamics affects the cosmic ray spectrum. Moreover, the gradient of the cosmic ray distribution function causes excitation of Alfvén waves, that in turn determines the scattering properties of cosmic rays, namely their diffusive transport. These effects all feed into each other so that what we see at the Earth is the result of these non-linear effects. Here, we investigate the launch and evolution of such winds, and we determine the implications for the spectrum of cosmic rays by solving together the hydrodynamical equations for the wind and the transport equation for cosmic rays under the action of self-generated diffusion and advection with the wind and the self-excited Alfvén waves.

  15. Diffusive propagation of cosmic rays from supernova remnants in the Galaxy. I: spectrum and chemical composition

    CERN Document Server

    Blasi, Pasquale

    2011-01-01

    In this paper we investigate the effect of stochasticity in the spatial and temporal distribution of supernova remnants on the spectrum and chemical composition of cosmic rays observed at Earth. The calculations are carried out for different choices of the diffusion coefficient D(E) experienced by cosmic rays during propagation in the Galaxy. In particular, at high energies we assume that D(E)\\sim E^{\\delta}, with $\\delta=1/3$ and $\\delta=0.6$ being the reference scenarios. The large scale distribution of supernova remnants in the Galaxy is modeled following the distribution of pulsars, with and without accounting for the spiral structure of the Galaxy. We find that the stochastic fluctuations induced by the spatial and temporal distribution of supernovae, together with the effect of spallation of nuclei, lead to mild but sensible violations of the simple, leaky-box-inspired rule that the spectrum observed at Earth is $N(E)\\propto E^{-\\alpha}$ with $\\alpha=\\gamma+\\delta$, where $\\gamma$ is the slope of the co...

  16. Cosmic rays on earth.

    Science.gov (United States)

    Allkofer, O. C.; Grieder, P. K. F.

    Contents: Cosmic rays in the atmosphere: Charged hadron data. Neutron data. Gamma-ray data. Electron data. Muon data. Data on nuclei. Data on antiparticles. Cosmic rays at sea level: Muon data. Charged hadron data.Neutron data. Electron data. Gamma-ray data. Data on nuclei. Cosmic rays underground: Muon data. Neutrino data.

  17. Cosmic Ray Diffusion from the Galactic Spiral Arms, Iron Meteorites, and a possible climatic connection?

    CERN Document Server

    Shaviv, N J

    2002-01-01

    We construct a Galactic cosmic ray (CR) diffusion model while considering that CR sources reside predominantly in the Galactic spiral arms. We find that the CR flux (CRF) reaching the solar system should periodically increase each crossing of a Galactic spiral arm. We search for this signal in the CR exposure age record of Iron meteorites and confirm this prediction. We then check the hypothesis that climate, and in particular the temperature, is affected by the CRF to the extent that glaciations can be induced or completely hindered by possible climatic variations. We find that although the geological evidence for the occurrence of IAEs in the past Eon is not unequivocal, it appears to have a nontrivial correlation with the spiral arm crossings--agreeing in period and phase. Thus, a better timing study of glaciations could either confirm this result as an explanation to the occurrence of IAEs or refute a CRF climatic connection.

  18. ALICE Cosmic Ray Detector

    CERN Multimedia

    Fernandez Tellez, A; Martinez Hernandez, M; Rodriguez Cahuantzi, M

    2013-01-01

    The ALICE underground cavern provides an ideal place for the detection of high energy atmospheric muons coming from cosmic ray showers. ACORDE detects cosmic ray showers by triggering the arrival of muons to the top of the ALICE magnet.

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

    Energy Technology Data Exchange (ETDEWEB)

    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

    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%.

  20. Galactic cosmic ray propagation models using Picard

    CERN Document Server

    Kissmann, Ralf; Strong, Andrew W

    2015-01-01

    We present results obtained from our newly developed Galactic cosmic-ray transport code PICARD, that solves the cosmic-ray transport equation. This code allows for the computation of cosmic-ray spectra and the resulting gamma-ray emission. Relying on contemporary numerical solvers allows for efficient computation of models with deca-parsec resolution. PICARD can handle locally anisotropic spatial diffusion acknowledging a full diffusion tensor. We used this framework to investigate the transition from axisymmetric to spiral-arm cosmic-ray source distributions. Wherever possible we compare model predictions with constraining observables in cosmic-ray astrophysics.

  1. Gas-phase recombination, grain neutralization and cosmic-ray ionization in diffuse gas

    CERN Document Server

    Liszt, H S

    2003-01-01

    Atomic ions are mostly neutralized by small grains (or PAH molecules) in current theories of heating and cooling in cool diffuse clouds; in the main they do not recombine with free electrons. This alters the ionization balance by depressing n(H+) and n(He+) while carbon generally remains nearly fully once-ionized: charge exchange with atomic oxygen and formation of H2 and OH also depress n(H+) in partly molecular gas. Seemingly restrictive empirical limits on the cosmic ray ionization rate of hydrogen ($\\zeta_H$) are relaxed and faster rates are favored in a wide range of circumstances, when grain neutralization is recognized. Maintenance of the proton density at levels needed to reproduce observations of HD requires $\\zeta_H$ at least 2x10^{-16} s^{-1}, but such models naturally explain the presence of both HD and H3^+ in relatively tenuous H I clouds. In dense gas, a higher ionization rate can account for high observed fractions of atomic hydrogen, and recognition of the effects of grain neutralization can ...

  2. Cosmic ray modulation

    Science.gov (United States)

    Agarwal Mishra, Rekha; Mishra, Rajesh Kumar

    2016-07-01

    Propagation of cosmic rays to and inside the heliosphere, encounter an outward moving solar wind with cyclic magnetic field fluctuation and turbulence, causing convection and diffusion in the heliosphere. Cosmic ray counts from the ground ground-based neutron monitors at different cut of rigidity show intensity changes, which are anti-correlated with sunspot numbers. They also lose energy as they propagate towards the Earth and experience various types of modulations due to different solar activity indices. In this work, we study the first three harmonics of cosmic ray intensity on geo-magnetically quiet days over the period 1965-2014 for Beijing, Moscow and Tokyo neutron monitoring stations located at different cut off rigidity. The amplitude of first harmonic remains high for low cutoff rigidity as compared to high cutoff rigidity on quiet days. The diurnal amplitude significantly decreases during solar activity minimum years. The diurnal time of maximum significantly shifts to an earlier time as compared to the corotational direction having different cutoff rigidities. The time of maximum for first harmonic significantly shifts towards later hours and for second harmonic it shifts towards earlier hours at low cutoff rigidity station as compared to the high cut off rigidity station on quiet days. The amplitude of second/third harmonics shows a good positive correlation with solar wind velocity, while the others (i.e. amplitude and phase) have no significant correlation on quiet days. The amplitude and direction of the anisotropy on quiet days does not show any significant dependence on high-speed solar wind streams for these neutron monitoring stations of different cutoff rigidity threshold. Keywords: cosmic ray, cut off rigidity, quiet days, harmonics, amplitude, phase.

  3. Non-linear diffusion of cosmic rays escaping from supernova remnants - I. The effect of neutrals

    Science.gov (United States)

    Nava, L.; Gabici, S.; Marcowith, A.; Morlino, G.; Ptuskin, V. S.

    2016-10-01

    Supernova remnants are believed to be the main sources of galactic cosmic rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs are released and the way in which they propagate still remain open issues. The main difficulty is the high non-linearity of the problem: CRs themselves excite the magnetic turbulence that confines them close to their sources. We solve numerically the coupled differential equations describing the evolution in space and time of the escaping particles and of the waves generated through the CR streaming instability. The warm ionized and warm neutral phases of the interstellar medium are considered. These phases occupy the largest fraction of the disc volume, where most supernovae explode, and are characterized by the significant presence of neutral particles. The friction between those neutrals and ions results in a very effective wave damping mechanism. It is found that streaming instability affects the propagation of CRs even in the presence of ion-neutral friction. The diffusion coefficient can be suppressed by more than a factor of ˜2 over a region of few tens of pc around the remnant. The suppression increases for smaller distances. The propagation of ≈10 GeV particles is affected for several tens of kiloyears after escape, while ≈1 TeV particles are affected for few kiloyears. This might have a great impact on the interpretation of gamma-ray observations of molecular clouds located in the vicinity of supernova remnants.

  4. Cosmic ray driven Galactic winds

    CERN Document Server

    Recchia, S; Morlino, G

    2016-01-01

    The escape of cosmic rays from the Galaxy leads to a gradient in the cosmic ray pressure that acts as a force on the background plasma, in the direction opposite to the gravitational pull. If this force is large enough to win against gravity, a wind can be launched that removes gas from the Galaxy, thereby regulating several physical processes, including star formation. The dynamics of these cosmic ray driven winds is intrinsically non-linear in that the spectrum of cosmic rays determines the characteristics of the wind (velocity, pressure, magnetic field) and in turn the wind dynamics affects the cosmic ray spectrum. Moreover, the gradient of the cosmic ray distribution function causes excitation of Alfven waves, that in turn determine the scattering properties of cosmic rays, namely their diffusive transport. These effects all feed into each other so that what we see at the Earth is the result of these non-linear effects. Here we investigate the launch and evolution of such winds, and we determine the impli...

  5. High energy cosmic rays

    CERN Document Server

    Stanev, Todor

    2010-01-01

    Offers an accessible text and reference (a cosmic-ray manual) for graduate students entering the field and high-energy astrophysicists will find this an accessible cosmic-ray manual Easy to read for the general astronomer, the first part describes the standard model of cosmic rays based on our understanding of modern particle physics. Presents the acceleration scenario in some detail in supernovae explosions as well as in the passage of cosmic rays through the Galaxy. Compares experimental data in the atmosphere as well as underground are compared with theoretical models

  6. An implicit scheme for solving the anisotropic diffusion of heat and cosmic rays in the RAMSES code

    CERN Document Server

    Dubois, Yohan

    2016-01-01

    Astrophysical plasmas are subject to a tight connection between magnetic fields and the diffusion of particles, which leads to an anisotropic transport of energy. Under the fluid assumption, this effect can be reduced to an advection-diffusion equation augmenting the equations of magnetohydrodynamics. We introduce a new method for solving the anisotropic diffusion equation using an implicit finite-volume method with adaptive mesh refinement and adaptive time-stepping in the RAMSES code. We apply this numerical solver to the diffusion of cosmic ray energy, and diffusion of heat carried by electrons, which couple to the ion temperature. We test this new implementation against several numerical experiments and apply it to a simple supernova explosion with a uniform magnetic field.

  7. The role of cosmic rays on magnetic field diffusion and the formation of protostellar discs

    CERN Document Server

    Padovani, Marco; Hennebelle, Patrick; Commerçon, Benoît; Joos, Marc

    2014-01-01

    The formation of protostellar discs is severely hampered by magnetic braking, as long as magnetic fields remain frozen in the gas. The latter condition depends on the levels of ionisation that characterise the innermost regions of a collapsing cloud. The chemistry of dense cloud cores and, in particular, the ionisation fraction is largely controlled by cosmic rays. The aim of this paper is to evaluate whether the attenuation of the flux of cosmic rays expected in the regions around a forming protostar is sufficient to decouple the field from the gas, thereby influencing the formation of centrifugally supported disc. We adopted the method developed in a former study to compute the attenuation of the cosmic-ray flux as a function of the column density and the field strength in clouds threaded by poloidal and toroidal magnetic fields. We applied this formalism to models of low- and high-mass star formation extracted from numerical simulations of gravitational collapse that include rotation and turbulence. For ea...

  8. Diffusion of cosmic rays in a multiphase interstellar medium swept-up by a supernova remnant blast wave

    Science.gov (United States)

    Roh, Soonyoung; Inutsuka, Shu-ichiro; Inoue, Tsuyoshi

    2016-01-01

    Supernova remnants (SNRs) are one of the most energetic astrophysical events and are thought to be the dominant source of Galactic cosmic rays (CRs). A recent report on observations from the Fermi satellite has shown a signature of pion decay in the gamma-ray spectra of SNRs. This provides strong evidence that high-energy protons are accelerated in SNRs. The actual gamma-ray emission from pion decay should depend on the diffusion of CRs in the interstellar medium. In order to quantitatively analyse the diffusion of high-energy CRs from acceleration sites, we have performed test particle numerical simulations of CR protons using a three-dimensional magnetohydrodynamics (MHD) simulation of an interstellar medium swept-up by a blast wave. We analyse the diffusion of CRs at a length scale of order a few pc in our simulated SNR, and find the diffusion of CRs is precisely described by a Bohm diffusion, which is required for efficient acceleration at least for particles with energies above 30 TeV for a realistic interstellar medium. Although we find the possibility of a superdiffusive process (travel distance ∝ t0.75) in our simulations, its effect on CR diffusion at the length scale of the turbulence in the SNR is limited.

  9. Diffusion of Cosmic Rays in a Multiphase Interstellar Medium Swept-Up by a Supernova Remnant Blast Wave

    CERN Document Server

    Roh, Soonyoung; Inoue, Tsuyoshi

    2015-01-01

    Supernova remnants (SNRs) are one of the most energetic astrophysical events and are thought to be the dominant source of Galactic cosmic rays (CRs). A recent report on observations from the Fermi satellite has shown a signature of pion decay in the gamma-ray spectra of SNRs. This provides strong evidence that high-energy protons are accelerated in SNRs. The actual gamma-ray emission from pion decay should depend on the diffusion of CRs in the interstellar medium. In order to quantitatively analyse the diffusion of high-energy CRs from acceleration sites, we have performed test particle numerical simulations of CR protons using a three-dimensional magnetohydrodynamics (MHD) simulation of an interstellar medium swept-up by a blast wave. We analyse the diffusion of CRs at a length scale of order a few pc in our simulated SNR, and find the diffusion of CRs is precisely described by a Bohm diffusion, which is required for efficient acceleration at least for particles with energies above 30 TeV for a realistic int...

  10. Effect of energy losses and interactions during diffusive shock acceleration: applications to SNR, AGN and UHE Cosmic Rays

    CERN Document Server

    Protheroe, R J

    2004-01-01

    I discuss the shape of the high energy end of the spectrum of particles arising from diffusive shock acceleration in the presence of (i) additional diffusive escape from the accelerator, (ii) continuous energy losses, (iii) energy changes arising from interactions. The form of the spectrum near cut-off is sensitive to these processes as well as to the momentum-dependence of the diffusion coefficients and the compression ratio, and so the spectrum of any radiation emitted by the accelerated particles may reflect the physical conditions of the acceleration region. Results presented in this paper have applications in interpreting the spectral energy distributions of many types of astrophysical object including supernova remnants (SNR), active galactic nuclei (AGN) and acceleration sources of ultra high energy cosmic rays (UHE CR). Except for extremely nearby sources, spectral features imprinted on the spectrum of UHE CR during the acceleration process will be largely eroded during propagation, but the spectrum o...

  11. Cosmic rays on earth

    Energy Technology Data Exchange (ETDEWEB)

    Allkofer, O.C.; Grieder, P.K.F.

    1984-01-01

    A data collection is presented that covers cosmic rays on earth. Included are all relevant data on flux and intensity measurements, energy spectra, and related data of all primary and secondary components of the cosmic radiation at all levels in the atmosphere, at sea level and underground. In those cases where no useful experimental data have been available, theoretical predictions were substituted.

  12. Eleventh European Cosmic Ray Symposium

    Science.gov (United States)

    1988-08-01

    The biannual Symposium includes all aspects of cosmic ray research. The scientific program was organized under three main headings: cosmic rays in the heliosphere, cosmic rays in the interstellar and extragalactic space, and properties of high-energy interactions as studied by cosmic rays. Selected short communications out of 114 contributed papers were indexed separately for the INIS database.

  13. Highest Energy Cosmic Rays

    CERN Document Server

    Frampton, Paul H

    1998-01-01

    It is proposed that the highest energy $\\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor whose high kinetic energy arises from decay of a distant (cosmological) superheavy particle, G. Such a scenario can occur in e.g. SU(15) grand unification and in some preon models, but is more generic; if true, these unusual cosmic rays provide a window into new physics.

  14. Cosmic Rays: What Gamma Rays Can Say

    OpenAIRE

    2014-01-01

    We will review the main channels of gamma ray emission due to the acceleration and propagation of cosmic rays, discussing the cases of both galactic and extra-galactic cosmic rays and their connection with gamma rays observations.

  15. The Morphology of the Galactic Dark Matter Synchrotron Emission with Self-Consistent Cosmic Ray Diffusion Models

    CERN Document Server

    Linden, Tim; Anderson, Brandon

    2010-01-01

    A generic prediction in the paradigm of weakly interacting dark matter is the production of relativistic particles from dark matter pair-annihilation in regions of high dark matter density. Ultra-relativistic electrons and positrons produced in the center of the Galaxy by dark matter annihilation should produce a diffuse synchrotron emission. While the spectral shape of the synchrotron dark matter haze depends on the particle model (and secondarily on the galactic magnetic fields), the morphology of the haze depends primarily on (1) the dark matter density distribution, (2) the galactic magnetic field morphology, and (3) the diffusion model for high-energy cosmic-ray leptons. Interestingly, an unidentified excess of microwave radiation with characteristics similar to those predicted by dark matter models has been claimed to exist near the galactic center region in the data reported by the WMAP satellite, and dubbed the "WMAP haze". In this study, we carry out a self-consistent treatment of the variables enume...

  16. Magnetic field amplification in nonlinear diffusive shock acceleration including resonant and non-resonant cosmic-ray driven instabilities

    CERN Document Server

    Bykov, Andrei M; Osipov, Sergei M; Vladimirov, Andrey E

    2014-01-01

    We present a nonlinear Monte Carlo model of efficient diffusive shock acceleration (DSA) where the magnetic turbulence responsible for particle diffusion is calculated self-consistently from the resonant cosmic-ray (CR) streaming instability, together with non-resonant short- and long-wavelength CR-current-driven instabilities. We include the backpressure from CRs interacting with the strongly amplified magnetic turbulence which decelerates and heats the super-alfvenic flow in the extended shock precursor. Uniquely, in our plane-parallel, steady-state, multi-scale model, the full range of particles, from thermal (~eV) injected at the viscous subshock, to the escape of the highest energy CRs (~PeV) from the shock precursor, are calculated consistently with the shock structure, precursor heating, magnetic field amplification (MFA), and scattering center drift relative to the background plasma. In addition, we show how the cascade of turbulence to shorter wavelengths influences the total shock compression, the d...

  17. Cosmic Ray Acceleration in Supernova Remnants

    CERN Document Server

    Blasi, Pasquale

    2010-01-01

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

  18. Non-linear diffusion of cosmic rays escaping from supernova remnants I: the effect of neutrals

    CERN Document Server

    Nava, Lara; Marcowith, Alexandre; Morlino, Giovanni; Ptuskin, Vladimir S

    2016-01-01

    Supernova remnants are believed to be the main sources of galactic Cosmic Rays (CR). Within this framework, particles are accelerated at supernova remnant shocks and then released in the interstellar medium. The mechanism through which CRs are released and the way in which they propagate still remain open issues. The main difficulty is the high non-linearity of the problem: CRs themselves excite the magnetic turbulence that confines them close to their sources. We solve numerically the coupled differential equations describing the evolution in space and time of the escaping particles and of the waves generated through the CR streaming instability. The warm ionized and warm neutral phases of the interstellar medium are considered. These phases occupy the largest fraction of the disk volume, where most supernovae explode, and are characterised by the significant presence of neutral particles. The friction between those neutrals and ions results in a very effective wave damping mechanism. It is found that stream...

  19. Prediction of the diffuse neutrino flux from cosmic ray interactions near supernova remnants

    Science.gov (United States)

    Mandelartz, Matthias; Becker Tjus, Julia

    2015-05-01

    In this paper, we present high-energy neutrino spectra from 21 Galactic supernova remnants (SNRs), derived from gamma-ray measurements in the GeV-TeV range. We find that only the strongest sources, i.e. G40.5-0.5 in the north and Vela Junior in the south could be detected as single point sources by IceCube or KM3NeT, respectively. For the first time, it is also possible to derive a diffuse signal by applying the observed correlation between gamma-ray emission and radio signal. Radio data from 234 supernova remnants listed in Green's catalog are used to show that the total diffuse neutrino flux is approximately a factor of 2.5 higher compared to the sources that are resolved so far. We show that the signal at above 10 TeV energies can actually become comparable to the diffuse neutrino flux component from interactions in the interstellar medium. Recently, the IceCube collaboration announced the detection of a first diffuse signal of astrophysical high-energy neutrinos. Directional information cannot unambiguously reveal the nature of the sources at this point due to low statistics. A number of events come from close to the Galactic center and one of the main questions is whether at least a part of the signal can be of Galactic nature. In this paper, we show that the diffuse flux from well-resolved SNRs is at least a factor of 20 below the observed flux.

  20. Cosmic Rays and Climate

    CERN Document Server

    Kirkby, Jasper

    2007-01-01

    Among the most puzzling questions in climate change is that of solar-climate variability, which has attracted the attention of scientists for more than two centuries. Until recently, even the existence of solar-climate variability has been controversial—perhaps because the observations had largely involved correlations between climate and the sunspot cycle that had persisted for only a few decades. Over the last few years, however, diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in cosmogenic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Although this remains a mystery, observations suggest that cloud cover may be influenced by cosmic rays, which are modulated by the solar wind and, on longer time scales, by the geomagnetic fiel...

  1. Bayesian analysis of cosmic-ray propagation: evidence against homogeneous diffusion

    CERN Document Server

    Jóhannesson, G; Vincent, A C; Moskalenko, I V; Orlando, E; Porter, T A; Strong, A W; Trotta, R; Feroz, F; Graff, P; Hobson, M P

    2016-01-01

    We present the results of the most complete ever scan of the parameter space for cosmic ray (CR) injection and propagation. We perform a Bayesian search of the main GALPROP parameters, using the MultiNest nested sampling algorithm, augmented by the BAMBI neural network machine learning package. This is the first such study to separate out low-mass isotopes ($p$, $\\bar p$ and He) from the usual light elements (Be, B, C, N, O). We find that the propagation parameters that best fit $p$, $\\bar p$, He data are significantly different from those that fit light elements, including the B/C and $^{10}$Be/$^9$Be secondary-to-primary ratios normally used to calibrate propagation parameters. This suggests each set of species is probing a very different interstellar medium, and that the standard approach of calibrating propagation parameters using B/C can lead to incorrect results. We present posterior distributions and best fit parameters for propagation of both sets of nuclei, as well as for the injection abundances of ...

  2. Cosmic ray driven outflows

    CERN Document Server

    Hanasz, Michal; Naab, Thorsten; Gawryszczak, Artur; Kowalik, Kacper; Wóltański, Dominik

    2013-01-01

    We present simulations of the magnetized interstellar medium (ISM) in models of massive star forming (40 Msun / yr) disk galaxies with high gas surface densities (~100 Msun / pc^2) similar to observed star forming high-redshift disks. We assume that type II supernovae deposit 10 per cent of their energy into the ISM as cosmic rays and neglect the additional deposition of thermal energy or momentum. With a typical Galactic diffusion coefficient for CRs (3e28 cm^2 / s) we demonstrate that this process alone can trigger the local formation of a strong low density galactic wind maintaining vertically open field lines. Driven by the additional pressure gradient of the relativistic fluid the wind speed can exceed 1000 km/s, much higher than the escape velocity of the galaxy. The global mass loading, i.e. the ratio of the gas mass leaving the galactic disk in a wind to the star formation rate becomes of order unity once the system has settled into an equilibrium. We conclude that relativistic particles accelerated i...

  3. Cosmic Ray Helium Hardening

    CERN Document Server

    Ohira, Yutaka

    2010-01-01

    Recent observations by CREAM, ATIC-2 and PAMELA experiments suggest that (1) the spectrum of cosmic ray (CR) helium is harder than that of CR proton below the knee $10^15 eV$ and (2) all CR spectra become hard at $\\gtrsim 10^{11} eV/n$. We propose a new picture that higher energy CRs are generated in more helium-rich region to explain the hardening (1) without introducing different sources for CR helium. The helium to proton ratio at $\\sim 100$ 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 the chemically enriched region, such as a superbubble, and the outward-decreasing abundance naturally leads to the hard spectrum of CR helium when escaping from the supernova remnant (SNR) shock. We provide a simple analytical spectrum that also fits well the hardening (2) because of the decreasing Mach number in the hot superbubble with $\\sim 10^6$ K. Our model predicts hard and con...

  4. Cosmic ray escape from supernova remnants

    CERN Document Server

    Gabici, Stefano

    2011-01-01

    Galactic cosmic rays are believed to be accelerated at supernova remnants via diffusive shock acceleration. Though this mechanism gives fairly robust predictions for the spectrum of particles accelerated at the shock, the spectrum of the cosmic rays which are eventually injected in the interstellar medium is more uncertain and depends on the details of the process of particle escape from the shock. Knowing the spectral shape of these escaping particles is of crucial importance in order to assess the validity of the supernova remnant paradigm for cosmic ray origin. Moreover, after escaping from a supernova remnant, cosmic rays interact with the surrounding ambient gas and produce gamma rays in the vicinity of the remnant itself. The detection of this radiation can be used as an indirect proof of the fact that the supernova remnant was indeed accelerating cosmic rays in the past.

  5. Antarctic Cosmic Ray Astronomy

    Science.gov (United States)

    Duldig, Marc

    Cosmic ray observations related to Antarctica commenced in the austral summer of 1947-48 from sub-Antarctic Heard and Macquarie Islands and from the HMAS Wyatt Earp. Muon telescope observations from Mawson station Antarctica commenced in 1955. The International Geophysical Year was the impetus for the installation of a number of neutron monitors around Antarctica observing the lowest energy cosmic rays accessible by ground based instruments. In 1971 a new observatory was built at Mawson including the only underground muon telescope system at polar latitudes in either hemisphere. In the 1980s the South Pole Air Shower Experiment (SPASE) opened the highest energy cosmic ray window over Antarctica and this was followed by the in-ice neutrino experiment AMANDA. Over more than half a century cosmic ray astronomy has been undertaken from Antarctica and its surrounding regions and these observations have been critical to our growing understanding of nearby astrophysical structures. For example the Parker spiral magnetic field of the sun was confirmed through Mawson observations of a Solar flare induced Ground Level Enahncement in 1960 long before spacecraft were able to directly observe the interplanetary magnetic field. A summary of the Antarctic instrumental developments and the scientific advances that resulted will be presented.

  6. Cosmic rays and climate

    CERN Multimedia

    2009-01-01

    Inside the new chamber the CLOUD team will be able to recreate the conditions of any part of the atmosphere, from the polar stratosphere to the low level tropics (top). The new chamber safely in position in the East hall. Once carefully cleaned the chamber will be turned sideways onto its legs ready for the beam of 'cosmic rays' (bottom).

  7. Frontiers in Cosmic Rays

    CERN Document Server

    Anchordoqui, Luis A; Ringwald, Andreas; Anchordoqui, Luis A.; Dermer, Charles D.; Ringwald, Andreas

    2004-01-01

    This rapporteur review covers selected results presented in the Parallel Session HEA2 (High Energy Astrophysics 2) of the 10th Marcel Grossmann Meeting on General Relativity, held in Rio de Janeiro, Brazil, July 2003. The subtopics are: ultra high energy cosmic ray anisotropies, the possible connection of these energetic particles with powerful gamma ray bursts, and new exciting scenarios with a strong neutrino-nucleon interaction in the atmosphere.

  8. Cosmic Rays at Earth

    Science.gov (United States)

    Grieder, P. K. F.

    In 1912 Victor Franz Hess made the revolutionary discovery that ionizing radiation is incident upon the Earth from outer space. He showed with ground-based and balloon-borne detectors that the intensity of the radiation did not change significantly between day and night. Consequently, the sun could not be regarded as the sources of this radiation and the question of its origin remained unanswered. Today, almost one hundred years later the question of the origin of the cosmic radiation still remains a mystery. Hess' discovery has given an enormous impetus to large areas of science, in particular to physics, and has played a major role in the formation of our current understanding of universal evolution. For example, the development of new fields of research such as elementary particle physics, modern astrophysics and cosmology are direct consequences of this discovery. Over the years the field of cosmic ray research has evolved in various directions: Firstly, the field of particle physics that was initiated by the discovery of many so-called elementary particles in the cosmic radiation. There is a strong trend from the accelerator physics community to reenter the field of cosmic ray physics, now under the name of astroparticle physics. Secondly, an important branch of cosmic ray physics that has rapidly evolved in conjunction with space exploration concerns the low energy portion of the cosmic ray spectrum. Thirdly, the branch of research that is concerned with the origin, acceleration and propagation of the cosmic radiation represents a great challenge for astrophysics, astronomy and cosmology. Presently very popular fields of research have rapidly evolved, such as high-energy gamma ray and neutrino astronomy. In addition, high-energy neutrino astronomy may soon initiate as a likely spin-off neutrino tomography of the Earth and thus open a unique new branch of geophysical research of the interior of the Earth. Finally, of considerable interest are the biological

  9. Cosmic rays and molecular clouds

    OpenAIRE

    2012-01-01

    This paper deals with the cosmic-ray penetration into molecular clouds and with the related gamma--ray emission. High energy cosmic rays interact with the dense gas and produce neutral pions which in turn decay into two gamma rays. This makes molecular clouds potential sources of gamma rays, especially if they are located in the vicinity of a powerful accelerator that injects cosmic rays in the interstellar medium. The amplitude and duration in time of the cosmic--ray overdensity around a giv...

  10. Spatial Dependent Diffusion of Cosmic Rays and the Excess of Primary Electrons Derived from High Precision Measurements by AMS-02

    CERN Document Server

    Jin, C; Hu, H B

    2016-01-01

    The precise spectra of Cosmic Ray (CR) electrons and positrons have been published by the measurement of AMS-02. It is reasonable to regard the difference between the electrons and positrons spectra ( $\\triangle \\Phi= \\Phi_{e^-}-\\Phi_{e^+}$ ) as being dominated by primary electrons. Noticing that the resulting electron spectrum shows no sign of spectral softening above 20 GeV, which is in contrast with the prediction of standard model. In this work, we generalize the analytic one dimensional two-halo model of diffusion to a three dimensional realistic calculation by implementing a spatial variant diffusion coefficients in DRAGON package. As a result, we can reproduce the spectral hardening of protons observed by several experiments, and predict an excess of high energy primary electrons which agrees with the measurement reasonably well. Unlike the break spectrum obtained for protons, the model calculation predicts a smooth electron excess and thus slightly over predicts the flux from tens of GeV to 100GeV. To...

  11. Dual Phase Cosmic Rays

    CERN Document Server

    Shurtleff, Richard

    2008-01-01

    A calculation based on flat spacetime symmetries shows how there can be two quantum phases. For one, extreme phase change determines a conventional classical trajectory and four-momentum, i.e. mass times four-velocity. The other phase occurs in an effective particle state, with the effective energy and momentum being the rate of change of the phase with respect to time and distance. A cosmic ray proton moves along a classical trajectory, but exists in an effective particle state with an effective energy that depends on the local gravitational potential. Assumptions are made so that a cosmic ray proton in an ultra-high energy state detected near the Earth was in a much less energetic state in interstellar space. A 300 EeV proton incident on the Earth was a 2 PeV proton in interstellar space. The model predicts such protons are in states with even more energy near the Sun than when near the Earth.

  12. Cosmic rays and climate

    CERN Document Server

    CERN. Geneva

    2009-01-01

    The current understanding of climate change in the industrial age is that it is predominantly caused by anthropogenic greenhouse gases, with relatively small natural contributions due to solar irradiance and volcanoes. However, palaeoclimatic reconstructions show that the climate has frequently varied on 100-year time scales during the Holocene (last 10 kyr) by amounts comparable to the present warming - and yet the mechanism or mechanisms are not understood. Some of these reconstructions show clear associations with solar variability, which is recorded in the light radio-isotope archives that measure past variations of cosmic ray intensity. However, despite the increasing evidence of its importance, solar-climate variability is likely to remain controversial until a physical mechanism is established. Estimated changes of solar irradiance on these time scales appear to be too small to account for the climate observations. This raises the question of whether cosmic rays may directly affect the climate, provi...

  13. Cosmic Rays in Thunderstorms

    Science.gov (United States)

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

    2013-04-01

    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)

  14. About cosmic gamma ray lines

    Science.gov (United States)

    Diehl, Roland

    2017-06-01

    Gamma ray lines from cosmic sources convey the action of nuclear reactions in cosmic sites and their impacts on astrophysical objects. Gamma rays at characteristic energies result from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. The gamma-ray line from the annihilation of positrons at 511 keV falls into the same energy window, although of different origin. We present here the concepts of cosmic gamma ray spectrometry and the corresponding instruments and missions, followed by a discussion of recent results and the challenges and open issues for the future. Among the lessons learned are the diffuse radioactive afterglow of massive-star nucleosynthesis in 26Al and 60Fe gamma rays, which is now being exploited towards the cycle of matter driven by massive stars and their supernovae; large interstellar cavities and superbubbles have been recognised to be of key importance here. Also, constraints on the complex processes making stars explode as either thermonuclear or core-collapse supernovae are being illuminated by gamma-ray lines, in this case from shortlived radioactivities from 56Ni and 44Ti decays. In particular, the three-dimensionality and asphericities that have recently been recognised as important are enlightened in different ways through such gamma-ray line spectroscopy. Finally, the distribution of positron annihilation gamma ray emission with its puzzling bulge-dominated intensity disctribution is measured through spatially-resolved spectra, which indicate that annihilation conditions may differ in different parts of our Galaxy. But it is now understood that a variety of sources may feed positrons into the interstellar medium, and their characteristics largely get lost during slowing down and propagation of positrons before annihilation; a recent microquasar flare was caught as an opportunity to see positrons annihilate at a source.

  15. Deep observation of the NGC 1275 region with MAGIC: search of diffuse gamma-ray emission from cosmic rays in the Perseus cluster

    CERN Document Server

    Ahnen, M L; Antonelli, L A; Antoranz, P; Babic, A; Banerjee, B; Bangale, P; de Almeida, U Barres; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Buson, S; Carmona, E; Carosi, A; Chatterjee, A; Clavero, R; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Lotto, B; Wilhelmi, E de Oña; Mendez, C Delgado; Di Pierro, F; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Glawion, D Eisenacher; Elsaesser, D; Fernández-Barral, A; Fidalgo, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giammaria, P; Godinović, N; Muñoz, A González; Gora, D; Guberman, D; Hadasch, D; Hahn, A; Hanabata, Y; Hayashida, M; Herrera, J; Hose, J; Hrupec, D; Hughes, G; Idec, W; Kodani, K; Konno, Y; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lindfors, E; Lombardi, S; Longo, F; López, M; López-Coto, R; Lorenz, E; Majumdar, P; Makariev, M; Mallot, K; Maneva, G; Manganaro, M; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Moretti, E; Nakajima, D; Neustroev, V; Niedzwiecki, A; Rosillo, M Nievas; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palacio, J; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Pedaletti, G; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Saito, T; Satalecka, K; Schultz, C; Schweizer, T; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Stamerra, A; Steinbring, T; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Torres, D F; Toyama, T; Treves, A; Acosta, M Vazquez; Verguilov, V; Vovk, I; Ward, J E; Will, M; Wu, M H; Zanin, R; and,; :,; Pfrommer, C; Pinzke, A; Zandanel, F

    2016-01-01

    Clusters of galaxies are expected to be reservoirs of cosmic rays (CRs) that should produce diffuse gamma-ray emission due to their hadronic interactions with the intra-cluster medium. The nearby Perseus cool-core cluster, identified as the most promising target to search for such an emission, has been observed with the MAGIC telescopes at very-high energies (VHE, E>100 GeV) for a total of 253 hr from 2009 to 2014. The active nuclei of NGC 1275, the central dominant galaxy of the cluster, and IC 310, lying at about 0.6$^\\circ$ from the centre, have been detected as point-like VHE gamma-ray emitters during the first phase of this campaign. We report an updated measurement of the NGC 1275 spectrum, which is well described by a power law with a photon index of $3.6\\pm0.2_{stat}\\pm0.2_{syst}$ between 90 GeV and 1.2 TeV. We do not detect any diffuse gamma-ray emission from the cluster and set stringent constraints on its CR population. In order to bracket the uncertainties over the CR spatial and spectral distribu...

  16. Cosmic-ray propagation in molecular clouds

    CERN Document Server

    Padovani, Marco

    2013-01-01

    Cosmic-rays constitute the main ionising and heating agent in dense, starless, molecular cloud cores. We reexamine the physical quantities necessary to determine the cosmic-ray ionisation rate (especially the cosmic ray spectrum at E < 1 GeV and the ionisation cross sections), and calculate the ionisation rate as a function of the column density of molecular hydrogen. Available data support the existence of a low-energy component (below about 100 MeV) of cosmic-ray electrons or protons responsible for the ionisation of diffuse and dense clouds. We also compute the attenuation of the cosmic-ray flux rate in a cloud core taking into account magnetic focusing and magnetic mirroring, following the propagation of cosmic rays along flux tubes enclosing different amount of mass and mass-to-flux ratios. We find that mirroring always dominates over focusing, implying a reduction of the cosmic-ray ionisation rate by a factor of 3-4 depending on the position inside the core and the magnetisation of the core.

  17. Impact of Cosmic Ray Transport on Galactic Winds

    Science.gov (United States)

    Farber, Ryan; Ruszkowski, Mateusz; Yang, Hsiang-Yi Karen; Gould Zweibel, Ellen

    2017-08-01

    Despite playing a fundamental role in galaxy evolution, the physical mechanisms responsible for driving galactic winds remain unclear. The role of cosmic rays generated by supernovae and young stars has very recently begun to receive significant attention due to the realization that cosmic rays can efficiently accelerate galactic winds. Microscopic cosmic ray transport processes are fundamental for determining the efficiency of cosmic ray wind driving. Previous studies focused on modeling of cosmic ray transport either via constant diffusion coefficient or via streaming proportional to the Alfv{é}n speed. However, in predominantly neutral gas, cosmic rays can propagate faster than in the ionized medium and the effective transport can be substantially larger, i.e., cosmic rays are decoupled from the gas. We perform three-dimensional magneto-hydrodynamical simulations of patches of galactic disks including the effects of cosmic rays. Our simulations include the decoupling of cosmic rays in the neutral ISM phases. We find that, compared to the ordinary diffusive cosmic ray transport case, accounting for the decoupling leads to significantly different wind properties such as the cosmic ray spatial distribution, wind speed, density, and temperature. These results have implications for the magnetization of the circumgalactic medium and the pollution of the circumgalactic medium with cosmic rays.

  18. Cosmic ray: Studying the origin

    Energy Technology Data Exchange (ETDEWEB)

    Szabelski, J. [Cosmic Ray Laboratory, Soltan Institute for Nuclear Studies, Lodz (Poland)

    1997-12-31

    Investigations of the origin of cosmic rays are presented. Different methods are discussed: studies of cosmic gamma rays of energy from 30 MeV to about 10{sup 15} eV (since photons point to their places of origin), studies of the mass composition of cosmic rays (because it reflects source morphology), and studies of cosmic rays with energy above 1O{sup 19} eV (for these are the highest energies observed in nature). (author) 101 refs, 19 figs, 7 tabs

  19. Analytical solutions of a fractional diffusion-advection equation for solar cosmic-ray transport

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, Yuri E.; Effenberger, Frederic, E-mail: yuril@waikato.ac.nz [Department of Mathematics, University of Waikato, P.B. 3105 Hamilton (New Zealand)

    2014-12-01

    Motivated by recent applications of superdiffusive transport models to shock-accelerated particle distributions in the heliosphere, we analytically solve a one-dimensional fractional diffusion-advection equation for the particle density. We derive an exact Fourier transform solution, simplify it in a weak diffusion approximation, and compare the new solution with previously available analytical results and with a semi-numerical solution based on a Fourier series expansion. We apply the results to the problem of describing the transport of energetic particles, accelerated at a traveling heliospheric shock. Our analysis shows that significant errors may result from assuming an infinite initial distance between the shock and the observer. We argue that the shock travel time should be a parameter of a realistic superdiffusive transport model.

  20. Cosmic rays: extragalactic and Galactic

    CERN Document Server

    Istomin, Ya N

    2014-01-01

    From the analysis of the flux of high energy particles, $E>3\\cdot 10^{18}eV$, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, ${\\bar q}(E)\\propto E^{-2.7}$, with the same index of $2.7$ that has the distribution of Galactic cosmic rays before so called 'knee', $E3\\cdot 10^{15}eV$, from the Galaxy because of the dependence of the coefficient of diffusion of cosmic rays on energy, $D\\propto E^{0.7}$. The obtained index of the density distribution of particles over energy, $N(E)\\propto E^{-2.7-0.7/2}=E^{-3.05}$, for $E>3\\cdot 10^{15}eV$ agrees well with the observed one, $N(E)\\propto E^{-3.1}$. Estimated time of termination of the jet in the Galaxy is $4.2\\cdot 10^{4}$ years ago.

  1. Cosmic X-ray Physics: Sounding rocket investigations of the diffuse X-ray background, including instrument development

    Science.gov (United States)

    McCammon, Dan

    We propose an investigation to improve our understanding of the Galactic diffuse X-ray background. The ultimate purpose of this is to determine the role of hot phases of the interstellar medium in mediating stellar feedback in star formation, in transport of metals, and in determining the structure and evolution of the Galaxy. It directly addresses SMD's astrophysics goal No. 2, to explore the origin and evolution of the galaxies, stars and planets that make up our universe. This work will involve a flight of an existing payload with small modifications in Woomera, South Australia, to observe the Galactic soft X-ray bulge and attempt to determine its nature and emission mechanisms. This flight should also either confirm or put strict upper limits on the "sterile neutrino" model for the 3.5 keV signal observed near the Galactic Center by XMM-Newton. Our investigation includes the development of thermal detectors with superconducting transition edge thermometers capable of 1-2 eV FWHM energy resolution in the 100-400 eV range with the intent of obtaining a scientifically useful spectrum on a sounding rocket flight of the emission from one million degree gas in this energy range. This will require a total area of 1-2 square centimeters for the detector array. To enable routine testing of such detectors in the lab and for necessary in-flight gain and resolution monitoring, we are trying to develop a pulsed-UV laser calibration source. In collaboration with Goddard Space Flight Center, we are investigating the practicality of waveguide-below-cutoff filters to provide the necessary attenuation of infrared radiation for these detectors while still allowing good x-ray transmission below 150 eV. The detectors, calibration source, filters, optimal high-rate pulse analysis and flight experience with the detector readouts are all relevant to future NASA major missions. The detectors we're working on for a low-energy sounding rocket flight would be an excellent match to what is

  2. Cosmic Ray ^3He Measurements

    OpenAIRE

    Mewaldt, R. A.

    1985-01-01

    Cosmic ray ^3He/^4He observations, including a new measurement at ~65 MeV/nucleon from ISEE-3, are compared with interstellar propagation and solar modulation models in an effort to understand the origin of cosmic ray He nuclei.

  3. Search for diffuse cosmic gamma-ray flux using Fractal and Wavelet analysis from Galactic region using single imaging Cerenkov telescopes

    CERN Document Server

    Bhat, C K

    2010-01-01

    We show from a simulations-based study of the TACTIC telescope that fractal and wavelet analysis of Cerenkov images, recorded in a single imaging Cerenkov telescope, enables almost complete segregation of isotropic gamma-ray initiated events from the overwhelming background of cosmic-ray hadron-initiated events. This presents a new method for measuring galactic and extragalactic gamma-ray background above 1 TeV energy. Preliminary results based on this method are reported here. Primary aim is to explore the possibility of using data recorded by a single imaging atmospheric Cerenkov telescope(IACT) for making accurate measurements of diffuse galactic and extragalactic gamma-ray flux above ~1 TeV energy. Using simulated data of atmospheric Cerenkov images recorded in an IACT, initiated both by cosmic ray protons and diffuse gamma-rays with energies above 4 TeV and 2 TeV respectively, we identify the most efficient fractal /wavelet parameters of the recorded images for primary identification. The method is based...

  4. Cosmic Ray Antimatter

    CERN Document Server

    CERN. Geneva

    2017-01-01

    Over the last decade, space-born experiments have delivered new measurements of high energy cosmic-ray (CR) antiprotons and positrons, opening new frontiers in energy reach and precision. While being a promising discovery tool for new physics or exotic astrophysical phenomena, an irreducible background of antimatter comes from CR collisions with interstellar matter in the Galaxy. Understanding this irreducible source or constraining it from first principles is an interesting challenge: a game of hide-and-seek where the objective is to identify the laws of basic particle physics among the forest of astrophysical uncertainties. I describe an attempt to obtain such understanding, combining information from a zoo of CR species including massive nuclei and relativistic radioisotopes. I show that: (i) CR antiprotons most likely come from CR-gas collisions; (ii) positron data is consistent with, and suggestive of the same astrophysical production mechanism responsible for antiprotons and dominated by proton-proton c...

  5. Acceleration of cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Berezhko, E [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation)], E-mail: berezhko@ikfia.ysn.ru

    2008-07-15

    Cosmic ray (CR) origin problem is briefly discussed. It is argued that CRs with energies up to 10{sup 17} eV are produced in galactic supernova remnants, whereas ultra high energy CRs are extragalactic. CR composition strongly changes within the transition from galactic to extragalactic CR component, therefore precise measurements of CR composition at energies 10{sup 17} - 10{sup 19} eV are needed for the reliable determination of this transition. The possible sources of extragalactic CRs are briefly discussed. It is argued that CR acceleration at the shock created by the expanding cocoons around active galactic nuclei has to be considered as a prime candidate for the sources of extragalactic CRs.

  6. Cosmic ray synergies

    CERN Multimedia

    Laëtitia Pedroso

    2010-01-01

    In laboratories, cosmic rays have been the subject of scientific research for many years. A more recent development is their appearance in schools, as educational tools. A recent workshop at CERN, organised by ASPERA in collaboration with EPPOG and EPPCN, had the goal of bringing together ideas and initiatives with a view to setting up a future common project.   Presentation at the workshop on 15 October. In research, as in education, you can sometimes get things done more rapidly and easily by joining forces. For roughly the past decade, physicists have been taking their particle detectors to secondary schools. “The challenge now is to bring all of these existing projects together in a network,” says Arnaud Marsollier, in charge of communication for the ASPERA network and organiser of the workshop. The workshop held on Friday, 15 October was attended by representatives of major European educational projects and members of the European Particle Physics Communication Network...

  7. Cosmic rays and global warming

    Energy Technology Data Exchange (ETDEWEB)

    Erlykin, A.D. [P.N. Lebedev Physical Institute, Moscow (Russian Federation); Sloan, T. [Lancaster University (United Kingdom); Wolfendale, A.W. [Durham University (United Kingdom)

    2010-07-01

    The possible effects of cosmic rays on clouds could contribute to global warming. The argument is that the observed increased solar activity during the last century caused a decrease in the ionization due to cosmic rays since the lower energy cosmic particles are deflected by the magnetic field created by the increasing solar wind. This would lead to a decrease in cloud cover allowing more heating of the earth by the sun. Meteorological data combined to solar activity observations and simulations show that any effect of solar activity on clouds and the climate is likely to be through irradiance rather than cosmic rays. Since solar irradiance transfers 8 orders of magnitude more energy to the atmosphere than cosmic rays it is more plausible that this can produce a real effect. The total contribution of variable solar activity to global warming is shown to be less than 14% of the total temperature rise. (A.C.)

  8. "Discrepant hardenings" in cosmic ray spectra: a first estimate of the effects on secondary antiproton and diffuse gamma-ray yields

    CERN Document Server

    Donato, Fiorenza

    2010-01-01

    Recent data from CREAM seem to confirm early suggestions that primary cosmic ray spectra at few TeV/nucleon are harder than in the 10-100 GeV range. Also, helium and heavier nuclei spectra appear systematically harder than the proton fluxes at corresponding energies. We note here that if the measurements reflect intrinsic features in the interstellar fluxes, appreciable modifications are expected in the sub-TeV range for the secondary yields, such as antiprotons and diffuse gamma-rays. Presently, this effect represents a systematic error in the extraction of astrophysical parameters as well as for background estimates for indirect dark matter searches. We find that the spectral modifications are appreciable above 100 GeV, and can be responsible for ~30% effects for antiprotons at energies close to 1 TeV or for gamma's at energies close to 300 GeV, compared to currently considered predictions based on simple extrapolation of input fluxes from low energy data.

  9. Cosmic Rays Accelerated at Cosmological Shock Waves

    Indian Academy of Sciences (India)

    Renyi Ma; Dongsu Ryu; Hyesung Kang

    2011-03-01

    Based on hydrodynamic numerical simulations and diffusive shock acceleration model, we calculated the ratio of cosmic ray (CR) to thermal energy. We found that the CR fraction can be less than ∼ 0.1 in the intracluster medium, while it would be of order unity in the warm-hot intergalactic medium.

  10. Protostars: forge of cosmic rays?

    CERN Document Server

    Padovani, M; Hennebelle, P; Ferrière, K

    2016-01-01

    Galactic cosmic rays (CR) are particles presumably accelerated in supernova remnant shocks that propagate in the interstellar medium up to the densest parts of molecular clouds, losing energy as well as their ionisation efficiency because of the presence of magnetic fields and collisions with molecular hydrogen. Recent observations hint at high levels of ionisation and to the presence of synchrotron emission in protostellar systems, therefore leading to an apparent contradiction. We want to explain the origin of these CRs accelerated within young protostars as suggested by observations. Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient CR acceleration through diffusive shock acceleration. We analyse three main acceleration sites, then we follow the propagation of these particles through the protostellar system up to the hot spot region. We find that jet shocks can be strong accelerators of CR protons, which can be boosted up to relativistic energies. Another ...

  11. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    cloud radiative properties. Thus, a moderate influence on atmospheric aerosol distributions from cosmic ray ionisation would have a strong influence on the Earth's radiation budget. Historical evidence over the past 1000 years indicates that changes in climate have occurred in accord with variability...... in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...... in cosmic ray intensities. Such changes are in agreement with the sign of cloud radiative forcing associated with cosmic ray variability as estimated from satellite observations....

  12. Stopping Cooling Flows with Cosmic Ray Feedback

    CERN Document Server

    Mathews, William G

    2009-01-01

    Multi-Gyr two-dimensional calculations describe the gasdynamical evolution of hot gas in the Virgo cluster resulting from intermittent cavities formed with cosmic rays. Without cosmic rays, the gas evolves into a cooling flow, depositing about 85 solar masses per year of cold gas in the cluster core -- such uninhibited cooling conflicts with X-ray spectra and many other observations. When cosmic rays are produced or deposited 10 kpc from the cluster center in bursts of about 10^{59} ergs lasting 20 Myrs and spaced at intervals of 200 Myrs, the central cooling rate is greatly reduced to 0.1 - 1 solar masses per year, consistent with observations. After cosmic rays diffuse through the cavity walls, the ambient gas density is reduced and is buoyantly transported 30-70 kpc out into the cluster. Cosmic rays do not directly heat the gas and the modest shock heating around young cavities is offset by global cooling as the cluster gas expands. After several Gyrs the hot gas density and temperature profiles remain sim...

  13. Cosmic Rays and Particle Physics

    Science.gov (United States)

    Gaisser, Thomas K.; Engel, Ralph; Resconi, Elisa

    2016-06-01

    Preface to the first edition; Preface to the second edition; 1. Cosmic rays; 2. Cosmic ray data; 3. Particle physics; 4. Hadronic interactions and accelerator data; 5. Cascade equations; 6. Atmospheric muons and neutrinos; 7. Neutrino masses and oscillations; 8. Muons and neutrinos underground; 9. Cosmic rays in the Galaxy; 10. Extragalactic propagation of cosmic rays; 11. Astrophysical - rays and neutrinos; 12. Acceleration; 13. Supernovae in the Milky Way; 14. Astrophysical accelerators and beam dumps; 15. Electromagnetic cascades; 16. Extensive air showers; 17. Very high energy cosmic rays; 18. Neutrino astronomy; A.1. Units, constants and definitions; A.2. References to flux measurements; A.3. Particle flux, density, and interaction cross section; A.4. Fundamentals of scattering theory; A.5. Regge amplitude; A.6. Glauber model of nuclear cross sections; A.7. Earth's atmosphere; A.8. Longitudinal development of air showers; A.9. Secondary positrons and electrons; A.10. Liouville's theorem and cosmic ray propagation; A.11. Cosmology and distances measures; A.12. The Hillas splitting algorithm; References; Index.

  14. Cosmic rays from thermal sources

    CERN Document Server

    Wlodarczyk, Z

    2007-01-01

    The energy spectrum of cosmic rays (CR) exhibits very characteristic power-like behavior with the "knee" structure. We consider a generalized statistical model for the production process of cosmic rays which accounts for such behavior in a natural way either by assuming the existence of temperature fluctuations in the source of CR, or by assuming specific temperature distribution of the CR sources. Both possibilities yield the so called Tsallis statistics and lead to the power-like distribution.

  15. Cosmic rays and Earth's climate

    DEFF Research Database (Denmark)

    Svensmark, Henrik

    2000-01-01

    During the last solar cycle the Earth's cloud cover underwent a modulation in phase with the cosmic ray flux. Assuming that there is a causal relationship between the two, it is expected and found that the Earth's temperature follows more closely decade variations in cosmic ray flux than other...... solar activity parameters. If the relationship is real the state of the Heliosphere affects the Earth's climate....

  16. High Energy Cosmic Rays From Supernovae

    CERN Document Server

    Morlino, Giovanni

    2016-01-01

    Cosmic rays are charged relativistic particles that reach the Earth with extremely high energies, providing striking evidence of the existence of effective accelerators in the Universe. Below an energy around $\\sim 10^{17}$ eV cosmic rays are believed to be produced in the Milky Way while above that energy their origin is probably extragalactic. In the early '30s supernovae were already identified as possible sources for the Galactic component of cosmic rays. After the '70s this idea has gained more and more credibility thanks to the the development of the diffusive shock acceleration theory, which provides a robust theoretical framework for particle energization in astrophysical environments. Afterwards, mostly in recent years, much observational evidence has been gathered in support of this framework, converting a speculative idea in a real paradigm. In this Chapter the basic pillars of this paradigm will be illustrated. This includes the acceleration mechanism, the non linear effects produced by accelerate...

  17. Origin of the Cosmic Ray Spectral Hardening

    CERN Document Server

    Tomassetti, N

    2012-01-01

    Recent data from ATIC, CREAM and PAMELA indicate that the cosmic ray energy spectra of protons and nuclei exhibit a remarkable hardening at energies above 100 GeV per nucleon. We propose that the hardening is an interstellar propagation effect that originates from a spatial change of the cosmic ray transport properties in different regions of the Galaxy. The key hypothesis is that the diffusion coefficient is not separable into energy and space variables as usually assumed. Under this scenario, we can reproduce well the observational data. Our model has several implications for the cosmic ray acceleration/propagation physics and can be tested by ongoing experiments such as AMS or Fermi/LAT.

  18. Acoustic instability driven by cosmic-ray streaming

    Science.gov (United States)

    Begelman, Mitchell C.; Zweibel, Ellen G.

    1994-01-01

    We study the linear stability of compressional waves in a medium through which cosmic rays stream at the Alfven speed due to strong coupling with Alfven waves. Acoustic waves can be driven unstable by the cosmic-ray drift, provided that the streaming speed is sufficiently large compared to the thermal sound speed. Two effects can cause instability: (1) the heating of the thermal gas due to the damping of Alfven waves driven unstable by cosmic-ray streaming; and (2) phase shifts in the cosmic-ray pressure perturbation caused by the combination of cosmic-ray streaming and diffusion. The instability does not depend on the magnitude of the background cosmic-ray pressure gradient, and occurs whether or not cosmic-ray diffusion is important relative to streaming. When the cosmic-ray pressure is small compared to the gas pressure, or cosmic-ray diffusion is strong, the instability manifests itself as a weak overstability of slow magnetosonic waves. Larger cosmic-ray pressure gives rise to new hybrid modes, which can be strongly unstable in the limits of both weak and strong cosmic-ray diffusion and in the presence of thermal conduction. Parts of our analysis parallel earlier work by McKenzie & Webb (which were brought to our attention after this paper was accepted for publication), but our treatment of diffusive effects, thermal conduction, and nonlinearities represent significant extensions. Although the linear growth rate of instability is independent of the background cosmic-ray pressure gradient, the onset of nonlinear eff ects does depend on absolute value of DEL (vector differential operator) P(sub c). At the onset of nonlinearity the fractional amplitude of cosmic-ray pressure perturbations is delta P(sub C)/P(sub C) approximately (kL) (exp -1) much less than 1, where k is the wavenumber and L is the pressure scale height of the unperturbed cosmic rays. We speculate that the instability may lead to a mode of cosmic-ray transport in which plateaus of uniform cosmic-ray

  19. Spatial-Dependent Diffusion of Cosmic Rays and the Ratio of pbar/p, B/C

    CERN Document Server

    Guo, Yi-Qing; Jin, Chao

    2015-01-01

    Recent precise measurements of cosmic ray spectral revealed an anomalous hardening at ~200 GV for nuclei from PAMELA, CREAM, ATIC, AMS02 experiments and at tens of GeV for primary electron derived from AMS02 experiment. Particularly, the latest observation of pbar/p ratio by AMS02 demonstrated a flat distribution, which further validated the spectrum anomalies of secondary particles. All those new phenomena indicated that the conventional propagation model of cosmic rays meet challenge. In this work, the spatial-dependent propagation coefficient D(r,z,\\rho) is employed by tracing the source distribution under the physical picture of two-halo model in DRAGON package. Under such scenario, the model calculation will result in a two-component spectral for primary nuclei and electron. Simultaneously, due to the smaller rigidity dependence of D(r,z,\\rho) in galactic disk, the ratio of secondary-to-primary will be inevitablly flatter than the calculation in the conventional propagation model. As a result, we can rep...

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

    Science.gov (United States)

    Shapiro, P.

    1983-09-01

    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.

  1. Cosmic Ray Origins: An Introduction

    Science.gov (United States)

    Blandford, Roger; Simeon, Paul; Yuan, Yajie

    2014-11-01

    Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

  2. Cosmic Ray Origins: An Introduction

    Energy Technology Data Exchange (ETDEWEB)

    Blandford, Roger; Simeon, Paul; Yuan, Yajie

    2014-11-15

    Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

  3. Cosmic Ray Origins: An Introduction

    CERN Document Server

    Blandford, Roger; Yuan, Yajie

    2014-01-01

    Physicists have pondered the origin of cosmic rays for over a hundred years. However the last few years have seen an upsurge in the observation, progress in the theory and a genuine increase in the importance attached to the topic due to its intimate connection to the indirect detection of evidence for dark matter. The intent of this talk is to set the stage for the meeting by reviewing some of the basic features of the entire cosmic ray spectrum from GeV to ZeV energy and some of the models that have been developed. The connection will also be made to recent developments in understanding general astrophysical particle acceleration in pulsar wind nebulae, relativistic jets and gamma ray bursts. The prospects for future discoveries, which may elucidate the origin of cosmic rays, are bright.

  4. Cosmic Ray Energetics and Mass

    CERN Document Server

    Baylon cardiel, J L; Wallace, K C; Anderson, T B; Copley, M

    The cosmic-ray energetics and mass (CREAM) investigation is designed to measure cosmic-ray composition to the supernova energy scale of 10$^{15}$ eV in a series of ultra long duration balloon (ULDB) flights. The first flight is planned to be launched from Antarctica in December 2004. The goal is to observe cosmic-ray spectral features and/or abundance changes that might signify a limit to supernova acceleration. The particle ($\\{Z}$) measurements will be made with a timing-based charge detector and a pixelated silicon charge detector to minimize the effect of backscatter from the calorimeter. The particle energy measurements will be made with a transition radiation detector (TRD) for $\\{Z}$ > 3 and a sampling tungsten/scintillator calorimeter for $\\{Z}$ $\\geq$1 particles, allowing inflight cross calibration of the two detectors. The status of the payload construction and flight preparation are reported in this paper.

  5. Aligned interactions in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Kempa, J., E-mail: kempa@pw.plock.pl [Warsaw University of Technology Branch Plock (Poland)

    2015-12-15

    The first clean Centauro was found in cosmic rays years many ago at Mt Chacaltaya experiment. Since that time, many people have tried to find this type of interaction, both in cosmic rays and at accelerators. But no one has found a clean cases of this type of interaction.It happened finally in the last exposure of emulsion at Mt Chacaltaya where the second clean Centauro has been found. The experimental data for both the Centauros and STRANA will be presented and discussed in this paper. We also present our comments to the intriguing question of the existence of a type of nuclear interactions at high energy with alignment.

  6. New insights from cosmic gamma rays

    CERN Document Server

    Diehl, Roland

    2016-01-01

    The measurement of gamma rays from cosmic sources at MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace nuclear processes most directly, as they originate from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this astronomical window and is discussed here: Cosmic positrons are often produced from beta-decays, thus also of nuclear physics origins. The nuclear reactions leading to radioactive isotopes occur inside stars and stellar explosions, which therefore constitute the main objects of such studies. In recent years, both thermonuclear and core-collapse supernova radioactivities have been measured, and complement conventional supernova observations with measurements of their prime energy sources. The diffuse radioactive afterglow of massi...

  7. Cosmic rays and hadronic interactions

    Directory of Open Access Journals (Sweden)

    Lipari Paolo

    2015-01-01

    Full Text Available The study of cosmic rays, and more in general of the “high energy universe” is at the moment a vibrant field that, thanks to the observations by several innovative detectors for relativistic charged particles, gamma–rays, and neutrinos continue to generate surprising and exciting results. The progress in the field is rapid but many fundamental problems remain open. There is an intimate relation between the study of the high energy universe and the study of the properties of hadronic interactions. High energy cosmic rays can only be studied detecting the showers they generate in the atmosphere, and for the interpretation of the data one needs an accurate modeling of the collisions between hadrons. Also the study of cosmic rays inside their sources and in the Galaxy requires a precise description of hadronic interactions. A program of experimental studies at the LHC and at lower energy, designed to address the most pressing problems, could significantly reduce the existing uncertainties and is very desirable. Such an experimental program would also have a strong intrinsic scientific interest, allowing the broadening and deepening of our understanding of Quantum Chromo Dynamics in the non–perturbative regime, the least understood sector of the Standard Model of particle physics. It should also be noted that the cosmic ray spectrum extends to particles with energy E ∼ 1020 eV, or a nucleon–nucleon c.m. energy √s ≃ 430 TeV, 30 times higher than the current LHC energy. Cosmic ray experiments therefore offer the possibility to perform studies on the properties of hadronic interactions that are impossible at accelerators.

  8. Secondary Cosmic Positrons in an Anisotropic Diffusion Model

    CERN Document Server

    Kappl, Rolf

    2016-01-01

    One aim of cosmic ray measurements is the search for possible signatures of annihilating or decaying dark matter. The so-called positron excess has attracted a lot of attention in this context. On the other hand it has been proposed that the data might challenge the established diffusion model for cosmic ray propagation. We investigate an anisotropic diffusion model by solving the corresponding equations analytically. Depending on the propagation parameters we find that the spectral features of the positron spectrum are affected significantly. We also discuss the influence of the anisotropy on hadronic spectra.

  9. The Cosmic Ray Electron Excess

    Science.gov (United States)

    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

    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.

  10. Cosmic Rays and Radiative Instabilities

    CERN Document Server

    Hartquist, T W; Falle, S A E G; Pittard, J M; Van Loo, S

    2011-01-01

    In the absence of magnetic fields and cosmic rays, radiative cooling laws with a range of dependences on temperature affect the stability of interstellar gas. For about four and a half decades, astrophysicists have recognised the importance of the thermal instablity for the formation of clouds in the interstellar medium. Even in the past several years, many papers have concerned the role of the thermal instability in the production of molecular clouds. About three and a half decades ago, astrophysicists investigating radiative shocks noticed that for many cooling laws such shocks are unstable. Attempts to address the effects of cosmic rays on the stablity of radiative media that are initially uniform or that have just passed through shocks have been made. The simplest approach to such studies involves the assumption that the cosmic rays behave as a fluid. Work based on such an approach is described. Cosmic rays have no effect on the stability of initially uniform, static media with respect to isobaric perturb...

  11. Cosmology, Relativity and Cosmic Rays

    Science.gov (United States)

    López, Rebeca; Martínez, Humberto; Zepeda, Arnulfo

    2009-04-01

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

  12. Surprising results from cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Wilk, G. [Soltan Institute for Nuclear Studies, Warsaw (Poland); Wlodarczyk, Z. [Institute for Physics, Pedagogical University, Kielce (Poland)

    1996-10-01

    A number of seemingly exotic phenomena seen in the highest cosmic-ray experiments are briefly discussed. We argue that they indicate existence of non-statistical fluctuations and strong correlations in the fragmentation region of multiparticle production processes unaccessible to the present accelerators. (author) 12 refs, 3 figs

  13. Cosmic-Ray Detectors With Interdigitated Electrodes

    Science.gov (United States)

    Cunningham, Thomas J.; Mazed, Mohammed; Holtzman, Melinda J.; Fossum, Eric R.

    1995-01-01

    Detectors measure both positions of incidence and energies of incident charged particles. Stack of detector wafers intercept cosmic ray. Measure positions of incidence to determine cosmic-ray trajectory and charge generated within them (proportional to cosmic-ray energy dissipated within them). Interdigital electrode pattern repeated over many rows and columns on tops of detector wafers in stack. Electrode pattern defines pixels within which points of incidence of incident cosmic rays located.

  14. Cosmic Ray elimination using the Wavelet Transform

    Science.gov (United States)

    Orozco-Aguilera, M. T.; Cruz, J.; Altamirano, L.; Serrano, A.

    2009-11-01

    In this work, we present a method for the automatic cosmic ray elimination in a single CCD exposure using the Wavelet Transform. The proposed method can eliminate cosmic rays of any shape or size. With this method we can eliminate over 95% of cosmic rays in a spectral image.

  15. COSMIC RAY ELIMINATION USING THE WAVELET TRANSFORM

    Directory of Open Access Journals (Sweden)

    M. T. Orozco-Aguilera

    2009-01-01

    Full Text Available In this work, we present a method for the automatic cosmic ray elimination in a single CCD exposure using the Wavelet Transform. The proposed method can eliminate cosmic rays of any shape or size. With this method we can eliminate over 95% of cosmic rays in a spectral image.

  16. Neutralino Clumps and Cosmic Rays

    CERN Document Server

    Salati, P

    2007-01-01

    The halo of the Miky Way might contain numerous and dense substructures inside which the putative weakly interacting massive particles (suggested as the main constituent of the astronomical dark matter) would produce a stronger annihilation signal than in the smooth regions. The closer the nearest clump, the larger the positron and antiproton cosmic ray fluxes at the Earth. But the actual distribution of these substructures is not known. The predictions on the antimatter yields at the Earth are therefore affected by a kind of cosmic variance whose analysis is the subject of this contribution. The statistical tools to achieve that goal are presented and Monte Carlo simulations are compared to analytic results.

  17. Cosmic rays in a galactic breeze

    Science.gov (United States)

    Taylor, Andrew M.; Giacinti, Gwenael

    2017-01-01

    Motivated by the discovery of the nonthermal Fermi bubble features both below and above the Galactic plane, we investigate a scenario in which these bubbles are formed through galacto-centric outflow. Cosmic rays (CR) both diffusing and advecting within a galactic breeze outflow, interacting with the ambient gas present, give rise to γ -ray emission, providing an approximately flat surface brightness profile of this emission, as observed. Applying the same outflow profile further out within the disk, the resultant effects on the observable CR spectral properties are determined. A hardening in the spectra due to the competition of advective and diffusive propagation within a particular energy range is noted, even in the limiting case of equal CR diffusion coefficients in the disk and halo. It is postulated that this hardening effect may relate to the observed hardening feature in the CR spectrum at a rigidity of ≈200 GV .

  18. Cosmic Rays in a Galactic Breeze

    CERN Document Server

    Taylor, Andrew M

    2016-01-01

    Motivated by the discovery of the non-thermal Fermi bubble features both below and above the Galactic plane, we investigate a scenario in which these bubbles are formed through Galacto-centric outflow. Cosmic rays (CR) both diffusing and advecting within a Galactic breeze outflow, interacting with the ambient gas present, give rise to gamma-ray emission, providing an approximately flat surface brightness profile of this emission, as observed. Applying the same outflow profile further out within the disk, the resultant effects on the observable CR spectral properties are determined. A hardening in the spectra due to the competition of advective and diffusive propagation within a particular energy range is noted, even in the limiting case of equal CR diffusion coefficients in the disk and halo. It is postulated that this hardening effect may relate to the observed hardening feature in the CR spectrum at a rigidity of $\\approx 200$ GV.

  19. Cosmic Ray Electron Science with GLAST

    Energy Technology Data Exchange (ETDEWEB)

    Ormes, J.F.; /Denver U.; Moiseev, Alexander; /NASA, Goddard

    2007-10-17

    Cosmic ray electrons at high energy carry information about their sources, their diffusion in local magnetic fields and their interactions with the photon fields through which they travel. The spectrum of the particles is affected by inverse Compton losses and synchrotron losses, the rates of which are proportional to the square of the particle's energy making the spectra very steep. However, GLAST will be able to make unique and very high statistics measurements of electrons from {approx}20 to {approx}700 GeV that will allow us to search for anisotropies in arrival direction and spectral features associated with some dark matter candidates. Complementary information on electrons of still higher energy will be required to see effects of possible individual cosmic ray sources.

  20. Cosmic ray acceleration at modified shocks

    CERN Document Server

    Meli, A; Dimitrakoudis, S

    2007-01-01

    The non-linear back reaction of accelerated cosmic rays at the shock fronts, leads to the formation of a smooth precursor with a length scale corresponding to the diffusive scale of the energetic particles. Past works claimed that shocklets could be created in the precursor region of a specific shock width, which might energize few thermal particles to sufficient acceleration and furthermore this precursor region may act as confining large angle scatterer for very high energy cosmic rays. On the other hand, it has been shown that the smoothing of the shock front could lower the acceleration efficiency. These controversies motivated us to investigate numerically by Monte Carlo simulations the particle acceleration efficiency in oblique modified shocks. The results show flatter spectra compared to the spectra of the pressumed sharp discontinuity shock fronts. The findings are in accordance with theoretical predictions, since the scattering inside the precursor confines high energy particles to further scatterin...

  1. Cosmic rays and particle physics

    CERN Document Server

    Gaisser, Thomas K; Resconi, Elisa

    2016-01-01

    Fully updated for the second edition, this book introduces the growing and dynamic field of particle astrophysics. It provides an overview of high-energy nuclei, photons and neutrinos, including their origins, their propagation in the cosmos, their detection on Earth and their relation to each other. Coverage is expanded to include new content on high energy physics, the propagation of protons and nuclei in cosmic background radiation, neutrino astronomy, high-energy and ultra-high-energy cosmic rays, sources and acceleration mechanisms, and atmospheric muons and neutrinos. Readers are able to master the fundamentals of particle astrophysics within the context of the most recent developments in the field. This book will benefit graduate students and established researchers alike, equipping them with the knowledge and tools needed to design and interpret their own experiments and, ultimately, to address a number of questions concerning the nature and origins of cosmic particles that have arisen in recent resea...

  2. The Heliosphere as Seen in TeV Cosmic Rays

    Science.gov (United States)

    Zhang, Ming; Pogorelov, Nikolai

    2016-11-01

    Measurements from several cosmic-ray air shower experiments reveal that the anisotropy of TeV cosmic-ray flux does not agree with a dipole pattern commonly expected from the Compton-Getting effect or from the diffusion of cosmic rays in Galactic magnetic fields. TeV cosmic-ray anisotropy maps often show fine features, some of which are slightly time-dependent. Because the size of the heliosphere is larger than the gyroradius of TeV cosmic rays in the interstellar magnetic field, the electric and magnetic fields of the heliosphere may distort the pattern of cosmic-ray anisotropy that one would see in the local interstellar medium without the presence of the heliosphere. We have developed a method of mapping cosmic-ray anisotropy using Liouville's theorem. In this paper, we show how to use cosmic-ray anisotropy features to determine the direction of the local interstellar magnetic field, the hydrogen deflection plane, the size and shape of the heliotail, and the geometry of the heliosphere bow wave.

  3. Aerosols Produced by Cosmic Rays

    DEFF Research Database (Denmark)

    Enghoff, Martin Andreas Bødker

    , it will be possible to develop the experiment to cover additional processes involved in the route to cloud droplet formation. The experiment will be conducted at the Danish National Space Center where a clean room facility has been provided. It comprises a 7 m3 reaction chamber across which an electric field......Satellite observations have shown that the Earth’s cloud cover is strongly correlated with the galactic cosmic ray flux. While this correlation is indicative of a possible physical connection, there is currently no confirmation that a physical mechanism exists. We are therefore setting up...... mechanism linking cosmic rays to clouds and climate is currently speculative, there have been various suggestions of the role atmospheric ions may play; these involve any one of a number of processes from the nucleation of aerosols up to the collection processes of cloud droplets. We have chosen to start...

  4. Markov Stochastic Technique to Determine Galactic Cosmic Ray Sources Distribution

    Indian Academy of Sciences (India)

    Ashraf Farahat

    2010-06-01

    A new numerical model of particle propagation in the Galaxy has been developed, which allows the study of cosmic-ray production and propagation in 2D. The model has been used to solve cosmic ray diffusive transport equation with a complete network of nuclear interactions using the time backward Markov stochastic process by tracing the particles’ trajectories starting from the Solar System back to their sources in the Galaxy. This paper describes a further development of the model to calculate the contribution of various galactic locations to the production of certain cosmic ray nuclei observed at the Solar System.

  5. Cosmic rays as regulators of molecular cloud properties

    CERN Document Server

    Padovani, Marco; Galli, Daniele

    2014-01-01

    Cosmic rays are the main agents in controlling the chemical evolution and setting the ambipolar diffusion time of a molecular cloud. We summarise the processes causing the energy degradation of cosmic rays due to their interaction with molecular hydrogen, focusing on the magnetic effects that influence their propagation. Making use of magnetic field configurations generated by numerical simulations, we show that the increase of the field line density in the collapse region results in a reduction of the cosmic-ray ionisation rate. As a consequence the ionisation fraction decreases, facilitating the decoupling between the gas and the magnetic field.

  6. Charged Cosmic Rays and Neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Kachelrieß, M.

    2013-04-15

    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”.

  7. Radio data and synchrotron emission in consistent cosmic ray models

    CERN Document Server

    Bringmann, Torsten; Lineros, Roberto A

    2011-01-01

    We consider the propagation of electrons in phenomenological two-zone diffusion models compatible with cosmic-ray nuclear data and compute the diffuse synchrotron emission resulting from their interaction with galactic magnetic fields. We find models in agreement not only with cosmic ray data but also with radio surveys at essentially all frequencies. Requiring such a globally consistent description strongly disfavors both a very large (L>15 kpc) and small (L<1 kpc) effective size of the diffusive halo. This has profound implications for, e.g., indirect dark matter searches.

  8. New insights from cosmic gamma rays

    Science.gov (United States)

    Roland, Diehl

    2016-04-01

    The measurement of gamma rays from cosmic sources at ~MeV energies is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and their impacts on objects and phenomena throughout the universe. Gamma rays trace nuclear processes most directly, as they originate from nuclear transitions following radioactive decays or high-energy collisions with excitation of nuclei. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this astronomical window and is discussed here: Cosmic positrons are often produced from β-decays, thus also of nuclear physics origins. The nuclear reactions leading to radioactive isotopes occur inside stars and stellar explosions, which therefore constitute the main objects of such studies. In recent years, both thermonuclear and core-collapse supernova radioactivities have been measured though 56Ni, 56Co, and 44Ti lines, and a beginning has thus been made to complement conventional supernova observations with such measurements of the prime energy sources of supernova light created in their deep interiors. The diffuse radioactive afterglow of massive-star nucleosynthesis in gamma rays is now being exploited towards astrophysical studies on how massive stars feed back their energy and ejecta into interstellar gas, as part of the cosmic cycle of matter through generations of stars enriching the interstellar gas and stars with metals. Large interstellar cavities and superbubbles have been recognised to be the dominating structures where new massive-star ejecta are injected, from 26Al gamma-ray spectroscopy. Also, constraints on the complex interiors of stars derive from the ratio of 60Fe/26Al gamma rays. Finally, the puzzling bulge-dominated intensity distribution of positron annihilation gamma rays is measured in greater detail, but still not understood; a recent microquasar flare provided evidence that such objects may be prime sources for positrons in interstellar space, rather than

  9. Closing CMS to hunt cosmic rays

    CERN Multimedia

    Claudia Marcelloni

    2006-01-01

    Every second the Earth is bombarded by billions of cosmic rays and occasionally one of these cosmic particles will collide with the Earth's atmosphere generating a shower of particles known as an 'air shower'. This is similiar to the collisions and subsequent particle showers observed in accelerators such as the LHC. Here the CMS detector is closed so that systems can be tested using muon cosmic rays in the 'Cosmic Challenge'.

  10. Cosmic-Ray Injection from Star-Forming Regions.

    Science.gov (United States)

    Carlson, Eric; Profumo, Stefano; Linden, Tim

    2016-09-01

    At present, all physical models of diffuse Galactic γ-ray emission assume that the distribution of cosmic-ray sources traces the observed populations of either OB stars, pulsars, or supernova remnants. However, since H_{2}-rich regions host significant star formation and numerous supernova remnants, the morphology of observed H_{2} gas (as traced by CO line surveys) should also provide a physically motivated, high-resolution tracer for cosmic-ray injection. We assess the impact of utilizing H_{2} as a tracer for cosmic-ray injection on models of diffuse Galactic γ-ray emission. We employ state-of-the-art 3D particle diffusion and gas density models, along with a physical model for the star-formation rate based on global Schmidt laws. Allowing a fraction, f_{H_{2}}, of cosmic-ray sources to trace the observed H_{2} density, we find that a theoretically well-motivated value f_{H_{2}}∼0.20-0.25 (i) provides a significantly better global fit to the diffuse Galactic γ-ray sky and (ii) highly suppresses the intensity of the residual γ-ray emission from the Galactic center region. Specifically, in models utilizing our best global fit values of f_{H_{2}}∼0.20-0.25, the spectrum of the galactic center γ-ray excess is drastically affected, and the morphology of the excess becomes inconsistent with predictions for dark matter annihilation.

  11. Cosmic ray injection spectrum at the galactic sources

    Science.gov (United States)

    Lagutin, Anatoly; Tyumentsev, Alexander; Volkov, Nikolay

    The spectra of cosmic rays measured at Earth are different from their source spectra. A key to understanding this difference, being crucial for solving the problem of cosmic-ray origin, is the determination of how cosmic-ray (CR) particles propagate through the turbulent interstellar medium (ISM). If the medium is a quasi-homogeneous the propagation process can be described by a normal diffusion model. However, during a last few decades many evidences, both from theory and observations, of the existence of multiscale structures in the Galaxy have been found. Filaments, shells, clouds are entities widely spread in the ISM. In such a highly non-homogeneous (fractal-like) ISM the normal diffusion model certainly is not kept valid. Generalization of this model leads to what is known as "anomalous diffusion". The main goal of the report is to retrieve the cosmic ray injection spectrum at the galactic sources in the framework of the anomalous diffusion (AD) model. The anomaly in this model results from large free paths ("Levy flights") of particles between galactic inhomogeneities. In order to evaluate the CR spectrum at the sources, we carried out new calculation of the CR spectra at Earth. AD equation in terms of fractional derivatives have been used to describe CR propagation from the nearby (r≤1 kpc) young (t≤ 1 Myr) and multiple old distant (r > 1 kpc) sources. The assessment of the key model parameters have been based on the results of the particles diffusion in the cosmic and laboratory plasma. We show that in the framework of the anomalous diffusion model the locally observed basic features of the cosmic rays (difference between spectral exponents of proton, He and other nuclei, "knee" problem, positron to electron ratio) can be explained if the injection spectrum at the main galactic sources of cosmic rays has spectral exponent p˜ 2.85. The authors acknowledge support from The Russian Foundation for Basic Research grant No. 14-02-31524.

  12. Cosmic ray propagation in a diffusion model: a new estimation of the diffusion parameters and of the secondary antiprotons flux; Propagation des rayons cosmiques dans un modele de diffusion: une nouvelle estimation des parametres de diffusion et du flux d'antiprotons secondaires

    Energy Technology Data Exchange (ETDEWEB)

    Maurin, D

    2001-02-01

    Dark matter is present at numerous scale of the universe (galaxy, cluster of galaxies, universe in the whole). This matter plays an important role in cosmology and can not be totally explained by conventional physic. From a particle physic point of view, there exists an extension of the standard model - supersymmetry - which predicts under certain conditions the existence of new stable and massive particles, the latter interacting weakly with ordinary matter. Apart from direct detection in accelerators, various indirect astrophysical detection are possible. This thesis focuses on one particular signature: disintegration of these particles could give antiprotons which should be measurable in cosmic rays. The present study evaluates the background corresponding to this signal i. e. antiprotons produced in the interactions between these cosmic rays and interstellar matter. In particular, uncertainties of this background being correlated to the uncertainties of the diffusion parameter, major part of this thesis is devoted to nuclei propagation. The first third of the thesis introduces propagation of cosmic rays in our galaxy, emphasizing the nuclear reaction responsibles of the nuclei fragmentation. In the second third, different models are reviewed, and in particular links between the leaky box model and the diffusion model are recalled (re-acceleration and convection are also discussed). This leads to a qualitative discussion about information that one can infer from propagation of these nuclei. In the last third, we finally present detailed solutions of the bidimensional diffusion model, along with constrains obtained on the propagation parameters. The latter is applied on the antiprotons background signal and it concludes the work done in this thesis. The propagation code for nuclei and antiprotons used here has proven its ability in data analysis. It would probably be of interest for the analysis of the cosmic ray data which will be taken by the AMS experiment on

  13. Transition from Galactic to extragalactic cosmic rays and cosmic ray anisotropy

    Directory of Open Access Journals (Sweden)

    Sigl G.

    2013-06-01

    Full Text Available This talk based on results of ref. [1], where we constrain the energy at which the transition from Galactic to extragalactic cosmic rays occurs by computing the anisotropy at Earth of cosmic rays emitted by Galactic sources. Since the diffusion approximation starts to loose its validity for E/Z ≳ 10(16−17 eV, we propagate individual cosmic rays using Galactic magnetic field models and taking into account both their regular and turbulent components. The turbulent field is generated on a nested grid which allows spatial resolution down to fractions of a parsec. If the primary composition is mostly light or intermediate around E ∼ 1018 eV, the transition at the ankle is ruled out, except in the unlikely case of an extreme Galactic magnetic field with strength >10 μG. Therefore, the fast rising proton contribution suggested by KASCADE-Grande data between 1017 eV and 1018 eV should be of extragalactic origin. In case heavy nuclei dominate the flux at E > 1018 eV, the transition energy can be close to the ankle, if Galactic cosmic rays are produced by sufficiently frequent transients as e.g. magnetars.

  14. Cosmic ray physics goes to school

    CERN Multimedia

    2002-01-01

    With the help of a CERN physicist, German Schools bring the Largest Cosmic Ray Detector in Europe one step closer to reality   Eric Berthier and Robert Porret (CERN, ST/HM), Frej Torp and Christian Antfolk from the Polytechnics Arcada in Finland, and Karsten Eggert, physicist at CERN who initiated this project, during the installation of cosmic ray detectors in the Pays de Gex, at point 4. Niina Patrikainen and Frej Torp, Finnish students from Rovaniemi and Arcada Polytechnics, installing cosmic ray counters at the Fachhochschule in Duesseldorf. The science of cosmic ray detection is growing, literally. Cosmic rays, energetic particles from space, strike our planet all the time. They collide with the air molecules in our upper atmosphere and initiate large showers of elementary particles (mainly electrons, photons, hadrons and muons) which rain down upon the earth. The shower size and the particle density in the showers reflect the initial energy of the cosmic ray particle, a detail which makes d...

  15. Cosmic-ray Acceleration and Propagation

    CERN Document Server

    Caprioli, Damiano

    2015-01-01

    The origin of cosmic rays (CRs) has puzzled scientists since the pioneering discovery by Victor Hess in 1912. In the last decade, however, modern supercomputers have opened a new window on the processes regulating astrophysical collisionless plasmas, allowing the study of CR acceleration via first-principles kinetic simulations. At the same time, a new-generation of X-ray and $\\gamma$-ray telescopes has been collecting evidence that Galactic CRs are accelerated in the blast waves of supernova remnants (SNRs). I present state-of-the-art particle-in-cells simulations of non-relativistic shocks, in which ion and electron acceleration efficiency and magnetic field amplification are studied in detail as a function of the shock parameters. I then discuss the theoretical and observational counterparts of these findings, comparing them with predictions of diffusive shock acceleration theory and with multi-wavelength observations of young SNRs. I especially outline some major open questions, such as the possible cause...

  16. On the Long-Term Variation of Galactic Cosmic Rays: Convection-Diffusion and Drift Modulations in the Heliosphere, Expected Radiation Hazard

    Science.gov (United States)

    Dorman, Lev

    On the basis of results obtained in our investigations of CR-SA hysteresis effects we determine the dimension of Heliosphere (modulation region), radial diffusion coefficient and other param-eters of convection-diffusion and drift mechanisms of cosmic ray (CR) long term variation in dependence of particles energy, level of solar activity (SA) and general solar magnetic field. This important information we obtain on the basis of CR and SA data in the past taking into account the theory of convection-diffusion and drift global modulation of galactic CR in the Heliosphere. By using these results and published regularly elsewhere predictions of expected sunspot number variation in near future and prediction of future next SA cycle we may made prediction of expected in near future (up to 10-12 years) long-term CR intensity variation. From other hand, we use estimated properties of connection between CR intensity long-term variation and some part of global climate change, controlled by solar activity through CR. We show that by this way we may made prediction of expected in near future (up to 10-12 years) radiation hazard from galactic CR in interplanetary space at different distances from the Sun (what is important for space probes and long-term missions to Mars and other planets and their satellites) and long-living objects on different orbits in the Earth's magnetosphere, as well as in the Earth's atmosphere (e.g. for airplanes at altitude about 10 km). Let us underline that in the last two cases become important to take into account also expected long-term changes in the planetary distribution of cutoff rigidities, which also influenced on observed galactic CR intensity, and corresponding radiation hazard.

  17. ACORDE - A Cosmic Ray Detector for ALICE

    CERN Document Server

    INSPIRE-00247175; Pagliarone, C.

    2006-01-01

    ACORDE, the ALICE COsmic Ray DEtector is one of the ALICE detectors, presently under construction. It consists of an array of plastic scintillator counters placed on the three upper faces of the ALICE magnet. This array will act as Level 0 cosmic ray trigger and, together with other ALICE sub-detectors, will provide precise information on cosmic rays with primary energies around $10^{15-17}$ eV. In this paper we will describe the ACORDE detector, trigger design and electronics.

  18. Cosmic rays, clouds, and climate

    DEFF Research Database (Denmark)

    Marsh, N.; Svensmark, Henrik

    2000-01-01

    in the Earth's radiation budget through trapping outgoing radiation and reflecting incoming radiation. If a physical link between these two features can be established, it would provide a mechanism linking solar activity and Earth's climate. Recent satellite observations have further revealed a correlation...... between cosmic ray flux and low cloud top temperature. The temperature of a cloud depends on the radiation properties determined by its droplet distribution. Low clouds are warm (> 273 K) and therefore consist of liquid water droplets. At typical atmospheric supersaturations (similar to1%) a liquid cloud...

  19. International Conference on Cosmic Rays

    CERN Multimedia

    W.O. LOCK

    1964-01-01

    Towards the end of last year the 8th International conference on cosmic rays, held under the auspices of the International Union of Pure and Applied Physics (I.U.P.A.P.) and the Department of Atomic Energy of the Government of India, was held at Jaipur, India. Among the participants was W.O. Lock, head of CERN's Emulsion Group, who gave an invited talk on recent work in the field of what is normally known as high-energy physics — though in the context of this conference such energies seem quite low. In this article, Dr. Lock gives a general review of the conference and of the subjects discussed.

  20. Ground level cosmic ray observations

    Energy Technology Data Exchange (ETDEWEB)

    Stephens, S.A. [Tata Institute of Fundamental Research, Bombay (International Commission on Radiation Units and Measurements); Grimani, C.; Brunetti, M.T.; Codino, A. [Perugia Univ. (Italy)]|[INFN, Perugia (Italy); Papini, P.; Massimo Brancaccio, F.; Piccardi, S. [Florence Univ. (Italy)]|[INFN, Florence (Italy); Basini, G.; Bongiorno, F. [INFN, Laboratori Nazionali di Frascati, Rome (Italy); Golden, R.L. [New Mexico State Univ., Las Cruces, NM (United States). Particle Astrophysics Lab.; Hof, M. [Siegen Univ. (Germany). Fachbereich Physik

    1995-09-01

    Cosmic rays at ground level have been collected using the NMSU/Wizard - MASS2 instrument. The 17-hr observation run was made on September 9. 1991 in Fort Sumner, New Mexico, Usa. Fort Sumner is located at 1270 meters a.s.l., corresponding to an atmospheric depth of about 887 g/cm{sup 2}. The geomagnetic cutoff is 4.5 GV/c. The charge ratio of positive and negative muons and the proton to muon ratio have been determined. These observations will also be compared with data collected at a higher latitude using the same basic apparatus.

  1. The Cosmic Ray Lepton Puzzle

    CERN Document Server

    Brun, Pierre; Cirelli, Marco; Moulin, Emmanuel; Glicenstein, Jean-Francois; Iocco, Fabio; Pieri, Lidia

    2010-01-01

    Recent measurements of cosmic ray electrons and positrons by PAMELA, ATIC, Fermi and HESS have revealed interesting excesses and features in the GeV-TeV range. Many possible explanations have been suggested, invoking one or more nearby primary sources such as pulsars and supernova remnants, or dark matter. Based on the output of the TANGO in PARIS --Testing Astroparticle with the New GeV/TeV Observations in Positrons And electRons : Identifying the Sources-- workshop held in Paris in May 2009, we review here the latest experimental results and we discuss some virtues and drawbacks of the many theoretical interpretations proposed so far.

  2. Dark Matter detection via lepton cosmic rays

    CERN Document Server

    Lineros, Roberto A

    2010-01-01

    Recent observations of lepton cosmic rays, coming from the PAMELA and FERMI experiments, have pushed our understanding of the interstellar medium and cosmic rays sources to unprecedented levels. The imprint of dark matter on lepton cosmic rays is the most exciting explanation of both PAMELA's positron excess and FERMI's total flux of electrons. Alternatively, supernovae are astrophysical objects with the same potential to explain these observations. In this work, we present an updated study of the astrophysical sources of lepton cosmic rays and the possible trace of a dark matter signal on the positron excess and total flux of electrons.

  3. CORRELATIVE ANALYSIS OF COSMIC RAY INTENSITY AND SOLAR ACTIVITY PARAMETERS

    Directory of Open Access Journals (Sweden)

    M. ROY

    2014-02-01

    Full Text Available Incoming cosmic ray shows significant intensity modulation in association with different solar geo parameters during their passage through heliosphere. Cosmic ray intensity is found anticorrelated with solar activity parameters. Using pressure corrected data of Mcmurdo neutron monitor, modulation of cosmic ray is analyzed covering solar cycles 21, 22, 23 and 24 (from 1976 to 2013. Negative and high correlations are obtained with some time lag for most of the solar parameters. Difference in shapes of hysteresis curves CRI~SSN, CRI~SRF. CRI~CI and CRI~FI for odd and even cycles pointed out that different mechanisms convection and diffusion are the dominating factors to drift cosmic ray particles.

  4. Cosmological Simulations of Dwarf Galaxies with Cosmic Ray Feedback

    CERN Document Server

    Chen, Jingjing; Salem, Munier

    2016-01-01

    We perform zoom-in cosmological simulations of a suite of dwarf galaxies, examining the impact of cosmic-rays generated by supernovae, including the effect of diffusion. We first look at the effect of varying the uncertain cosmic ray parameters by repeatedly simulating a single galaxy. Then we fix the comic ray model and simulate five dwarf systems with virial masses range from 8-30 $\\times 10^{10}$ Msun. We find that including cosmic ray feedback (with diffusion) consistently leads to disk dominated systems with relatively flat rotation curves and constant star formation rates. In contrast, our purely thermal feedback case results in a hot stellar system and bursty star formation. The CR simulations very well match the observed baryonic Tully-Fisher relation, but have a lower gas fraction than in real systems. We also find that the dark matter cores of the CR feedback galaxies are cuspy, while the purely thermal feedback case results in a substantial core.

  5. The B/C and sub-Iron/Iron Cosmic ray ratios - further evidence in favor of the spiral arm diffusion model

    CERN Document Server

    Benyamin, David; Piran, Tsvi; Shaviv, Nir j

    2016-01-01

    The Boron to Carbon (B/C) and sub-Fe/Fe ratios provides an important clue on Cosmic Ray (CR) propagation within the Galaxy. These ratios estimate the grammage that the CR path as they propagate from their sources to Earth. Attempts to explain these ratios within the standard CR propagation models require ad hoc modifications and even with those these models necessitate inconsistent grammages to explain both ratios. As an alternative, physically motivated model, we have proposed that CR originate preferably within the galactic spiral arms. CR propagation from dynamic spiral arms has important imprints on various secondary to primary ratios, such as the B/C ratio and the positron fraction. We use our spiral arm diffusion model with the spallation network extended up to Nickel to calculate the sub-Fe/Fe ratio. We show that without any additional parameters the spiral arm model consistently explains both ratios with the same grammage, providing further evidence in favor of this model.

  6. Cosmic ray physics with ACORDE at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Pagliarone, C [Universita degli Studi di Cassino and INFN Pisa, Largo B. Pontecorvo, 3 - Pisa (Italy); Fernandez-Tellez, A [Benemerita Universidad Autonoma de Puebla (BUAP), Puebla (Mexico)], E-mail: pagliarone@fnal.gov

    2008-05-15

    The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2{center_dot}10{sup 10} to 2{center_dot} 10{sup 12} eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10{sup 15} to 10{sup 17} eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.

  7. Cosmic Ray Physics with ACORDE at LHC

    CERN Document Server

    Pagliarone, C.

    2008-01-01

    The use of large underground high-energy physics experiments, for comic ray studies, have been used, in the past, at CERN, in order to measure, precisely, the inclusive cosmic ray flux in the energy range from 2x10^10 - 2x10^12 eV. ACORDE, ALICE Cosmic Rays DEtector, will act as Level 0 cosmic ray trigger and, together with other ALICE apparatus, will provide precise information on cosmic rays with primary energies around 10^15 - 10^17 eV. This paper reviews the main detector features, the present status, commissioning and integration with other apparatus. Finally, we discuss the ACORDE-ALICE cosmic ray physics program.

  8. Cosmic Rays and Stochastic Magnetic Reconnection in the Heliotail

    CERN Document Server

    Desiati, P

    2012-01-01

    Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by the nearest and youngest ones. Transport to Earth through the interstellar medium is expected to affect the cosmic ray properties as well. However, the observed anisotropy of TeV cosmic rays and its energy dependence cannot be explained with diffusion models of particle propagation in the Galaxy. Within a distance of a few parsec, diffusion regime is not valid and particles with energy below about 100 TeV must be influenced by the heliosphere and its elongated tail. The observation of a highly significant localized excess region of cosmic rays from the apparent direction of the downstream interstellar flow at 1-10 TeV energies might provide the first experimental evidence that the heliotail can affect the transport of energetic particles. In particular, TeV cosmic rays propa...

  9. Some Aspects of Galactic Cosmic Ray Acceleration

    CERN Document Server

    Butt, Y M

    2003-01-01

    I give a synopsis of two aspects of the Galactic Cosmic Ray (GCR) acceleration problem: the importance of the medium energy gamma-ray window, and several specific astrophysical sources which merit further investigation.

  10. History of cosmic ray research in Finland

    Science.gov (United States)

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

    2009-11-01

    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.

  11. Cosmic-ray acceleration in supernova remnants

    NARCIS (Netherlands)

    Helder, E.A.

    2010-01-01

    Supernovae are among the most energetic events in the Universe. During the event, they expel their material with enormous speeds into the surroundings. In addition, supernovae are thought to transfer a sizable fraction of their energy into just a few particles: cosmic rays. These cosmic rays acquire

  12. The Pierre Auger Cosmic Ray Observatory

    NARCIS (Netherlands)

    Aab, A.; Abreu, P.; Aglietta, M.; Ahn, E. J.; Al Samarai, I.; Albert, J. N.; Albuquerque, I. F. M.; Allekotte, I.; Allen, J.; Allison, P.; Almela, A.; Alvarez Castillo, J.; Alvarez-Muniz, J.; Batista, R. Alves; Ambrosio, M.; Aminaei, A.; Anchordoqui, L.; Andringa, S.; Aramo, C.; Aranda, V. M.; Argiro, S.; Arisaka, K.; Arneodo, F.; Arqueros, F.; Asch, T.; Asorey, H.; Assis, P.; Aublin, J.; Ave, M.; Avenier, M.; Avila, G.; Awal, N.; Badescu, A. M.; Balzer, M.; Barber, K. B.; Barbosa, A.; Barenthien, N.; Barkhausen, M.; Baeuml, J.; Baus, C.; Beatty, J.; Becker, K. H.; Bellido, J. A.; BenZvi, S.; Berat, C.; Bergmann, T.; Bertaina, M. E.; Biermann, P. L.; Bilhaut, R.; Billoir, P.; Blaes, S. G.; Blanco, M.; Bleve, C.; Bluemer, H.; Bohacova, M.; Bolz, H.; Boncioli, D.; Bonifaz, C.; Bonino, R.; Boratav, M.; Borodai, N.; Bracci, F.; Brack, J.; Brancus, I.; Bridgeman, A.; Brogueira, P.; Brown, W. C.; Buchholz, P.; Bueno, A.; Buitink, S.; Buscemi, M.; Caballero-Mora, K. S.; Caccianiga, B.; Caccianiga, L.; Camin, D.; Candusso, M.; Caramete, L.; Caruso, R.; Castellina, A.; Castera, A.; Cataldi, G.; Cazon, L.; Cester, R.; Chavez, A. G.; Chiavassa, A.; Chinellato, J. A.; Chiosso, M.; Chudoba, J.; Cilmo, M.; Clark, P. D. J.; Clay, R. W.; Cocciolo, G.; Colalillo, R.; Coleman, A.; Collica, L.; Colombo, E.; Colonges, S.; Coluccia, M. R.; Conceicao, R.; Contreras, F.; Cooper, M. J.; Coppens, J.; Cordier, A.; Courty, B.; Coutu, S.; Covault, C. E.; Cronin, J.; Curutiu, A.; Dallier, R.; Daniel, B.; Dasso, S.; Daumiller, K.; Dawson, B. R.; de Almeida, R. M.; De Domenico, M.; De Donato, C.; de Jong, S. J.; de Mello Neto, J. R. T.; De Mitri, I.; de Oliveira, J.; de Souza, V.; de Vries, K. D.; del Peral, L.; Deligny, O.; Dembinski, H.; Dhital, N.; Di Giulio, C.; Di Matteo, A.; Diaz, J. C.; Diaz Castro, M. L.; Diogo, F.; Dobrigkeit, C.; Docters, W.; D'Olivo, C.; Dolron, P.; Dorofeev, A.; Hasankiadeh, Q. Dorosti; Dova, M. T.; D'Urso, D.; Ebr, J.; Engel, R.; Epele, L. N.; Erdmann, M.; Erfani, M.; Escobar, C. O.; Espadanal, J.; Etchegoyen, A.; Facal San Luis, P.; Falcke, H.; Fang, K.; Farrar, G.; Fauth, A. C.; Fazzini, N.; Ferguson, A. P.; Fernandes, M.; Ferrero, A.; Fick, B.; Figueira, J. M.; Filevich, A.; Filipcic, A.; Fox, B. D.; Fraenkel, E. D.; Fratu, O.; Freire, M. M.; Froehlich, U.; Fuchs, B.; Fulgione, W.; Fujii, T.; Garcia, B.; Garcia-Gamez, D.; Garcia-Pinto, D.; Garilli, G.; Gascon Bravo, A.; Gate, F.; Geenen, H.; Gemmeke, H.; Genolini, B.; Ghia, P. L.; Giaccari, U.; Giammarchi, M.; Gibbs, K.; Giller, M.; Giudice, N.; Glaser, C.; Glass, H.; Gomez Berisso, M.; Gomez Vitale, P. F.; Goncalves, P.; Gonzalez, J. G.; Gonzalez, N.; Gookin, B.; Gora, D.; Gordon, J.; Gorgi, A.; Gorham, P.; Gotink, W.; Gouffon, P.; Grebe, S.; Griffith, N.; Grillo, A. F.; Grubb, T. D.; Grygar, J.; Guardone, N.; Guarino, F.; Guedes, G. P.; Guglielmi, L.; Habraken, R.; Hampel, M. R.; Hansen, P.; Harari, D.; Harmsma, S.; Harrison, T. A.; Hartmann, S.; Harton, J. L.; Haungs, A.; Hebbeker, T.; Heck, D.; Heimann, P.; Herve, A. E.; Hill, G. C.; Hojvat, C.; Hollon, N.; Holt, E.; Homola, P.; Hoerandel, J. R.; Horneffer, A.; Horvat, M.; Horvath, P.; Hrabovsky, M.; Huber, D.; Hucker, H.; Huege, T.; Iarlori, M.; Insolia, A.; Isar, P. G.; Jandt, I.; Jansen, S.; Jarne, C.; Johnsen, J. A.; Josebachuili, M.; Kaeaepae, A.; Kambeitz, O.; Kampert, K. H.; Kasper, P.; Katkov, I.; Kegl, B.; Keilhauer, B.; Keivani, A.; Kelley, J.; Kemp, E.; Kieckhafer, R. M.; Klages, H. O.; Kleifges, M.; Kleinfeller, J.; Knapp, J.; Kopmann, A.; Krause, R.; Krohm, N.; Kroemer, O.; Kuempel, D.; Kunka, N.; LaHurd, D.; Latronico, L.; Lauer, R.; Lauscher, M.; Lautridou, P.; Le Coz, S.; Leao, M. S. A. B.; Lebrun, D.; Lebrun, P.; Leigui de Oliveira, M. A.; Letessier-Selvon, A.; Lhenry-Yvon, I.; Link, K.; Lopez, R.; Lopez Casado, A.; Louedec, K.; Lozano Bahilo, J.; Lu, L.; Lucero, A.; Ludwig, M.; Malacari, M.; Maldera, S.; Mallamaci, M.; Maller, J.; Mandat, D.; Mantsch, P.; Mariazzi, A. G.; Marin, V.; Maris, I. C.; Marsella, G.; Martello, D.; Martina, L.; Martinez, H.; Martinez, N.; Martinez Bravo, O.; Martraire, D.; Masias Meza, J. J.; Mathes, H. J.; Mathys, S.; Matthews, J.; Matthews, J. A. J.; Matthiae, G.; Maurel, D.; Maurizio, D.; Mayotte, E.; Mazur, P. O.; Medina, C.; Medina-Tanco, G.; Meissner, R.; Melissas, M.; Mello, V. B. B.; Melo, D.; Menichetti, E.; Menshikov, A.; Messina, S.; Meyhandan, R.; Micanovic, S.; Micheletti, M. I.; Middendorf, L.; Minaya, I. A.; Miramonti, L.; Mitrica, B.; Molina-Bueno, L.; Mollerach, S.; Monasor, M.; Montanet, F.; Morello, C.; Mostafa, M.; Moura, C. A.; Muller, M. A.; Mueller, G.; Mueller, S.; Muenchmeyer, M.; Mussa, R.; Navarra, G.; Navas, S.; Necesal, P.; Nellen, L.; Nelles, A.; Neuser, J.; Nguyen, P. H.; Nicotra, D.; Niechciol, M.; Niemietz, L.; Niggemann, T.; Nitz, D.; Nosek, D.; Novotny, V.; Nozka, L.; Ochilo, L.; Ohnuki, T.; Oikonomou, F.; Olinto, A.; Oliveira, M.; Olmos-Gilbaja, V. M.; Pacheco, N.; PakkSelmi-Dei, D.; Palatka, M.; Pallotta, J.; Palmieri, N.; Papenbreer, P.; Parente, G.; Parra, A.; Patel, M.; Paul, T.; Pech, M.; Pekala, J.; Pelayo, R.; Pepe, I. M.; Perrone, L.; Petermann, E.; Peters, C.; Petrera, S.; Petrinca, P.; Petrov, Y.; Phuntsok, J.; Piegaia, R.; Pierog, T.; Pieroni, P.; Pimenta, M.; Pirronello, V.; Platino, M.; Plum, M.; Porcelli, A.; Porowski, C.; Porter, T.; Pouryamout, J.; Pouthas, J.; Prado, R. R.; Privitera, P.; Prouza, M.; Pryke, C. L.; Purrello, V.; Quel, E. J.; Querchfeld, S.; Quinn, S.; Randriatoamanana, R.; Rautenberg, J.; Ravel, O.; Ravignani, D.; Revenua, B.; Ridky, J.; Risse, M.; Ristori, P.; Rizi, V.; Robbins, S.; Roberts, M.; Rodrigues de Carvalho, W.; Rodriguez Fernandez, G.; Rodriguez Rojo, J.; Rodriguez-Frias, M. D.; Rogozin, D.; Ros, G.; Rosado, J.; Rossler, T.; Roth, M.; Roulet, E.; Rovero, A. C.; Saffi, S. J.; Saftoiu, A.; Salamida, F.; Salazar, H.; Saleh, A.; Salesa Greus, F.; Salina, G.; Sanchez, F.; Sanchez-Lucas, P.; Santo, C. E.; Santos, E.; Santos, E. M.; Sarazin, F.; Sarkar, B.; Sarmento, R.; Sato, R.; Scharf, N.; Scherini, V.; Schieler, H.; Schiffer, P.; Schmidt, A.; Schmidt, D.; Scholten, O.; Schoorlemmer, H.; Schovanek, P.; Schreuder, F.; Schroeder, F. G.; Schulz, A.; Schulz, J.; Schuessler, F.; Schumacher, J.; Sciutto, S. J.; Segreto, A.; Sequeiros, G.; Settimo, M.; Shadkam, A.; Shellard, R. C.; Sidelnik, I.; Sigl, G.; Sima, O.; Smialkowski, A.; Smida, R.; Smith, A. G. K.; Snow, G. R.; Sommers, P.; Sorokin, J.; Speelman, R.; Spinka, H.; Squartini, R.; Srivastava, Y. N.; Stanic, S.; Stapleton, J.; Stasielak, J.; Stephan, M.; Stutz, A.; Suarez, F.; Suomijaervi, T.; Supanitsky, A. D.; Sutherland, M. S.; Sutter, M.; Swain, J.; Szadkowski, Z.; Szuba, M.; Taborda, O. A.; Tapia, A.; Tcherniakhovski, D.; Tepe, A.; Theodoro, V. M.; Timmermans, C.; Tkaczyk, W.; Todero Peixoto, C. J.; Toma, G.; Tomankova, L.; Tome, B.; Tonachini, A.; Torralba Elipe, G.; Torres Machado, D.; Travnicek, P.; Trovato, E.; Trung, T. N.; Tunnicliffe, V.; Tusi, E.; Ulrich, R.; Unger, M.; Urban, M.; Valdes Galicia, J. F.; Valino, I.; Valore, L.; van Aar, G.; van Bodegom, P.; van den Berg, A. M.; van Velzen, S.; van Vliet, A.; Varela, E.; Vargas Cardenas, B.; Varnav, D. M.; Varner, G.; Vasquez, R.; Vazquez, J. R.; Vazquez, R. A.; Veberic, D.; Verkooijen, H.; Verzi, V.; Vicha, J.; Videla, M.; Villasenor, L.; Vitali, G.; Vlcek, B.; Vorenholt, H.; Vorobiov, S.; Voyvodic, L.; Wahlberg, H.; Wainberg, O.; Walker, P.; Walz, D.; Watson, A. A.; Weber, M.; Weidenhaupt, K.; Weindl, A.; Werner, F.; Westerhoff, S.; Widom, A.; Wiebusch, C.; Wiencke, L.; Wijnen, T.; Wilczynska, B.; Wilczynski, H.; Wild, N.; Winchen, T.; Wittkowski, D.; Woerner, G.; Wundheiler, B.; Wykes, S.; Yamamoto, T.; Yapici, T.; Yuan, G.; Yushkov, A.; Zamorano, B.; Zas, E.; Zavrtanik, D.; Zavrtanik, M.; Zepeda, A.; Zhou, J.; Zhu, Y.; Silva, M. Zimbres; Zimmermann, B.; Ziolkowski, M.; Zuccarello, F.

    2015-01-01

    The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above 10(17) eV and to study the interactions of these, the most energetic par

  13. High energy physics in cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-02-07

    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.

  14. Anisotropy and Corotation of Galactic Cosmic Rays

    CERN Document Server

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

    2006-01-01

    The intensity of Galactic cosmic rays is nearly isotropic because of the influence of magnetic fields in the Milky Way. Here, we present two-dimensional high-precision anisotropy measurement for energies from a few to several hundred teraelectronvolts (TeV), using the large data sample of the Tibet Air Shower Arrays. Besides revealing finer details of the known anisotropies, a new component of Galactic cosmic ray anisotropy in sidereal time is uncovered around the Cygnus region direction. For cosmic-ray energies up to a few hundred TeV, all components of anisotropies fade away, showing a corotation of Galactic cosmic rays with the local Galactic magnetic environment. These results have broad implications for a comprehensive understanding of cosmic rays, supernovae, magnetic fields, and heliospheric and Galactic dynamic environments.

  15. Heavy precipitation episodes and cosmic rays variation

    Directory of Open Access Journals (Sweden)

    A. Mavrakis

    2006-01-01

    Full Text Available In this paper an attempt is made to investigate the possible temporal correlation between heavy precipitation episodes and cosmic rays' activity, on various time scales. Cosmic rays measurements are sparse and cover less extended periods than those of precipitation. Precipitation is largely influenced by local climatic and even physiographic conditions, while cosmic rays' distribution is far more uniform over an area. Thus, in an effort to cover a larger range of climatic characteristics, each cosmic rays station was correlated with several nearby precipitation stations. Selected statistical methods were employed for the data processing. The analysis was preformed on annual, seasonal, monthly and daily basis whenever possible. Wet and dry regions and/or seasons seem to present a different response of precipitation to cosmic rays variations. Also Forbush decreases in most cases will not lead to heavy precipitation, yet this might be sensitive to precipitable water availability.

  16. Cosmic Ray Removal in Fiber Spectroscopic Image

    Science.gov (United States)

    Bai, Zhongrui; Zhang, Haotong; Yuan, Hailong; Carlin, Jeffrey L.; Li, Guangwei; Lei, Yajuan; Dong, Yiqiao; Yang, Huiqin; Zhao, Yongheng; Cao, Zihuang

    2017-02-01

    Single-exposure spectra in large spectral surveys are valuable for time domain studies such as stellar variability, but there is no available method to eliminate cosmic rays for single-exposure, multi-fiber spectral images. In this paper, we describe a new method to detect and remove cosmic rays in multi-fiber spectroscopic single exposures. Through the use of two-dimensional profile fitting and a noise model that considers the position-dependent errors, we successfully detect as many as 80% of the cosmic rays and correct the cosmic ray polluted pixels to an average accuracy of 97.8%. Multiple tests and comparisons with both simulated data and real LAMOST data show that the method works properly in detection rate, false detection rate, and validity of cosmic ray correction.

  17. Status of cosmic-ray antideuteron searches

    CERN Document Server

    von Doetinchem, P; Boggs, S; Bufalino, S; Dal, L; Donato, F; Fornengo, N; Fuke, H; Grefe, M; Hailey, C; Hamilton, B; Ibarra, A; Mitchell, J; Mognet, I; Ong, R A; Pereira, R; Perez, K; Putze, A; Raklev, A; Salati, P; Sasaki, M; Tarle, G; Urbano, A; Vittino, A; Wild, S; Xue, W; Yoshimura, K

    2015-01-01

    The precise measurement of cosmic-ray antiparticles serves as important means for identifying the nature of dark matter. Recent years showed that identifying the nature of dark matter with cosmic-ray positrons and higher energy antiprotons is difficult, and has lead to a significantly increased interest in cosmic-ray antideuteron searches. Antideuterons may also be generated in dark matter annihilations or decays, offering a potential breakthrough in unexplored phase space for dark matter. Low-energy antideuterons are an important approach because the flux from dark matter interactions exceeds the background flux by more than two orders of magnitude in the low-energy range for a wide variety of models. This review is based on the "dbar14 - dedicated cosmic-ray antideuteron workshop", which brought together theorists and experimentalists in the field to discuss the current status, perspectives, and challenges for cosmic-ray antideuteron searches and discusses the motivation for antideuteron searches, the theor...

  18. Cosmic Ray transport in turbulent magnetic field

    CERN Document Server

    Yan, Huirong

    2013-01-01

    Cosmic ray (CR) transport and acceleration is determined by the properties of magnetic turbulence. Recent advances in MHD turbulence call for revisions in the paradigm of cosmic ray transport. We use the models of magnetohydrodynamic turbulence that were tested in numerical simulation, in which turbulence is injected at large scale and cascades to to small scales. We shall address the issue of the transport of CRs, both parallel and perpendicular to the magnetic field. We shall demonstrate compressible fast modes are dominant cosmic ray scatterer from both quasilinear and nonlinear theories. We shall also show that the self-generated wave growth by CRs are constrained by preexisting turbulence and discuss the process in detail in the context of shock acceleration at supernova remnants and their implications. In addition, we shall dwell on the nonlinear growth of kinetic gyroresonance instability of cosmic rays induced by large scale compressible turbulence. This gyroresonance of cosmic rays on turbulence is d...

  19. The Galactic Center: A Petaelectronvolt Cosmic-ray Acceleration Factory

    Science.gov (United States)

    Guo, Yi-Qing; Tian, Zhen; Wang, Zhen; Li, Hai-Jin; Chen, Tian-Lu

    2017-02-01

    The multiteraelectronvolt γ-rays from the galactic center (GC) have a cutoff at tens of teraelectronvolts, whereas the diffuse emission has no such cutoff, which is regarded as an indication of petaelectronvolt proton acceleration by the HESS experiment. It is important to understand the inconsistency and study the possibility that petaelectronvolt cosmic-ray acceleration could account for the apparently contradictory point and diffuse γ-ray spectra. In this work, we propose that the cosmic rays are accelerated up to greater than petaelectronvolts in the GC. The interaction between cosmic rays and molecular clouds is responsible for the multiteraelectronvolt γ-ray emissions from both the point and diffuse sources today. Enhanced by the small volume filling factor (VFF) of the clumpy structure, the absorption of the γ-rays leads to a sharp cutoff spectrum at tens of teraelectronvolts produced in the GC. Away from the GC, the VFF grows, and the absorption enhancement becomes negligible. As a result, the spectra of γ-ray emissions for both point and diffuse sources can be successfully reproduced under such a self-consistent picture. In addition, a “surviving tail” at ∼100 TeV is expected from the point source, which can be observed by future projects CTA and LHAASO. Neutrinos are simultaneously produced during proton-proton (PP) collision. With 5–10 years of observations, the KM3Net experiment will be able to detect the petaelectronvolt source according to our calculation.

  20. Cosmic Ray Small Scale Anisotropies and Local Turbulent Magnetic Fields

    CERN Document Server

    López-Barquero, Vanessa; Xu, S; Desiati, P; Lazarian, A

    2015-01-01

    Cosmic ray anisotropy is observed in a wide energy range and at different angular scales by a variety of experiments. However, a comprehensive and satisfactory explanation has been elusive for over a decade now. The arrival distribution of cosmic rays on Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium and small angular scale structure could be an effect of non diffusive propagation of cosmic rays in perturbed magnetic fields. In particular, a possible explanation of the observed small scale anisotropy observed at TeV energy scale, may come from the effect of particle scattering in turbulent magnetized plasmas. We perform numerical integration of test particle trajectories in low-$\\beta$ compressible mag...

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

    Science.gov (United States)

    Kusenko, Alexander

    2013-12-01

    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.

  2. Cosmic rays: a review for astrobiologists.

    Science.gov (United States)

    Ferrari, Franco; Szuszkiewicz, Ewa

    2009-05-01

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

  3. The anisotropy of multi-TeV cosmic rays

    Science.gov (United States)

    Dingus, Brenda

    2013-02-01

    The arrival directions of cosmic rays will be isotropized by the deflection of these charged particles in the Galactic magnetic fields. For example, a 10 TeV proton in a typical Galactic field of 2 micro Gauss has a gyroradius of only 0.005 parsec (=1000 AU) which is much smaller than the distance to any postulated sources. However, observations of TeV cosmic rays by Milagro, Tibet III, ARGO, and IceCube, show anisotropies on both large and small angular scales. These observations require the detection of large numbers of cosmic rays because the anisotropies are less than a few parts in 1000. The large angular scale anisotropies, such as a dipole, could point to diffusion from a nearby source, but the smaller scale anisotropies of extent ~10 degrees are much more difficult to explain. Possibilities that have been explored in the literature include magnetic funneling of cosmic rays from nearby sources and acceleration by magnetic reconnection in the heliosphere's magnetotail. No matter what the mechanism, these observations provide new information about cosmic ray production, nearby magnetic fields, and how the cosmic rays observed at Earth are affected by their propagation.

  4. Galactic cosmic-ray modulation near the heliopause

    Energy Technology Data Exchange (ETDEWEB)

    Guo, X.; Florinski, V. [Center for Space Plasma and Aeronomic Research, University of Alabama, Huntsville, AL 35899 (United States)

    2014-09-20

    We investigate the modulation of galactic cosmic rays in the inner and outer heliosheaths using three-dimensional numerical simulations. The model is based on the Parker transport equation integrated using a stochastic phase-space trajectory method. Integration is performed on a plasma background obtained from a global three-dimensional magnetohydrodynamic simulations. Our results predict a negligible amount of modulation in the outer heliosheath because of weak scattering of cosmic ray ions owing to very low levels of magnetic fluctuation power at wavenumbers relevant to the transport of cosmic rays with MeV to GeV energies. This means that the heliopause may be treated as a Dirichlet-type boundary for the purpose of energetic particle modeling. We present models with and without drift velocity to facilitate comparison with papers published earlier. We also attempt to reproduce the sudden step-like increases of cosmic-ray intensity observed by Voyager 1 before its encounter with the heliopause. Our results indicate that very slow cross-field diffusion in the outer heliosheath could produce a large gradient of cosmic rays inside the heliospheric boundary. The resulting large gradient in cosmic-ray intensity near the heliopause qualitatively agrees with recent Voyager 1 observations.

  5. Gamma-ray signatures of cosmic ray acceleration, propagation, and confinement in the era of CTA

    CERN Document Server

    Acero, F; Casanova, S; de Cea, E; Wilhelmi, E de Ona; Gabici, S; Gallant, Y; Hadasch, D; Marcowith, A; Pedaletti, G; Reimer, O; Renaud, M; Torres, D F; Volpe, F

    2012-01-01

    Galactic cosmic rays are commonly believed to be accelerated at supernova remnants via diffusive shock acceleration. Despite the popularity of this idea, a conclusive proof for its validity is still missing. Gamma-ray astronomy provides us with a powerful tool to tackle this problem, because gamma rays are produced during cosmic ray interactions with the ambient gas. The detection of gamma rays from several supernova remnants is encouraging, but still does not constitute a proof of the scenario, the main problem being the difficulty in disentangling the hadronic and leptonic contributions to the emission. Once released by their sources, cosmic rays diffuse in the interstellar medium, and finally escape from the Galaxy. The diffuse gamma-ray emission from the Galactic disk, as well as the gamma-ray emission detected from a few galaxies is largely due to the interactions of cosmic rays in the interstellar medium. On much larger scales, cosmic rays are also expected to permeate the intracluster medium, since the...

  6. News from Cosmic Gamma-ray Line Observations

    CERN Document Server

    Diehl, Roland

    2016-01-01

    The measurement of gamma rays at MeV energies from cosmic radioactivities is one of the key tools for nuclear astrophysics, in its study of nuclear reactions and how they shape objects such as massive stars and supernova explosions. Additionally, the unique gamma-ray signature from the annihilation of positrons falls into this same astronomical window, and positrons are often produced from radioactive beta decays. Nuclear gamma-ray telescopes face instrumental challenges from penetrating gamma rays and cosmic-ray induced backgrounds. But the astrophysical benefits of such efforts are underlined by the discoveries of nuclear gamma~rays from the brightest of the expected sources. In recent years, both thermonuclear and core-collapse supernova radioactivity gamma~rays have been measured in spectral detail, and complement conventional supernova observations with measurements of origins in deep supernova interiors, from the decay of $^{56}$Ni, $^{56}$Co, and $^{44}$Ti. The diffuse afterglow in gamma rays of radioa...

  7. Buoyancy Instabilities in Galaxy Clusters: Convection Due to Adiabatic Cosmic Rays and Anisotropic Thermal Conduction

    CERN Document Server

    Sharma, P; Quataert, E; Parrish, I J

    2009-01-01

    Using a linear stability analysis and two and three-dimensional nonlinear simulations, we study the physics of buoyancy instabilities in a combined thermal and relativistic (cosmic ray) plasma, motivated by the application to clusters of galaxies. We argue that cosmic ray diffusion is likely to be slow compared to the buoyancy time on large length scales, so that cosmic rays are effectively adiabatic. If the cosmic ray pressure $p_{cr}$ is $\\gtrsim 25 %$ of the thermal pressure, and the cosmic ray entropy ($p_{\\rm cr}/\\rho^{4/3}$; $\\rho$ is the thermal plasma density) decreases outwards, cosmic rays drive an adiabatic convective instability analogous to Schwarzschild convection in stars. Global simulations of galaxy cluster cores show that this instability saturates by reducing the cosmic ray entropy gradient and driving efficient convection and turbulent mixing. At larger radii in cluster cores, the thermal plasma is unstable to the heat flux-driven buoyancy instability (HBI), a convective instability genera...

  8. Cosmic ray propagation and interactions in the Galaxy

    CERN Document Server

    Zirakashvili, V N

    2014-01-01

    Cosmic ray propagation in the Galaxy is shortly reviewed. In particular we consider the self-consistent models of CR propagation. In these models CR streaming instability driven by CR anisotropy results in the Alfv\\'enic turbulence which in turn determines the scattering and diffusion of particles.

  9. Cosmological simulations of galaxy formation with cosmic rays

    CERN Document Server

    Salem, Munier; Hummels, Cameron

    2014-01-01

    We investigate the dynamical impact of cosmic rays in cosmological simulations of galaxy formation using adaptive-mesh refinement simulations of a $10^{12}$ solar mass halo. In agreement with previous work, a run with only our standard thermal energy feedback model results in a massive spheroid and unrealistically peaked rotation curves. However, the addition of a simple two-fluid model for cosmic rays drastically changes the morphology of the forming disk. We include an isotropic diffusive term and a source term tied to star formation due to (unresolved) supernova-driven shocks. Over a wide range of diffusion coefficients, the CRs generate thin, extended disks with a significantly more realistic (although still not flat) rotation curve. We find that the diffusion of CRs is key to this process, as they escape dense star forming clumps and drive outflows within the more diffuse ISM.

  10. Cosmic Ray Spectrum in Supernova Remnant Shocks

    Science.gov (United States)

    Kang, H.

    2011-10-01

    We performed kinetic simulations of diffusive shock acceleration in Type Ia supernova remnants (SNRs) expanding into a uniform interstellar medium (ISM). The preshock gas temperature is the primary parameter that governs the cosmic ray (CR) acceleration, while magnetic field strength and CR injection rate are secondary parameters. SNRs in the hot ISM, with an injection fraction smaller than 10-4, are inefficient accelerators with less than 10 % energy getting converted to CRs. The shock structure is almost test-particle like and the ensuing CR spectrum can be steeper than E-2. Although the particles can be accelerated to the knee energy of 1015.5ZeV with amplified magnetic fields in the precursor, Alfvénic drift of scattering centers softens the source spectrum as steep as E-2.1 and reduces the CR acceleration efficiency.

  11. Cosmic Ray Spectrum in Supernova Remnant Shocks

    CERN Document Server

    Kang, Hyesung

    2011-01-01

    We performed kinetic simulations of diffusive shock acceleration in Type Ia supernova remnants (SNRs) expanding into a uniform interstellar medium (ISM). The preshock gas temperature is the primary parameter that governs the cosmic ray (CR) acceleration, while magnetic field strength and CR injection rate are secondary parameters. SNRs in the hot ISM, with an injection fraction smaller than 10^{-4}, are inefficient accelerators with less than 10 % energy getting converted to CRs. The shock structure is almost test-particle like and the ensuing CR spectrum can be steeper than E^{-2}. Although the particles can be accelerated to the knee energy of 10^{15.5}Z eV with amplified magnetic fields in the precursor, Alfv'enic drift of scattering centers softens the source spectrum as steep as E^{-2.1} and reduces the CR acceleration efficiency.

  12. Cosmic-ray acceleration in young protostars

    CERN Document Server

    Padovani, Marco; Marcowith, Alexandre; Ferrière, Katia

    2015-01-01

    The main signature of the interaction between cosmic rays and molecular clouds is the high ionisation degree. This decreases towards the densest parts of a cloud, where star formation is expected, because of energy losses and magnetic effects. However recent observations hint to high levels of ionisation in protostellar systems, therefore leading to an apparent contradiction that could be explained by the presence of energetic particles accelerated within young protostars. Our modelling consists of a set of conditions that has to be satisfied in order to have an efficient particle acceleration through the diffusive shock acceleration mechanism. We find that jet shocks can be strong accelerators of protons which can be boosted up to relativistic energies. Another possibly efficient acceleration site is located at protostellar surfaces, where shocks caused by impacting material during the collapse phase are strong enough to accelerate protons. Our results demonstrate the possibility of accelerating particles du...

  13. Anisotropy and Corotation of Galactic Cosmic Rays

    Institute of Scientific and Technical Information of China (English)

    The Chinese collaboration team at YangBaJing Cosmi

    2007-01-01

    @@ Based on some 40 billion cosmic ray events collected from 1997 to 2005 by the Tibet Air Shower Array experiment (a major scientific collaboration between China and Japan) operating at the YangBaJing Cosmic Ray Observatory (90.522 E, 30. 102 N; 4300 m above sea level) near Lhasa in Tibet, a two-dimensiondl cosmic-ray intensity map in the sky was obtained with very high directional granularity and unprecedented precision in intensity at a level of 10-4.

  14. High-energy cosmic-ray acceleration

    CERN Document Server

    Bustamante, M; de Paula, W; Duarte Chavez, J A; Gago, A M; Hakobyan, H; Jez, P; Monroy Montañez, J A; Ortiz Velasquez, A; Padilla Cabal, F; Pino Rozas, M; Rodriguez Patarroyo, D J; Romeo, G L; Saldaña-Salazar , U J; Velasquez, M; von Steinkirch, M

    2010-01-01

    We briefly review the basics of ultrahigh-energy cosmic-ray acceleration. The Hillas criterion is introduced as a geometrical criterion that must be fulfilled by potential acceleration sites, and energy losses are taken into account in order to obtain a more realistic scenario. The different available acceleration mechanisms are presented, with special emphasis on Fermi shock acceleration and its prediction of a power-law cosmic-ray energy spectrum. We conclude that first-order Fermi acceleration, though not entirely satisfactory, is the most promising mechanism for explaining the ultra-high-energy cosmic-ray flux.

  15. Cosmic rays and stochastic magnetic reconnection in the heliotail

    Directory of Open Access Journals (Sweden)

    P. Desiati

    2012-06-01

    Full Text Available Galactic cosmic rays are believed to be generated by diffusive shock acceleration processes in Supernova Remnants, and the arrival direction is likely determined by the distribution of their sources throughout the Galaxy, in particular by the nearest and youngest ones. Transport to Earth through the interstellar medium is expected to affect the cosmic ray properties as well. However, the observed anisotropy of TeV cosmic rays and its energy dependence cannot be explained with diffusion models of particle propagation in the Galaxy. Within a distance of a few parsec, diffusion regime is not valid and particles with energy below about 100 TeV must be influenced by the heliosphere and its elongated tail. The observation of a highly significant localized excess region of cosmic rays from the apparent direction of the downstream interstellar flow at 1–10 TeV energies might provide the first experimental evidence that the heliotail can affect the transport of energetic particles. In particular, TeV cosmic rays propagating through the heliotail interact with the 100–300 AU wide magnetic field polarity domains generated by the 11 yr cycles. Since the strength of non-linear convective processes is expected to be larger than viscous damping, the plasma in the heliotail is turbulent. Where magnetic field domains converge on each other due to solar wind gradient, stochastic magnetic reconnection likely occurs. Such processes may be efficient enough to re-accelerate a fraction of TeV particles as long as scattering processes are not strong. Therefore, the fractional excess of TeV cosmic rays from the narrow region toward the heliotail direction traces sightlines with the lowest smearing scattering effects, that can also explain the observation of a harder than average energy spectrum.

  16. Cosmic ray transport in astrophysical plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Schlickeiser, R. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- & Astrophysik, Ruhr-Universität, Bochum (Germany)

    2015-09-15

    Since the development of satellite space technology about 50 years ago the solar heliosphere is explored almost routinely by several spacecrafts carrying detectors for measuring the properties of the interplanetary medium including energetic charged particles (cosmic rays), solar wind particle densities, and electromagnetic fields. In 2012, the Voyager 1 spacecraft has even left what could be described as the heliospheric modulation region, as indicated by the sudden disappearance of low energy heliospheric cosmic ray particles. With the available in-situ measurements of interplanetary turbulent electromagnetic fields and of the momentum spectra of different cosmic ray species in different interplanetary environments, the heliosphere is the best cosmic laboratory to test our understanding of the transport and acceleration of cosmic rays in space plasmas. I review both the historical development and the current state of various cosmic ray transport equations. Similarities and differences to transport theories for terrestrial fusion plasmas are highlighted. Any progress in cosmic ray transport requires a detailed understanding of the electromagnetic turbulence that is responsible for the scattering and acceleration of these particles.

  17. THE TELEGRAPH APPROXIMATION FOR FOCUSED COSMIC-RAY TRANSPORT IN THE PRESENCE OF BOUNDARIES

    Energy Technology Data Exchange (ETDEWEB)

    Litvinenko, Yuri E.; Effenberger, Frederic [Department of Mathematics, University of Waikato, P. B. 3105, Hamilton (New Zealand); Schlickeiser, Reinhard [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany)

    2015-06-20

    Diffusive cosmic-ray transport in nonuniform large-scale magnetic fields in the presence of boundaries is considered. Reflecting and absorbing boundary conditions are derived for a modified telegraph equation with a convective term. Analytical and numerical solutions of illustrative boundary problems are presented. The applicability and accuracy of the telegraph approximation for focused cosmic-ray transport in the presence of boundaries are discussed, and potential applications to modeling cosmic-ray transport are noted.

  18. Gamma rays and the origin of Galactic Cosmic Rays

    Science.gov (United States)

    de Ona Wilhelmi, Emma

    2015-08-01

    Cosmic rays (CRs) are highly energetic nuclei (plus a small fraction of electrons) which fill the Galaxy and carry on average as much energy per unit volume as the energy density of starlight, the interstellar magnetic fields, or the kinetic energy density of interstellar gas. The CR spectrum extends as a featureless power-law up to ~2 PeV (the 'knee') and it is believed to be the result of acceleration of those CRs in Galactic Sources and later diffusion and convection in galactic magnetic fields. Those energetic CRs can interact with the surrounding medium via proton-proton collision resulting in secondary gamma-ray photons, observed from 100 MeV to a few tens of TeV. The results obtained by the current Cherenkov telescopes and gamma-ray satellites with the support of X-ray observations have discovered and identified more than 50 Galactic gamma-ray sources. Among them, the number of Supernova remnants (SNRs) and very-high-energy hard-spectrum sources (natural candidates to originate CRs) are steadily increasing. We expect to increase by a factor 10 at least this population of source with the future CTA experiment. I will review our current knowledge of Galactic gamma-ray sources and their connection with energetic CRs and the scientific prospects for CTA in this field. Those observations, together with a strong multi-wavelenght support from radio to hard X-rays, will finally allow us to establish the origin of the Galactic CRs.

  19. Solar Modulation of Cosmic Rays

    CERN Document Server

    Potgieter, Marius

    2013-01-01

    This is an overview of the solar modulation of cosmic rays in the heliosphere. It is a broad topic with numerous intriguing aspects so that a research framework has to be chosen to concentrate on. The review focuses on the basic paradigms and departure points without presenting advanced theoretical or observational details for which there exists a large number of comprehensive reviews. Instead, emphasis is placed on numerical modeling which has played an increasingly signi?cant role as computational resources have become more abundant. A main theme is the progress that has been made over the years. The emphasis is on the global features of CR modulation and on the causes of the observed 11-year and 22-year cycles and charge-sign dependent modulation. Illustrative examples of some of the theoretical and observational milestones are presented, without attempting to review all details or every contribution made in this ?eld of research. Controversial aspects are discussed where appro- priate, with accompanying c...

  20. Cosmic ray physics with ARGO-YBJ

    CERN Document Server

    ,

    2016-01-01

    The ARGO--YBJ experiment has been in stable data taking for more than five years at the Yangbajing cosmic ray observatory (Tibet, P.R. China, 4300 m a.s.l.). The detector collected about $5\\times10^{11}$ events in a wide energy range from few TeVs up to the PeV region. In this work we summarize the latest results in cosmic ray physics particularly focusing on the cosmic ray energy spectrum. The results of the measurement of the all-particle and proton plus helium energy spectra in the energy region between $10^{12} - 10^{16}$ eV are discussed. A precise measurement of the cosmic ray energy spectrum and composition in this energy region allows a better understanding of the origin of the knee and provides a powerful cross-check among different experimental techniques.

  1. A Simplified Model for the Acceleration of Cosmic Ray Particles

    Science.gov (United States)

    Gron, Oyvind

    2010-01-01

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

  2. Longevity and Highest-Energy Cosmic Rays

    CERN Document Server

    Frampton, Paul H; Ng, Y J; Frampton, Paul H.; Keszthelyi, Bettina

    1999-01-01

    It is proposed that the highest energy $\\sim 10^{20}$eV cosmic ray primaries are protons, decay products of a long-lived progenitor which has propagated from typically $\\sim 100$Mpc. Such a scenario can occur in e.g. SU(15) grand unification and in some preon models, but is more generic; if true, these unusual cosmic rays provide a window into new physics.

  3. Cosmic ray test of INO RPC stack

    Energy Technology Data Exchange (ETDEWEB)

    Bhuyan, M. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Datar, V.M. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400085 (India); Kalmani, S.D.; Lahamge, S.M.; Mondal, N.K.; Nagaraj, P.; Pal, S.; Reddy, L.V.; Redij, A.; Samuel, D.; Saraf, M.N. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Satyanarayana, B., E-mail: bsn@tifr.res.in [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India); Shinde, R.R.; Verma, P. [Department of High Energy Physics, Tata Institute of Fundamental Research, Mumbai 400005 (India)

    2012-01-01

    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 Multiplication-Sign 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.

  4. Are there strangelets in cosmic rays?

    CERN Document Server

    Rybczynski, M; Wilk, G

    2004-01-01

    Assuming that cosmic rays entering the Earth's atmosphere contain a small admixture of nuggets of strange quark matter in form of strangelets one can explain a number of apparently "strange" effects observed in different cosmic rays experiments. We shall demonstrate here that the mass spectrum of such strangelets filles the "nuclear desert" gap existing between the heaviest elements observed in Universe and the next "nuclear-like objects" represented by neutron and strange stars.

  5. Cosmic Ray Interaction Models: an Overview

    Directory of Open Access Journals (Sweden)

    Ostapchenko Sergey

    2016-01-01

    Full Text Available I review the state-of-the-art concerning the treatment of high energy cosmic ray interactions in the atmosphere, discussing in some detail the underlying physical concepts and the possibilities to constrain the latter by current and future measurements at the Large Hadron Collider. The relation of basic characteristics of hadronic interactions tothe properties of nuclear-electromagnetic cascades induced by primary cosmic rays in the atmosphere is addressed.

  6. Pinpointing cosmic ray propagation with the AMS-02 experiment

    Energy Technology Data Exchange (ETDEWEB)

    Pato, Miguel [Dipartimento di Fisica, Università degli Studi di Padova, via Marzolo 8, I-35131, Padova (Italy); Hooper, Dan [Center for Particle Astrophysics, Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Simet, Melanie, E-mail: pato@iap.fr, E-mail: dhooper@fnal.gov, E-mail: msimet@uchicago.edu [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States)

    2010-06-01

    The Alpha Magnetic Spectrometer (AMS-02), which is scheduled to be deployed onboard the International Space Station later this year, will be capable of measuring the composition and spectra of GeV-TeV cosmic rays with unprecedented precision. In this paper, we study how the projected measurements from AMS-02 of stable secondary-to-primary and unstable ratios (such as boron-to-carbon and beryllium-10-to-beryllium-9) can constrain the models used to describe the propagation of cosmic rays throughout the Milky Way. We find that within the context of fairly simple propagation models, all of the model parameters can be determined with high precision from the projected AMS-02 data. Such measurements are less constraining in more complex scenarios, however, which allow for departures from a power-law form for the diffusion coefficient, for example, or for inhomogeneity or stochasticity in the distribution and chemical abundances of cosmic ray sources.

  7. Recent developments in cosmic ray physics

    Energy Technology Data Exchange (ETDEWEB)

    Blasi, P. [INAF/Osservatorio Astrofisico di Arcetri, Largo E. Fermi, 5 50125 Firenze (Italy); Gran Sasso Science Institute (INFN), Viale F. Crispi 6, 60100 L' Aquila (Italy)

    2014-11-15

    The search for a theory of the origin of cosmic rays that may be considered as a standard, agreeable model is still ongoing. On one hand, much circumstantial evidence exists of the fact that supernovae in our Galaxy play a crucial role in producing the bulk of cosmic rays observed on Earth. On the other hand, important questions about their ability to accelerate particles up to the knee remain unanswered. The common interpretation of the knee as a feature coinciding with the maximum energy of the light component of cosmic rays and a transition to a gradually heavier mass composition is mainly based on KASCADE results. Some recent data appear to question this finding: YAC1 – Tibet Array and ARGO-YBJ find a flux reduction in the light component at ∼ 700 TeV, appreciably below the knee. Whether the maximum energy of light nuclei is as high as 3000 TeV or rather as low as a few hundred TeV has very important consequences on the supernova remnant paradigm for the origin of cosmic rays, as well on the crucial issue of the transition from Galactic to extragalactic cosmic rays. In such a complex phenomenological situation, it is important to have a clear picture of what is really known and what is not. Here I will discuss some solid and less solid aspects of the theory (or theories) for the origin of cosmic rays and the implications for future searches in this field.

  8. Spaced-based Cosmic Ray Astrophysics

    Science.gov (United States)

    Seo, Eun-Suk

    2016-03-01

    The bulk of cosmic ray data has been obtained with great success by balloon-borne instruments, particularly with NASA's long duration flights over Antarctica. More recently, PAMELA on a Russian Satellite and AMS-02 on the International Space Station (ISS) started providing exciting measurements of particles and anti-particles with unprecedented precision upto TeV energies. In order to address open questions in cosmic ray astrophysics, future missions require spaceflight exposures for rare species, such as isotopes, ultra-heavy elements, and high (the ``knee'' and above) energies. Isotopic composition measurements up to about 10 GeV/nucleon that are critical for understanding interstellar propagation and origin of the elements are still to be accomplished. The cosmic ray composition in the knee (PeV) region holds a key to understanding the origin of cosmic rays. Just last year, the JAXA-led CALET ISS mission, and the DAMPE Chinese Satellite were launched. NASA's ISS-CREAM completed its final verification at GSFC, and was delivered to KSC to await launch on SpaceX. In addition, a EUSO-like mission for ultrahigh energy cosmic rays and an HNX-like mission for ultraheavy nuclei could accomplish a vision for a cosmic ray observatory in space. Strong support of NASA's Explorer Program category of payloads would be needed for completion of these missions over the next decade.

  9. Reminiscences of cosmic ray research in Mexico

    Science.gov (United States)

    Pérez-Peraza, Jorge

    2009-11-01

    Cosmic ray research in Mexico dates from the early 1930s with the work of the pioneering physicist, Manuel Sandoval Vallarta and his students from Mexico. Several experiments of international significance were carried out during that period in Mexico: they dealt with the geomagnetic latitude effect, the north-south and west-east asymmetry of cosmic ray intensity, and the sign of the charge of cosmic rays. The international cosmic ray community has met twice in Mexico for the International Cosmic Ray Conferences (ICRC): the fourth was held in Guanajuato in 1955, and the 30th took place in Mérida, in 2007. In addition, an international meeting on the Pierre Auger Collaboration was held in Morelia in 1999, and the International Workshop on Observing UHE Cosmic Rays took place in Metepec in 2000. A wide range of research topics has been developed, from low-energy Solar Energetic Particles (SEP) to the UHE. Instrumentation has evolved since the early 1950s, from a Simpson type neutron monitor installed in Mexico City (2300 m asl) to a solar neutron telescope and an EAS Cherenkov array, (within the framework of the Auger International Collaboration), both at present operating on Mt. Sierra La Negra in the state of Puebla (4580 m asl). Research collaboration has been undertaken with many countries; in particular, the long-term collaboration with Russian scientists has been very fruitful.

  10. Cosmic-Ray Modulation: an Ab Initio Approach

    Science.gov (United States)

    Engelbrecht, N. E.; Burger, R. A.

    2014-10-01

    A better understanding of cosmic-ray modulation in the heliosphere can only be gained through a proper understanding of the effects of turbulence on the diffusion and drift of cosmic rays. We present an ab initio model for cosmic-ray modulation, incorporating for the first time the results yielded by a two-component turbulence transport model. This model is solved for periods of minimum solar activity, utilizing boundary values chosen so that model results are in fair to good agreement with spacecraft observations of turbulence quantities, not only in the solar ecliptic plane but also along the out-of-ecliptic trajectory of the Ulysses spacecraft. These results are employed as inputs for modelled slab and 2D turbulence energy spectra. The latter spectrum is chosen based on physical considerations, with a drop-off at the very lowest wavenumbers commencing at the 2D outerscale. There currently exist no models or observations for this quantity, and it is the only free parameter in this study. The modelled turbulence spectra are used as inputs for parallel mean free path expressions based on those derived from quasi-linear theory and perpendicular mean free paths from extended nonlinear guiding center theory. Furthermore, the effects of turbulence on cosmic-ray drifts are modelled in a self-consistent way, employing a recently developed model for drift along the wavy current sheet. The resulting diffusion coefficients and drift expressions are applied to the study of galactic cosmic-ray protons and antiprotons using a three-dimensional, steady-state cosmic-ray modulation code, and sample solutions in fair agreement with multiple spacecraft observations are presented.

  11. Anomalous Transport of High Energy Cosmic Rays in Galactic Superbubbles

    Science.gov (United States)

    Barghouty, Nasser F.

    2014-01-01

    High-energy cosmic rays may exhibit anomalous transport as they traverse and are accelerated by a collection of supernovae explosions in a galactic superbubble. Signatures of this anomalous transport can show up in the particles' evolution and their spectra. In a continuous-time-random- walk (CTRW) model assuming standard diffusive shock acceleration theory (DSA) for each shock encounter, and where the superbubble (an OB stars association) is idealized as a heterogeneous region of particle sources and sinks, acceleration and transport in the superbubble can be shown to be sub-diffusive. While the sub-diffusive transport can be 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 CTRW simulations point to a new and intriguing phenomenon associated with the statistical nature of collective acceleration of high energy cosmic rays in galactic superbubbles.

  12. Cosmic ray driven dynamo in galactic disks. A parameter study

    CERN Document Server

    MichałHanasz,; Kowal, Grzegorz; Lesch, Harald

    2008-01-01

    We present a parameter study of the magnetohydrodynamical dynamo driven by cosmic rays in the interstellar medium (ISM) focusing on the efficiency of magnetic field amplification and the issue of energy equipartition between magnetic, kinetic and cosmic ray (CR) energies. We perform numerical CR-MHD simulations of the ISM using the extended version of ZEUS-3D code in the shearing box approximation and taking into account the presence of Ohmic resistivity, tidal forces and vertical disk gravity. CRs are supplied in randomly distributed supernova (SN) remnants and are described by the diffusion-advection equation, which incorporates an anisotropic diffusion tensor. The azimuthal magnetic flux and total magnetic energy are amplified depending on a particular choice of model parameters. We find that the most favorable conditions for magnetic field amplification correspond to magnetic diffusivity of the order of $3\\times 10^{25} \\cm^2\\s^{-1}$, SN rates close to those observed in the Milky Way, periodic SN activity...

  13. Cosmic ray effects in microcalorimeter arrays

    Energy Technology Data Exchange (ETDEWEB)

    Stahle, C.K. E-mail: cak@lheapop.gsfc.nasa.gov; Boyce, K.R.; Brown, G.V.; Cottam, J.; Figueroa-Feliciano, E.; Galeazzi, M.; Kelley, R.L.; McCammon, D.; Porter, F.S.; Szymkowiak, A.E.; Tillotson, W.A

    2004-03-11

    We have identified signals resulting from cosmic rays and environmental gamma rays depositing energy in the pixels and in the silicon frame of the Astro-E2/X-Ray Spectrometer microcalorimeter array. Coincidences between pixels and between the array and an anti-coincidence detector determined the nature of the events. Pulse shapes and amplitudes from the cosmic ray events helped refine the thermal model of the array chip. We discuss how future arrays can be optimized either for the greatest background rejection or for the highest source count rates.

  14. Galactic neutrino background from cosmic ray interaction with the ISM content

    CERN Document Server

    De Donato, C; D'Olivo, J C

    2007-01-01

    We use a diffusive model for the propagation of Galactic cosmic rays to estimate the charged pion production in interactions with protons of the interstellar medium. Cosmic ray nuclei from proton to iron are considered and the corresponding contribution to the neutrino secondary flux produced as a result of spallation is also estimated.

  15. Development of the cosmic ray techniques

    Science.gov (United States)

    Rossi, B.

    1982-12-01

    It has been found that most advances of cosmic-ray physics have been directly related to the development of observational techniques. The history of observational techniques is discussed, taking into account ionization chambers, refinements applied to ionization chambers to make them suitable for an effective use in the study of cosmic radiation, the Wulf-type electrometer, the electrometer designed by Millikan and Neher, the Geiger-Mueller counter, the experiment of Bothe and Kolhoerster, the coincidence circuit, and a cosmic-ray 'telescope'. Attention is given to a magnetic lens for cosmic rays, a triangular arrangement of Geiger-Mueller counters used to demonstrate the production of a secondary radiation, a stereoscopic cloud-chamber photograph of showers, the cloud-chamber picture which provided the first evidence of the positive electron, and arrangements for studying photon components, mu-mesons, and air showers.

  16. Spiral arms as cosmic ray source distributions

    Science.gov (United States)

    Werner, M.; Kissmann, R.; Strong, A. W.; Reimer, O.

    2015-04-01

    The Milky Way is a spiral galaxy with (or without) a bar-like central structure. There is evidence that the distribution of suspected cosmic ray sources, such as supernova remnants, are associated with the spiral arm structure of galaxies. It is yet not clearly understood what effect such a cosmic ray source distribution has on the particle transport in our Galaxy. We investigate and measure how the propagation of Galactic cosmic rays is affected by a cosmic ray source distribution associated with spiral arm structures. We use the PICARD code to perform high-resolution 3D simulations of electrons and protons in galactic propagation scenarios that include four-arm and two-arm logarithmic spiral cosmic ray source distributions with and without a central bar structure as well as the spiral arm configuration of the NE2001 model for the distribution of free electrons in the Milky Way. Results of these simulation are compared to an axisymmetric radial source distribution. Also, effects on the cosmic ray flux and spectra due to different positions of the Earth relative to the spiral structure are studied. We find that high energy electrons are strongly confined to their sources and the obtained spectra largely depend on the Earth's position relative to the spiral arms. Similar finding have been obtained for low energy protons and electrons albeit at smaller magnitude. We find that even fractional contributions of a spiral arm component to the total cosmic ray source distribution influences the spectra on the Earth. This is apparent when compared to an axisymmetric radial source distribution as well as with respect to the Earth's position relative to the spiral arm structure. We demonstrate that the presence of a Galactic bar manifests itself as an overall excess of low energy electrons at the Earth. Using a spiral arm geometry as a cosmic ray source distributions offers a genuine new quality of modeling and is used to explain features in cosmic ray spectra at the Earth

  17. Cosmic ray composition measurements and cosmic ray background free gamma-ray observations with Cherenkov telescopes

    CERN Document Server

    Neronov, A; Vovk, Ie; Mirzoyan, R

    2016-01-01

    Muon component of extensive air showers (EAS) initiated by cosmic ray particles carries information on the primary particle identity. We show that the muon content of EAS could be measured in a broad energy range from 10-100 TeV up to ultra-high-energy cosmic ray range using wide field-of-view imaging atmospheric Cherenkov telescopes observing strongly inclined or nearly horizontal EAS from the ground of from high altitude. Cherenkov emission from muons in such EAS forms a distinct component (halo or tail) of the EAS image in the telescope camera. We show that detection of the muon signal could be used to measure composition of the cosmic ray spectrum in the energy ranges of the knee, the ankle and of the Galactic-to-extragalactic transition. It could also be used to veto the cosmic ray background in gamma-ray observations. This technique provides a possibility for up to two orders of magnitude improvement of sensitivity for gamma-ray flux in the energy band above 10 PeV, compared to KASCADE-Grande, and an or...

  18. Propagation of Cosmic Rays: Nuclear Physics in Cosmic-ray Studies

    Science.gov (United States)

    Moskalenko, Igor V.; Strong, Andrew W.; Mashnik, Stepan G.

    2004-01-01

    The nuclei fraction in cosmic rays (CR) far exceeds the fraction of other CR species, such as antiprotons, electrons, and positrons. Thus the majority of information obtained from CR studies is based on interpretation of isotopic abundances using CR propagation models where the nuclear data and isotopic production cross sections in p- and alpha-induced reactions are the key elements. This paper presents an introduction to the astrophysics of CR and diffuse gamma-rays and dimsses some of the puzzles that have emerged recently due to more precise data and improved propagation models. Merging with cosmology and particle physics, astrophysics of CR has become a very dynamic field with a large potential of breakthrough and discoveries in the near fume. Exploiting the data collected by the CR experiments to the fullest requires accurate nuclear cross sections.

  19. Cosmic Ray Spectrum in Supernova Remnant Shocks

    CERN Document Server

    Kang, Hyesung

    2010-01-01

    We perform kinetic simulations of diffusive shock acceleration (DSA) in Type Ia supernova remnants (SNRs) expanding into a uniform interstellar medium (ISM). Bohm-like diffusion assumed, and simple models for Alfvenic drift and dissipation are adopted. Phenomenological models for thermal leakage injection are considered as well. We find that the preshock gas temperature is the primary parameter that governs the cosmic ray (CR) acceleration efficiency and energy spectrum, while the CR injection rate is a secondary parameter. For SNRs in the warm ISM, if the injection fraction is larger than 10^{-4}, the DSA is efficient enough to convert more than 20 % of the SN explosion energy into CRs and the accelerated CR spectrum exhibits a concave curvature flattening to E^{-1.6}. Such a flat source spectrum near the knee energy, however, may not be reconciled with the CR spectrum observed at Earth. On the other hand, SNRs in the hot ISM, with an injection fraction smaller than 10^{-4}, are inefficient accelerators with...

  20. The HAWC Gamma-Ray Observatory: Observations of Cosmic Rays

    CERN Document Server

    Abeysekara, A U; Alvarez, C; Álvarez, J D; Arceo, R; Arteaga-Velázquez, J C; Solares, H A Ayala; Barber, A S; Baughman, B M; Bautista-Elivar, N; Belmont, E; BenZvi, S Y; Berley, D; Rosales, M Bonilla; Braun, J; Caballero-Lopez, R A; Caballero-Mora, K S; Carramiñana, A; Castillo, M; Cotti, U; Cotzomi, J; de la Fuente, E; De León, C; DeYoung, T; Hernandez, R Diaz; Díaz-Vélez, J C; Dingus, B L; DuVernois, M A; Ellsworth, R W; Fernandez, A; Fiorino, D W; Fraija, N; Galindo, A; Garfias, F; González, L X; González, M M; Goodman, J A; Grabski, V; Gussert, M; Hampel-Arias, Z; Hui, C M; Hüntemeyer, P; Imran, A; Iriarte, A; Karn, P; Kieda, D; Kunde, G J; Lara, A; Lauer, R J; Lee, W H; Lennarz, D; Vargas, H León; Linares, E C; Linnemann, J T; Longo, M; Luna-GarcIa, R; Marinelli, A; Martinez, H; Martinez, O; Martínez-Castro, J; Matthews, J A J; Miranda-Romagnoli, P; Moreno, E; Mostafá, M; Nava, J; Nellen, L; Newbold, M; Noriega-Papaqui, R; Oceguera-Becerra, T; Patricelli, B; Pelayo, R; Pérez-Pérez, E G; Pretz, J; Rivière, C; Rosa-González, D; Salazar, H; Salesa, F; Sanchez, F E; Sandoval, A; Santos, E; Schneider, M; Silich, S; Sinnis, G; Smith, A J; Sparks, K; Springer, R W; Taboada, I; Toale, P A; Tollefson, K; Torres, I; Ukwatta, T N; Villaseñor, L; Weisgarber, T; Westerhoff, S; Wisher, I G; Wood, J; Yodh, G B; Younk, P W; Zaborov, D; Zepeda, A; Zhou, H

    2013-01-01

    We describe measurements of GeV and TeV cosmic rays with the High-Altitude Water Cherenkov Gamma-Ray Observatory, or HAWC. The measurements include the observation of the shadow of the moon; the observation of small-scale and large-scale angular clustering of the TeV cosmic rays; the prospects for measurement of transient solar events with HAWC; and the observation of Forbush decreases with the HAWC engineering array and HAWC-30.

  1. Modelling cosmic ray intensities along the Ulysses trajectory

    Directory of Open Access Journals (Sweden)

    D. C. Ndiitwani

    2005-03-01

    Full Text Available Time dependent cosmic ray modulation in the inner heliosphere is studied by comparing results from a 2-D, time-dependent cosmic ray transport model with Ulysses observations. A compound approach, which combines the effects of the global changes in the heliospheric magnetic field magnitude with drifts to establish a realistic time-dependence, in the diffusion and drift coefficients, are used. We show that this model results in realistic cosmic ray modulation from the Ulysses launch (1990 until recently (2004 when compared to 2.5-GV electron and proton and 1.2-GV electron and Helium observations from this spacecraft. This approach is also applied to compute radial gradients present in 2.5-GV cosmic ray electron and protons in the inner heliosphere. The observed latitude dependence for both positive and negative charged particles during both the fast latitude scan periods, corresponding to different solar activity conditions, could also be realistically computed. For this an additional reduction in particle drifts (compared to diffusion toward solar maximum is needed. This results in a realistic charge-sign dependent modulation at solar maximum and the model is also applied to predict charge-sign dependent modulation up to the next expected solar minimum.

  2. Global simulations of galactic winds including cosmic ray streaming

    CERN Document Server

    Ruszkowski, Mateusz; Zweibel, Ellen

    2016-01-01

    Galactic outflows play an important role in galactic evolution. Despite their importance, a detailed understanding of the physical mechanisms responsible for the driving of these winds is lacking. In an effort to gain more insight into the nature of these flows, we perform global three-dimensional magneto-hydrodynamical simulations of an isolated Milky Way-size starburst galaxy. We focus on the dynamical role of cosmic rays injected by supernovae, and specifically on the impact of the streaming and anisotropic diffusion of cosmic rays along the magnetic fields. We find that these microphysical effects can have a significant effect on the wind launching and mass loading factors depending on the details of the plasma physics. Due to the cosmic ray streaming instability, cosmic rays propagating in the interstellar medium scatter on self-excited Alfven waves and couple to the gas. When the wave growth due to the streaming instability is inhibited by some damping process, such as the turbulent damping, the cosmic ...

  3. Galactic Winds and Cosmic Ray Transport in a Multiphase Interstellar Medium

    Science.gov (United States)

    Farber, Ryan; Ruszkowski, Mateusz; Hsiang-Yi, Karen; Gould Zweibel, Ellen

    2017-01-01

    Making up roughly one third the pressure budget of the ISM, cosmic rays are likely to play a fundamental role in galaxy evolution. Recent 3D magnetohydrodynamic simulations have shown that advected cosmic rays puff up galactic disks and suppress star formation. Additionally, cosmic rays diffusing away from the galactic midplane can drive gas out of the galaxy with mass loss rates comparable to the star formation rate, thus regulating star formation. Yet, the impact of cosmic rays decoupling from cold, neutral gas in a multiphase interstellar medium has hithertofore not been studied. Preliminary work suggests that cosmic ray decoupling produces significantly more explosive feedback, dramatically affecting the evolution of the ISM and the efficiency of cosmic ray driven outflows.

  4. Jupiter as a Giant Cosmic Ray Detector

    CERN Document Server

    Rimmer, Paul B; Helling, Christiane

    2014-01-01

    We explore the feasibility of using the atmosphere of Jupiter to detect Ultra-High-Energy Cosmic Rays (UHECR's). 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 $3.3 \\times 10^7$ km$^2$. We predict that Fermi-LAT should be able to detect events of energy $>10^{21}$ 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 $\\gtrsim 10^{20}$ eV. Extensive air showers also produce a synchrotron signature that may ...

  5. Cosmic-Ray Observations with HAWC30

    Science.gov (United States)

    Fiorino, Daniel

    2013-04-01

    The High-Altitude Water Cherenkov (HAWC) Observatory is a TeV gamma-ray and cosmic-ray detector currently under construction at an altitude of 4100 meters on the slope of Volc'an Sierra Negra near Puebla, Mexico. HAWC is an extensive air-shower array comprising 300 optically-isolated water Cherenkov detectors. Each detector contains 200,000 liters of filtered water and four upward-facing photomultiplier tubes. Since September 2012, 30 water Cherenkov detectors have been instrumented and operated in data acquisition. With 10 percent of the detector complete and six months of operation, the event statistics are already sufficient to perform detailed studies of cosmic rays observed at the site. We will report on cosmic-ray observations with HAWC30, in particular the detection and study of the shadow of the moon. From these observations, we infer the pointing accuracy of the detector and our angular resolution of the detector reconstruction.

  6. Molecular Clouds as Cosmic-Ray Barometers

    CERN Document Server

    Casanova, S; Fukui, Y; Gabici, S; Jones, D I; Kawamura, A; Onishi, T; Rowell, G; Torii, K; Yamamoto, H

    2009-01-01

    It is generally assumed that the flux of cosmic-rays observed at the top of the Earth's atmosphere is representative of the flux in the Galaxy at large. The advent of high sensitivity, high resolution gamma-ray detectors, together with a knowledge of the distribution of the atomic hydrogen and especially of the molecular hydrogen in the Galaxy on sub-degree scales, as provided by the NANTEN survey, creates a unique opportunity to explore the flux of cosmic rays in the Galaxy. We present a methodology which aims to provide a test bed for current and future gamma-ray observatories to explore the cosmic ray flux at various positions in our Galaxy. In particular, for a distribution of molecular clouds and local cosmic ray density as measured at the Earth, we estimate the expected GeV to TeV gamma-ray signal, which can then be compared with observations. An observed gamma-ray flux less than predicted would imply a CR density in specific regions of the Galaxy less than that observed at Earth, and vice versa. The me...

  7. Tracks of cosmic rays in plastics.

    Science.gov (United States)

    Fleischer, R L; Price, P B; Walker, R M; Filz, R C; Fukui, K; Friedlander, M W; Holeman, E; Rajan, R S; Tamhane, A S

    1967-01-13

    Cosmic ray nuclei have been observed with the use of plastic trackdetecting solids in satellites and high-altitude balloon flights. Nuclear emulsions in the stacks of plastic sheets allowed the positive identification of cosmic raynuclei as light as nitrogen. The most striking new information was the failure to observe relativistic iron nuclei, a result which has led to an advance in the understanding of track registration criteria.

  8. Polycyclic aromatic hydrocarbon processing by cosmic rays

    CERN Document Server

    Micelotta, E R; Tielens, A G G M

    2010-01-01

    Context: Cosmic rays are present in almost all phases of the ISM. PAHs and cosmic rays represent an abundant and ubiquitous component of the interstellar medium. However, the interaction between them has never before been fully investigated. Aims: To study the effects of cosmic ray ion (H, He, CNO and Fe-Co-Ni) and electron bombardment of PAHs in galactic and extragalactic environments. Methods: We calculate the nuclear and electronic interactions for collisions between PAHs and cosmic ray ions and electrons with energies between 5 MeV/nucleon and 10 GeV, above the threshold for carbon atom loss, in normal galaxies, starburst galaxies and cooling flow galaxy clusters. Results: The timescale for PAH destruction by cosmic ray ions depends on the electronic excitation energy Eo and on the amount of energy available for dissociation. Small PAHs are destroyed faster, with He and the CNO group being the more effective projectiles. For electron collisions, the lifetime is independent of the PAH size and varies with ...

  9. Cosmic Ray Interactions in Shielding Materials

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-09-08

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

  10. LHCf sheds new light on cosmic rays

    CERN Multimedia

    Anaïs Schaeffer

    2011-01-01

    The energy spectrum of the single photon obtained using data from the LHCf experiment has turned out to be very different from that predicted by the theoretical models used until now to describe the interactions between very high-energy cosmic rays and the earth's atmosphere. The consequences of this discrepancy for cosmic ray studies could be significant.   Artistic impression of cosmic rays entering Earth's atmosphere. (Credit: Asimmetrie/Infn). It took physicists by surprise when analysis of the data collected by the two LHCf calorimeters in 2010 showed that high-energy cosmic rays don't interact with the atmosphere in the manner predicted by theory. The LHCf detectors, set up 140 metres either side of the ATLAS interaction point, are dedicated to the study of the secondary particles emitted at very small angles during proton-proton collisions in the LHC, with energies comparable to cosmic rays entering the earth's atmosphere at 2.5x1016 eV. The aim of the experiment is to r...

  11. K-alpha X-rays from cosmic-ray oxygen. [subrelativistic interstellar oxygen ions

    Science.gov (United States)

    Pravdo, S. H.; Boldt, E. A.

    1975-01-01

    Equilibrium charge fractions are calculated for subrelativistic cosmic-ray oxygen ions in the interstellar medium. These are used to determine the expected flux of K-alpha rays arising from atomic processes for a number of different postulated interstellar oxygen spectra. Relation of these results to the diffuse X-ray background measured at the appropriate energy (about 0.6 keV) suggests an observable broadened line feature.

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

    Science.gov (United States)

    Moiseev, Alexander

    2011-01-01

    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,

  13. One century of cosmic rays – A particle physicist's view

    Directory of Open Access Journals (Sweden)

    Sutton Christine

    2015-01-01

    Full Text Available Experiments on cosmic rays and the elementary particles share a common history that dates back to the 19th century. Following the discovery of radioactivity in the 1890s, the paths of the two fields intertwined, especially during the decades after the discovery of cosmic rays. Experiments demonstrated that the primary cosmic rays are positively charged particles, while other studies of cosmic rays revealed various new sub-atomic particles, including the first antiparticle. Techniques developed in common led to the birth of neutrino astronomy in 1987 and the first observation of a cosmic γ-ray source by a ground-based cosmic-ray telescope in 1989.

  14. He-3 in galactic cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Mewaldt, R.A.

    1986-12-01

    Cosmic-ray He-3/He-4 observations, including a new measurement around 65 MeV per nucleon from ISEE-3, are compared with interstellar propagation and solar modulation calculations in an effort to understand the origin of cosmic-ray He nuclei. A survey of spacecraft and balloon observations of the He-3/He-4 ratio shows improved consistency among measurements in the 50-300 MeV per nucleon energy range when a previously neglected contribution from atmospheric secondary He-3 is taken into account. These low-energy observations imply a mean escape length of 6-8 g/sq cm in the standard leaky box model for cosmic-ray propagation in the Galaxy, a value consistent with that derived from studies of heavier nuclei. No evidence is found for an excess of low-energy He-3 such as that reported at high energies. 42 references.

  15. Cosmic ray antiprotons at high energies

    Science.gov (United States)

    Winkler, Martin Wolfgang

    2017-02-01

    Cosmic ray antiprotons provide a powerful tool to probe dark matter annihilations in our galaxy. The sensitivity of this important channel is, however, diluted by sizable uncertainties in the secondary antiproton background. In this work, we improve the calculation of secondary antiproton production with a particular focus on the high energy regime. We employ the most recent collider data and identify a substantial increase of antiproton cross sections with energy. This increase is driven by the violation of Feynman scaling as well as by an enhanced strange hyperon production. The updated antiproton production cross sections are made publicly available for independent use in cosmic ray studies. In addition, we provide the correlation matrix of cross section uncertainties for the AMS-02 experiment. At high energies, the new cross sections improve the compatibility of the AMS-02 data with a pure secondary origin of antiprotons in cosmic rays.

  16. Low cloud properties influenced by cosmic rays

    DEFF Research Database (Denmark)

    Marsh, Nigel; Svensmark, Henrik

    2000-01-01

    The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (less than or equal to3 ......), which points to a microphysical mechanism involving aerosol formation that is enhanced by ionization due to cosmic rays. If confirmed it suggests that the average state of the heliosphere is important for climate on Earth.......The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Surprisingly the influence of solar variability is strongest in low clouds (less than or equal to3 km...

  17. Thirty-Year Periodicity of Cosmic Rays

    Directory of Open Access Journals (Sweden)

    Jorge Pérez-Peraza

    2012-01-01

    Full Text Available Cosmogenic isotopes have frequently been employed as proxies of ancient cosmic ray fluxes. On the basis of periodicities of the 10Be time series (using data from both the South and North Poles and the 14C time series (with data from Intercal-98, we offer evidence of the existence of cosmic ray fluctuations with a periodicity of around 30 years. Results were obtained by using the wavelet transformation spectral technique, signal reconstruction by autoregressive spectral analysis (ARMA, and the Lomb-Scargle periodogram method. This 30-year periodicity seems to be significant in nature because several solar and climatic indexes exhibit the same modulation, which may indicate that the 30-year frequency of cosmic rays is probably a modulator agent for terrestrial phenomena, reflecting the control source, namely, solar activity.

  18. Does electromagnetic radiation accelerate galactic cosmic rays

    Science.gov (United States)

    Eichler, D.

    1977-01-01

    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.

  19. Anomalous Galactic Cosmic Rays in the Framework of AMS-02

    Science.gov (United States)

    Khiali, Behrouz; Haino, Sadakazu; Feng, Jie

    2017-02-01

    The cosmic-ray (CR) energy spectra of protons and helium nuclei, which are the most abundant components of cosmic radiation, exhibit a remarkable hardening at energies above 100 GeV/nucleon. Recent data from AMS-02 confirm this feature with a higher significance. These data challenge the current models of CR acceleration in Galactic sources and propagation in the Galaxy. Here, we explain the observed break in the spectra of protons and helium nuclei in light of recent advances in CR diffusion theories in turbulent astrophysical sources as being a result of a transition between different CR diffusion regimes. We reconstruct the observed CR spectra using the fact that a transition from normal diffusion to superdiffusion changes the efficiency of particle acceleration and causes the change in the spectral index. We find that calculated proton and helium spectra match the data very well.

  20. GALPROP: modeling cosmic ray propagation and associated interstellar emissions

    CERN Document Server

    Moskalenko, Igor V

    2011-01-01

    Research in many areas of modern physics and astrophysics such as, e.g., indirect searches for dark matter (DM), particle acceleration in SNR shocks, and the spectrum and origin of extragalactic gamma-ray background, rely heavily on studies of cosmic rays (CRs) and associated diffuse emissions. New or improved instrumentation to explore these open issues is ready or under development. A fleet of ground-based, balloon-borne, and spacecraft instruments measures many CR species, gamma rays, radio, and synchrotron emission. Exploiting the data collected by the scientific missions to the fullest requires reliable and detailed calculations using a numerical model. GALPROP is the current state-of-the-art numerical CR propagation code that has become a standard analysis tool in CR and diffuse gamma-ray research. It uses astrophysical information, nuclear and particle data as input to self-consistently predict CRs, gamma rays, synchrotron emission and other observables. This paper reviews recent GALPROP developments a...

  1. Cosmic ray-driven winds in the Galactic environment and the cosmic ray spectrum

    Science.gov (United States)

    Recchia, S.; Blasi, P.; Morlino, G.

    2017-09-01

    Cosmic rays escaping the Galaxy exert a force on the interstellar medium directed away from the Galactic disc. If this force is larger than the gravitational pull due to the mass embedded in the Galaxy, then galactic winds may be launched. Such outflows may have important implications for the history of star formation of the host galaxy, and in turn affect in a crucial way the transport of cosmic rays, both due to advection with the wind and to the excitation of waves by the same cosmic rays, through streaming instability. The possibility to launch cosmic ray-induced winds and the properties of such winds depend on environmental conditions, such as the density and temperature of the plasma at the base of the wind and the gravitational potential, especially the one contributed by the dark matter halo. In this paper, we make a critical assessment of the possibility to launch cosmic ray-induced winds for a Milky Way-like galaxy and how the properties of the wind depend upon the conditions at the base of the wind. Special attention is devoted to the implications of different conditions for wind launching on the spectrum of cosmic rays observed at different locations in the disc of the galaxy. We also comment on how cosmic ray-induced winds compare with recent observations of Oxygen absorption lines in quasar spectra and emission lines from blank sky, as measured by XMM-Newton/EPIC-MOS.

  2. Cosmic Rays: studies and measurements before 1912

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, Alessandro [INFN and Università di Udine, Via delle Scienze 206, I-33100 Udine (Italy); LIP/IST Lisboa (Portugal)

    2013-06-15

    The discovery of cosmic rays, a milestone in science, was based on the work by scientists in Europe and the New World and took place during a period characterised by nationalism and lack of communication. Many scientists that took part in this research a century ago were intrigued by the penetrating radiation and tried to understand the origin of it. Several important contributions to the discovery of the origin of cosmic rays have been forgotten; historical, political and personal facts might have contributed to their substantial disappearance from the history of science.

  3. Cosmic rays from trans-relativistic supernovae

    CERN Document Server

    Budnik, R; MacFadyen, A; Waxman, E

    2007-01-01

    We derive constraints which must be satisfied by the sources of ~10^{15} to ~10^{18} eV cosmic rays, under the assumption that the sources are Galactic. We show that while these constraints are not satisfied by ordinary supernovae, which are believed to be the sources of 10^{-2}, of the explosion energy in mildly relativistic, \\gamma\\beta>1, ejecta. Galactic TRSNe may therefore be the sources of cosmic rays with energies up to ~10^{18} eV.

  4. Solar Cosmic Ray Acceleration and Propagation

    Science.gov (United States)

    Podgorny, I. M.; Podgorny, A. I.

    2016-05-01

    The GOES data for emission of flare protons with the energies of 10 - 100 MeV are analyzed. Proton fluxes of ~1032 accelerated particles take place at the current sheet decay. Proton acceleration in a flare occurs along a singular line of the current sheet by the Lorentz electric field, as in the pinch gas discharge. The duration of proton flux measured on the Earth orbit is by 2 - 3 orders of magnitude longer than the duration of flares. The high energy proton flux from the flares that appear on the western part of the solar disk arrives to Earth with the time of flight. These particles propagate along magnetic lines of the Archimedes spiral connecting the flare with the Earth. Protons from the flare on the eastern part of the solar disk begin to register with a delay of several hours. Such particles cannot get on the magnetic field line connecting the flare with the Earth. These protons reach the Earth, moving across the interplanetary magnetic field. The particles captured by the magnetic field in the solar wind are transported with solar wind and due to diffusion across the magnetic field. The patterns of solar cosmic rays generation demonstrated in this paper are not always observed in the small ('1 cm-2 s-1 ster-1) proton events.

  5. Microphysics of cosmic ray driven plasma instabilities

    CERN Document Server

    Bykov, A M; Malkov, M A; Osipov, S M

    2013-01-01

    Energetic nonthermal particles (cosmic rays, CRs) are accelerated in supernova remnants, relativistic jets and other astrophysical objects. The CR energy density is typically comparable with that of the thermal components and magnetic fields. In this review we discuss mechanisms of magnetic field amplification due to instabilities induced by CRs. We derive CR kinetic and magnetohydrodynamic equations that govern cosmic plasma systems comprising the thermal background plasma, comic rays and fluctuating magnetic fields to study CR-driven instabilities. Both resonant and non-resonant instabilities are reviewed, including the Bell short-wavelength instability, and the firehose instability. Special attention is paid to the longwavelength instabilities driven by the CR current and pressure gradient. The helicity production by the CR current-driven instabilities is discussed in connection with the dynamo mechanisms of cosmic magnetic field amplification.

  6. PRECISE COSMIC RAYS MEASUREMENTS WITH PAMELA

    Directory of Open Access Journals (Sweden)

    A. Bruno

    2013-12-01

    Full Text Available The PAMELA experiment was launched on board the Resurs-DK1 satellite on June 15th 2006. The apparatus was designed to conduct precision studies of charged cosmic radiation over a wide energy range, from tens of MeV up to several hundred GeV, with unprecedented statistics. In five years of continuous data taking in space, PAMELA accurately measured the energy spectra of cosmic ray antiprotons and positrons, as well as protons, electrons and light nuclei, sometimes providing data in unexplored energetic regions. These important results have shed new light in several astrophysical fields like: an indirect search for Dark Matter, a search for cosmological antimatter (anti-Helium, and the validation of acceleration, transport and secondary production models of cosmic rays in the Galaxy. Some of the most important items of Solar and Magnetospheric physics were also investigated. Here we present the most recent results obtained by the PAMELA experiment.

  7. A database of charged cosmic rays

    Science.gov (United States)

    Maurin, D.; Melot, F.; Taillet, R.

    2014-09-01

    Aims: This paper gives a description of a new online database and associated online tools (data selection, data export, plots, etc.) for charged cosmic-ray measurements. The experimental setups (type, flight dates, techniques) from which the data originate are included in the database, along with the references to all relevant publications. Methods: The database relies on the MySQL5 engine. The web pages and queries are based on PHP, AJAX and the jquery, jquery.cluetip, jquery-ui, and table-sorter third-party libraries. Results: In this first release, we restrict ourselves to Galactic cosmic rays with Z ≤ 30 and a kinetic energy per nucleon up to a few tens of TeV/n. This corresponds to more than 200 different sub-experiments (i.e., different experiments, or data from the same experiment flying at different times) in as many publications. Conclusions: We set up a cosmic-ray database (CRDB) and provide tools to sort and visualise the data. New data can be submitted, providing the community with a collaborative tool to archive past and future cosmic-ray measurements. http://lpsc.in2p3.fr/crdb; Contact: crdatabase@lpsc.in2p3.fr

  8. Cosmic Ray Origin, Acceleration and Propagation

    CERN Document Server

    Baring, M G

    1999-01-01

    This paper summarizes highlights of the OG3.1, 3.2 and 3.3 sessions of the XXVIth International Cosmic Ray Conference in Salt Lake City, which were devoted to issues of origin/composition, acceleration and propagation.

  9. Cosmic ray muons in the deep ocean

    Science.gov (United States)

    Dumand Collaboration; Babson, J.; Barish, B.; Becker-Szenzy, R.; Bradner, H.; Cady, R.; Clem, J.; Dye, S.; Gaidos, J.; Gorham, P.; Grieder, P.; Kitamura, T.; Kropp, W.; Learned, J.; Matsuno, S.; March, R.; Mitsui, K.; O'Conner, D.; Ohashi, Y.; Okada, A.; Peterson, V.; Price, L.; Reines, F.; Roberts, A.; Roos, C.; Sobel, H.; Stenger, V.; Webster, M.; Wilson, C.

    1990-03-01

    A measurement of cosmic ray muon flux was obtained at ocean depths ranging from 2 km to 4 km at 500 m intervals off the West Coast of the Big Island of Hawaii. A brief description of the experiment and the results will be presented in this paper.

  10. Cosmic ray muons in the deep ocean

    Energy Technology Data Exchange (ETDEWEB)

    Babson, J.; Becker-Szenzy, R.; Cady, R.; Dye, S.; Gorham, P.; Learned, J.; Matsuno, S.; O' Conner, D.; Peterson, V.; Roberts, A.; Stenger, V. (Hawaii Univ., Honolulu (USA)); Barish, B. (California Inst. of Tech., Pasadena (USA)); Bradner, H. (California Univ., San Diego, La Jolla (USA)); Clem, J.; Roos, C.; Webster, M. (Vanderbilt Univ., Nashville, TN (USA)); Gaidos, J.; Wilson, C. (Purdue Univ., Lafayette, IN (USA)); Grieder, P. (Bern Univ. (Switzerland)); Kitamura, T.; Mitsui, K.; Ohashi, Y.; Okada, A. (Tokyo Univ. (Japan). Inst. for Cosmic Ray Research); Kropp, W.; Price, L.; Reines, F.; Sobel, H. (California Univ., Irvine (USA)); March, R. (Wisconsin Univ., Madison (USA)); DUMAND Collaboration

    1990-03-01

    A measurement of cosmic ray muon flux was obtained at ocean depths ranging from 2 km to 4 km at 500 m intervals off the West Coast of the Big Island of Hawaii. A brief description of the experiment and the results will be presented in this paper. (orig.).

  11. Recent developments in cosmic ray physics

    CERN Document Server

    Blasi, P

    2014-01-01

    The search for a theory of the origin of cosmic rays that may be considered as a standard, agreeable model is still ongoing. On one hand, much circumstantial evidence exists of the fact that supernovae in our Galaxy play a crucial role in producing the bulk of cosmic rays observed on Earth. On the other hand, important questions about their ability to accelerate particles up to the knee remain unanswered. The common interpretation of the knee as a feature coinciding with the maximum energy of the light component of cosmic rays and a transition to a gradually heavier mass composition is mainly based on KASCADE results. Some recent data appear to question this finding: YAC1 - Tibet Array and ARGO-YBJ find a flux reduction in the light component at $\\sim 700$ TeV, appreciably below the knee. Whether the maximum energy of light nuclei is as high as $3000$ TeV or rather as low as a few hundred TeV has very important consequences on the supernova remnant paradigm for the origin of cosmic rays, as well on the crucia...

  12. Spiral Arms as Cosmic Ray Source Distributions

    CERN Document Server

    Werner, M; Strong, A W; Reimer, O

    2014-01-01

    There is evidence that the distribution of suspected cosmic ray sources are associated with the spiral arm structure of galaxies. It is yet not clearly understood what effect such a cosmic ray source distribution has on the particle transport in our Galaxy. We use the PICARD code to perform high-resolution 3D simulations of electrons and protons in galactic propagation scenarios that include four-arm and two-arm logarithmic spiral cosmic ray source distributions with and without a central bar structure as well as the spiral arm configuration of the NE2001 model for the distribution of free electrons in the Milky Way. Results of these simulation are compared to an axisymmetric radial source distribution. Also, effects on the cosmic ray flux and spectra due to different positions of the Earth relative to the spiral structure are studied. We find that high energy electrons are strongly confined to their sources and the obtained spectra largely depend on the Earth's position relative to the spiral arms. Similar f...

  13. Interacting Cosmic Rays with Molecular Clouds: A Bremsstrahlung Origin of Diffuse High Energy Emission from the Inner 2deg by 1deg of the Galactic Center

    CERN Document Server

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

    2012-01-01

    The high energy activity in the inner few degrees of the Galactic center is traced by diffuse radio, X-ray and gamma-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 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 FeI 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 multi-wavelength emission in the context of bremsstrahlung emission...

  14. Isotopic Composition of Cosmic Rays:. Results from the Cosmic Ray Isotope Spectrometer on the Ace Spacecraft

    Science.gov (United States)

    Israel, M. H.

    Over the past seven years the Cosmic Ray Isotope Spectrometer (CRIS) on the ACE spacecraft has returned data with an unprecedented combination of excellent mass resolution and high statistics, describing the isotopic composition of elements from lithium through nickel in the energy interval ~ 50 to 500 MeV/nucleon. These data have demonstrated: * The time between nucleosynthesis and acceleration of the cosmic-ray nuclei is at least 105 years. The supernova in which nucleosynthesis takes place is thus not the same supernova that accelerates a heavy nucleus to cosmic-ray energy. * The mean confinement time of cosmic rays in the Galaxy is 15 Myr. * The isotopic composition of the cosmic-ray source is remarkably similar to that of solar system. The deviations that are observed, particularly at 22Ne and 58Fe, are consistent with a model in which the cosmic-ray source is OB associations in which the interstellar medium has solar-system composition enriched by roughly 20% admixture of ejecta from Wolf-Rayet stars and supernovae. * Cosmic-ray secondaries that decay only by electron capture provide direct evidence for energy loss of cosmic rays as they penetrate the solar system. This invited overview paper at ECRS 19 was largely the same as an invited paper presented a month earlier at the 8th Nuclei in the Cosmos Conference in Vancouver. The proceedings of that conference will be published shortly by Elsevier as a special edition of Nuclear Physics A. For further summary of results from CRIS, the reader is referred to URL and links on that page to CRIS and to Science News.

  15. Heliospheric Impact on Cosmic Rays Modulation

    Science.gov (United States)

    Tiwari, Bhupendra Kumar

    2016-07-01

    Heliospheric Impact on Cosmic RaysModulation B. K. Tiwari Department of Physics, A. P. S. University, Rewa (M.P.), btiwari70@yahoo.com Cosmic rays (CRs) flux at earth is modulated by the heliosphereric magnetic field and the structure of the heliosphere, controls by solar outputs and their variability. Sunspots numbers (SSN) is often treated as a primary indicator of solar activity (SA). GCRs entering the helioshphere are affected by the interplanetary magnetic field (IMF) and solar wind speed, their modulation varies with the varying solar activity. The observation based on data recoded from Omniweb data Centre for solar- interplanetary activity indices and monthly mean count rate of cosmic ray intensity (CRI) data from neutron monitors of different cut-off rigidities(Rc) (Moscow Rc=2.42Gv and Oulu Rc=0.80Gv). During minimum solar activity periodof solar cycle 23/24, the sun is remarkably quiet, weakest strength of the IMF and least dense and slowest, solar wind speed, whereas, in 2003, highest value of yearly averaged solar wind speed (~568 Km/sec) associated with several coronal holes, which generate high speed wind stream has been recorded. It is observed that GCRs fluxes reduces and is high anti-correlated with SSN (0.80) and IMF (0.86). CRI modulation produces by a strong solar flare, however, CME associated solar flare produce more disturbance in the interplanetary medium as well as in geomagnetic field. It is found that count rate of cosmic ray intensity and solar- interplanetary parameters were inverse correlated and solar indices were positive correlated. Keywords- Galactic Cosmic rays (GCRs), Sunspot number (SSN), Solar activity (SA), Coronal Mass Ejection (CME), Interplanetary magnetic field (IMF)

  16. Cosmic Rays Astrophysics: The Discipline, Its Scope, and Its Applications

    Science.gov (United States)

    Barghouty, A. F.

    2009-01-01

    This slide presentation gives an overview of the discipline surrounding cosmic ray astrophysics. It includes information on recent assertions surrounding cosmic rays, exposure levels, and a short history with specific information on the origin, acceleration, transport, and modulation of cosmic rays.

  17. Re-evaluation of cosmic ray cutoff terminology

    Science.gov (United States)

    Cooke, D. J.; Humble, J. E.; Shea, M. A.; Smart, D. F.; Lund, N.; Rasmussen, I. L.; Byrnak, B.; Goret, P.; Petrou, N.

    1985-01-01

    The study of cosmic ray access to locations inside the geomagnetic field has evolved in a manner that has led to some misunderstanding and misapplication of the terminology originally developed to describe particle access. This paper presents what is believed to be a useful set of definitions for cosmic ray cutoff terminology for use in theoretical and experimental cosmic ray studies.

  18. On the Origin of Ultra High Energy Cosmic Rays

    Energy Technology Data Exchange (ETDEWEB)

    Fowler, T; Colgate, S; Li, H

    2009-07-01

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

  19. Cosmic ray propagation with CRPropa 3

    Science.gov (United States)

    Alves Batista, R.; Erdmann, M.; Evoli, C.; Kampert, K.-H.; Kuempel, D.; Mueller, G.; Sigl, G.; Van Vliet, A.; Walz, D.; Winchen, T.

    2015-05-01

    Solving the question of the origin of ultra-high energy cosmic rays (UHECRs) requires the development of detailed simulation tools in order to interpret the experimental data and draw conclusions on the UHECR universe. CRPropa is a public Monte Carlo code for the galactic and extragalactic propagation of cosmic ray nuclei above ∼ 1017 eV, as well as their photon and neutrino secondaries. In this contribution the new algorithms and features of CRPropa 3, the next major release, are presented. CRPropa 3 introduces time-dependent scenarios to include cosmic evolution in the presence of cosmic ray deflections in magnetic fields. The usage of high resolution magnetic fields is facilitated by shared memory parallelism, modulated fields and fields with heterogeneous resolution. Galactic propagation is enabled through the implementation of galactic magnetic field models, as well as an efficient forward propagation technique through transformation matrices. To make use of the large Python ecosystem in astrophysics CRPropa 3 can be steered and extended in Python.

  20. Direct Measurements of Cosmic Rays (up to ~TeV and beyond)

    Science.gov (United States)

    Coutu, Stéphane; Cabezas, Denis; Salinas, C. J. Solano; Xoxocotzi, Reyna

    2009-04-01

    The objective of this paper is to provide a brief overview of selected experimental measurements in the field of cosmic rays. Galactic cosmic rays are composed of primary and secondary particles. Primary cosmic rays are thought to be energized by supernova shocks within our Galaxy. The cosmic rays that eventually arrive at the Earth are mainly protons and atomic nuclei, but also contain electrons. Secondary cosmic rays are produced in collisions of primary particles with the diffuse interstellar gas and are scarce but carry important information on the Galactic propagation of the primary particles. The secondary component includes a small fraction of antimatter particles, antiprotons and positrons; these may also come from unusual sources and could possibly provide a window into new physics. For example, in the Galactic halo there could take place annihilations of heavy supersymmetric dark matter particles, which could lead to positrons or antiprotons.

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

    CERN Document Server

    Thoudam, Satyendra

    2011-01-01

    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 $\\sim (20-30)$ TeV energies.

  2. Resolving photons from cosmic ray in DAMPE

    Science.gov (United States)

    Xu, Zunlei; Chang, Jin; Li, Xiang; Dong, TieKuang; Zang, Jingjing

    2016-07-01

    The Dark Matter Particle Explorer(DAMPE), which took to the skies on 17 December, is designed for high energy cosmic ray ion detection. The proportion of photons in the cosmic ray is very small, so it's difficult to distinguish between photons and 'background', but necessary for any DAMPE gamma-ray science goals.The paper present a algorithm to identify photons from 'background' mainly by the tracker/converter, which promote pair conversion and measure the directions of incident particles, and an anticoincidence detector,featuring an array of plastic scintillator to detect the charged particles.The method has been studied by simulating using the GEANT4 Monte Carlo simulation code and adjusted by the BeamTest at CERN in December,2014.In addition,DAMPE photon detection capabilities can be checked using the flight data.

  3. HD/H2 as a probe of the roles of gas, dust, light, metallicity and cosmic rays in promoting the growth of molecular hydrogen in the diffuse interstellar medium

    CERN Document Server

    Liszt, H S

    2014-01-01

    We modelled recent observations of UV absorption of HD and \\HH\\ in the Milky Way and toward damped/sub-damped Lyman alpha systems at z=0.18 and z $>$ 1.7. N(HD)/N(\\HH) ratios reflect the separate self-shieldings of HD and \\HH\\ and the coupling introduced by deuteration chemistry. Locally, observations are explained by diffuse molecular gas with $ 16 \\pccc \\la$ n(H) $\\la 128 \\pccc $ if the cosmic-ray ionization rate per H-nucleus \\zetaH $= 2\\times 10^{-16}\\ps$ as inferred from \\H3\\p\\ and OH\\p. The dominant influence on N(HD)/N(\\HH) is the cosmic-ray ionization rate with a much weaker downward dependence on n(H) at Solar metallicity, but dust-extinction can drive N(HD) higher as with N(\\HH). At z $>$ 1.7, N(HD) is comparable to the Galaxy but with 10x smaller N(\\HH) and somewhat smaller N(\\HH)/N(H I). Comparison of our Galaxy and the Magellanic Clouds shows that smaller \\HH/H is expected at sub-Solar metallicity and we show by modelling that HD/\\HH\\ increases with density at low metallicity, opposite to the Mil...

  4. Cosmological structure formation shocks and cosmic rays in hydrodynamical simulations

    CERN Document Server

    Pfrommer, C; Ensslin, T A; Jubelgas, M; Pfrommer, Christoph; Springel, Volker; Ensslin, Torsten A.; Jubelgas, Martin

    2006-01-01

    Cosmological shock waves during structure formation not only play a decisive role for the thermalization of gas in virializing structures but also for the acceleration of relativistic cosmic rays (CRs) through diffusive shock acceleration. We discuss a novel numerical treatment of the physics of cosmic rays in combination with a formalism for identifying and measuring the shock strength on-the-fly during a smoothed particle hydrodynamics simulation. In our methodology, the non-thermal CR population is treated self-consistently in order to assess its dynamical impact on the thermal gas as well as other implications on cosmological observables. Using this formalism, we study the history of the thermalization process in high-resolution hydrodynamic simulations of the Lambda cold dark matter model. Collapsed cosmological structures are surrounded by shocks with high Mach numbers up to 1000, but they play only a minor role in the energy balance of thermalization. However, this finding has important consequences fo...

  5. Time-Dependent Modulation of Cosmic Rays in the Heliosphere

    CERN Document Server

    Manuel, Rex; Potgieter, Marius

    2013-01-01

    The time-dependent modulation of galactic cosmic rays in the heliosphere is studied by computing intensities using a time-dependent modulation model. By introducing recent theoretical advances in the transport coefficients in the model, computed intensities are compared with Voyager 1, International Monitoring Platform (IMP) 8, and Ulysses proton observations in search of compatibility. The effect of different modulation parameters on computed intensities is also illustrated. It is shown that this approach produces, on a global scale, realistic cosmic-ray proton intensities along the Voyager 1 spacecraft trajectory and at Earth upto ~2004, whereafter the computed intensities recovers much slower towards solar minimum than observed in the inner heliosphere. A modified time dependence in the diffusion coefficients is proposed to improve compatibility with the observations at Earth after ~2004. This modified time dependence led to an improved compatibility between computed intensities and the observations along ...

  6. Cosmic ray physics with the ALEPH detector

    CERN Document Server

    Besier, H; Kempa, J; Luitz, S; Maggi, M; Maier, D; Misiejuk, A; Müller, A S; Putzer, A; Rensch, B; Sander, H G; Schmeling, S; Schmelling, M; Schreiber, V; Wachsmuth, H W; Ziegler, T; Zuber, K

    2000-01-01

    ALEPH is one of the four detectors at the Large Electron-Positron Collider (LEP) at a depth of about 320 m.w.e. Its hadron calorimeter and scintillator arrays installed at distances up to about 1 km away from ALEPH are used to measure cosmic muon induced time coincidences over large distances. The aim of this experiment (CosmoALEPH) is (1) to study the muon component above 70 GeV of extensive air showers (EAS) and (2) to test the feasibility of searching for time correlations over even larger distances (up to 8 km) between the four LEP detectors. Layout and first results of CosmoALEPH are presented demonstrating the potential for cosmic ray physics in the LEP tunnel. The multiplicity distribution of muons in cosmic events recorded in ALEPH's tracking detector is presented. (28 refs).

  7. Diffuse flux of galactic neutrinos and gamma rays

    Science.gov (United States)

    Carceller, J. M.; Masip, M.

    2017-03-01

    We calculate the fluxes of neutrinos and gamma rays from interactions of cosmic rays with interstellar matter in our galaxy. We use EPOS-LHC, SIBYLL and GHEISHA to parametrize the yield of these particles in proton, helium and iron collisions at kinetic energies between 1 and 108 GeV, and we correlate the cosmic ray density with the mean magnetic field strength in the disk and the halo of our galaxy. We find that at E > 1 PeV the fluxes depend very strongly on the cosmic-ray composition, whereas at 1–5 GeV the main source of uncertainty is the cosmic-ray spectrum out of the heliosphere. We show that the diffuse flux of galactic neutrinos becomes larger than the conventional atmospheric one at E>1 PeV, but that at all IceCube energies it is 4 times smaller than the atmospheric flux from forward-charm decays.

  8. Transport of Cosmic Rays in Chaotic Magnetic Fields

    CERN Document Server

    Casse, F; Pelletier, G; Casse, Fabien; Lemoine, Martin; Pelletier, Guy

    2002-01-01

    The transport of charged particles in disorganised magnetic fields is an important issue which concerns the propagation of cosmic rays of all energies in a variety of astrophysical environments, such as the interplanetary, interstellar and even extra-galactic media, as well as the efficiency of Fermi acceleration processes. We have performed detailed numerical experiments using Monte-Carlo simulations of particle propagation in stochastic magnetic fields in order to measure the parallel and transverse spatial diffusion coefficients and the pitch angle scattering time as a function of rigidity and strength of the turbulent magnetic component. We confirm the extrapolation to high turbulence levels of the scaling predicted by the quasi-linear approximation for the scattering frequency and parallel diffusion coefficient at low rigidity. We show that the widely used Bohm diffusion coefficient does not provide a satisfactory approximation to diffusion even in the extreme case where the mean field vanishes. We find ...

  9. K-alpha X-rays from cosmic ray oxygen. [Detection and calculation of equilibrium charge fractions

    Science.gov (United States)

    Pravdo, S. H.; Boldt, E. A.

    1975-01-01

    Equilibrium charge fractions are calculated for subrelativistic cosmic ray oxygen ions in the interstellar medium. These are used to determine the expected flux of K-alpha rays arising from atomic processes for a number of different postulated interstellar oxygen spectra. Relating these results to the diffuse X-ray background measured at the appropriate energy level suggests an observable line feature. If the flux of low energy cosmic ray oxygen is sufficiently large, K-alpha X-ray line emission from these nuclei will comprise a significant fraction of the total diffuse flux at approximately 0.6 keV. A satellite borne detector with a resolution greater than 30 percent could observe this feature if the subrelativistic interstellar cosmic ray oxygen spectrum is as large as certain theoretical estimates expressed in the text.

  10. 3D heliospheric simulations of cosmic rays in the light of Ulysses

    Energy Technology Data Exchange (ETDEWEB)

    Jokipii, J.R.; Kota, J. [Tucson, The Univ. of Arizona (United States)

    1996-11-01

    Recent Ulysses observations in the polar regions of the heliosphere have provided fundamental new insights into the modes of cosmic-ray transport in the heliosphere. Ulysses discovered variations in the magnetic field which are large enough to produce significant cosmic-ray effects, and which are consistent which a previous prediction. In addition to impeding the inward, radial diffusive and drift access of cosmic rays over the poles as discussed previously, the magnetic fluctuations imply a significantly larger latitudinal diffusion. These effects directly lead to both a much reduced latitudinal gradient and significant 27 day time variations near the pole. The author concludes that the general picture of cosmic-ray transport and modulation development over the past decade, with reasonable parameters, can account for most of the observed global, large-scale phenomena.

  11. Long-lived staus from cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Ahlers, M. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Illana, J.I.; Masip, M. [Granada Univ. (Spain). CAFPE y Dept. de Fisica Teorica y del Cosmos; Meloni, D. [Univ. degli Studi di Roma La Spienza (Italy). Dipt. di Fisica; INFN, Roma (Italy)

    2007-05-15

    The collision of a high energy cosmic ray with a nucleon in the upper atmosphere could produce long-lived heavy particles. Such particles would be very penetrating, since the energy loss in matter scales as the inverse mass, and could reach a neutrino telescope like IceCube from large zenith angles. Here we study this possibility and focus on the long-lived stau of SUSY models with a gravitino LSP. The signal would be a pair of muon-like parallel tracks separated by 50 meters along the detector. We evaluate the background of muon pairs and show that any events from zenith angles above 80. could be explained by the production of these heavy particles by cosmic rays. (orig.)

  12. Cosmic Ray physics with ARGO-YBJ

    Energy Technology Data Exchange (ETDEWEB)

    Iacovacci, M. [Dipartimento di Fisica dell' Università di Napoli ”Federico II” and INFN Napoli, Complesso Universitario MSA, Via Cintia, 80126 Napoli (Italy)

    2013-06-15

    The ARGO-YBJ experiment has been in stable data taking from November 2007 till February 2013 at the Yang-BaJing Cosmic Ray Laboratory (Tibet, P.R.China, 4300 m a.s.l.). It exploits the full coverage and the high altitude to detect air showers with an energy threshold as low as a few hundred GeV. The detector is made of a single layer of RPCs operated in streamer mode, fully instrumenting a central carpet of about 5800 m{sup 2}. A guard ring extends the partially instrumented area to about 11,000 m{sup 2}. The main results so far achieved on Cosmic Ray physics are reported.

  13. The glacial cycles and cosmic rays

    CERN Document Server

    Kirkby, Jasper; Müller, R A

    2004-01-01

    The cause of the glacial cycles remains a mystery. The origin is widely accepted to be astronomical since paleoclimatic archives contain strong spectral components that match the frequencies of Earth's orbital modulation. Milankovitch insolation theory contains similar frequencies and has become established as the standard model of the glacial cycles. However, high precision paleoclimatic data have revealed serious discrepancies with the Milankovitch model that fundamentally challenge its validity and re-open the question of what causes the glacial cycles. We propose here that the ice ages are initially driven not by insolation cycles but by cosmic ray changes, probably through their effect on clouds. This conclusion is based on a wide range of evidence, including results presented here on speleothem growth in caves in Austria and Oman, and on a record of cosmic ray flux over the past 220 kyr obtained from the 10Be composition of deep-ocean sediments.

  14. The Pierre Auger Cosmic Ray Observatory

    CERN Document Server

    ,

    2015-01-01

    The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above $10^{17}$ eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water-Cherenkov particle detector stations spread over 3000 km$^2$ overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5 km$^2$, 61 detector infill array. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000 km$^2$ sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Auger Observatory.

  15. Ultra High Energy Cosmic Rays: Strangelets?

    Institute of Scientific and Technical Information of China (English)

    徐仁新; 吴飞

    2003-01-01

    The conjecture that ultra-high-energy cosmic rays (UHECRs) are actually strangelets is discussed. Besides the reason that strangelets can do as cosmic rays beyond the Greisen-Zatsepin-Kuzmin-cutoff, another argument to support the conjecture is addressed by the study of formation of Te V-scale microscopic black holes when UHECRs bombarding bare strange stars. It is proposed that the exotic quark surface of a bare strange star could be an effective astro-laboratory in the investigations of the extra dimensions and of the detection of ultra-high-energy neutrino fluxes. The flux of neutrinos (and other point-like particles) with energy larger than 2.3 × 1020 eV could be expected to be smaller than 10-26 cm-2 s-1 if there are two extra spatial dimensions.

  16. Are ultrahigh energy cosmic rays heavy nuclei?

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, A.A. [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation)

    2008-01-15

    A new approach to estimate the composition of cosmic rays is proposed. It is found that the zenith angle distributions and muon components of extensive air showers observed by the Yakutsk and AGASA arrays for energies E>10{sup 19} eV and E>4x10{sup 19} eV differ from each other. It is suggested that the primary cosmic rays at E>4x10{sup 19}eV are heavier than those at E{approx}10{sup 19} eV. In our method we selected one variant to estimate the shower energy from two variants, as suggested by physicists of the SUGAR array. According to the 'Hillas-E' model, the SUGAR array has detected 8 showers with energy E>10{sup 20} eV.

  17. The Pierre Auger Cosmic Ray Observatory

    Science.gov (United States)

    Pierre Auger Collaboration

    2015-10-01

    The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and characteristics of cosmic rays above 1017 eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water Cherenkov particle detector stations spread over 3000 km2 overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5 km2, 61-detector infilled array with 750 m spacing. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000 km2 sr yr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Observatory.

  18. Solar cosmic rays fundamentals and applications

    CERN Document Server

    Miroshnichenko, Leonty

    2015-01-01

    The book summarizes the results of solar cosmic ray (SCR) investigations since 1942. The present monograph, unlike the reviews published earlier, treats the problem in self-contained form, in all its associations—from fundamental astrophysical aspects to geophysical, aeronautical and cosmonautical applications. It includes a large amount of new data, accumulated during the last several decades of space research. As a result of the "information burst" in space physics, there are a lot of new interesting theoretical concepts, models and ideas that deserve attention. The author gives an extensive bibliography, which covers non-partially the main achievements and failures in this field. The book will be helpful for a wide audience of space physicists and it will be relevant to graduate and postgraduate courses. The book will serve as a reference work for researchers and students in solar physics and astrophysical plasma physics, as well as in cosmic rays physics, astroparticle physics, space science, solar-terr...

  19. Astroparticle Physics: Detectors for Cosmic Rays

    Science.gov (United States)

    Salazar, Humberto; Villaseñor, Luis

    2006-09-01

    We describe the work that we have done over the last decade to design and construct instruments to measure properties of cosmic rays in Mexico. We describe the measurement of the muon lifetime and the ratio of positive to negative muons in the natural background of cosmic ray muons at 2000 m.a.s.l. Next we describe the detection of decaying and crossing muons in a water Cherenkov detector as well as a technique to separate isolated particles. We also describe the detection of isolated muons and electrons in a liquid scintillator detector and their separation. Next we describe the detection of extensive air showers (EAS) with a hybrid detector array consisting of water Cherenkov and liquid scintillator detectors, located at the campus of the University of Puebla. Finally we describe work in progress to detect EAS at 4600 m.a.s.l. with a water Cherenkov detector array and a fluorescence telescope at the Sierra Negra mountain.

  20. Cosmic-ray knee and flux of secondaries from interactions of cosmic rays with dark matter

    CERN Document Server

    Masip, Manuel

    2009-01-01

    We discuss possible implications of a large interaction cross section between cosmic rays and dark matter particles due to new physics at the TeV scale. In particular, in models with extra dimensions and a low fundamental scale of gravity the cross section grows very fast at transplanckian energies. We argue that the knee observed in the cosmic ray flux could be caused by such interactions. We show that this hypothesis implies a well defined flux of secondary gamma rays that seems consistent with MILAGRO observations.

  1. Ultrahigh Energy Cosmic Rays: New Physics or Old Physics?

    CERN Document Server

    Stecker, F W

    2004-01-01

    We consider the advantages of and the problems associated with hypotheses to explain the origin of ulthrahigh energy cosmic rays (UHECR: E > 10 EeV) and the "trans GZK" cosmic rays (TGZK: E > 100 EeV), both through "old physics" (acceleration in cosmic sources) and "new physics" (new particles, topological defects, fat neutrino cross sections, Lorentz invariance violation).

  2. Longevity and Highest-Energy Cosmic Rays

    Science.gov (United States)

    Frampton, Paul H.; Keszthelyi, Bettina; Ng, Y. Jack

    It is proposed that the highest energy ~1020 eV cosmic ray primaries are protons which are decay products of a superheavy particle, G. The protons may be decay products either directly of a nearby (galactic) G or of a long-lived intermediate particle X which arises from decay of a distant (cosmological) G, then decays in or near our Galaxy. Such scenarios can occur in e.g. SU(15) grand unification and in some preon models.

  3. Cosmic ray test station for ATLAS RPC

    CERN Document Server

    Pietra, M Della; Canale, V; Caprio, M A; Carlino, G; Conventi, F; De Asmundis, R; Iengo, P; Patricelli, S; Romanó, L; Sekhniaidze, G; Della Volpe, D

    2003-01-01

    We describe the facility for RPC test with cosmic rays, designed and built at the laboratory of INFN and University of Naples. Trigger and tracking systems consist of a scintillator hodoscope and two drift chambers with track reconstruction resolution of similar to 400 mum. Trigger is provided by the twofold coincidence of scintillators covering a surface of 1 m**2. Two step motors move chambers synchronously along the station for RPC scanning. Up to eight RPCs can be tested simultaneously.

  4. Cosmic ray air showers from sphalerons

    Science.gov (United States)

    Brooijmans, Gustaaf; Schichtel, Peter; Spannowsky, Michael

    2016-10-01

    The discovery of the Higgs boson marks a key ingredient to establish the electroweak structure of the Standard Model. Its non-abelian gauge structure gives rise to, yet unobserved, non-perturbative baryon and lepton number violating processes. We propose to use cosmic ray air showers, as measured, for example, at the Pierre Auger Observatory, to set a limit on the hadronic production cross section of sphalerons. We identify several observables to discriminate between sphaleron and QCD induced air showers.

  5. PeV neutrinos from intergalactic interactions of cosmic rays emitted by active galactic nuclei

    CERN Document Server

    Kalashev, Oleg E; Essey, Warren

    2013-01-01

    The observed spectra of distant blazars are well described by secondary gamma rays produced in line-of-sight interactions of cosmic rays with background photons. In the absence of the cosmic-ray contribution, these spectra would appear surprisingly hard, but the cosmic ray interactions generate very high energy gamma rays relatively close to the observer, and the spectra agree with the data. The same interactions of cosmic rays are expected to produce a flux of neutrinos with energies peaked around 1 PeV. We show that the predicted diffuse isotropic neutrino background from many distant sources can explain the neutrino events recently detected by the IceCube experiment. We also find that the flux from any individual nearby source is insufficient to account for these events. The narrow spectrum around 1 PeV implies that a typical active galactic nucleus can accelerate protons to EeV energies.

  6. Cosmic Ray Data in TRT Barrel

    CERN Multimedia

    M. Hance

    "I had a great day in August when I went into SR1," said Daniel Froidevaux, former project leader of the ATLAS Transition Radiation Tracker, "not only had all SCT barrels arrived at CERN, but there were cosmic ray tracks seen in the TRT!" Daniel's excitement was mirrored by the rest of the TRT collaboration when, on July 29, the first cosmic ray tracks were seen in the barrel. Along with many others in the community, Daniel was quick to point out that this is the cumulative result of years of R&D, test beam work, and an intense installation and integration schedule. Indeed, the cosmic ray readout is only possible through the coordination of many efforts, from detector mechanics to module assembly, power and high voltage control, cooling, gas systems, electronics and cabling, data acquisition, and monitoring. "Many people have worked very hard on the the TRT, some of them for more than 10 years," said Brig Williams, the leader of the UPenn group responsible for much of the TRT front end electronics. He ...

  7. High energy cosmic ray and neutrino astronomy

    CERN Document Server

    Waxman, E

    2011-01-01

    Cosmic-rays with energies exceeding 10^{19} eV are referred to as Ultra High Energy Cosmic Rays (UHECRs). The sources of these particles and their acceleration mechanism are unknown, and for many years have been the issue of much debate. The first part of this review describes the main constraints, that are implied by UHECR observations on the properties of candidate UHECR sources, the candidate sources, and the related main open questions. In order to address the challenges of identifying the UHECR sources and of probing the physical mechanisms driving them, a "multi-messenger" approach will most likely be required, combining electromagnetic, cosmic-ray and neutrino observations. The second part of the review is devoted to a discussion of high energy neutrino astronomy. It is shown that detectors, which are currently under construction, are expected to reach the effective mass required for the detection of high energy extra-Galactic neutrino sources, and may therefore play a key role in the near future in re...

  8. Electrons and Positrons in Cosmic Rays

    CERN Document Server

    Panov, A D

    2013-01-01

    This review concentrates on the results obtained, over the last ten years, on the astrophysics of high-energy cosmic ray electrons and positrons. The anomalies, observed in the data of recent experiments (possible bump in the electron spectrum and the PAMELA anomaly in the positron fraction) are discussed through the systematic use of simple analytical solutions of the transport equations for cosmic ray electrons. Three main ways of explaining the origin of the anomalies are considered: the conservative way supposing the positrons to be pure secondary particles; the nearby sources like pulsars origin; and the dark matter origin. This review discusses, also, the inability to select the pulsars model or the dark matter model to explain the electron anomalies on the basis of the electron spectra with the usual large energy binning ($\\gtrsim15%$). It is argued that the signature of nearby pulsars origin of the anomalies against the dark matter origin could be the fine structure of the cosmic ray electron spectrum...

  9. Solar panels as cosmic-ray detectors

    CERN Document Server

    Stella, Carlo; Assis, Pedro; Brogueira, Pedro; Santo, Catarina Espirito; Goncalves, Patricia; Pimenta, Mario; De Angelis, Alessandro

    2014-01-01

    Due to fundamental limitations of accelerators, only cosmic rays can give access to centre-of- mass energies more than one order of magnitude above those reached at the LHC. In fact, extreme energy cosmic rays (1018 eV - 1020 eV) are the only possibility to explore the 100 TeV energy scale in the years to come. This leap by one order of magnitude gives a unique way to open new horizons: new families of particles, new physics scales, in-depth investigations of the Lorentz symmetries. However, the flux of cosmic rays decreases rapidly, being less than one particle per square kilometer per year above 1019 eV: one needs to sample large surfaces. A way to develop large-effective area, low cost, detectors, is to build a solar panel-based device which can be used in parallel for power generation and Cherenkov light detection. Using solar panels for Cherenkov light detection would combine power generation and a non-standard detection device.

  10. The theoretical and experimental investigation of cosmic ray Forbush-effects

    Science.gov (United States)

    Alania, M. V.; Bakradze, T. S.; Borchorishvili, T.; Bochikashvili, D. P.; Despotashvili, M. A.; Nachkebia, N. A.

    1985-01-01

    The theoretical results of analysis of the expected spatial distributions of density, gradients and anisotropy of cosmic rays, obtained on the basis of the numerical solution of anisotropic diffusion equation in the presence of the disturbances of shock wave type in the interplanetary space are presented. The theoretical calculations on the definition of the energy spectrum and anisotropy of galactic cosmic rays during Forbush effect are compared with the experimental data.

  11. Extremely fast acceleration of cosmic rays in a supernova remnant.

    Science.gov (United States)

    Uchiyama, Yasunobu; Aharonian, Felix A; Tanaka, Takaaki; Takahashi, Tadayuki; Maeda, Yoshitomo

    2007-10-04

    Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of the SNR RX J1713.7-3946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RX J1713.7-3946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (10(15) eV) and beyond in young supernova remnants.

  12. Extremely Fast Acceleration of Cosmic Rays in a Supernova Remnant

    Energy Technology Data Exchange (ETDEWEB)

    Uchiyama, Y.; Aharonian, F.A.; Tanaka, T.; Takahashi, T.; Maeda, Y.; /JAERI, Tokai /Dublin Inst. /Heidelberg, Max Planck Inst. /SLAC

    2007-10-23

    Galactic cosmic rays (CRs) are widely believed to be accelerated by shock waves associated with the expansion of supernova ejecta into the interstellar medium. A key issue in this long-standing conjecture is a theoretical prediction that the interstellar magnetic field can be substantially amplified at the shock of a young supernova remnant (SNR) through magnetohydrodynamic waves generated by cosmic rays. Here we report a discovery of the brightening and decay of X-ray hot spots in the shell of theSNRRXJ1713.723946 on a one-year timescale. This rapid variability shows that the X-rays are produced by ultrarelativistic electrons through a synchrotron process and that electron acceleration does indeed take place in a strongly magnetized environment, indicating amplification of the magnetic field by a factor of more than 100. The X-ray variability also implies that we have witnessed the ongoing shock-acceleration of electrons in real time. Independently, broadband X-ray spectrometric measurements of RXJ1713.723946 indicate that electron acceleration proceeds in the most effective ('Bohm-diffusion') regime. Taken together, these two results provide a strong argument for acceleration of protons and nuclei to energies of 1 PeV (10{sup 15} eV) and beyond in young supernova remnants.

  13. Cosmic X-ray background and solitars.

    Science.gov (United States)

    Chiu, H.-Y.

    In this paper the authors has examined the observational consequences of a class of new astronomical objects proposed by Friedberg, Lee and Pang, called solitars which are degenerate vacuum states embedded with particles. A study is made to include finite temperature effect and pair creation. Quark is believed to be the only species that can exist in the interior of solitars. Massive quark solitars are primarily X-ray emitters and may account for the large unexplained thermal component of the cosmic X-ray background.

  14. Stable laws and cosmic ray physics

    Science.gov (United States)

    Genolini, Y.; Salati, P.; Serpico, P. D.; Taillet, R.

    2017-03-01

    Context. In the new "precision era" for cosmic ray astrophysics, scientists making theoretical predictions cannot content themselves with average trends, but need to correctly take into account intrinsic uncertainties. The space-time discreteness of the cosmic ray sources, together with a substantial ignorance of their precise epochs and locations (with the possible exception of the most recent and close ones) play an important role in this sense. Aims: We elaborate a statistical theory to deal with this problem, relating the composite probability P(Ψ) to obtain a flux Ψ at the Earth and the single-source probability p(ψ) to contribute with a flux ψ. The main difficulty arises from the fact that p(ψ) is a "heavy tail" distribution, characterized by power-law or broken power-law behavior up to very large fluxes, for which the central limit theorem does not hold, and leading to distributions different from Gaussian. The functional form of the distribution for the aggregated flux is nonetheless unchanged by its own convolution, that is, it belongs to the so-called stable laws class. Methods: We analytically discuss the regime of validity of the stable laws associated with the distributions arising in cosmic ray astrophysics, as well as the limitations to the treatment imposed by causal considerations and partial source catalog knowledge. We validate our results with extensive Monte Carlo simulations, for different regimes of propagation parameters and energies. Results: We find that relatively simple recipes provide a satisfactory description of the probability P(Ψ). We also find that a naive Gaussian fit to simulation results would underestimate the probability of very large fluxes, that is, several times above the average, while overestimating the probability of relatively milder excursions. At large energies, large flux fluctuations are prevented by causal considerations, while at low energies, a partial knowledge of the recent and nearby population of

  15. Cosmic-ray Driven Outflows in Global Galaxy Disk Models

    CERN Document Server

    Salem, Munier

    2013-01-01

    Galactic-scale winds are a generic feature of massive galaxies with high star formation rates across a broad range of redshifts. Despite their importance, a detailed physical understanding of what drives these mass-loaded global flows has remained elusive. In this paper, we explore the dynamical impact of cosmic rays by performing the first three-dimensional, adaptive mesh refinement simulations of an isolated starbursting galaxy that includes a basic model for the production, dynamics and diffusion of galactic cosmic rays. We find that including cosmic rays naturally leads to robust, massive, bipolar outflows from our 10^12 Msun halo, with a mass-loading factor Mout/SFR = 0.3 for our fiducial run. Other reasonable parameter choices led to mass-loading factors above unity. The wind is multiphase and is accelerated to velocities well in excess of the escape velocity. We employ a two-fluid model for the thermal gas and relativistic CR plasma and model a range of physics relevant to galaxy formation, including r...

  16. Variance of the Galactic nuclei cosmic ray flux

    CERN Document Server

    Bernard, G; Salati, P; Taillet, R

    2012-01-01

    Measurements of cosmic ray fluxes by the PAMELA and CREAM experiments show unexpected spectral features between 200 GeV and 100 TeV. They could be due to the presence of nearby and young cosmic ray sources. This can be studied in the myriad model, in which cosmic rays diffuse from point-like instantaneous sources located randomly throughout the Galaxy. To test this hypothesis, one must compute the flux due to a catalog of local sources, but also the error bars associated to this quantity. This turns out not to be as straightforward as it seems, as the standard deviation is infinite when computed for the most general statistical ensemble. The goals of this paper are to provide a method to associate error bars to the flux measurements which has a clear statistical meaning, and to explore the relation between the myriad model and the more usual source model based on a continuous distribution. To this end, we show that the quantiles of the flux distribution are well-defined, even though the standard deviation is ...

  17. Cosmological simulations of dwarf galaxies with cosmic ray feedback

    Science.gov (United States)

    Chen, Jingjing; Bryan, Greg L.; Salem, Munier

    2016-08-01

    We perform zoom-in cosmological simulations of a suite of dwarf galaxies, examining the impact of cosmic rays (CRs) generated by supernovae, including the effect of diffusion. We first look at the effect of varying the uncertain CR parameters by repeatedly simulating a single galaxy. Then we fix the comic ray model and simulate five dwarf systems with virial masses range from 8 to 30 × 1010 M⊙. We find that including CR feedback (with diffusion) consistently leads to disc-dominated systems with relatively flat rotation curves and constant star formation rates. In contrast, our purely thermal feedback case results in a hot stellar system and bursty star formation. The CR simulations very well match the observed baryonic Tully-Fisher relation, but have a lower gas fraction than in real systems. We also find that the dark matter cores of the CR feedback galaxies are cuspy, while the purely thermal feedback case results in a substantial core.

  18. Ultra-high energy cosmic ray escape from gamma-ray bursts, and the cosmic ray-neutrino connection

    Energy Technology Data Exchange (ETDEWEB)

    Baerwald, Philipp; Bustamante, Mauricio; Huemmer, Svenja; Winter, Walter [Institut fuer Theoretische Physik und Astrophysik, Universitaet Wuerzburg, 97074 Wuerzburg (Germany); Spector, Amyad; Waxman, Eli [Physics Faculty, Weizman Institute of Science, POB 26, Rehovot (Israel)

    2013-07-01

    Recent IceCube searches for GRB neutrinos have strongly constrained current models predicting GRBs as the source of UHECR. We show that updated calculations based on the connection of gamma-rays and neutrinos give significantly lower neutrino bounds [Phys. Rev. Lett. 108 (2012) 231101]. However additional constraints from the theoretical connection of cosmic rays to neutrinos, based on the assumption that UHECR escape as neutrons, still persist. We therefore explore the possibility of having an additional direct cosmic ray escape component which circumvents these constraints. We show that it is possible to distinguish three distinct regimes with this approach, with the standard (one neutrino per cosmic ray) escape via neutrons only accounting for a small range in the parameter space. Moreover we show how this additional component could improve cosmic ray predictions.

  19. The intergalactic propagation of ultrahigh energy cosmic ray nuclei

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-08-01

    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).

  20. Key scientific problems from Cosmic Ray History

    Science.gov (United States)

    Lev, Dorman

    2016-07-01

    Recently was published the monograph "Cosmic Ray History" by Lev Dorman and Irina Dorman (Nova Publishers, New York). What learn us and what key scientific problems formulated the Cosmic Ray History? 1. As many great discoveries, the phenomenon of cosmic rays was discovered accidentally, during investigations that sought to answer another question: what are sources of air ionization? This problem became interesting for science about 230 years ago in the end of the 18th century, when physics met with a problem of leakage of electrical charge from very good isolated bodies. 2. At the beginning of the 20th century, in connection with the discovery of natural radioactivity, it became apparent that this problem is mainly solved: it was widely accepted that the main source of the air ionization were α, b, and γ - radiations from radioactive substances in the ground (γ-radiation was considered as the most important cause because α- and b-radiations are rapidly absorbed in the air). 3. The general accepted wrong opinion on the ground radioactivity as main source of air ionization, stopped German meteorologist Franz Linke to made correct conclusion on the basis of correct measurements. In fact, he made 12 balloon flights in 1900-1903 during his PhD studies at Berlin University, carrying an electroscope to a height of 5500 m. The PhD Thesis was not published, but in Thesis he concludes: "Were one to compare the presented values with those on ground, one must say that at 1000 m altitude the ionization is smaller than on the ground, between 1 and 3 km the same amount, and above it is larger with values increasing up to a factor of 4 (at 5500 m). The uncertainties in the observations only allow the conclusion that the reason for the ionization has to be found first in the Earth." Nobody later quoted Franz Linke and although he had made the right measurements, he had reached the wrong conclusions, and the discovery of CR became only later on about 10 years. 4. Victor Hess, a

  1. Cosmic-ray exposure ages of chondrules

    Science.gov (United States)

    Roth, Antoine S. G.; Metzler, Knut; Baumgartner, Lukas P.; Leya, Ingo

    2016-07-01

    If chondrules were exposed to cosmic rays prior to meteorite compaction, they should retain an excess of cosmogenic noble gases. Beyersdorf-Kuis et al. (2015) showed that such excesses can be detected provided that the chemical composition of each individual chondrule is precisely known. However, their study was limited to a few samples as they had to be irradiated in a nuclear reactor for instrumental neutron activation analysis. We developed a novel analytical protocol that combines the measurements of He and Ne isotopic concentrations with a fast method to correct for differences in chemical composition using micro X-ray computed tomography. Our main idea is to combine noble gas, nuclear track, and petrography data for numerous chondrules to understand the precompaction exposure history of the chondrite parent bodies. Here, we report our results for a total of 77 chondrules and four matrix samples from NWA 8276 (L3.00), NWA 8007 (L3.2), and Bjurböle (L/LL4). All chondrules from the same meteorite have within uncertainty identical 21Ne exposure ages, and all chondrules from Bjurböle have within uncertainty identical 3He exposure ages. However, most chondrules from NWA 8276 and a few from NWA 8007 show small but resolvable differences in 3He exposure age that we attribute to matrix contamination and/or gas loss. The finding that none of the chondrules has noble gas excesses is consistent with the uniform track density found for each meteorite. We conclude that the studied chondrules did not experience a precompaction exposure longer than a few Ma assuming present-day flux of galactic cosmic rays. A majority of chondrules from L and LL chondrites thus rapidly accreted and/or was efficiently shielded from cosmic rays in the solar nebula.

  2. Improved Cosmic-Ray Injection Models and the Galactic Center Gamma-Ray Excess

    CERN Document Server

    Carlson, Eric; Profumo, Stefano

    2016-01-01

    Fermi-LAT observations of the Galactic Center (GC) have revealed a spherically- symmetric excess of GeV gamma rays extending to at least 10 deg from the dynamical center of the Galaxy. A critical uncertainty in extracting the intensity, spectrum, and morphology of this excess concerns the accuracy of astrophysical diffuse gamma-ray emission models near the GC. Recently, it has been noted that many diffuse emission models utilize a cosmic-ray injection rate far below that predicted based on the observed star formation rate in the Central Molecular Zone. In this study, we add a cosmic-ray injection component which non-linearly traces the Galactic H2 density determined in three-dimensions, and find that the associated gamma-ray emission is degenerate with many properties of the GC gamma-ray excess. In models that utilize a large sideband (40x40 deg surrounding the GC) to normalize the best-fitting diffuse emission models, the intensity of the GC excess decreases by a factor of 2, and the morphology of the excess...

  3. The basis for cosmic ray feedback: Written on the wind.

    Science.gov (United States)

    Zweibel, Ellen G

    2017-05-01

    Star formation and supermassive black hole growth in galaxies appear to be self-limiting. The mechanisms for self-regulation are known as feedback. Cosmic rays, the relativistic particle component of interstellar and intergalactic plasma, are among the agents of feedback. Because cosmic rays are virtually collisionless in the plasma environments of interest, their interaction with the ambient medium is primarily mediated by large scale magnetic fields and kinetic scale plasma waves. Because kinetic scales are much smaller than global scales, this interaction is most conveniently described by fluid models. In this paper, I discuss the kinetic theory and the classical theory of cosmic ray hydrodynamics (CCRH) which follows from assuming cosmic rays interact only with self-excited waves. I generalize CCRH to generalized cosmic ray hydrodynamics, which accommodates interactions with extrinsic turbulence, present examples of cosmic ray feedback, and assess where progress is needed.

  4. Are cosmic rays effective for ionization of the solar nebula?

    Science.gov (United States)

    Dolginov, A. Z.; Stepinski, T. F.

    1993-01-01

    In this paper, we argue that the effectiveness of cosmic rays to ionize the bulk of the nebular gas may be further impaired by the influence of the magnetic field on the propagation of cosmic rays. When cosmic rays enter the nebular disk they ionize the gas and make the dynamo generation of magnetic fields possible. However, once magnetic fields are embedded in the nebular gas, the upcoming cosmic rays can no longer penetrate directly into the nebular disk because they start to interact with the magnetic field and lose their energy before propagating significantly toward the midplane. That, in turn, undercuts the ionization source within the bulk of the gas stopping the dynamo action. Nebular dynamo models ignored this back reaction of magnetic fields on cosmic rays. We calculate this back reaction effect, but for the sake of mathematical simplicity, we ignore the effect of magnetic field weakening due to diminishing ionization by cosmic rays.

  5. Modeling cosmic ray propagation and associated interstellar emissions

    Science.gov (United States)

    Moskalenko, Igor

    2012-07-01

    Last several years were highlighted by many breakthroughs and discoveries in astrophysics of cosmic rays (CRs), thanks to superior instruments such as BESS, PAMELA, Fermi-LAT, Agile, INTEGRAL, HESS, VERITAS, Milagro, ATIC, CREAM, ACE and others. They provide key pieces of information that may lead to the solution of the century-old puzzle of the origin of CRs and may contain signatures of new physics. Exploiting the data collected by the scientific missions to the fullest requires reliable and detailed model of the Milky Way galaxy. GALPROP is the current state-of-the-art numerical CR propagation code that has become a standard analysis tool in CR and gamma-ray research. It uses extensive astrophysical information along with nuclear and particle data as input to self-consistently predict CRs, diffuse gamma rays, synchrotron emission and other observables. I will review recent GALPROP developments and results.

  6. Inter-galactic Shock Acceleration and the Cosmic Gamma-ray Background

    CERN Document Server

    Miniati, F

    2002-01-01

    We investigate numerically the contribution to the cosmic gamma-ray background from cosmic-rays ions and electrons accelerated at inter-galactic (IG) shocks associated with cosmological structure formation. We show that the kinetic energy of accretion flows in the low-red-shift IG medium is thermalized primarily through moderately strong shocks, which allow for an efficient conversion of shock ram pressure into cosmic-ray pressure. Cosmic-rays accelerated at these shocks produce a diffuse gamma-ray flux which is dominated by inverse Compton emission from electrons scattering off cosmic microwave background photons. Decay of neutral pions generated in p-p inelastic collisions of the ionic cosmic-ray component with the thermal gas contribute about 30% of the computed emission. Based on experimental upper limits on the photon flux above 100 MeV from nearby clusters we constrain the efficiency of conversion of shock energy into relativistic CR electrons to less than 1%. Thus, we find that cosmic-rays of cosmologi...

  7. Bremsstrahlung Energy Losses for Cosmic Ray Electrons and Positrons

    CERN Document Server

    Widom, A; Srivastava, R

    2015-01-01

    Recently cosmic ray electrons and positrons, i.e. cosmic ray charged leptons, have been observed. To understand the distances from our solar system to the sources of such lepton cosmic rays, it is important to understand energy losses from cosmic electrodynamic fields. Energy losses for ultra-relativistic electrons and/or positrons due to classical electrodynamic bremsstrahlung are computed. The energy losses considered are (i) due to Thompson scattering from fluctuating electromagnetic fields in the background cosmic thermal black body radiation and (ii) due to the synchrotron radiation losses from quasi-static domains of cosmic magnetic fields. For distances to sources of galactic length proportions, the lepton cosmic ray energy must be lass than about a TeV.

  8. Observations of cosmic gamma ray bursts with WATCH on EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, N.; Castro-Tirado, A. J.

    1995-01-01

    19 Cosmic Gamma-Ray Bursts were detected by the WATCH wide field X-ray monitor during the 11 months flight of EURECA. The identification of the bursts were complicated by a high frequency of background of events caused by high energy cosmic ray interactions in the detector and by low energy, trap...

  9. Celestial messengers. Cosmic rays. The story of a scientific adventure

    Energy Technology Data Exchange (ETDEWEB)

    Bertolotti, Mario [Roma Univ. (Italy). Dipt. die Scienze di Base e Applicate per l' Ingegneria (SBAI)

    2013-07-01

    The book describes from a historical point of view how cosmic rays were discovered. The book describes the research in cosmic rays. The main focus is on how the knowledge was gained, describing the main experiments and the conclusions drawn. Biographical sketches of main researchers are provided. Cosmic rays have an official date of discovery which is linked to the famous balloon flights of the Austrian physicist Hess in 1912. The year 2012 can therefore be considered the centenary of the discovery.

  10. New approach to cosmic ray investigations above the knee

    Science.gov (United States)

    Bogdanov, A. G.; Kokoulin, R. P.; Petrukhin, A. A.

    2016-05-01

    It is assumed that at energies around the knee the nucleus-nucleus interaction is drastically changed due to production of blobs of quark-gluon matter with very large orbital momentum. This approach allows explain all so-called unusual events observed in cosmic rays and gives a new connection between results of EAS investigations and energy spectrum and mass composition of primary cosmic rays. To check this approach, the experiments in cosmic rays and at LHC are proposed.

  11. Supernova-Remnant Origin of Cosmic Rays?

    CERN Document Server

    Butt, Y M; Romero, G E; Dame, T M; Combi, J A; Butt, Yousaf M.; Torres, Diego F.; Romero, Gustavo E.; Dame, Thomas M.; Combi, Jorge A.

    2002-01-01

    It is thought that Galactic cosmic ray (CR) nuclei are gradually accelerated to high energies (up to ~300 TeV/nucleon, where 1TeV=10^12eV) in the expanding shock-waves connected with the remnants of powerful supernova explosions. However, this conjecture has eluded direct observational confirmation^1,2 since it was first proposed in 1953 (ref. 3). Enomoto et al.^4 claim to have finally found definitive evidence that corroborates this model, proposing that the very-high-energy, TeV-range, gamma-rays from the supernova remnant (SNR) RX J1713.7-3946 are due to the interactions of energetic nuclei in this region. Here we argue that their claim is not supported by the existing multiwavelength spectrum of this source. The search for the origin(s) of Galactic cosmic ray nuclei may be closing in on the long-suspected supernova-remnant sources, but it is not yet over.

  12. Origin and propagation of galactic cosmic rays

    Science.gov (United States)

    Cesarsky, Catherine J.; Ormes, Jonathan F.

    1987-01-01

    The study of systematic trends in elemental abundances is important for unfolding the nuclear and/or atomic effects that should govern the shaping of source abundances and in constraining the parameters of cosmic ray acceleration models. In principle, much can be learned about the large-scale distributions of cosmic rays in the galaxy from all-sky gamma ray surveys such as COS-B and SAS-2. Because of the uncertainties in the matter distribution which come from the inability to measure the abundance of molecular hydrogen, the results are somewhat controversial. The leaky-box model accounts for a surprising amount of the data on heavy nuclei. However, a growing body of data indicates that the simple picture may have to be abandoned in favor of more complex models which contain additional parameters. Future experiments on the Spacelab and space station will hopefully be made of the spectra of individual nuclei at high energy. Antiprotons must be studied in the background free environment above the atmosphere with much higher reliability and presion to obtain spectral information.

  13. Semi-implicit anisotropic cosmic ray transport on an unstructured moving mesh

    CERN Document Server

    Pakmor, Ruediger; Simpson, Christine M; Kannan, Rahul; Springel, Volker

    2016-01-01

    In the interstellar medium of galaxies and the intracluster gas of galaxy clusters, the charged particles making up cosmic rays are moving almost exclusively along (but not across) magnetic field lines. The resulting anisotropic transport of cosmic rays in the form of diffusion or streaming not only affects the gas dynamics but also rearranges the magnetic fields themselves. The coupled dynamics of magnetic fields and cosmic rays can thus impact the formation and evolution of galaxies and the thermal evolution of galaxy clusters in critical ways. Numerically studying these effects requires solvers for anisotropic diffusion that are accurate, efficient, and robust, requirements that have proven difficult to satisfy in practice. Here, we present an anisotropic diffusion solver on an unstructured moving mesh that is conservative, does not violate the entropy condition, allows for semi-implicit time integration with individual timesteps, and only requires solving a single linear system of equations per timestep. ...

  14. Correlation between cosmic rays and ozone depletion.

    Science.gov (United States)

    Lu, Q-B

    2009-03-20

    This Letter reports reliable satellite data in the period of 1980-2007 covering two full 11-yr cosmic ray (CR) cycles, clearly showing the correlation between CRs and ozone depletion, especially the polar ozone loss (hole) over Antarctica. The results provide strong evidence of the physical mechanism that the CR-driven electron-induced reaction of halogenated molecules plays the dominant role in causing the ozone hole. Moreover, this mechanism predicts one of the severest ozone losses in 2008-2009 and probably another large hole around 2019-2020, according to the 11-yr CR cycle.

  15. Cosmic rays from active galactic nuclei

    CERN Document Server

    Berezhko, E G

    2008-01-01

    Cosmic ray (CR) acceleration at the shock created by the expanding cocoons around active galactic nuclei (AGNs) is studied. It is shown that above the energy $10^{18}$ eV the overall energy spectrum of CRs, produced during the AGN evolution and released in the intergalactic space, has the form $N\\propto \\epsilon^{-\\gamma}$, with $\\gamma\\approx 2.6$, which extends up to $\\epsilon_{max}\\sim 10^{20}$ eV. It is concluded that cocoons shocks have to be considered as a main source of extragalactic CRs, which together with Galactic supernova remnants provide the observed CR spectrum.

  16. Cosmic Ray Acceleration by Supernova Shocks

    CERN Document Server

    Berezhko, E G

    2008-01-01

    We analyse the results of recent measurements of nonthermal emission from individual supernova remnants (SNRs) and their correspondence to the nonlinear kinetic theory of cosmic ray (CR) acceleration in SNRs. It is shown that the theory fits these data in a satisfactory way and provides the strong evidences for the efficient CR production in SNRs accompanied by significant magnetic field amplification. Magnetic field amplification leads to considerable increase of CR maximum energy so that the spectrum of CRs accelerated in SNRs is consistent with the requirements for the formation of Galactic CR spectrum up to the energy ~10^17 eV.

  17. Low cloud properties influenced by cosmic rays

    CERN Document Server

    Marsh, N D; Marsh, Nigel D; Svensmark, Henrik

    2000-01-01

    The influence of solar variability on climate is currently uncertain. Recent observations have indicated a possible mechanism via the influence of solar modulated cosmic rays on global cloud cover. Here we show that the influence of solar variability is strongest in low clouds (<= 3.2km). These are liquid water clouds which points to a microphysical mechanism involving enhanced aerosol formation. If confirmed it suggests that the average state of the Heliosphere is important for climate on Earth. The estimated response in low clouds due to a doubling of solar activity is a 1.4 W/m2 warming.

  18. Theory Summary: Very High Energy Cosmic Rays

    Directory of Open Access Journals (Sweden)

    Sarkar Subir

    2013-06-01

    Full Text Available This is a summary of ISVHECRI 2012 from a theorist’s perspective. A hundred years after their discovery, there is renewed interest in very high energy cosmic raysand their interactions which can provide unique information on new physics well beyond the Standard Model if only we knew how to unambiguously decipher the experimental data. While the observational situation has improved dramatically on the past decade with regard to both improved statistics and better understood systematics, the long standing questions regarding the origin of cosmic rays remain only partially answered, while further questions have been raised by new data. A recent development discussed at this Symposium is the advent of forward physics data from several experiments at the LHC, which have broadly vindicated the air shower simulation Monte Carlos currently in use and reduced their uncertainties further. Nevertheless there is still a major extrapolation required to interpret the highest energy air showers observed which appear to be undergoing a puzzling change in their elemental composition, even casting doubt on whether the much vaunted GZK cutoff has indeedbeen observed. The situation is further compounded by the apparent disagreement between Auger and Telescope Array data. A crucial diagnostic will be provided by the detection of the accompanying ultra-high energy cosmic neutrinos — two intriguing events have recently been recorded by IceCube.

  19. Final Report for NA-22/DTRA Cosmic Ray Project

    Energy Technology Data Exchange (ETDEWEB)

    Wurtz, Ron E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Chapline, George F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Glenn, Andrew M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Nakae, Les F. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Pawelczak, Iwona A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Sheets, Steven A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2015-07-21

    The primary objective of this project was to better understand the time-correlations between the muons and neutrons produced as a result of high energy primary cosmic ray particles hitting the atmosphere, and investigate whether these time correlations might be useful in connection with the detection of special nuclear materials. During the course of this project we did observe weak correlations between secondary cosmic ray muons and cosmic ray induced fast neutrons. We also observed strong correlations between tertiary neutrons produced in a Pb pile by secondary cosmic rays and minimum ionizing particles produced in association with the tertiary neutrons.

  20. The contribution of cosmic rays to global warming

    CERN Document Server

    Sloan, Terry

    2011-01-01

    A search has been made for a contribution of the changing cosmic ray intensity to the global warming observed in the last century. The cosmic ray intensity shows a strong 11 year cycle due to solar modulation and the overall rate has decreased since 1900. These changes in cosmic ray intensity are compared to those of the mean global surface temperature to attempt to quantify any link between the two. It is shown that, if such a link exists, the changing cosmic ray intensity contributes less than 8% to the increase in the mean global surface temperature observed since 1900.

  1. Galactic cosmic rays on extrasolar Earth-like planets I. Cosmic ray flux

    CERN Document Server

    Grießmeier, J -M; Stadelmann, A; Grenfell, J L; Atri, D

    2015-01-01

    (abridged abstract) 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 that protect the planet against cosmic-ray particles. In particular, a weak magnetic field results in a high flux of Galactic cosmic rays that extends to the top of the planetary atmosphere. We wish to quantify the flux of Galactic cosmic rays to an exoplanetary atmosphere as a function of the particle energy and of the planetary magnetic moment. We numerically analyzed the propagation of Galactic cosmic-ray particles through planetary magnetospheres. We evaluated the efficiency of magnetospheric shielding as a function of the particle energy (in the range 16 MeV $\\le$ E $\\le$ 524 GeV) and as a function of the planetary magnetic field strength (in the range 0 ${M}_\\oplus$ $\\le$ {M} $\\le$ 10 ${M}_\\oplus$). Combined with the flux outside the planeta...

  2. Investigating the origin of high-energy cosmic-ray electrons with Monte Carlo simulation

    Science.gov (United States)

    Attallah, R.

    2017-06-01

    Due to severe radiative energy losses during propagation, high-energy cosmic-ray electrons can reach Earth only from nearby sources. Although these sources clearly manifest themselves in the special features of the energy spectrum observed by recent space-borne experiments, especially the increase in the positron fraction, their exact nature is still a matter of debate. The standard method for interpreting cosmic-ray electron data consists in solving appropriate transport equations. It can be supplemented with a Monte Carlo approach taking advantage of the intrinsic random nature of cosmic-ray diffusive propagation. This analysis gives valuable information on the electron-by-electron fluctuations and hence allows to address the issue from a different angle. Here we show how to implement a fully three-dimensional time-dependent Monte Carlo simulation of the propagation of high-energy cosmic-ray electrons from nearby sources and discuss the “single-source” astrophysical scenario.

  3. The TeV-scale cosmic ray proton and helium spectra: Contributions from the local sources

    Indian Academy of Sciences (India)

    Yong-Yeon Keum; Pierre Salati

    2016-02-01

    Recent measurements of cosmic ray proton and helium spectra show a hardening above a few hundreds of GeV. This excess is hard to understand in the framework of the conventional models of galactic cosmic ray production and propagation. Here, we propose to explain this anomaly by the presence of local sources. Cosmic ray propagation is described as a diffusion process taking place inside a two-zone magnetic halo. We calculate the proton and helium fluxes at the Earth between 50 GeV and 100 TeV. Improving over a similar analysis, we consistently derive these fluxes by taking into account both local and remote sources for which a unique injection rate is assumed. We find cosmic ray propagation parameters for which the proton and helium spectra remarkably agree with the PAMELA and CREAM measurements over four decades in energy.

  4. No More Anomaly in the TeV Cosmic Ray Proton and Helium Spectra

    CERN Document Server

    Bernard, Guilhem; Keum, Yong-Yeon; Liu, Wei; Salati, Pierre; Taillet, Richard

    2013-01-01

    Recent measurements of cosmic ray proton and helium spectra show a hardening above a few hundreds of GeV. This excess is hard to understand in the framework of the conventional models of Galactic cosmic ray production and propagation. We propose here to explain this anomaly by the presence of local sources. Cosmic ray propagation is described as a diffusion process taking place inside a two-zone magnetic halo. We calculate the proton and helium fluxes at the Earth between 50 GeV and 100 TeV. Improving over a similar analysis, we consistently derive these fluxes by taking into account both local and remote sources for which a unique injection rate is assumed. We find cosmic ray propagation parameters for which the proton and helium spectra remarkably agree with the PAMELA and CREAM measurements over four decades in energy.

  5. The shape of the extragalactic cosmic ray spectrum from galaxy clusters

    Science.gov (United States)

    Harari, Diego; Mollerach, Silvia; Roulet, Esteban

    2016-08-01

    We study the diffusive escape of cosmic rays from a central source inside a galaxy cluster to obtain the suppression in the outgoing flux appearing when the confinement times get comparable or larger than the age of the sources. We also discuss the attenuation of the flux due to the interactions of the cosmic rays with the cluster medium, which can be sizeable for heavy nuclei. The overall suppression in the total cosmic ray flux expected on Earth is important to understand the shape of the extragalactic contribution to the cosmic ray spectrum for E/Z < 1 EeV . This suppression can also be relevant to interpret the results of fits to composition-sensitive observables measured at ultra-high energies.

  6. The shape of the extragalactic cosmic ray spectrum from Galaxy Clusters

    CERN Document Server

    Harari, Diego; Roulet, Esteban

    2016-01-01

    We study the diffusive escape of cosmic rays from a central source inside a galaxy cluster to obtain the suppression in the outgoing flux appearing when the confinement times get comparable or larger than the age of the sources. We also discuss the attenuation of the flux due to the interactions of the cosmic rays with the cluster medium, which can be sizeable for heavy nuclei. The overall suppression in the total cosmic ray flux expected on Earth is important to understand the shape of the extragalactic contribution to the cosmic ray spectrum for $E/Z<1$ EeV. This suppression can also be relevant to interpret the results of fits to composition-sensitive observables measured at ultra-high energies.

  7. A New Maximum-Likelihood Technique for Reconstructing Cosmic-Ray Anisotropy at All Angular Scales

    CERN Document Server

    Ahlers, Markus; Desiati, Paolo; Díaz-Vélez, Juan Carlos; Fiorino, Daniel W; Westerhoff, Stefan

    2016-01-01

    The arrival directions of TeV-PeV cosmic rays show weak but significant anisotropies with relative intensities at the level of one per mille. Due to the smallness of the anisotropies, quantitative studies require careful disentanglement of detector effects from the observation. We discuss an iterative maximum-likelihood reconstruction that simultaneously fits cosmic ray anisotropies and detector acceptance. The method does not rely on detector simulations and provides an optimal anisotropy reconstruction for ground-based cosmic ray observatories located in the middle latitudes. It is particularly well suited to the recovery of the dipole anisotropy, which is a crucial observable for the study of cosmic ray diffusion in our Galaxy. We also provide general analysis methods for recovering large- and small-scale anisotropies that take into account systematic effects of the observation by ground-based detectors.

  8. Modeling the Gamma-Ray Emission in the GALACTIC CENTER with a Fading Cosmic-ray Accelerator

    Science.gov (United States)

    Liu, Ruo-Yu; Wang, Xiang-Yu; Prosekin, Anton; Chang, Xiao-Chuan

    2016-12-01

    Recent HESS observations of the ∼200 pc scale diffuse gamma-ray emission from the central molecular zone (CMZ) suggest the presence of a PeV cosmic-ray accelerator (PeVatron) located in the inner 10 pc region of the Galactic center. Interestingly, the gamma-ray spectrum of the point-like source (HESS J1745-290) in the Galactic center shows a cutoff at ∼10 TeV, implying a cutoff around 100 TeV in the cosmic-ray proton spectrum. Here we propose that the gamma-ray emission from the inner and the outer regions may be explained self-consistently by run-away protons from a single yet fading accelerator. In this model, gamma-rays from the CMZ region are produced by protons injected in the past, while gamma-rays from the inner region are produced by protons injected more recently. We suggest that the blast wave formed in a tidal disruption event (TDE) caused by the supermassive black hole (Sgr A*) could serve as such a fading accelerator. With typical parameters of the TDE blast wave, gamma-ray spectra of both the CMZ region and HESS J1745-290 can be reproduced simultaneously. Meanwhile, we find that the cosmic-ray energy density profile in the CMZ region may also be reproduced in the fading accelerator model when appropriate combinations of the particle injection history and the diffusion coefficient of cosmic rays are adopted.

  9. Transition from galactic to extragalactic cosmic rays

    CERN Document Server

    Berezinsky, V

    2007-01-01

    The transition from galactic to extragalactic cosmic rays is discussed. One of critical indications for transition is given by the Standard Model of Galactic cosmic rays, according to which the maximum energy of acceleration for iron nuclei is of order of $E_{\\rm Fe}^{\\rm max} \\approx 1\\times 10^{17}$ eV. At $E > E_{\\rm Fe}^{\\rm max}$ the spectrum is predicted to be very steep and thus the Standard Model favours the transition at energy not much higher than $E_{\\rm Fe}^{\\rm max}$. As observations are concerned there are two signatures of transition: change of energy spectra and elongation rate (depth of shower maximum in the atmosphere $X_{\\rm max}$ as function of energy). Three models of transition are discussed: dip-based model, mixed composition model and ankle model. In the latter model the transition occurs at the observed spectral feature, ankle, which starts at $E_a \\approx 1\\times 10^{19}$ eV and is characterised by change of mass compostion from galactic iron to extragalactic protons. In the dip mode...

  10. Cosmic ray studies with the MINOS detectors

    Science.gov (United States)

    Habig, Alec; Minos Collaboration

    2008-11-01

    The MINOS experiment uses two layered scintillator and steel detectors along with a muon neutrino beam to search for νμ 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 νμ and νμ 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).

  11. Optical and Ionization Basic Cosmic Ray Detector

    Science.gov (United States)

    Felix, Julian; Andrade, Diego A.; Araujo, Aurora C.; Arceo, Luis; Cervantes, Carlos A.; Molina, Jorge A.; Palacios, Luz R.

    2014-03-01

    There are drift tubes, operating in the Geiger mode, to detect ionization radiation and there are Cerenkov radiation detectors based on photomultiplier tubes. Here is the design, the construction, the operation and the characterization of a hybrid detector that combines both a drift tube and a Cerenkov detector, used mainly so far to detect cosmic rays. The basic cell is a structural Aluminum 101.6 cm-long, 2.54 cm X 2.54 cm-cross section, 0.1 cm-thick tube, interiorly polished to mirror and slightly covered with TiCO2, and filed with air, and Methane-Ar at different concentrations. There is a coaxial 1 mil Tungsten wire Au-coated at +700 to +1200 Volts electronically instrumented to read out in both ends; and there is in each end of the Aluminum tube a S10362-11-100U Hamamatsu avalanche photodiode electronically instrumented to be read out simultaneously with the Tungsten wire signal. This report is about the technical operation and construction details, the characterization results and potential applications of this hybrid device as a cosmic ray detector element. CONACYT, Mexico.

  12. Stable laws and cosmic ray physics

    CERN Document Server

    Genolini, Yoann; Serpico, Pasquale; Taillet, Richard

    2016-01-01

    In the new precision era for cosmic ray astrophysics, theoretical predictions cannot content themselves with average trends, but need to correctly take into account intrinsic uncertainties. The space-time discreteness of the cosmic ray sources, joined with a substantial ignorance of their precise epochs and locations (with the possible exception of the most recent and close ones) plays an important role in this sense. We elaborate a statistical theory to deal with this problem, relating the composite probability P({\\Psi}) to obtain a flux {\\Psi} at the Earth to the single-source probability p({\\psi}) to contribute with a flux {\\psi}. The main difficulty arises since p({\\psi}) is a fat tail distribution, characterized by power-law or broken power-law behaviour up to very large fluxes for which central limit theorem does not hold, and leading to well-known stable laws as opposed to Gaussian distributions. We find that relatively simple recipes provide a satisfactory description of the probability P({\\Psi}). We ...

  13. Cosmic-ray pitch-angle scattering in imbalanced MHD turbulence simulations

    CERN Document Server

    Weidl, Martin S; Teaca, Bogdan; Schlickeiser, Reinhard

    2015-01-01

    Pitch-angle scattering rates for cosmic-ray particles in magnetohydrodynamic (MHD) simulations with imbalanced turbulence are calculated for fully evolving electromagnetic turbulence. We compare with theoretical predictions derived from the quasilinear theory of cosmic-ray diffusion for an idealized slab spectrum and demonstrate how cross helicity affects the shape of the pitch-angle diffusion coefficient. Additional simulations in evolving magnetic fields or static field configurations provide evidence that the scattering anisotropy in imbalanced turbulence is not primarily due to coherence with propagating Alfven waves, but an effect of the spatial structure of electric fields in cross-helical MHD turbulence.

  14. Cosmic ray feedback in hydrodynamical simulations of galaxy formation

    CERN Document Server

    Jubelgas, M; Pfrommer, C; Springel, V; Ensslin, Torsten A.; Jubelgas, Martin; Pfrommer, Christoph; Springel, Volker

    2006-01-01

    It is well known that cosmic rays (CRs) contribute significantly to the pressure of the interstellar medium in our own Galaxy, suggesting that they may play an important role in regulating star formation during the formation and evolution of galaxies. We here discuss a novel numerical treatment of the physics of CRs and its implementation in the parallel smoothed particle hydrodynamics code GADGET-2. In our methodology, the non-thermal CR population of each gaseous fluid element is approximated by a simple power law spectrum in particle momentum, characterized by an amplitude, a cut-off, and a fixed slope. Adiabatic compression, and a number of physical source and sink terms are modelled which modify the CR pressure of each particle. The most important sources considered are injection by supernovae and diffusive shock acceleration, while the primary sinks are thermalization by Coulomb interactions, and catastrophic losses by hadronic interactions. We also include diffusion of CRs. Our scheme allows us to carr...

  15. Simulating cosmic ray physics on a moving mesh

    CERN Document Server

    ,

    2016-01-01

    We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled to magneto-hydrodynamics (MHD) on an unstructured moving mesh, as realised in the massively parallel AREPO code for cosmological simulations. We account for diffusive shock acceleration of CRs at resolved shocks and at supernova remnants in the interstellar medium (ISM), and follow the advective CR transport within the magnetised plasma, as well as anisotropic diffusive transport of CRs along the local magnetic field. CR losses are included in terms of Coulomb and hadronic interactions with the thermal plasma. We demonstrate the accuracy of our formalism for CR acceleration at shocks through simulations of plane-parallel shock tubes that are compared to newly derived exact solutions of the Riemann shock tube problem with CR acceleration. We find that the increased compressibility of the post-shock plasma due to the produced CRs decreases the shock speed. However, CR acceleration at spherically expanding blast waves does not si...

  16. Diffuse flux of galactic neutrinos and gamma rays

    CERN Document Server

    Carceller, J M

    2016-01-01

    We calculate the fluxes of neutrinos and gamma rays from interactions of cosmic rays with interstellar matter in our galaxy. We use EPOS-LHC, SIBYLL and GHEISHA to obtain the yield of these particles in proton, helium and iron collisions at kinetic energies between 1 and 10^8 GeV. We find that at E>1 PeV the fluxes depend very strongly on the cosmic-ray composition, whereas at 1-5 GeV the main source of uncertainty is the cosmic-ray spectrum out of the heliosphere. We show that the diffuse flux of galactic neutrinos becomes larger than the conventional atmospheric one at E>1 PeV, but that at all IceCube energies it is up to 5 times smaller than the atmospheric flux from forward-charm decays.

  17. Cosmic Rays in Magnetospheres of the Earth and other Planets

    CERN Document Server

    Dorman, Lev

    2009-01-01

    This monograph describes the behaviour of cosmic rays in the magnetosphere of the Earth and of some other planets. Recently this has become an important topic both theoretically, because it is closely connected with the physics of the Earth’s magnetosphere, and practically, since cosmic rays determine a significant part of space weather effects on satellites and aircraft. The book contains eight chapters, dealing with – The history of the discovery of geomagnetic effects caused by cosmic rays and their importance for the determination of the nature of cosmic rays or gamma rays – The first explanations of geomagnetic effects within the framework of the dipole approximation of the Earth’s magnetic field – Trajectory computations of cutoff rigidities, transmittance functions, asymptotic directions, and acceptance cones in the real geomagnetic field taking into account higher harmonics – Cosmic ray latitude-longitude surveys on ships, trains, tracks, planes, balloons and satellites for determining the...

  18. Observations of cosmic gamma ray bursts with WATCH on EURECA

    DEFF Research Database (Denmark)

    Brandt, Søren; Lund, N.; Castro-Tirado, A. J.

    1995-01-01

    19 Cosmic Gamma-Ray Bursts were detected by the WATCH wide field X-ray monitor during the 11 months flight of EURECA. The identification of the bursts were complicated by a high frequency of background of events caused by high energy cosmic ray interactions in the detector and by low energy......, trapped particle streams. These background events may simulate the count rate increases characteristic of cosmic gamma bursts. For 12 of the detected events, their true cosmic nature have been confirmed through consistent localizations of the burst sources based on several independent WATCH data sets...

  19. New look on the origin of cosmic rays

    Directory of Open Access Journals (Sweden)

    Istomin Ya.N.

    2017-01-01

    Full Text Available From the analysis of the flux of high energy particles, E > 3 · 1018 eV, it is shown that the distribution of the power density of extragalactic rays over energy is of the power law, q̅(E ∝ E−2.7, with the same index of 2.7 that has the distribution of Galactic cosmic rays before the so called ‘knee', E 3 · 1015 eV, from the Galaxy because of the dependence of the coefficient of diffusion of cosmic rays on energy, D∝E0.7. The obtained index of the density distribution of particles over energy, N(E∝E−2.7−0.7/2=E−3.05, for E > 3 · 1015 eV agrees well with the observed one, N(E∝E−3.1. The estimated time of the termination of the jet in the Galaxy is 4.2 · 104 years ago.

  20. Cosmic Ray Excesses from Multi-component Dark Matter Decays

    CERN Document Server

    Geng, Chao-Qiang; Tsai, Lu-Hsing

    2014-01-01

    We use multi-component decaying dark matter (DM) scenario to explain the possible cosmic ray excesses in the positron fraction recently confirmed by AMS-02 and the total $e^+ +e^-$ flux observed by Fermi-LAT. In the two-component DM models, we find an interesting variation of the flavor structure along with the cutoff of the heavy DM. For the three-component DM case, we focus on a particular parameter range in which the best fits prefer to open only 2 DM decay channels with a third DM contributing nothing to the electron and positron spectra. We show that all models give the reasonable fits to both the AMS-02 positron fraction and the Fermi-LAT total $e^++e^-$ flux, which are also consistent with the measured diffuse $\\gamma$-ray flux by Fermi-LAT.

  1. Testing the Origin of High-Energy Cosmic Rays

    CERN Document Server

    Vladimirov, Andrey E; Moskalenko, Igor V; Porter, Troy A

    2011-01-01

    Recent accurate measurements of cosmic-ray (CR) protons and nuclei by ATIC-2, CREAM, and PAMELA reveal: a) unexpected spectral hardening in the spectra of CR species above a few hundred GeV per nucleon, b) a harder spectrum of He compared to protons, and c) 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 CR isotopic 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.

  2. Low-energy cosmic rays in the Orion region

    DEFF Research Database (Denmark)

    Pohl, M.

    1998-01-01

    The recently observed nuclear gamma-ray line emission from the Orion complex implies a high flux of low-energy cosmic rays (LECR) with unusual abundance. This cosmic ray component would dominate the energy density, pressure, and ionising power of cosmic rays, and thus would have a strong impact...... sections, thus it depends only weakly on the LECR spectrum and not on any other parameter. Observations with HEPC will allow us to derive the bremsstrahlung spectrum over the weakly extended gamma-ray emission regions....

  3. CRIME - cosmic ray interactions in molecular environments

    CERN Document Server

    Krause, Julian; Gabici, Stefano

    2015-01-01

    Molecular clouds act as targets for cosmic rays (CR), revealing their presence through either gamma-ray emission due to proton-proton interactions, and/or through the ionization level in the cloud, produced by the CR flux. The ionization rate is a unique tool, to some extent complementary to the gamma-ray emission, in that it allows to constrain the CR spectrum especially for energies below the pion production rate ($\\approx 280$ MeV). Here we study the effect of ionization on $H_2$ clouds due to both CR protons and electrons, using the fully relativistic ionization cross sections, which is important to correctly account for the contribution due to relativistic CRs. The contribution to ionization due to secondary electrons is also included self-consistently. The whole calculation has been implemented into a numerical code which is publicly accessible through a web-interface. The code also include the calculation of gamma-ray emission once the CR spectrum

  4. From cosmic ray source to the Galactic pool

    Science.gov (United States)

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

    2014-01-01

    The Galactic cosmic ray spectrum is a remarkably straight power law. Our current understanding is that the dominant sources that accelerate cosmic rays up to the knee (3 × 1015 eV) or perhaps even the ankle (3 × 1018 eV), are young Galactic supernova remnants. In theory, however, there are various reasons why the spectrum may be different for different sources, and may not even be a power law if non-linear shock acceleration applies during the most efficient stages of acceleration. We show how the spectrum at the accelerator translates to the spectrum that makes up the escaping cosmic rays that replenish the Galactic pool of cosmic rays. We assume that cosmic ray confinement, and thus escape, is linked to the level of magnetic field amplification, and that the magnetic field is amplified by streaming cosmic rays according to the non-resonant hybrid or resonant instability. When a fixed fraction of the energy is transferred to cosmic rays, it turns out that a source spectrum that is flatter than E-2 will result in an E-2 escape spectrum, whereas a steeper source spectrum will result in an escape spectrum with equal steepening. This alleviates some of the concern that may arise from expected flat or concave cosmic ray spectra associated with non-linear shock modification.

  5. MAGIC contributions to the 32nd International Cosmic Ray Conference

    CERN Document Server

    Aleksić, J; Antonelli, L A; Antoranz, P; Asensio, M; Backes, M; Barrio, J A; Bastieri, D; González, J Becerra; Bednarek, W; Berdyugin, A; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Boller, A; Bonnoli, G; Tridon, D Borla; Braun, I; Bretz, T; Cañellas, A; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Cossio, L; Covino, S; Dazzi, F; De Angelis, A; De Caneva, G; del Pozo, E De Cea; De Lotto, B; Mendez, C Delgado; Ortega, A Diago; Doert, M; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Eisenacher, D; Elsaesser, D; Ferenc, D; Fonseca, M V; Font, L; Fruck, C; López, R J García; Garczarczyk, M; Garrido, D; Giavitto, G; Godinović, N; Hadasch, D; Häfner, D; Herrero, A; Hildebrand, D; Höhne-Mönch, D; Hose, J; Hrupec, D; Jogler, T; Kellermann, H; Klepser, S; Krähenbühl, T; Krause, J; Kushida, J; La Barbera, A; Lelas, D; Leonardo, E; Lindfors, E; Lombardi, S; López, M; López-Oramas, A; Lorenz, E; Makariev, M; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Miranda, J M; Mirzoyan, R; Moldón, J; Moralejo, A; Munar-Adrover, P; Nieto, D; Nilsson, K; Orito, R; Otte, N; Oya, I; Paneque, D; Paoletti, R; Pardo, S; Paredes, J M; Partini, S; Perez-Torres, M A; Persic, M; Peruzzo, L; Pilia, M; Pochon, J; Prada, F; Moroni, P G Prada; Prandini, E; Gimenez, I Puerto; Puljak, I; Reichardt, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rissi, M; Rügamer, S; Saggion, A; Saito, K; Saito, T Y; Salvati, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shayduk, M; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Spiro, S; Stamatescu, V; Stamerra, A; Steinke, B; Storz, J; Strah, N; Surić, T; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Tibolla, O; Torres, D F; Treves, A; Uellenbeck, M; Vankov, H; Vogler, P; Wagner, R M; Weitzel, Q; Zabalza, V; Zandanel, F; Zanin, R

    2011-01-01

    Compilation of the papers contributed by the MAGIC collaboration to the 32nd International Cosmic Ray Conference, which took place between August 11 and 18, 2011 in Beijing, China. The papers are sorted in 6 categories: Overview and Highlight papers; Instrument, software and techniques; Galactic sources; Extragalactic sources; Multi-wavelength and joint campaigns; Fundamental physics, dark matter and cosmic rays.

  6. Direct Measurements, Acceleration and Propagation of Cosmic Rays

    CERN Document Server

    Blasi, Pasquale

    2008-01-01

    This paper summarizes highlights of the OG1 session of the 30th International Cosmic Ray Conference, held in Merida (Yucatan, Mexico). The subsessions (OG1.1, OG1.2, OG1.3, OG1.4 and OG1.5) summarized here were mainly devoted to direct measurements, acceleration and propagation of cosmic rays.

  7. Supernova Remnants as the Sources of Galactic Cosmic Rays

    NARCIS (Netherlands)

    Vink, J.

    2013-01-01

    The origin of cosmic rays holds still manymysteries hundred years after they were first discovered. Supernova remnants have for long been the most likely sources of Galactic cosmic rays. I discuss here some recent evidence that suggests that supernova remnants can indeed efficiently accelerate cosmi

  8. Study of cosmic ray nuclei detection by an image calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Casolino, M.; Sparvoli, R.; Morselli, A.; Picozza, P. [Rome Univ. `Tor Vergata` (Italy)]|[INFN, Sezione Univ. `Tor Vergata` Rome (Italy); Ozerov, Yu.V.; Zemskov, V.M.; Zverev, V.G.; Galper, A.M. [Moscow Engineering Physics Institute, Moscow (Russian Federation); Carlson, P. [Royal Institute of Technology, Stockholm (Sweden); Fuglesang, C. [ESA-EAC, Cologne (Germany)

    1995-09-01

    It is shown that a cosmic gamma-ray telescope made of a multilayer silicon tracker and a imaging CsI calorimeter, is capable of identifying cosmic ray nuclei. The telescope charge resolution is estimated around 4% independently of charge. Simulation methods are used to determine the telescope properties for nuclei detection.

  9. Measurement of cosmic ray chemical composition at Mt. Chacaltaya

    Energy Technology Data Exchange (ETDEWEB)

    Ogio, S.; Kakimoto, F.; Harada, D.; Tokunou, H.; Burgoa, O.; Tsunesada, Y. [Institute of Technology, Dept. of Physics, Tokuo (Japan); Shirasaki, Y. [National Space Development Agency of Japan, Tsukuba (Japan); Gotoh, E.; Nakatani, H.; Shimoda, S.; Nishi, K.; Tajima, N.; Yamada, Y. [The Institute of Physical and Chemical Research, Wako, Saitama (Japan); Kaneko, T. [Okayama University, Dept. of Physics, Oakayama (Japan); Matsubara, Y. [Nagoya University, Solar-Terrestrial Environment Laboratory, Nagoya, Aichi (Japan); Miranda, P.; Velarde, A. [Universidad Mayor de San Andres, Institute de Investigaciones Fisicas, La Paz (Bolivia); Mizumoto, T. [National Astronomical Observatory, Mitaka, Tokyo (Japan); Yoshii, H.; Morizawa, A. [Ehime University, Dept. of Physics, Matsuyama, Ehime (Japan); Murakami, K. [Nagoya University of Foreign Studies, Nissin, Aichi (Japan); Toyoda, Y. [Fukui University of Technology, Faculty of General Education, Fukui (Japan)

    2001-10-01

    BASJE group has measured the chemical composition of primary cosmic rays with energies around the knee with several methods. These measurements show that the averaged mass number of cosmic ray particles increases with energy up to the knee. In order to measure the chemical composition in much wider energy range, it was started a new experiment at Mt. Chacaltaya in 2000.

  10. Supernova Remnants as the Sources of Galactic Cosmic Rays

    NARCIS (Netherlands)

    J. Vink

    2012-01-01

    The origin of cosmic rays holds still manymysteries hundred years after they were first discovered. Supernova remnants have for long been the most likely sources of Galactic cosmic rays. I discuss here some recent evidence that suggests that supernova remnants can indeed efficiently accelerate cosmi

  11. Energetic-Particle Populations and Cosmic-Ray Entry.

    Science.gov (United States)

    1981-03-17

    H., E. Fl~ickiger. H. von Mandach , and M. Arens, Determina- tion of the ring current radii from cosmic ray neutron monitor data for the 17 December... Mandach , and M. Arens, Determination of the ring current radii from cosmic ray neutron monitor data for the 17 December 1971 magnetic storm, Planet. Space

  12. Nuclear enhancement of the photon yield in cosmic ray interactions

    CERN Document Server

    Kachelriess, Michael; Ostapchenko, Sergey S

    2014-01-01

    The concept of the nuclear enhancement factor has been used since the beginning of gamma-ray astronomy. It provides a simple and convenient way to account for the contribution of nuclei (A>1) in cosmic rays (CRs) and in the interstellar medium (ISM) to the diffuse gamma-ray emission. An accurate treatment of the dominant emission process, such as hadronic interactions of CRs with the ISM, enables one to study CR acceleration processes, CR propagation in the ISM, and provides a reliable background model for searches of new phenomena. The Fermi Large Area Telescope (Fermi-LAT) launched in 2008 provides excellent quality data in a wide energy range 30 MeV - 1 TeV where the diffuse emission accounts for the majority of photons. Exploiting its data to the fullest requires a new study of the processes of gamma-ray production in hadronic interactions. In this paper we point out that several commonly used studies of the nuclear enhancement factor miss to account for the spectrally averaged energy loss fraction which ...

  13. A Study Of Cosmic Ray Beryllium With The Isotope Magnet Experiment (isomax)

    CERN Document Server

    Geier, S

    2000-01-01

    Secondary nuclei in the cosmic radiation, which are produced in the process of propagation and nuclear fragmentation of primary particles through the interstellar medium, can be used to gain information on the propagation mechanism, and the details of the cosmic ray diffusion and the gas distribution in the galaxy. The Goddard ISOMAX experiment is a state-of-the-art mass spectrometer constructed for the purpose of measuring the abundance ratios of the isotopes of Beryllium, especially [10]Be which has a half life of 1.51 Myrs, at energies around 1 GeV per nucleon. This will enable the balloon borne instrument, which was launched for the first time in summer 1998, to put constraints on the typical travel times of cosmic rays and the density of the propagated medium—hence on the question how much time cosmic rays spend traveling outside the galactic disk. Construction and calibration of the instrument are presented and the first results are reported.

  14. Implications of supernova remnant origin model of galactic cosmic rays on gamma rays from young supernova remnants

    Science.gov (United States)

    Banik, Prabir; Bhadra, Arunava

    2017-06-01

    It is widely believed that Galactic cosmic rays are originated in supernova remnants (SNRs), where they are accelerated by a diffusive shock acceleration (DSA) process in supernova blast waves driven by expanding SNRs. In recent theoretical developments of the DSA theory in SNRs, protons are expected to accelerate in SNRs at least up to the knee energy. If SNRs are the true generators of cosmic rays, they should accelerate not only protons but also heavier nuclei with the right proportions, and the maximum energy of the heavier nuclei should be the atomic number (Z ) times the mass of the proton. In this work, we investigate the implications of the acceleration of heavier nuclei in SNRs on energetic gamma rays produced in the hadronic interaction of cosmic rays with ambient matter. Our findings suggest that the energy conversion efficiency has to be nearly double for the mixed cosmic ray composition compared to that of pure protons to explain observations. In addition, the gamma-ray flux above a few tens of TeV would be significantly higher if cosmic ray particles could attain energies Z times the knee energy in lieu of 200 TeV, as suggested earlier for nonamplified magnetic fields. The two stated maximum energy paradigms will be discriminated in the future by upcoming gamma-ray experiments like the Cherenkov telescope array (CTA).

  15. A Cosmic-Ray and Thermally Driven Kiloparsec-scale Outflow from the Milky Way

    Science.gov (United States)

    Everett, John; Schiller, Quintin; Zweibel, Ellen

    2009-05-01

    We review the importance of cosmic-ray pressure in helping to drive kpc-scale galactic outflows. In particular, we examine the case of the Milky Way, and outline a theory that the ``Galactic X-ray Bulge'' discovered by Snowden et al. (1997) is the signature of a large-scale outflow driven by combined thermal and cosmic-ray pressure. We confront this model with observations of the synchrotron halo from Haslam et al. (1981), and discuss the constraints that these observations place on the wind model and perhaps any model of the ``Galactic X-ray Bulge''. We also outline further advances to the model including a more detailed cosmic-ray diffusion model, and the possible role of clumping and mass loading in the outflow.

  16. Dissipation of Magnetohydrodynamic Waves on Energetic Particles: Impact on Interstellar Turbulence and Cosmic Ray Transport

    Energy Technology Data Exchange (ETDEWEB)

    Ptuskin, V.S.; /Troitsk, IZMIRAN /Maryland U.; Moskalenko, Igor V.; /Stanford U., HEPL; Jones, F.C.; /NASA, Goddard; Strong, A.W.; /Garching, Max Planck Inst., MPE; Zirakashvili, V.N.; /Troitsk, IZMIRAN /Heidelberg, Max Planck Inst. Astron.

    2006-01-17

    The physical processes involved in diffusion of Galactic cosmic rays in the interstellar medium are addressed. We study the possibility that the nonlinear MHD cascade sets the power-law spectrum of turbulence which scatters charged energetic particles. We find that the dissipation of waves due to the resonant interaction with cosmic ray particles may terminate the Kraichnan-type cascade below wavelengths 10{sup 13} cm. The effect of this wave dissipation has been incorporated in the GALPROP numerical propagation code in order to asses the impact on measurable astrophysical data. The energy-dependence of the cosmic-ray diffusion coefficient found in the resulting self-consistent model may explain the peaks in the secondary to primary nuclei ratios observed at about 1 GeV/nucleon.

  17. Clusters of Galaxies Shock Waves and Cosmic Rays

    CERN Document Server

    Ryu, D; Ryu, Dongsu; Kang, Hyesung

    2002-01-01

    Recent observations of galaxy clusters in radio and X-ray indicate that cosmic rays and magnetic fields may be energetically important in the intracluster medium. According to the estimates based on theses observational studies, the combined pressure of these two components of the intracluster medium may range between $10% \\sim 100 %$ of gas pressure, although their total energy is probably time dependent. Hence, these non-thermal components may have influenced the formation and evolution of cosmic structures, and may provide unique and vital diagnostic information through various radiations emitted via their interactions with surrounding matter and cosmic background photons. We suggest that shock waves associated with cosmic structures, along with individual sources such as active galactic nuclei and radio galaxies, supply the cosmic rays and magnetic fields to the intracluster medium and to surrounding large scale structures. In order to study 1) the properties of cosmic shock waves emerging during the larg...

  18. Cosmic ray energetics and mass (CREAM) calibrating a cosmic ray calorimeter

    CERN Document Server

    Ganel, O; Ahn, S H; Alford, R; Kim, K C; Lee, M H; Liu, L; Lutz, L; Malinin, A; Schindhelm, E; Wang, J Z; Wu, J; Beatty, J J; Coutu, S; Minnick, S A; Nutter, S; Duvernois, M A; Choi, M J; Kim, H J; Kim, S K; Park, I H; Swordy, S P

    2002-01-01

    CREAM is slated to fly as the first NASA ultra long duration balloon (ULDB) payload in late 2003. On this 60-plus-day flight CREAM is expected to collect more direct high-energy cosmic ray events than the current world total. With three such flights CREAM is expected to have a proton energy reach above 5*10/sup 14/ eV, probing near 100 Te V for the predicted kink in the cosmic-ray proton spectrum. With a transition radiation detector (TRD) above a sampling tungsten /scintillator calorimeter, an in-flight cross-calibration of the absolute energy scale becomes possible with heavy ions. We report on results from a 2001 beam test of the calorimeter in an SPS beam at the European High Energy Physics lab (CERN) and on the planned in- flight calibration. (7 refs).

  19. Cosmic ray neon, Wolf-Rayet stars, and the superbubble origin of galactic cosmic rays

    CERN Document Server

    Binns, W R; Arnould, M; Cummings, A C; George, J S; Goriely, S; Israel, M H; Leske, R A; Mewaldt, R A; Meynet, G; Scott, L M; Stone, Edward C; Von Rosenvinge, T T

    2005-01-01

    The abundances of neon isotopes in the galactic cosmic rays (GCRs) are reported using data from the Cosmic Ray Isotope Spectrometer (CRIS) aboard the Advanced Composition Explorer (ACE). We compare our ACE-CRIS data for neon and refractory isotope ratios, and data from other experiments, with recent results from two-component Wolf-Rayet (WR) models. The three largest deviations of GCR isotope ratios from solar-system ratios predicted by these models are indeed present in the GCRs. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of these data with WR models suggests that superbubbles are the likely source of at least a substantial fraction of GCRs.

  20. Underground cosmic-ray experiment EMMA

    DEFF Research Database (Denmark)

    Kuusiniemi, P.; Bezrukov, L.; Enqvist, T.

    2013-01-01

    EMMA (Experiment with MultiMuon Array) is a new approach to study the composition of cosmic rays at the knee region (1 – 10 PeV). The array will measure the multiplicity and lateral distribution of the high-energy muon component of an air shower and its arrival direction on an event-by-event basis....... The array operates in the Pyhäsalmi Mine, Finland, at a depth of 75 metres (or 210 m.w.e) corresponding to the cut-off energy of approximately 50 GeV for vertical muons. The data recording with a partial array has started and preliminary results of the first test runs are presented....

  1. Global Atmospheric Models for Cosmic Ray Detectors

    CERN Document Server

    Will, Martin

    2014-01-01

    The knowledge of atmospheric parameters -- such as temperature, pressure, and humidity -- is very important for a proper reconstruction of air showers, especially with the fluorescence technique. The Global Data Assimilation System (GDAS) provides altitude-dependent profiles of these state variables of the atmosphere and several more. Every three hours, a new data set on 23 constant pressure level plus an additional surface values is available for the entire globe. These GDAS data are now used in the standard air shower reconstruction of the Pierre Auger Observatory. The validity of the data was verified by comparisons with monthly models that were averaged from on-site meteorological radio soundings and weather station measurements obtained at the Observatory in Malarg\\"ue. Comparisons of reconstructions using the GDAS data and the monthly models are also presented. Since GDAS is a global model, the data can potentially be used for other cosmic and gamma ray detectors. Several studies were already performed ...

  2. Ultra-High-Energy Cosmic Rays

    CERN Document Server

    Dova, M T

    2015-01-01

    The origin of the ultra high energy cosmic rays (UHECR) with energies above E > 10 17 eV, is still unknown. The discovery of their sources will reveal the engines of the most energetic astrophysical accelerators in the universe. This is a written version of a series of lectures devoted to UHECR at the 2013 CERN-Latin-American School of High-Energy Physics. We present anintroduction to acceleration mechanisms of charged particles to the highest energies in astrophysical objects, their propagation from the sources to Earth, and the experimental techniques for their detection. We also discuss some of the relevant observational results from Telescope Array and Pierre Auger Observatory. These experiments deal with particle interactions at energies orders of magnitude higher than achieved in terrestrial accelerators.

  3. Cosmic ray transport in MHD turbulence

    CERN Document Server

    Yan, Huirong

    2007-01-01

    Numerical simulations shed light onto earlier not trackable problem of magnetohydrodynamic (MHD) turbulence. They allowed to test the predictions of different models and choose the correct ones. Inevitably, this progress calls for revisions in the picture of cosmic ray (CR) transport. It also shed light on the problems with the present day numerical modeling of CR. In this paper we focus on the analytical way of describing CR propagation and scattering, which should be used in synergy with the numerical studies. In particular, we use recently established scaling laws for MHD modes to obtain the transport properties for CRs. We include nonlinear effects arising from large scale trapping, to remove the 90 degree divergence. We determine how the efficiency of the scattering and CR mean free path depend on the characteristics of ionized media, e.g. plasma $\\beta$, Coulomb collisional mean free path. Implications for particle transport in interstellar medium and solar corona are discussed. We also examine the perp...

  4. Cosmic ray decreases and magnetic clouds

    Energy Technology Data Exchange (ETDEWEB)

    Cane, H.V. (NASA Goddard Space Flight Center, Greenbelt, MD (United States))

    1993-03-01

    A study has been made of energetic particle data, obtained from IMP 8, in conjunction with solar wind field and plasma data at the times of reported magnetic clouds. It is shown that magnetic clouds can cause a depression of the cosmic ray flux but high fields are required. A depression of 3% in a neutron monitor requires a field of about 25 nT. Such high fields are found only in a subset of coronal ejecta. The principal cause for Forbush decreases associated with energetic shocks is probably turbulence in the postshock region, although some shocks will be followed by an ejecta with a high field. Each event is different. The lower-energy particles can help in identifying the dominant processes in individual events. 19 refs., 5 figs.

  5. Composition of UHE Cosmic Ray Primaries

    CERN Document Server

    Poirier, J; Gress, J; Lin, T F; Rösch, A

    2000-01-01

    Project GRAND presents results on the atomic composition of primary cosmic rays. This is accomplished by determining the average height of primary particles that cause extensive air showers detected by Project GRAND. Particles with a larger cross sectional area, such as iron nuclei, are likely to start an extensive air shower higher in the atmosphere whereas protons, with a smaller cross section, would pass through more air before interacting and thus start showers at lower heights. Such heights can be determined by extrapolating identified muon tracks backward (upward) to determine their height of origin (Gress et al., 1997). Since muons are from the top, hadronic part of the shower, they are a good estimator for the beginning of the shower. The data for this study were taken during the previous year with 20 million shower events.

  6. Temporal and energy behavior of cosmic ray fluxes in the periods of low solar activity

    CERN Document Server

    Bazilevskaya, G A; Krainev, M B; Makhmutov, V S; Svirzhevskaya, A K; Svirzhevsky, N S

    2014-01-01

    Modulation of galactic cosmic ray intensity is governed by several mechanisms including diffusion, convection, adiabatic energy losses and drift. Relative roles of these factors change in the course of an 11-year solar cycle. That can result in the changes in the energy dependence of the 11-year cosmic ray modulation. The minimum between the solar cycles 23 and 24 was extremely deep and long-lasting which led to the record high cosmic ray fluxes low-energy particles dominating. This was a signature of unusually soft energy spectrum of the cosmic rays. In this work we examine the energy dependence of the 11-year modulation during the last three solar cycles and argue that a soft energy spectrum was observed in the minimum of each cycle however only for particles below of energy around 10 GeV. From mid 1980s the energy dependence of cosmic rays became softer from minimum to minimum of solar activity. The work is based on the cosmic ray data of the spacecraft, balloon-borne and the ground-based observations.

  7. Low-energy cosmic ray protons from nuclear interactions of cosmic rays with the interstellar medium.

    Science.gov (United States)

    Wang, H. T.

    1973-01-01

    The intensity of low-energy (less than 100 MeV) protons from nuclear interactions of higher-energy (above 100 MeV) cosmic rays with the interstellar medium is calculated. The resultant intensity in the 10- to 100-MeV range is larger by a factor of 3-5 than the observed proton intensity near earth. The calculated intensity from nuclear interactions constitutes a lower limit on the actual proton intensity in interstellar space.

  8. Heliospheric influence on the anisotropy of TeV cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming; Zuo, Pingbing [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, FL 32901 (United States); Pogorelov, Nikolai, E-mail: mzhang@fit.edu [Center for Space Plasma and Aeronomic Research and Department of Space Science, University of Alabama in Huntsville, AL 35899 (United States)

    2014-07-20

    This paper provides a theory of using Liouville's theorem to map the anisotropy of TeV cosmic rays seen at Earth using the particle distribution function in the local interstellar medium (LISM). The ultimate source of cosmic ray anisotropy is the energy, pitch angle, and spatial dependence of the cosmic ray distribution function in the LISM. Because young nearby cosmic ray sources can make a special contribution to the cosmic ray anisotropy, the anisotropy depends on the source age, distance and magnetic connection, and particle diffusion of these cosmic rays, all of which make the anisotropy sensitive to the particle energy. When mapped through the magnetic and electric field of a magnetohydrodynamic model heliosphere, the large-scale dipolar and bidirectional interstellar anisotropy patterns become distorted if they are seen from Earth, resulting in many small structures in the observations. Best fits to cosmic ray anisotropy measurements have allowed us to estimate the particle density gradient and pitch angle anisotropies in the LISM. It is found that the heliotail, hydrogen deflection plane, and the plane perpendicular to the LISM magnetic field play a special role in distorting cosmic ray anisotropy. These features can lead to an accurate determination of the LISM magnetic field direction and polarity. The effects of solar cycle variation, the Sun's coronal magnetic field, and turbulence in the LISM and heliospheric magnetic fields are minor but clearly visible at a level roughly equal to a fraction of the overall anisotropy amplitude. The heliospheric influence becomes stronger at lower energies. Below 1 TeV, the anisotropy is dominated by small-scale patterns produced by disturbances in the heliosphere.

  9. Cosmic-ray composition measurements and cosmic ray background-free γ -ray observations with Cherenkov telescopes

    Science.gov (United States)

    Neronov, Andrii; Semikoz, Dmitri V.; Vovk, Ievgen; Mirzoyan, Razmik

    2016-12-01

    The muon component of extensive air showers (EAS) initiated by cosmic-ray particles carries information on the primary particle identity. We show that the muon content of EAS could be measured in a broad energy range from 10-100 TeV up to ultra-high-energy cosmic-ray range using wide field-of-view imaging atmospheric Cherenkov telescopes observing strongly inclined or nearly horizontal EAS from the ground of from high altitude. Cherenkov emission from muons in such EAS forms a distinct component (halo or tail) of the EAS image in the telescope camera. We show that detection of the muon signal could be used to measure composition of the cosmic-ray spectrum in the energy ranges of the knee, the ankle and of the Galactic-to-extragalactic transition. It could also be used to veto the cosmic-ray background in gamma-ray observations. This technique provides a possibility for up to 2 orders of magnitude improvement of sensitivity for γ -ray flux in the energy band above 10 PeV, compared to KASCADE-Grande, and an order-of-magnitude improvement of sensitivity in the multi-EeV energy band, compared to Pierre Auger Observatory.

  10. Advanced applications of cosmic-ray muon radiography

    Science.gov (United States)

    Perry, John

    The passage of cosmic-ray muons through matter is dominated by the Coulomb interaction with electrons and atomic nuclei. The muon's interaction with electrons leads to continuous energy loss and stopping through the process of ionization. The muon's interaction with nuclei leads to angular diffusion. If a muon stops in matter, other processes unfold, as discussed in more detail below. These interactions provide the basis for advanced applications of cosmic-ray muon radiography discussed here, specifically: 1) imaging a nuclear reactor with near horizontal muons, and 2) identifying materials through the analysis of radiation lengths weighted by density and secondary signals that are induced by cosmic-ray muon trajectories. We have imaged a nuclear reactor, type AGN-201m, at the University of New Mexico, using data measured with a particle tracker built from a set of sealed drift tubes, the Mini Muon Tracker (MMT). Geant4 simulations were compared to the data for verification and validation. In both the data and simulation, we can identify regions of interest in the reactor including the core, moderator, and shield. This study reinforces our claims for using muon tomography to image reactors following an accident. Warhead and special nuclear materials (SNM) imaging is an important thrust for treaty verification and national security purposes. The differentiation of SNM from other materials, such as iron and aluminum, is useful for these applications. Several techniques were developed for material identification using cosmic-ray muons. These techniques include: 1) identifying the radiation length weighted by density of an object and 2) measuring the signals that can indicate the presence of fission and chain reactions. By combining the radiographic images created by tracking muons through a target plane with the additional fission neutron and gamma signature, we are able to locate regions that are fissionable from a single side. The following materials were imaged

  11. Where is the cosmic-ray modulation boundary of the heliosphere?

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Ming, E-mail: mzhang@fit.edu [Department of Physics and Space Sciences, Florida Institute of Technology, Melbourne, Florida 32901 (United States); Luo, Xi [Center for Space Research, North-West University, Potchefstroom 2520 (South Africa); State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Pogorelov, Nikolai [Center for Space Plasma and Aeronomic Research and Department of Space Science, University of Alabama in Huntsville, Huntsville, Alabama 35899 (United States)

    2015-09-15

    The intensity of Galactic cosmic rays in the heliosphere is modulated by solar activities. The outer boundary where the solar modulation begins has always been a subject matter of debate in the cosmic-ray and heliophysics community. Various experimental methods and theoretical model calculations have been used to determine the boundary. Although the heliopause was always suspected to be the boundary, it is only until very recently after Voyager 1 had crossed the heliopause did we confirm that the boundary is indeed the heliopause. In this paper, we use a model simulation and detailed Voyager observation of cosmic rays at the heliopause crossing to show that the modulation boundary, in fact, is a fraction of an AU beyond the heliopause. Such a conclusion requires a very low turbulence level of the interstellar magnetic field in the outer heliosheath. According to the quasi-linear theory, a low level of turbulence should result in a very large diffusion coefficient parallel to the magnetic field and a very small perpendicular diffusion coefficient. For the first time, we are confident that Voyager 1 has obtained the truly pristine local interstellar cosmic-ray spectra down to the energies below 1 MeV. The cosmic-ray intensity is rapidly filtered by a thin layer of the interstellar magnetic field immediately outside of the heliopause. Its filtration amount depends on the conditions of magnetic field turbulence on the both sides of the heliopause, thus making it solar-cycle dependent as well.

  12. A NUMERICAL SIMULATION OF COSMIC-RAY MODULATION NEAR THE HELIOPAUSE

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xi; Feng, Xueshang [SIGMA Weather Group, State Key Laboratory of Space Weather, Center for Space Science and Applied Research, Chinese Academy of Sciences, Beijing 100190 (China); Zhang, Ming [Department of Physics and Space Sciences, Florida Institute of Technology,150 West University Boulevard, Melbourne, FL 32901 (United States); Potgieter, Marius [Centre for Space Research, North-West University, Potchefstroom 2520 (South Africa); Pogorelov, N. V. [Department of Physics and Center for Space Plasma and Aeronomic Research, University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 (United States)

    2015-07-20

    Based on a hybrid galactic cosmic-ray transport model, which incorporated MHD global heliospheric data into Parker’s cosmic-ray transport equation, we studied the behavior of the transport of galactic cosmic rays and the corresponding gradients in their flux near the heliopause (HP). We found that, (1) by increasing the ratio of the parallel diffusion coefficient to the perpendicular diffusion coefficient in the interstellar magnetic field of the outer heliosheath, the simulated radial flux near the HP increases as well. As the ratio multiplying factor reached 10{sup 10}, the radial flux experienced a sudden jump near the HP, similar to what Voyager 1 observed in 2012. (2) The effect of changing the diffusion coefficients’ ratio on the radial flux variation depends on the energy of the cosmic rays, the lower the energy, the more pronounced the effect is. (3) The magnitude of the diffusion coefficients also affect the radial flux near the HP, the modulation beyond the HP varies by adjusting the magnitude multiplying factor.

  13. Plasma effects on extragalactic ultra-high-energy cosmic ray hadron beams in cosmic voids

    Energy Technology Data Exchange (ETDEWEB)

    Krakau, Steffen; Schlickeiser, Reinhard [Institut fur Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universitaet Bochum (Germany)

    2015-05-01

    The linear instability of an ultrarelativistic hadron beam (Γ{sub b} ∼ 10{sup 6}) in the unmagnetized intergalactic medium 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 > 10{sup 15} eV) from their distant sources to Earth. We calculate minimum instability growth times which 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 stabilize and can propagate with nearly no energy loss through the intergalactic medium.

  14. From cosmic ray source to the Galactic pool

    CERN Document Server

    Schure, K M

    2013-01-01

    The Galactic cosmic ray spectrum is a remarkably straight power law. Our current understanding is that the dominant sources that accelerate cosmic rays up to the knee ($3 \\times 10^{15}$ eV) or perhaps even the ankle ($3 \\times 10^{18}$ eV), are young Galactic supernova remnants. In theory, however, there are various reasons why the spectrum may be different for different sources, and may not even be a power law if nonlinear shock acceleration applies during the most efficient stages of acceleration. We show how the spectrum at the accelerator translates to the spectrum that make up the escaping cosmic rays that replenish the Galactic pool of cosmic rays. We assume that cosmic ray confinement, and thus escape, is linked to the level of magnetic field amplification, and that the magnetic field is amplified by streaming cosmic rays according to the non-resonant hybrid or resonant instability. When a fixed fraction of the energy is transferred to cosmic rays, it turns out that a source spectrum that is flatter t...

  15. Astrophysical origins of ultrahigh energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Torres, Diego F [Lawrence Livermore National Laboratory, 7000 East Avenue, L-413, Livermore, CA 94550 (United States); Anchordoqui, Luis A [Department of Physics, Northeastern University, Boston, MA 02115 (United States)

    2004-09-01

    In the first part of this review we discuss the basic observational features at the end of the cosmic ray (CR) energy spectrum. We also present there the main characteristics of each of the experiments involved in the detection of these particles. We then briefly discuss the status of the chemical composition and the distribution of arrival directions of CRs. After that, we examine the energy losses during propagation, introducing the Greisen-Zaptsepin-Kuzmin (GZK) cutoff, and discuss the level of confidence with which each experiment has detected particles beyond the GZK energy limit. In the second part of the review, we discuss the astrophysical environments that are able to accelerate particles up to such high energies, including active galactic nuclei, large scale galactic wind termination shocks, relativistic jets and hot-spots of Fanaroff-Riley radio galaxies, pulsars, magnetars, quasar remnants, starbursts, colliding galaxies, and gamma ray burst fireballs. In the third part of the review we provide a brief summary of scenarios which try to explain the super-GZK events with the help of new physics beyond the standard model. In the last section, we give an overview on neutrino telescopes and existing limits on the energy spectrum and discuss some of the prospects for a new (multi-particle) astronomy. Finally, we outline how extraterrestrial neutrino fluxes can be used to probe new physics beyond the electroweak scale.

  16. The Cosmic Gamma-Ray Bursts

    CERN Document Server

    Djorgovski, S G; Kulkarni, S R; Sari, R; Bloom, J S; Galama, T J; Harrison, F A; Price, P A; Fox, D; Reichart, D; Yost, S; Berger, E; Diercks, A H; Goodrich, R; Chaffee, F H

    2001-01-01

    Cosmic gamma-ray bursts are one of the great frontiers of astrophysics today. They are a playground of relativists and observers alike. They may teach us about the death of stars and the birth of black holes, the physics in extreme conditions, and help us probe star formation in the distant and obscured universe. In this review we summarise some of the remarkable progress in this field over the past few years. While the nature of the GRB progenitors is still unsettled, it now appears likely that at least some bursts originate in explosions of very massive stars, or at least occur in or near the regions of massive star formation. The physics of the burst afterglows is reasonably well understood, and has been tested and confirmed very well by the observations. Bursts are found to be beamed, but with a broad range of jet opening angles; the mean gamma-ray energies after the beaming corrections are ~ 10^51 erg. Bursts are associated with faint ~ 25 mag) galaxies at cosmological redshifts, with ~ 1. The host gal...

  17. Cosmic-ray acceleration at collisionless astrophysical shocks using Monte-Carlo simulations

    CERN Document Server

    Wolff, M

    2015-01-01

    Context. The diffusive shock acceleration mechanism has been widely accepted as the acceleration mechanism for galactic cosmic rays. While self-consistent hybrid simulations have shown how power-law spectra are produced, detailed information on the interplay of diffusive particle motion and the turbulent electromagnetic fields responsible for repeated shock crossings are still elusive. Aims. The framework of test-particle theory is applied to investigate the effect of diffusive shock acceleration by inspecting the obtained cosmic-ray energy spectra. The resulting energy spectra can be obtained this way from the particle motion and, depending on the prescribed turbulence model, the influence of stochastic acceleration through plasma waves can be studied. Methods. A numerical Monte-Carlo simulation code is extended to include collisionless shock waves. This allows one to trace the trajectories of test particle while they are being accelerated. In addition, the diffusion coefficients can be obtained directly fro...

  18. Detailed analysis of observed antiprotons in cosmic rays

    Directory of Open Access Journals (Sweden)

    P Davoudifar

    2009-12-01

    Full Text Available In the present work, the origin of antiprotons observed in cosmic rays (above the atmosphere is analyzed in details. We have considered the origin of the primaries, (which their interactions with the interstellar medium is one of the most important sources of antiprotons is a supernova type II then used a diffusion model for their propagation. We have used the latest parameterization for antiproton production cross section in pp collisions (instead of well known parameterization introduced by Tan et al. as well as our calculated residence time for primaries. The resulted intensity shows the secondary antiprotons produced in pp collisions in the galaxy, have a high population as one can not consider an excess for extragalactic antiprotons. Also there is a high degree of uncertainty in different parameters.

  19. Cosmic ray propagation in the Galaxy and associated interstellar emissions

    Science.gov (United States)

    Moskalenko, Igor

    Last several years were highlighted by many breakthroughs and discoveries in astrophysics of cosmic rays (CRs), thanks to superior instruments such as PAMELA, Fermi-LAT, Agile, INTEGRAL, HESS, VERITAS, Milagro, ATIC, CREAM, ACE, Voyager 1, 2 and others. They provide key pieces of information that may lead to the solution of the century-old puzzle of the origin of CRs and may contain signatures of new physics. The long-awaited AMS-02 data will be published by the time of the conference; they may confirm earlier measurements at the new precision level and/or outline significant discrepancies. I will review the CR measurements and relevant observations of the Galactic CR sources and the diffuse emissions and discuss what we can learn about CRs and their propagation in the Galaxy.

  20. Deciphering the Dipole Anisotropy of Galactic Cosmic Rays

    CERN Document Server

    Ahlers, Markus

    2016-01-01

    Recent measurements of the dipole anisotropy in the arrival directions of Galactic cosmic rays (CRs) indicate a strong energy dependence of the dipole amplitude and phase in the TeV-PeV range. We argue here that these observations can be well understood within standard diffusion theory as a combined effect of (i) one or more local sources at Galactic longitude 120deg < l < 300deg dominating the CR gradient below 0.1-0.3 PeV, (ii) the presence of a strong ordered magnetic field in our local environment, (iii) the relative motion of the solar system, and (iv) the limited reconstruction capabilities of ground-based observatories. We show that an excellent candidate of the local CR source responsible for the dipole anisotropy at 1-100 TeV is the Vela supernova remnant.

  1. High energy nucleonic component of cosmic rays at mountain altitudes

    CERN Document Server

    Stora, Raymond Félix

    The diffusion equations describing the unidimensional propagation of .the high energy nucleonic component of cosmic rays throughout the atmosphere are sol"V'ed under two assumptions: (l) The nucleon-nucleon collisions are described according to Fermi's therlnOdynamical model involving completely inelastic pion and.nucleon-antinucleon pair production. (2) A somewhat opposite assumption is made assuming partially elastic collisions without nucleon-anti.nucleon pair production. Due to the present inaccuracy of experiments, we are able to derive only tentati v.e conclusions. The values computed under both hypotheses for the absorption mean free path and the charged to neutral particles ratio are found in acceptable ranges when compared to experimental data. The diffeential energy spectrum at a given depth is always found steeper than the primary, and steeper than indicated by experimental values if the primary is taken proportional to the 2.5 inverse power of energy.

  2. Effect of cosmic ray on global high cloud from MODIS

    Science.gov (United States)

    Kim, H.-S.; Choi, Y.-S.

    2012-04-01

    The Earth's climate is affected by not only internal forcings but also external forcings related with solar activities. The energetic particles called "cosmic rays" from outer space have been considered as a potentially important external climate forcing since the first report by Svensemark and Friis-Christensen (1997) which showed a significant correlation between cloudiness and cosmic ray. This correlation is a basis of a couple of hypotheses in microphysical processes: ion-aerosol clear-air mechanism and ion-aerosol near-cloud mechanism. These mechanisms have been either supported or objected by many successive studies, most of which correlated long-term trends of cloud and cosmic ray. However, it is most likely that such methodology is not suitable to find actual connection, because long-term trends of clouds may invite affection by many factors other than cosmic ray. It is therefore necessary to find the relation at shorter time scale, since cosmic ray affect the process of cloud formation in a moment. Here we show spatial distributions of correlation between global high cloud fraction data from MODIS and cosmic ray of neutron monitor data from McMurdo, Antarctic. We removed 3-month running means from the original data in order to get high frequency fluctuations. As results, positive correlations are dominant in the spatial distribution, especially over lands on the northern hemisphere and oceans on the Southern hemisphere. On the other hand, negative correlations exist over limited area including the Indian Ocean. According to the cross-correlation (with time lags), the areas with positive correlation is widely distributed at zero lag. At ±1 month lags, the signs of correlations become the opposite of that at zero lag. Furthermore, the correlation between relative high cloud amount to total cloud and cosmic ray shows similar distribution to the correlation between absolute high cloud amount and cosmic ray, implying stronger high cloud response to cosmic ray

  3. AMS results on positrons and antiprotons in cosmic rays

    Science.gov (United States)

    Kounine, Andrei; AMS Collaboration

    2017-01-01

    AMS-02 is a particle physics detector collecting data on the International Space Station since May 2011. Precision measurements of charged cosmic ray particles have been performed by AMS using a data sample of 85 billion cosmic ray events collected during the first five years of operations on the Station. The latest AMS results on the fluxes and flux ratios of the cosmic ray particles are presented with the emphasis on the measurements of positrons and antiprotons. They show unique features that require accurate theoretical interpretation as to their origin, be it from dark matter collisions or new astrophysical sources. On behalf of AMS.

  4. Latest AMS Results on elementary particles in cosmic rays

    Science.gov (United States)

    Kounine, Andrei; AMS Collaboration

    2017-01-01

    AMS-02 is a particle physics detector collecting data on the International Space Station since May 2011. Precision measurements of all elementary charged cosmic ray particles have been performed by AMS using a data sample of 85 billion cosmic ray events collected during the first five years of operations on the Station. The latest AMS results on the fluxes and flux ratios of the elementary cosmic ray particles are presented. They show unique features that require accurate theoretical interpretation as to their origin, be it from dark matter collisions or new astrophysical sources. On behalf of the AMS Collaboration.

  5. Measurements at LHC and their relevance for cosmic ray physics

    CERN Document Server

    CERN. Geneva

    2016-01-01

    Many LHC measurements are already used to improve hadronic interaction models used in cosmic ray analyses. This already had a positive effect on the model dependence of crucial data analyses. Some of the data and the model tuning is reviewed. However, the LHC still has a lot more potential to provide crucial information. Since the start of Run2 the highest accelerator beam energies are reached and no further increase can be expected for a long time. First data of Run2 are published and the fundamental performance of cosmic ray hadronic interaction models can be scrutinized. The relevance of LHC data in general for cosmic ray data analyses is demonstrated.

  6. Observation of a rare cosmic ray event at mountain altitude

    Science.gov (United States)

    Basu, Basudhara; Raha, Sibaji; Saha, Swapan K.; Biswas, Sukumar; Dey, Sandhya; Maulik, Atanu; Mazumdar, Amal; Saha, Satyajit; Syam, Debapriyo

    2015-02-01

    Existence of strangelets in cosmic rays has been predicted even at mountain altitudes ∼ 3-4 km with extremely low abundance. We exposed an appropriate passive detector to cosmic rays at Darjeeling, India, at an atmospheric pressure of 765 hPa, as a pilot study to determine its suitability for the detection of strangelets in a large area detector array through long-term exposure. During the analysis we found a highly unusual event consisting of a cluster of six identical nuclear tracks. We argue that even the most mundane explanation of this event requires unusual physics, the first possible observation of multifragmentation involving cosmic rays.

  7. The Telescope Array Ultra High Energy Cosmic Ray Obsrevatory

    Science.gov (United States)

    Matthews, John

    2016-07-01

    The Telescope Array measures the properties of ultra high energy cosmic ray induced extensive air showers. We do this using a variety of techniques including an array of scintillator detectors to sample the footprint of the air shower when it reaches the Earth's surface and telescopes to measure the fluorescence and Cerenkov light of the air shower. From this we determine the energy spectrum and chemical composition of the primary particles. We also search for sources of cosmic rays and anisotropy. We have found evidence of a possible source of ultra high energy cosmic rays in the northern sky. The experiment and its most recent measurements will be discussed.

  8. Restrictive scenarios from Lorentz Invariance Violation to cosmic rays propagation

    CERN Document Server

    Martínez-Huerta, H

    2016-01-01

    Lorentz Invariance Violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov radiation, as in models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well defined secondary threshold.

  9. Fibre laser hydrophones for cosmic ray particle detection

    NARCIS (Netherlands)

    Buis, E.J.; Doppenberg, E.J.J.; Nieuwland, R.A.; Toet, P.M.

    2014-01-01

    The detection of ultra high energetic cosmic neutrinos provides a unique means to search for extragalactic sources that accelerate particles to extreme energies. It allows to study the neutrino component of the GZK cut-off in the cosmic ray energy spectrum and the search for neutrinos beyond this li

  10. The Diffuse Gamma-Ray Background from Type Ia Supernovae

    Science.gov (United States)

    Lien, Amy; Fields, Brian D.

    2012-01-01

    The origin of the diffuse extragalactic gamma-ray background (EGB) has been intensively studied but remains unsettled. Current popular source candidates include unresolved star-forming galaxies, starburst galaxies, and blazars. In this paper we calculate the EGB contribution from the interactions of cosmic rays accelerated by Type Ia supernovae, extending earlier work which only included core-collapse supernovae. We consider Type Ia events in star-forming galaxies, but also in quiescent galaxies that lack star formation. In the case of star-forming galaxies, consistently including Type Ia events makes little change to the star-forming EGB prediction, so long as both supernova types have the same cosmic-ray acceleration efficiencies in star-forming galaxies. Thus our updated EGB estimate continues to show that star-forming galaxies can represent a substantial portion of the signal measured by Fermi. In the case of quiescent galaxies, conversely, we find a wide range of possibilities for the EGB contribution. The dominant uncertainty we investigated comes from the mass in hot gas in these objects, which provides targets for cosmic rays: total gas masses are as yet poorly known, particularly at larger radii. Additionally, the EGB estimation is very sensitive to the cosmic-ray acceleration efficiency and confinement, especially in quiescent galaxies. In the most optimistic allowed scenarios, quiescent galaxies can be an important source of the EGB. In this case, star-forming galaxies and quiescent galaxies together will dominate the EGB and leave little room for other contributions. If other sources, such as blazars, are found to have important contributions to the EGB, then either the gas mass or cosmic-ray content of quiescent galaxies must be significantly lower than in their star-forming counterparts. In any case, improved Fermi EGB measurements will provide important constraints on hot gas and cosmic rays in quiescent galaxies.

  11. Features of the galactic magnetic field regarding deflections of ultra-high-energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Wirtz, Marcus; Erdmann, Martin; Mueller, Gero; Urban, Martin [III. Physikalisches Institut A, RWTH Aachen University (Germany)

    2016-07-01

    Most recent models of the galactic magnetic field have been derived from Faraday rotation measurements and imply strong deflections even for ultra-high energy cosmic rays. We investigate the characteristics of the different field parametrizations and point out similarities and interesting features. Among them are extragalactic regions which are invisible for an Earth bound observation and the transition from diffuse to ballistic behaviour in the 1 EeV energy regime. Applying this knowledge to a directional analysis, there are indications for deflection patterns by the galactic magnetic field in cosmic ray arrival directions measured by the Pierre Auger Observatory.

  12. On the Energy Spectra of GeV/TeV Cosmic Ray Leptons

    Energy Technology Data Exchange (ETDEWEB)

    Stawarz, Lukasz; /KIPAC, Menlo Park /Jagiellonian U., Astron. Observ.; Petrosian, Vahe; /KIPAC, Menlo Park /Stanford U., Phys. Dept. /Stanford U., Appl. Phys. Dept.; Blandford, Roger D.; /KIPAC, Menlo Park

    2011-08-19

    Recent observations of cosmic ray electrons from several instruments have revealed various degrees of deviation in the measured electron energy distribution from a simple power-law, in a form of an excess around 0.1 to 1 TeV energies. An even more prominent deviation and excess has been observed in the fraction of cosmic ray positrons around 10 and 100 GeV energies. These observations have received considerable attention and many theoretical models have been proposed to explain them. The models rely on either dark matter annihilation/decay or specific nearby astrophysical sources, and involve several additional assumptions regarding the dark matter distribution or particle acceleration. In this paper we show that the observed excesses in the electron spectrum may be easily reproduced without invoking any unusual sources other than the general diffuse Galactic components of cosmic rays. The model presented here assumes a power-law injection of electrons (and protons) by supernova remnants, and evaluates their expected energy spectrum based on a simple kinetic equation describing the propagation of charged particles in the interstellar medium. The primary physical effect involved is the Klein-Nishina suppression of the electron cooling rate around TeV energies. With a very reasonable choice of the model parameters characterizing the local interstellar medium, we can reproduce the most recent observations by Fermi and HESS experiments. Interestingly, in our model the injection spectral index of cosmic ray electrons becomes comparable to, or even equal to that of cosmic ray protons. The Klein-Nishina effect may also affect the propagation of the secondary e{sup {+-}} pairs, and therefore modify the cosmic ray positron-to-electron ratio. We have explored this possibility by considering two mechanisms for production of e{sup {+-}} pairs within the Galaxy. The first is due to the decay of {pi}{sup {+-}}'s produced by interaction of cosmic ray nuclei with ambient

  13. Revisiting the hardening of the cosmic-ray energy spectrum at TeV energies

    CERN Document Server

    Thoudam, Satyendra

    2013-01-01

    Measurements of cosmic rays by experiments such as ATIC, CREAM, and PAMELA indicate a hardening of the cosmic-ray energy spectrum at TeV energies. In our recent work (Thoudam & H\\"orandel 2012a), we showed that the hardening can be due to the effect of nearby supernova remnants. We showed it for the case of proton and helium. In this paper, we present an improved and detailed version of our previous work, and extend our study to heavier cosmic-ray species such as boron, carbon, oxygen, and iron nuclei. Unlike our previous study, the present work involves a detailed calculation of the background cosmic rays and follows a consistent treatment of cosmic-ray source parameters between the background and the nearby components. Moreover, we also present a detailed comparison of our results on the secondary-to-primary ratios, secondary spectra, and the diffuse gamma-ray spectrum with the results expected from other existing models, which can be checked by future measurements at high energies.

  14. On the radial distribution of Galactic cosmic rays

    Science.gov (United States)

    Recchia, S.; Blasi, P.; Morlino, G.

    2016-10-01

    The spectrum and morphology of the diffuse Galactic γ-ray emission carries valuable information on cosmic ray (CR) propagation. Recent results obtained by analyzing Fermi-LAT data accumulated over 7 yr of observation show a substantial variation of the CR spectrum as a function of the distance from the Galactic Centre. The spatial distribution of the CR density in the outer Galaxy appears to be weakly dependent upon the galactocentric distance, as found in previous studies as well, while the density in the central region of the Galaxy was found to exceed the value measured in the outer Galaxy. At the same time, Fermi-LAT data suggest a gradual spectral softening while moving outwards from the centre of the Galaxy to its outskirts. These findings represent a challenge for standard calculations of CR propagation based on assuming a uniform diffusion coefficient within the Galactic volume. Here, we present a model of non-linear CR propagation in which transport is due to particle scattering and advection off self-generated turbulence. We find that for a realistic distribution of CR sources following the spatial distribution of supernova remnants and the space dependence of the magnetic field on galactocentric distance, both the spatial profile of CR density and the spectral softening can easily be accounted for.

  15. On the radial distribution of Galactic cosmic rays

    CERN Document Server

    Recchia, S; Morlino, G

    2016-01-01

    The spectrum and morphology of the diffuse Galactic gamma-ray emission carries valuable information on cosmic ray (CR) propagation. Recent results obtained by analyzing Fermi-LAT data accumulated over seven years of observation show a substantial variation of the CR spectrum as a function of the distance from the Galactic Center. The spatial distribution of the CR density in the outer Galaxy appears to be weakly dependent upon the galactocentric distance, as found in previous studies as well, while the density in the central region of the Galaxy was found to exceed the value measured in the outer Galaxy. At the same time, Fermi-LAT data suggest a gradual spectral softening while moving outward from the center of the Galaxy to its outskirts. These findings represent a challenge for standard calculations of CR propagation based on assuming a uniform diffusion coefficient within the Galactic volume. Here we present a model of non-linear CR propagation in which transport is due to particle scattering and advectio...

  16. Propagation of high-energy cosmic rays in extragalactic turbulent magnetic fields: resulting energy spectrum and composition

    CERN Document Server

    Globus, N; Parizot, E

    2007-01-01

    We extend previous studies of mixed-composition extragalactic cosmic-ray source models, by investigating the influence of a non-negligible extragalactic magnetic field on the propagated cosmic-ray spectrum and composition. We study the transport of charged particles in turbulent fields and the transition from a ballistic to a diffusive propagation regime. We introduce a method allowing a fast integration of the particle trajectories, which allows us to calculate extragalactic cosmic-ray spectra in the general case, without using either the diffusive or the rectilinear approximation. We find that the main features of the mixed-composition models -- regarding the interpretation of the ankle and the non-monotonous evolution of the average cosmic-ray mass -- remain essentially unchanged as long as the magnetic field intensity does not exceed a few nG.

  17. Role of Cosmic Rays in the Circumgalactic Medium

    CERN Document Server

    Salem, Munier; Corlies, Lauren

    2015-01-01

    We explore the impact of cosmic rays (CRs) on cosmological adaptive-mesh refinement simulations of a forming 10^12 Msolar halo, focusing on the circumgalactic medium (CGM), and its resulting low-redshift structure and composition. In contrast to a run with star formation and energetic feedback but no CRs, the CR-inclusive runs feature a CGM substantially enriched with CRs and with metals to roughly 0.1 Zsolar, thanks to robust, persistent outflows from the disk. The CR-inclusive CGMs also feature more diffuse gas at lower temperatures, down to 10^4 K, than the non-CR run, with diffuse material often receiving a majority of its pressure support from the CR proton fluid. We compare to recent observations of the CGM of L ~ L* galaxies at low redshift, including UV absorption lines within background quasar spectra. The combination of metal-enriched, CR-driven winds and large swaths of CR pressure-supported, cooler diffuse gas leads to a CGM that provides a better match to data from COS-Halos (for HI, SiIV, CIII a...

  18. Analysis of North Sky Cosmic Ray Anisotropy with Atmospheric Neutrinos

    Science.gov (United States)

    Wills, Elizabeth; IceCube Collaboration

    2017-01-01

    Since the discovery of Cosmic Ray anisotropy, no experiment has definitively discovered the source of this unexpected phenomenon. Studying the cosmic rays' neutral daughter particles with pointing capabilities, like neutrinos, could shed new light. This can be done at two levels; a source which produces cosmic rays must also produce high energy astrophysical neutrinos, and low energy atmospheric neutrinos are made when the cosmic rays interact with the atmosphere. This analysis focuses on atmospheric neutrinos detected by IceCube, a Cherenkov detector instrumenting a kilometer cubed of glacial ice at the South Pole. The anisotropy and its energy dependence have been studied in the Southern sky using atmospheric muons by IceCube. In the North, gamma ray detectors, such as HAWC, and Argo-YBJ, have observed this anisotropy in cosmic ray showers. Thus far, no single- detector full-sky map exists of the anisotropy. Using IceCube's neutrino data, we can complement these studies with an exploration of the northern sky anisotropy at higher energies of cosmic rays. This could bring us much closer to understanding the complete picture of this anisotropy across energy levels and the whole sky.

  19. Maximum entropy analysis of cosmic ray composition

    CERN Document Server

    Nosek, Dalibor; Vícha, Jakub; Trávníček, Petr; Nosková, Jana

    2016-01-01

    We focus on the primary composition of cosmic rays with the highest energies that cause extensive air showers in the Earth's atmosphere. A way of examining the two lowest order moments of the sample distribution of the depth of shower maximum is presented. The aim is to show that useful information about the composition of the primary beam can be inferred with limited knowledge we have about processes underlying these observations. In order to describe how the moments of the depth of shower maximum depend on the type of primary particles and their energies, we utilize a superposition model. Using the principle of maximum entropy, we are able to determine what trends in the primary composition are consistent with the input data, while relying on a limited amount of information from shower physics. Some capabilities and limitations of the proposed method are discussed. In order to achieve a realistic description of the primary mass composition, we pay special attention to the choice of the parameters of the sup...

  20. The ATLAS Trigger Commissioning with cosmic rays

    CERN Document Server

    Abolins, M; Adragna, P; Aielli, G; Aleksandrov, E; Aleksandrov, I; Aloisio, A; Alviggi, M G; Amorim, A; Anderson, K; Andrei, V; Anduaga, X; Antonelli, S; Aracena, I; Ask, S; Asquith, L; Avolio, G; Backlund, S; Badescu, E; Bahat Treidel, O; Baines, J; Barnett, B M; Barria, P; Bartoldus, R; Batreanu, S; Bauss, B; Beck, H P; Bee, C; Bell, P; Bell, W H; Bellagamba, L; Bellomo, M; Ben Ami, S; Bendel, M; Benhammou, Ya; Benslama, K; Berge, D; Berger, N; Berry, T; Bianco, M; Biglietti, M; Blair, R R; Bogaerts, A; Bohm, C; Bold, T; Booth, J R A; Boscherini, D; Bosman, M; Boyd, J; Brawn, I P; Brelier, B; Bressler, S; Bruni, A; Bruni, G; Buda, S; Burckhart-Chromek, D; Buttar, C; Camarri, P; Campanelli, M; Canale, V; Caprini, M; Caracinha, D; Cardarelli, R; Carlino, G; Casadei, D; Casado, M P; Cataldi, G; Cerri, A; Charlton, D G; Chiodini, G; Ciapetti, G; Cimino, D; Ciobotaru, M; Clements, D; Coccaro, A; Coluccia, M R; Conde-Muíño, P; Constantin, S; Conventi, F; Corso-Radu, A; Costa, M J; Coura Torres, R; Cranfield, R; Cranmer, K; Crone, G; Curtis, C J; Dam, M; Damazio, D; Davis, A O; Dawson, I; Dawson, J; De Almeida Simoes, J; De Cecco, S; De Pedis, D; De Santo, A; DeAsmundis, R; DellaPietra, M; DellaVolpe, D; Delsart, P A; Demers, S; Demirkoz, B; Di Mattia, A; Di Ciaccio, A; Di Girolamo, A; Dionisi, C; Djilkibaev, R; Dobinson, Robert W; Dobson, M; Dogaru, M; Dotti, A; Dova, M; Drake, G; Dufour, M -A; Eckweiler, S; Ehrenfeld, W; Eifert, T; Eisenhandler, E F; Ellis, Nick; Emeliyanov, D; Enoque Ferreira de Lima, D; Ermoline, Y; Eschrich, I; Etzion, E; Facius, K; Falciano, S; Farthouat, P; Faulkner, P J W F; Feng, E; Ferland, J; Ferrari, R; Ferrer, M L; Fischer, G; Fonseca-Martin, T; Francis, D; Fukunaga, C; Föhlisch, F; Gadomski, S; Garitaonandia Elejabarrieta, H; Gaudio, G; Gaumer, O; Gee, C N P; George, S; Geweniger, C; Giagu, S; Gillman, A R; Giusti, P; Goncalo, R; Gorini, B; Gorini, E; Gowdy, S; Grabowska-Bold, I; Grancagnolo, F; Grancagnolo, S; Green, B; Galllno, P; Haas, S; Haberichter, W; Hadavand, H; Haeberli, C; Haller, J; Hamilton, A; Hanke, P; Hansen, J R; Hasegawa, Y; Hauschild, M; Hauser, R; Head, S; Hellman, S; Hidvegi, A; Hillier, S J; Höcker, A; Hrynóva, T; Hughes-Jones, R; Huston, J; Iacobucci, G; Idarraga, J; Iengo, P; Igonkina, O; Ikeno, M; Inada, M; Ishino, M; Iwasaki, H; Izzo, V; Jain, V; Johansen, M; Johns, K; Joos, M; Kadosaka, T; Kajomovitz, E; Kama, S; Kanaya, N; Kawagoe, K; Kawamoto, T; Kazarov, A; Kehoe, R; Khoriauli, G; Kieft, G; Kilvington, G; Kirk, J; Kiyamura, H; Klofver, P; Klous, S; Kluge, E E; Kobayashi, T; Kolos, S; Kono, T; Konstantinidis, N; Korcyl, K; Kordas, K; Kotov, V; Krasznahorkay, A; Kubota, T; Kugel, A; Kuhn, D; Kurashige, H; Kurasige, H; Kuwabara, T; Kwee, R; Landon, M; Lankford, A; LeCompte, T; Leahu, L; Leahu, M; Ledroit, F; Lehmann-Miotto, G; Lei, X; Lellouch, D; Lendermann, V; Levinson, L; Leyton, M; Li, S; Liberti, B; Lifshitz, R; Lim, H; Lohse, T; Losada, M; Luci, C; Luminari, L; Lupu, N; Mahboubi, K; Mahout, G; Mapelli, L; Marchese, F; Martin, B; Martin, B T; Martínez, A; Marzano, F; Masik, J; McMahon, T; McPherson, R; Medinnis, M; Meessen, C; Meier, K; Meirosu, C; Messina, A; Migliaccio, A; Mikenberg, G; Mincer, A; Mineev, M; Misiejuk, A; Mönig, K; Monticelli, F; Moraes, A; Moreno, D; Morettini, P; Murillo Garcia, R; Nagano, K; Nagasaka, Y; Negri, A; Némethy, P; Neusiedl, A; Nisati, A; Niwa, T; Nomachi, M; Nomoto, H; Nozaki, M; Nozicka, M; Ochi, A; Ohm, C; Okumura, Y; Omachi, C; Osculati, B; Oshita, H; Osuna, C; Padilla, C; Panikashvili, N; Parodi, F; Pasqualucci, E; Pastore, F; Patricelli, S; Pauly, T; Pectu, M; Perantoni, M; Perera, V; Perera, V J O; Pérez, E; Pérez-Réale, V; Perrino, R; Pessoa Lima Junior, H; Petersen, J; Petrolo, E; Piegaia, R; Pilcher, J E; Pinto, F; Pinzon, G; Polini, A; Pope, B; Potter, C; Prieur, D P F; Primavera, M; Qian, W; Radescu, V; Rajagopalan, S; Renkel, P; Rescigno, M; Rieke, S; Risler, C; Riu, I; Robertson, S; Roda, C; Rodríguez, D; Rogriquez, Y; Roich, A; Romeo, G; Rosati, S; Ryabov, Yu; Ryan, P; Rühr, F; Sakamoto, H; Salamon, A; Salvatore, D; Sankey, D P C; Santamarina, C; Santamarina-Rios, C; Santonico, R; Sasaki, O; Scannicchio, D; Scannicchio, D A; Schiavi, C; Schlereth, J L; Schmitt, K; Scholtes, I; Schooltz, D; Schuler, G; Schultz-Coulon, H -C; Schäfer, U; Scott, W; Segura, E; Sekhniaidze, G; Shimbo, N; Sidoti, A; Silva, L; Silverstein, S; Siragusa, G; Sivoklokov, S; Sloper, J E; Smizanska, M; Solfaroli, E; Soloviev, I; Soluk, R; Spagnolo, S; Spila, F; Spiwoks, R; Staley, R J; Stamen, R; Stancu, S; Steinberg, P; Stelzer, J; Stradling, A; Strom, D; Strong, J; Su, D; Sugaya, Y; Sugimoto, T; Sushkov, S; Sutton, M; Szymocha, T; Takahashi, Y; Takeda, H; Takeshita, T; Tanaka, S; Tapprogge, S; Tarem, S; Tarem, Z; Teixeira-Dias, P; Thomas, J P; Tokoshuku, K; Tomoto, M; Torrence, E; Touchard, F

    2008-01-01

    The ATLAS detector at CERN's LHC will be exposed to proton-proton collisions from beams crossing at 40 MHz. At the design luminosity there are roughly 23 collisions per bunch crossing. ATLAS has designed a three-level trigger system to select potentially interesting events. The first-level trigger, implemented in custom-built electronics, reduces the incoming rate to less than 100 kHz with a total latency of less than 2.5$\\mu$s. The next two trigger levels run in software on commercial PC farms. They reduce the output rate to 100-200 Hz. In preparation for collision data-taking which is scheduled to commence in May 2008, several cosmic-ray commissioning runs have been performed. Among the first sub-detectors available for commissioning runs are parts of the barrel muon detector including the RPC detectors that are used in the first-level trigger. Data have been taken with a full slice of the muon trigger and readout chain, from the detectors in one sector of the RPC system, to the second-level trigger algorit...

  1. Measurement of cosmic rays with LOFAR

    Science.gov (United States)

    Rossetto, L.; Buitink, S.; Corstanje, A.; Enriquez, J. E.; Falcke, H.; Hörandel, J. R.; Nelles, A.; Rachen, J. P.; Schellart, P.; Scholten, O.; ter Veen, S.; Thoudam, S.; Trinh, T. N. G.

    2016-05-01

    The LOw Frequency ARay (LOFAR) is a multipurpose radio-antenna array aimed to detect radio signals in the 10 - 240 MHz frequency range, covering a large surface in Northern Europe with a higher density in the Northern Netherlands. Radio emission in the atmosphere is produced by cosmic-ray induced air showers through the interaction of charged particles with the Earth magnetic field. The detection of radio signals allows to reconstruct several properties of the observed cascade. We review here all important results achieved in the last years. We proved that the radio-signal distribution at ground level is described by a two-dimensional pattern, which is well fitted by a double Gaussian function. The radio-signal arrival time and polarization have been measured, thus providing additional information on the extensive air shower geometry, and on the radio emission processes. We also showed that the radio signal reaches ground in a thin, curved wavefront which is best parametrized by a hyperboloid shape centred around the shower axis. Radio emission has also been studied under thunderstorm conditions and compared to fair weather conditions. Moreover, by using a hybrid reconstruction technique, we performed mass composition measurements in the energy range 1017 - 1018 eV.

  2. Cosmic-ray ionisation in collapsing clouds

    CERN Document Server

    Padovani, Marco; Galli, Daniele

    2013-01-01

    Cosmic rays (CR) play an important role in dense molecular cores, affecting their thermal and dynamical evolution and initiating the chemistry. Several studies have shown that the formation of protostellar discs in collapsing clouds is severely hampered by the braking torque exerted by the entrained magnetic field on the infalling gas, as long as the field remains frozen to the gas. We examine the possibility that the concentration and twisting of the field lines in the inner region of collapse can produce a significant reduction of the ionisation fraction. To check whether the CR ionisation rate (CRir) can fall below the critical value required to maintain good coupling, we first study the propagation of CRs in a model of a static magnetised cloud varying the relative strength of the toroidal/poloidal components and the mass-to-flux ratio. We then follow the path of CRs using realistic magnetic field configurations generated by numerical simulations of a rotating collapsing core. We find that an increment of...

  3. Cosmic ray measurements around the knee

    Science.gov (United States)

    Chiavassa, Andrea

    2016-07-01

    Primary cosmic rays of energy greater than ˜ 1014 eV must be studied by indirect experiments measuring the particles generated in the EAS (Extensive Air Shower) development in atmosphere. These experiments are mainly limited by the systematic errors due to their energy calibration. I will discuss the main sources of these errors: the choice of the hadronic interaction model and of the mass of the primary particle (that cannot be measured on a event by event basis). I will then summarize some recent measurements of the all particle spectrum, and I will show that, keeping into account the differences due to the energy calibration, they all agree on the spectral shape. Then I will describe the measurements of the light and heavy primaries mass groups spectra, discussing the claimed features. Using a simple calculation of the elemental spectra (based on the hypothesis that the knee energies follow a Peter's cycle) I will try to discuss if all these results can be interpreted in a common picture.

  4. Cosmological Structure Formation Shocks and Cosmic Rays in Hydrodynamical Simulations

    Science.gov (United States)

    Pfrommer, C.; Springel, V.; Enβlin, T. A.; Jubelgas, M.

    Cosmological shock waves during structure formation not only play a decisive role for the thermalization of gas in virializing structures but also for the acceleration of relativistic cosmic rays (CRs) through diffusive shock acceleration. We discuss a novel numerical treatment of the physics of cosmic rays in combination with a formalism for identifying and measuring the shock strength on-the-fly during a smoothed particle hydrodynamics simulation. In our methodology, the non-thermal CR population is treated self-consistently in order to assess its dynamical impact on the thermal gas as well as other implications on cosmological observables. Using this formalism, we study the history of the thermalization process in high-resolution hydrodynamic simulations of the Lambda cold dark matter model. Collapsed cosmological structures are surrounded by shocks with high Mach numbers up to 1000, but they play only a minor role in the energy balance of thermalization. However, this finding has important consequences for our understanding of the spatial distribution of CRs in the large-scale structure. In high resolution simulations of galaxy clusters, we find a low contribution of the averaged CR pressure, due to the small acceleration efficiency of lower Mach numbers of flow shocks inside halos and the softer adiabatic index of CRs. These effects disfavour CRs when a composite of thermal gas and CRs is adiabatically compressed. However, within cool core regions, the CR pressure reaches equipartition with the thermal pressure leading, to a lower effective adiabatic index and thus to an enhanced compressibility of the central intracluster medium. This effect increases the central density and pressure of the cluster, and thus the resulting X-ray emission and the central Sunyaev-Zel'dovich flux decrement. The integrated Sunyaev-Zel'dovich effect, however, is only slightly changed.

  5. Cosmic Rays in Extragalactic Systems: Clusters and Beyond

    Science.gov (United States)

    Jones, Thomas

    The existence of cosmic rays (CRs) accelerated outside our galaxy is by now established fact. For instance, the angular and spectral distributions of ultra high energy CRs (UHECRs) above roughly an EeV point clearly to their extragalactic origins. Diffuse nonthermal radio emis-sions in clusters and along their perimeters reveal GeV electrons filling volumes sometimes approaching Mpc scales. The radiative lifetimes of those leptonic CRs are so short that they must be accelerated or produced as secondaries in situ. The dominant energy sources for such extragalactic CRs are not clearly established, although they are likely to be consequences of strucure formation. Large-scale shocks (including cluster accretion shocks) and turbulence in-duced by structure formation are strong candidates. There is also the possibility that CRs may be produced through structure formation process on still larger scales associated with cos-mic filaments, although current evidence for that is sketchy. The effectiveness of processes in these environments that might accelerate CRs depends sensitively on poorly understood "mi-crophysics" in very dilute and weakly magnetized plasmas. All of these CR populations have the potential to produce diagnostic gamma rays in the GeV to TeV range. Consequently, detec-tion or improved detection limits by current and coming gamma ray observatories can provide unique and crucial information about physical processes and conditions in these environments. My talk will outline the current status of these issues. This work is supported by the US NSF, NASA and by the Minnesota Supercomputing Institute.

  6. Cosmic Ray Results from the CosmoALEPH Experiment

    CERN Document Server

    Grupen, C; Jost, B; Maciuc, F; Luitz, S; Mailov, A; Müller, A S; Putzer, A; Rensch, B; Sander, H G; Schmeling, S; Schmelling, M; Tcaciuc, R; Wachsmuth, H; Ziegler, T; Zuber, K

    2008-01-01

    CosmoALEPH is an experiment operated in conjunction with the ALEPH detector. The ALEPH experiment took data from 1989 until the year 2000 at the Large Electron Positron Collider (LEP) at CERN. It provides, among others, high resolution tracking and calorimetry. CosmoALEPH used this e+e− detector for cosmic ray studies. In addition, six scintillator telescopes were installed in the ALEPH pit and the LEP tunnel. The whole experiment operated underground at a vertical depth of 320 meter water equivalent. Data from ALEPH and the scintillator telescopes provide informaton on the lateral distribution of energetic cosmic ray muons in extensive air showers. The decoherence curve of these remnant air shower muons is sensitive to the chemical composition of primary cosmic rays and to the interaction characteristics of energetic hadrons in the atmosphere. An attempt is made to extract the various interdependencies in describing the propagation of primary and secondary cosmic rays through the atmosphere and the rock ov...

  7. Cosmic Rays. Citations from the NTIS data base

    Science.gov (United States)

    Carrigan, B.

    1980-04-01

    Measurement techniques, isotopic composition, distribution, intensity, anisotropy, and sources of cosmic rays are covered in the citations. This updated bibliography contains 75 abstracts, 22 of which are new entries to the previous edition.

  8. The 1953 Cosmic Ray Conference at Bagneres de Bigorre

    CERN Document Server

    Cronin, James W

    2011-01-01

    The cosmic ray conference at Bagn`eres de Bigorre in July, 1953 organized by Patrick Blackett and Louis Leprince-Ringuet was a seminal one. It marked the beginning of sub atomic physics and its shift from cosmic ray research to research at the new high energy accelerators. The knowledge of the heavy unstable particles found in the cosmic rays was essentially correct in fact and interpretation and defined the experiments that needed to be carried out with the new accelerators. A large fraction of the physicists who had been using cosmic rays for their research moved to the accelerators. This conference can be placed in importance in the same category as two other famous conferences, the Solvay congress of 1927 and the Shelter Island Conference of 1948.

  9. Cosmic Rays - A Word-Wide Student Laboratory

    Science.gov (United States)

    Adams, Mark

    2017-01-01

    The QuarkNet program has distributed hundreds of cosmic ray detectors for use in high schools and research facilities throughout the world over the last decade. Data collected by those students has been uploaded to a central server where web-based analysis tools enable users to characterize and to analyze everyone's cosmic ray data. Since muons rain down on everyone in the world, all students can participate in this free, high energy particle environment. Through self-directed inquiry students have designed their own experiments: exploring cosmic ray rates and air shower structure; and using muons to measure their speed, time dilation, lifetime, and affects on biological systems. We also plan to expand our annual International Muon Week project to create a large student-led collaboration where similar cosmic ray measurements are performed simultaneously throughout the world.

  10. Cosmic rays score direct hits with Apollo crew

    CERN Multimedia

    1971-01-01

    Apollo 14 astronauts conduted experiments during the spaceflight to help scientists to understand why previous crews have seen flashes of light during missions, believed to be caused by cosmic rays (1 page).

  11. The gamma-ray sky points to radial gradients in cosmic-ray transport

    CERN Document Server

    Gaggero, Daniele; Valli, Mauro; Ullio, Piero

    2014-01-01

    The standard approach to cosmic-ray (CR) propagation in the Galaxy is based on the assumption that local transport properties can be extrapolated to the whole CR confining volume. Such models tend to underestimate the gamma-ray flux above few GeV measured by the Fermi Large Area Telescope towards the inner Galactic plane. We consider here for the first time a phenomenological scenario allowing for both the rigidity scaling of the diffusion coefficient and convective effects to be position-dependent. We show that within this approach we can reproduce the observed gamma-ray spectra at both low and mid Galactic latitudes - including the Galactic center - without spoiling any local CR observable.

  12. THE COSMIC-RAY INTENSITY NEAR THE ARCHEAN EARTH

    Energy Technology Data Exchange (ETDEWEB)

    Cohen, O.; Drake, J. J. [Harvard-Smithsonian Center for Astrophysics, 60 Garden St., Cambridge, MA 02138 (United States); Kota, J. [Lunar and Planetary Laboratory, University of Arizona, Tucson, AZ 85721-0092 (United States)

    2012-11-20

    We employ three-dimensional state-of-the-art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic-ray transport to investigate the cosmic-ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic-ray spectrum is to changes in the sunspot placement and magnetic field strength, the large-scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic-ray flux than is the case today. The cosmic-ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic-ray flux at 1 AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variations in the dipole field component. The wind ram pressure affects the cosmic-ray flux through its influence on the size of the heliosphere via the pressure balance with the ambient interstellar medium. Variations in the interstellar medium pressure experienced by the solar system in orbit through the Galaxy could lead to order of magnitude changes in the cosmic-ray flux at Earth on timescales of a few million years.

  13. The end of the galactic cosmic-ray energy spectrum - a phenomenological view

    CERN Document Server

    Hörandel, J R; Timokhin, A V; Hoerandel, Joerg R.

    2005-01-01

    Two structures in the all-particle energy spectrum of cosmic rays, the knee at 4 PeV and the second knee around 400 PeV are proposed to be explained by a phenomenological model, the poly gonato model, connecting direct and indirect measurements. Within this approach the knee is caused by a successive cut-off of the flux for individual elements starting with protons at 4.5 PeV. The second knee is interpreted as the end of the stable nuclei of the periodic table. To check some key features of this model calculations of the cosmic ray energy spectrum and the propagation path length at energies from 10^14 to 10^19 eV have been performed within the framework of a combined approach based on the diffusion model of cosmic rays and a direct simulation of charged-particle trajectories in the Galaxy.

  14. Probing the astrophysical origin of high-energy cosmic-ray electrons with Monte Carlo simulation

    CERN Document Server

    Attallah, Reda

    2016-01-01

    High-energy cosmic-ray electrons reveal some remarkable spectral features, the most noteworthy of which is the rise in the positron fraction above 10 GeV. Due to strong energy loss during propagation, these particles can reach Earth only from nearby sources. Yet, the exact nature of these sources, which most likely manifest themselves in the observed anomalies, remains elusive. The many explanations put forward to resolve this case range from standard astrophysics to exotic physics. In this paper, we discuss the possible astrophysical origin of high-energy cosmic-ray electrons through a fully three-dimensional time-dependent Monte Carlo simulation. This approach takes advantage of the intrinsic random nature of cosmic-ray diffusive propagation. It provides valuable information on the electron-by-electron fluctuations, making it particularly suitable for analyzing in depth the single-source astrophysical scenario.

  15. Probing the astrophysical origin of high-energy cosmic-ray electrons with Monte Carlo simulation

    Science.gov (United States)

    Attallah, R.

    2016-12-01

    High-energy cosmic-ray electrons reveal some remarkable spectral features, the most noteworthy of which is the rise in the positron fraction above 10 GeV. Due to strong energy loss during propagation, these particles can reach Earth only from nearby sources. Yet, the exact nature of these sources, which most likely manifest themselves in the observed anomalies, remains elusive. The many explanations put forward to resolve this case range from standard astrophysics to exotic physics. In this paper, we discuss the possible astrophysical origin of high-energy cosmic-ray electrons through a fully three-dimensional time-dependent Monte Carlo simulation. This approach, which takes advantage of the intrinsic random nature of cosmic-ray diffusive propagation, provides valuable information on the electron-by-electron fluctuations, making it particularly suitable for analyzing in depth the single-source scenario.

  16. Spectrum and anisotropy of cosmic rays at TeV-PeV-energies and contribution of nearby sources

    Science.gov (United States)

    Sveshnikova, L. G.; Strelnikova, O. N.; Ptuskin, V. S.

    2013-12-01

    The role of nearby galactic sources, the supernova remnants, in formation of observed energy spectrum and large-scale anisotropy of high-energy cosmic rays is studied. The list of these sources is made up based on radio, X-ray and gamma-ray catalogues. The distant sources are treated statistically as ensemble of sources with random positions and ages. The source spectra are defined based on the modern theory of cosmic ray acceleration in supernova remnants while the propagation of cosmic rays in the interstellar medium is described in the frameworks of galactic diffusion model. Calculations of dipole component of anisotropy are made to reproduce the experimental procedure of "two-dimensional" anisotropy measurements. The energy dependence of particle escape time in the process of acceleration in supernova remnants and the arm structure of sources defining the significant features of anisotropy are also taken into account. The essential new trait of the model is a decreasing number of core collapse SNRs being able to accelerate cosmic rays up to the given energy, that leads to steeper total cosmic ray source spectrum in comparison with the individual source spectrum. We explained simultaneously the new cosmic ray data on the fine structure of all particle spectrum around the knee and the amplitude and direction of the dipole component of anisotropy in the wide energy range 1 TeV-1 EeV. Suggested assumptions do not look exotic, and they confirm the modern understanding of cosmic ray origin.

  17. The Cosmic Ray Intensity Near the Archean Earth

    CERN Document Server

    Cohen, O; Kota, J

    2012-01-01

    We employ three-dimensional state of the art magnetohydrodynamic models of the early solar wind and heliosphere and a two-dimensional model for cosmic ray transport to investigate the cosmic ray spectrum and flux near the Archean Earth. We assess how sensitive the cosmic ray spectrum is to changes in the sunspot placement and magnetic field strength, the large scale dipole magnetic field strength, the wind ram pressure, and the Sun's rotation period. Overall, our results confirm earlier work that suggested the Archean Earth would have experienced a greatly reduced cosmic ray flux than is the case today. The cosmic ray reduction for the early Sun is mainly due to the shorter solar rotation period and tighter winding of the Parker spiral, and to the different surface distribution of the more active solar magnetic field. These effects lead to a global reduction of the cosmic ray flux at 1AU by up to two orders of magnitude or more. Variations in the sunspot magnetic field have more effect on the flux than variat...

  18. COSMOS: the COsmic-ray Soil Moisture Observing System

    Directory of Open Access Journals (Sweden)

    M. Zreda

    2012-11-01

    Full Text Available The newly-developed cosmic-ray method for measuring area-average soil moisture at the hectometer horizontal scale is being implemented in the COsmic-ray Soil Moisture Observing System (or the COSMOS. The stationary cosmic-ray soil moisture probe measures the neutrons that are generated by cosmic rays within air and soil and other materials, moderated by mainly hydrogen atoms located primarily in soil water, and emitted to the atmosphere where they mix instantaneously at a scale of hundreds of meters and whose density is inversely correlated with soil moisture. The COSMOS has already deployed more than 50 of the eventual 500 cosmic-ray probes, distributed mainly in the USA, each generating a time series of average soil moisture over its horizontal footprint, with similar networks coming into existence around the world. This paper is written to serve a community need to better understand this novel method and the COSMOS project. We describe the cosmic-ray soil moisture measurement method, the instrument and its calibration, the design, data processing and dissemination used in the COSMOS project, and give example time series of soil moisture obtained from COSMOS probes.

  19. Review and interpretation of recent cosmic ray beryllium isotope measurements

    Energy Technology Data Exchange (ETDEWEB)

    Buffington, A.

    1978-04-26

    Be/sup 10/ has long been of interest for cosmic ray propagation, because its radioactive decay half-life is well matched to the expected cosmic ray age. Recent beryllium isotope measurements from satellites and balloons have covered an energy range from about 30 to 300 MeV/nucleon/sup 1-3/. At the lowest energies, most of the Be/sup 10/ is absent, indicating a cosmic ray lifetime of order 2 x 10/sup 7/ years and the rather low average density of 0.2 atoms/cc traversed by the cosmic rays. At higher energies, a greater proportion of Be/sup 10/ is observed, indicating a somewhat shorter lifetime. These experiments will be reviewed and then compared with a new experiment covering from 100 to 1000 Mev/nucleon/sup 4/. Although improved experiments will be necessary to realize the full potential of cosmic ray beryllium isotope measurements, these first results are already disclosing interesting and unexpected facts about cosmic ray acceleration and propagation.

  20. Cosmic rays and space weather: effects on global climate change

    Directory of Open Access Journals (Sweden)

    L. I. Dorman

    2012-01-01

    Full Text Available We consider possible effects of cosmic rays and some other space factors on the Earth's climate change. It is well known that the system of internal and external factors formatting the climate is very unstable; decreasing planetary temperature leads to an increase of snow surface, and decrease of the total solar energy input into the system decreases the planetary temperature even more, etc. From this it follows that even energetically small factors may have a big influence on climate change. In our opinion, the most important of these factors are cosmic rays and cosmic dust through their influence on clouds, and thus, on climate.

  1. On the Mechanism for Breaks in the Cosmic Ray Spectrum

    Science.gov (United States)

    Malkov, Mikhail

    2011-11-01

    Recent observations of galactic supernova remnants by the Fermi spacecraft observatory strongly support the idea that the bulk of galactic cosmic rays are accelerated in such remnants by a Fermi mechanism, also known as diffusive shock acceleration. However, the remnants most visible in gamma rays expand into weakly ionized dense gas, and so a significant revision of the basic mechanism is required. In this talk, I provide the necessary modifications and demonstrate that strong ion- neutral collisions in the remnant lead to steepening of the energy spectrum of accelerated particles by exactly one power. The spectral break is caused by Alfven wave evanescence leading to fractional particle losses. The gamma-ray spectrum generated in collisions of the accelerated protons with the ambient gas is also calculated and successfully fitted to the Fermi data. The parent proton spectrum is best represented by a classical test particle power law E-2, steepening to E-3 at Ebr=7GeV due to deteriorated particle confinement.

  2. A young SNR illuminating nearby Molecular Clouds with cosmic rays

    CERN Document Server

    Cui, Y; Santangelo, A

    2016-01-01

    The Supernova Remnant (SNR) HESS J1731-347 displays strong non-thermal TeV gamma-ray and X-ray emission, thus the object is at present time accelerating particles to very high energies. A distinctive feature of this young SNR is the nearby (~30 pc in projection) extended source HESS J1729-345, which is currently unidentified but is in spatial projection coinciding with known molecular clouds (MC). We model the SNR evolution to explore if the TeV emission from HESS J1729-345 can be explained as emission from runaway hadronic cosmic rays (CRs) that are illuminating these MCs. The observational data of HESS J1729-345 and HESS J1731-347 can be reproduced using core-collapse SN models for HESS J1731-347. Starting with different progenitor stars and their pre-supernova environment, we model potential SNR evolution histories along with the CR acceleration in the SNR and the diffusion of the CRs. A simplified 3-dimensional structure of the MCs is introduced based on 12CO data, adopting a distance of 3.2 kpc to the so...

  3. Multi-wavelength constraints on cosmic-ray leptons in the Galaxy

    CERN Document Server

    Orlando, E; Moskalenko, I V; Dickinson, C; Digel, S; Jaffe, T R; Jóhannesson, G; Leahy, J P; Porter, T A; Vidal, M

    2015-01-01

    Cosmic rays (CRs) interact with the gas, the radiation field and the magnetic field in the Milky Way, producing diffuse emission from radio to gamma rays. Observations of this diffuse emission and comparison with detailed predictions are powerful tools to unveil the CR properties and to study CR propagation. We present various GALPROP CR propagation scenarios based on current CR measurements. The predicted synchrotron emission is compared to radio surveys, and synchrotron temperature maps from WMAP and Planck, while the predicted interstellar gamma-ray emission is compared to Fermi-LAT observations. We show how multi-wavelength observations of the Galactic diffuse emission can be used to help constrain the CR lepton spectrum and propagation. Finally we discuss how radio and microwave data could be used in understanding the diffuse Galactic gamma-ray emission observed with Fermi-LAT, especially at low energies.

  4. Astrophysical Sources of Cosmic Rays and Related Measurements with the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Abraham, : J.; Abreu, P.; Aglietta, M.; Aguirre, C.; Ahn, E.J.; Allard, D.; Allekotte, I.; Allen, J.; Alvarez-Muniz, J.; Ambrosio, M.; Anchordoqui, L.

    2009-06-01

    These are presentations to be presented at the 31st International Cosmic Ray Conference, in Lodz, Poland during July 2009. It consists of the following presentations: (1) Correlation of the highest energy cosmic rays with nearby extragalactic objects in Pierre Auger Observatory data; (2) Discriminating potential astrophysical sources of the highest energy cosmic rays with the Pierre Auger Observatory; (3) Intrinsic anisotropy of the UHECR from the Pierre Auger Observatory; (4) Ultra-high energy photon studies with the Pierre Auger Observatory; (5) Limits on the flux of diffuse ultra high energy neutrinos set using the Pierre Auger Observatory; (6) Search for sidereal modulation of the arrival directions of events recorded at the Pierre Auger Observatory; (7) Cosmic Ray Solar Modulation Studies in the Pierre Auger Observatory; (8) Investigation of the Displacement Angle of the Highest Energy Cosmic Rays Caused by the Galactic Magnetic Field; (9) Search for coincidences with astrophysical transients in Pierre Auger Observatory data; and (10) An alternative method for determining the energy of hybrid events at the Pierre Auger Observatory.

  5. Connections between cosmic-ray physics, gamma-ray data analysis and Dark Matter detection

    CERN Document Server

    Gaggero, Daniele

    2015-01-01

    Cosmic-ray (CR) physics has been a prolific field of research for over a century. The open problems related to CR acceleration, transport and modulation are deeply connected with the indirect searches for particle dark matter (DM). In particular, the high-quality gamma-ray data released by Fermi-LAT are under the spotlight in the scientific community because of a recent claim about a inner Galaxy anomaly: The necessity to disentangle the astrophysical emission due to CR interactions from a possible DM signal is therefore compelling and requires a deep knowledge of several non-trivial aspects regarding CR physics. I review all these connections in this contribution. In the first part, I present a detailed overview on recent results regarding modeling of cosmic-ray (CR) production and propagation: I focus on the necessity to go beyond the standard and simplified picture of uniform and homogeneous diffusion, showing that gamma-ray data point towards different transport regimes in different regions of the Galaxy;...

  6. Gamma-ray and neutrino diffuse emissions of the Galaxy above the TeV

    Science.gov (United States)

    Gaggero, D.; Grasso, D.; Marinelli, A.; Urbano, A.; Valli, M.

    2016-05-01

    Conventional cosmic ray propagation models face problems reproducing the diffuse 7-ray spectrum measured by Fermi-LAT over the entire sky. Those models also fail to smoothly connect Fermi-LAT results with data above the TeV as those taken by Milagro in the inner Galactic plane. In this contribution we show that a representative model adopting a spatial dependent rigidity scaling of the diffusion coefficient can reproduce all those experimental results without spoiling the consistency with local cosmic-ray measurements. We use the same model to compute the diffuse neutrino emission of the Galaxy and compare it with IceCube and ANTARES results.

  7. Ionization and heating by X-rays and cosmic rays*

    Directory of Open Access Journals (Sweden)

    Güdel Manuel

    2015-01-01

    Full Text Available High-energy radiation from the central T Tauri and protostars plays an important role in shaping protoplanetary disks and influences their evolution. Such radiation, in particular X-rays and extreme-ultraviolet (EUV radiation, is predominantly generated in unstable stellar magnetic fields (e.g., the stellar corona, but also in accretion hot spots. Even jets may produce X-ray emission. Cosmic rays, i.e., high-energy particles either from the interstellar space or from the star itself, are of crucial importance. Both highenergy photons and particles ionize disk gas and lead to heating. Ionization and heating subsequently drive chemical networks, and the products of these processes are accessible through observations of molecular line emission. Furthermore, ionization supports the magnetorotational instability and therefore drives disk accretion, while heating of the disk surface layers induces photoevaporative flows. Both processes are crucial for the dispersal of protoplanetary disks and therefore critical for the time scales of planet formation. This chapter introduces the basic physics of ionization and heating starting from a quantum mechanical viewpoint, then discusses relevant processes in astrophysical gases and their applications to protoplanetary disks, and finally summarizes some properties of the most important high-energy sources for protoplanetary disks.

  8. Self-Similar Evolution of Cosmic-Ray-Modified Quasi-Parallel Plane Shocks

    CERN Document Server

    Kang, Hyesung

    2007-01-01

    Using an improved version of the previously introduced CRASH (Cosmic Ray Acceleration SHock) code, we have calculated the time evolution of cosmic-ray (CR) modified quasi-parallel plane shocks for Bohm-like diffusion, including self-consistent models of Alfven wave drift and dissipation, along with thermal leakage injection of CRs. The new simulations follow evolution of the CR distribution to much higher energies than our previous study, providing a better examination of evolutionary and asymptotic behaviors. The postshock CR pressure becomes constant after quick initial adjustment, since the evolution of the CR partial pressure expressed in terms of a momentum similarity variable is self-similar. The shock precursor, which scales as the diffusion length of the highest energy CRs, subsequently broadens approximately linearly with time, independent of diffusion model, so long as CRs continue to be accelerated to ever-higher energies. This means the nonlinear shock structure can be described approximately in t...

  9. Simulating cosmic ray physics on a moving mesh

    Science.gov (United States)

    Pfrommer, C.; Pakmor, R.; Schaal, K.; Simpson, C. M.; Springel, V.

    2017-03-01

    We discuss new methods to integrate the cosmic ray (CR) evolution equations coupled to magnetohydrodynamics on an unstructured moving mesh, as realized in the massively parallel AREPO code for cosmological simulations. We account for diffusive shock acceleration of CRs at resolved shocks and at supernova remnants in the interstellar medium (ISM) and follow the advective CR transport within the magnetized plasma, as well as anisotropic diffusive transport of CRs along the local magnetic field. CR losses are included in terms of Coulomb and hadronic interactions with the thermal plasma. We demonstrate the accuracy of our formalism for CR acceleration at shocks through simulations of plane-parallel shock tubes that are compared to newly derived exact solutions of the Riemann shock-tube problem with CR acceleration. We find that the increased compressibility of the post-shock plasma due to the produced CRs decreases the shock speed. However, CR acceleration at spherically expanding blast waves does not significantly break the self-similarity of the Sedov-Taylor solution; the resulting modifications can be approximated by a suitably adjusted, but constant adiabatic index. In first applications of the new CR formalism to simulations of isolated galaxies and cosmic structure formation, we find that CRs add an important pressure component to the ISM that increases the vertical scaleheight of disc galaxies and thus reduces the star formation rate. Strong external structure formation shocks inject CRs into the gas, but the relative pressure of this component decreases towards halo centres as adiabatic compression favours the thermal over the CR pressure.

  10. Measurement of cosmic-ray muons with the Distributed Electronic Cosmic-ray Observatory, a network of smartphones

    Science.gov (United States)

    Vandenbroucke, J.; BenZvi, S.; Bravo, S.; Jensen, K.; Karn, P.; Meehan, M.; Peacock, J.; Plewa, M.; Ruggles, T.; Santander, M.; Schultz, D.; Simons, A. L.; Tosi, D.

    2016-04-01

    Solid-state camera image sensors can be used to detect ionizing radiation in addition to optical photons. We describe the Distributed Electronic Cosmic-ray Observatory (DECO), an app and associated public database that enables a network of consumer devices to detect cosmic rays and other ionizing radiation. In addition to terrestrial background radiation, cosmic-ray muon candidate events are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular distribution of muons at sea level. We use a sample of candidate muon events detected by DECO to measure the thickness of the depletion region of the camera image sensor in a particular consumer smartphone model, the HTC Wildfire S. The track length distribution is fit better by a cosmic-ray muon angular distribution than an isotropic distribution, demonstrating that DECO can detect and identify cosmic-ray muons despite a background of other particle detections. Using the cosmic-ray distribution, we measure the depletion thickness to be 26.3 ± 1.4 μm. With additional data, the same method can be applied to additional models of image sensor. Once measured, the thickness can be used to convert track length to incident polar angle on a per-event basis. Combined with a determination of the incident azimuthal angle directly from the track orientation in the sensor plane, this enables direction reconstruction of individual cosmic-ray events using a single consumer device. The results simultaneously validate the use of cell phone camera image sensors as cosmic-ray muon detectors and provide a measurement of a parameter of camera image sensor performance which is not otherwise publicly available.

  11. Galactic Cosmic Rays and the Environment

    Science.gov (United States)

    Castagnoli, G. Cini

    SH.3.6.14 Galactic Cosmic Rays and the Environment G. Cini Castagnoli, G. Bonino, P. Della Monica, C. Taricco Istituto di Cosmogeofisica, CNR, Corso Fiume 4, 10133 Torino, Italy and Dipartimento di Fisica Generale, Università di Torino, Via P. Giuria 1, 10125 Torino Recently Svensmark and Friis-Christensen (1997) reported an indication that the Galactic Cosmic Rays (GCR) modulated by the solar wind may contribute to the variations in the formation of clouds, which in turn should follow the 11 y solar cycle. On the other hand experiments, conducted in vitro, on the variations of δ3C in symbiont bearing 1 foraminifera have shown that the carbon isotope fractionation from sea water, of the calcite of their shells, depends mainly on the photosynthetic activity (primary productivity) of the symbionts and therefore from the illumination level of their habitat. We have measured and analyzed (Cini Castagnoli et al., 1999) the δ3C profile of G. ruber in an Ionian sea 1 shallow water core very precisely dated. This allows us to acquire information on the ambient light level (connected to the solar irradiance modulation and to the cloud coverage) of the Gallipoli terrace in the past Millenium. The record (1205-1975 AD) of 200 points with time resolution 3.87 years shows a highly significant 11 y cyclicity covariant with Sunspots of amplitude 0.04 ‰ . A test for determining the δ3C-irradiance relation has been 1 13 performed by studying variations of δ C and the percentage annual number of rainy days during the last century in this region. Our results agree with the expectations on the basis of experiments performed in vitro on G. sacculifer ( on G. ruber is not available). The amplitude of the 11 y δ3C signal turns out to be of the order of 1.5 W/m2. This value seems to be 1 quite high (although of the same order) to be directly induced solely by changes in the solar constant, if in past times they were similar to those measured in space during solar cycles 22-23. The

  12. A Quantum Phase Transition in the Cosmic Ray Energy Distribution

    CERN Document Server

    Widom, A; Srivastava, Y

    2015-01-01

    We here argue that the "knee" of the cosmic ray energy distribution at $E_c \\sim 1$ PeV represents a second order phase transition of cosmic proportions. The discontinuity of the heat capacity per cosmic ray particle is given by $\\Delta c=0.450196\\ k_B$. However the idea of a deeper critical point singularity cannot be ruled out by present accuracy in neither theory nor experiment. The quantum phase transition consists of cosmic rays dominated by bosons for the low temperature phase E E_c$. The low temperature phase arises from those nuclei described by the usual and conventional collective boson models of nuclear physics. The high temperature phase is dominated by protons. The transition energy $E_c$ may be estimated in terms of the photo-disintegration of nuclei.

  13. A connection between star formation activity and cosmic rays in the starburst galaxy M 82

    CERN Document Server

    Acciari, V A; Arlen, T; Aune, T; Bautista, M; Beilicke, M; Benbow, W; Boltuch, D; Bradbury, S M; Buckley, J H; Bugaev, V; Byrum, K; Cannon, A; Celik, O; Cesarini, A; Chow, Y C; Ciupik, L; Cogan, P; Colin, P; Cui, W; Dickherber, R; Duke, C; Fegan, S J; Finley, J P; Finnegan, G; Fortin, P; Fortson, L; Furniss, A; Galante, N; Gall, D; Gibbs, K; Gillanders, G H; Godambe, S; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Holder, J; Horan, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, Philip; Karlsson, N; Kertzman, M; Kieda, D; Kildea, J; Konopelko, A; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Maier, G; McArthur, S; McCann, A; McCutcheon, M; Millis, J; Moriarty, P; Mukherjee, R; Nagai, T; Ong, R A; Otte, A N; Pandel, D; Perkins, J S; Pizlo, F; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Rose, H J; Schroedter, M; Sembroski, G H; Smith, A W; Steele, D; Swordy, S P; Theiling, M; Thibadeau, S; Varlotta, A; Vasilev, V V; Vincent, S; Wagner, R G; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; Weisgarber, T; Williams, D A; Wissel, S; Wood, M; Zitzer, B; 10.1038/nature08557

    2009-01-01

    Although Galactic cosmic rays (protons and nuclei) are widely believed to be dominantly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery [1]. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size, more than 50 times the diameter of similar Galactic regions, uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density [2]. The cosmic rays produced in the formation, life, and death of their massive stars are expected to eventually produce diffuse gamma-ray emission via their interactions with interstellar gas and radiation. M 82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in gamma rays [3, 4]. Here we report the detection of >700 GeV gamma rays from M 82. From these data we determine a cosmic-ray density of 250 eV cm-3 in the starburst core of M 82, or about 500 times the averag...

  14. Do cosmic ray air showers initiate lightning?: A statistical analysis of cosmic ray air showers and lightning mapping array data

    Science.gov (United States)

    Hare, B. M.; Dwyer, J. R.; Winner, L. H.; Uman, M. A.; Jordan, D. M.; Kotovsky, D. A.; Caicedo, J. A.; Wilkes, R. A.; Carvalho, F. L.; Pilkey, J. T.; Ngin, T. K.; Gamerota, W. R.; Rassoul, H. K.

    2017-08-01

    It has been argued in the technical literature, and widely reported in the popular press, that cosmic ray air showers (CRASs) can initiate lightning via a mechanism known as relativistic runaway electron avalanche (RREA), where large numbers of high-energy and low-energy electrons can, somehow, cause the local atmosphere in a thundercloud to transition to a conducting state. In response to this claim, other researchers have published simulations showing that the electron density produced by RREA is far too small to be able to affect the conductivity in the cloud sufficiently to initiate lightning. In this paper, we compare 74 days of cosmic ray air shower data collected in north central Florida during 2013-2015, the recorded CRASs having primary energies on the order of 1016 eV to 1018 eV and zenith angles less than 38°, with Lightning Mapping Array (LMA) data, and we show that there is no evidence that the detected cosmic ray air showers initiated lightning. Furthermore, we show that the average probability of any of our detected cosmic ray air showers to initiate a lightning flash can be no more than 5%. If all lightning flashes were initiated by cosmic ray air showers, then about 1.6% of detected CRASs would initiate lightning; therefore, we do not have enough data to exclude the possibility that lightning flashes could be initiated by cosmic ray air showers.

  15. Global Simulations of Galactic Winds Including Cosmic-ray Streaming

    Science.gov (United States)

    Ruszkowski, Mateusz; Yang, H.-Y. Karen; Zweibel, Ellen

    2017-01-01

    Galactic outflows play an important role in galactic evolution. Despite their importance, a detailed understanding of the physical mechanisms responsible for the driving of these winds is lacking. In an effort to gain more insight into the nature of these flows, we perform global three-dimensional magnetohydrodynamical simulations of an isolated Milky Way-size starburst galaxy. We focus on the dynamical role of cosmic rays (CRs) injected by supernovae, and specifically on the impact of the streaming and anisotropic diffusion of CRs along the magnetic fields. We find that these microphysical effects can have a significant effect on the wind launching and mass loading factors, depending on the details of the plasma physics. Due to the CR streaming instability, CRs propagating in the interstellar medium scatter on self-excited Alfvén waves and couple to the gas. When the wave growth due to the streaming instability is inhibited by some damping process, such as turbulent damping, the coupling of CRs to the gas is weaker and their effective propagation speed faster than the Alfvén speed. Alternatively, CRs could scatter from “extrinsic turbulence” that is driven by another mechanism. We demonstrate that the presence of moderately super-Alfvénic CR streaming enhances the efficiency of galactic wind driving. Cosmic rays stream away from denser regions near the galactic disk along partially ordered magnetic fields and in the process accelerate more tenuous gas away from the galaxy. For CR acceleration efficiencies broadly consistent with the observational constraints, CRs reduce the galactic star formation rates and significantly aid in launching galactic winds.

  16. Phantom Cosmic Ray Decreases and their Extraterrestrial Origins

    Science.gov (United States)

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

    2014-05-01

    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.

  17. Galactic origin of ultrahigh energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Mikhailov, A.A. [Yu.G. Shafer Institute of Cosmophysical Research and Aeronomy, 31 Lenin Ave., 677980 Yakutsk (Russian Federation)

    2009-05-15

    The arrival directions of ultrahigh energy extensive air showers (EAS) by Yakutsk, AGASA, P. Auger array data are analyzed. For the first time, the maps of equal exposition of celestial sphere for the distribution of particles by AGASA and P. Auger arrays data have been constructed. The large-scale anisotropy of cosmic particles at E>4x10{sup 19} eV by Yakutsk, AGASA and P. Auger array data has been detected. The problem of cosmic particle origin is discussed.

  18. Hunting for Cosmic-Ray Origins with SuperTIGER

    Science.gov (United States)

    Kohler, Susanna

    2016-11-01

    Illustration of cosmic-ray nuclei impacting Earths atmosphere and decaying into lighter particles. [ESA]The SuperTIGER (Trans-Iron Galactic Element Recorder) experiment flew over Antarctica for 55 days, collecting millions of galactic cosmic rays. What can it tell us about the origins of these high-energy particles?High-Energy ImpactsGalactic cosmic rays are immensely high-energy protons and atomic nuclei that impact our atmosphere, originating from outside of our solar system. Where do they come from, and how are they accelerated? These are both open topics of research.One of the leading theories is that cosmic-ray source material is primarily a mixture of material that has been ejected from massive stars either from supernovae or in stellar wind outflows and normal interstellar medium (ISM). This material is then accelerated to cosmic-ray energies by supernova shocks.Number of nuclei of each element detected by SuperTIGER. Note the change of scale between the two plots (click for a closer look)! [Murphy et al. 2016]How can we test this model? An important step is understanding the composition of galactic cosmic rays: what elemental nuclei are they made up of? If abundances are similar to solar-system abundances, then the material is likely mostly ISM. If the abundances of rarer heavy elements are high, however, then the material is more likely to have come from massive stars in star-forming regions.Balloon-Borne DetectionsEnter SuperTIGER, an experiment designed to collect cosmic rays and measure the abundances of the rare heavy elements those with atomic number between iron (Z=26) and zirconium (Z=40).The path that SuperTIGER took over Antarctica during its flight, with a different color denoting each circuit around the pole. Note where it got stuck in an eddy over the Transarctic Mountains at the end of its second circuit! [Columbia Scientific Balloon Facility]To gather galactic cosmic rays, the detector must be above the Earths atmosphere; interactions with

  19. Sharp knee phenomenon of primary cosmic ray energy spectrum

    CERN Document Server

    Ter-Antonyan, Samvel

    2014-01-01

    Primary energy spectral models are tested in the energy range of 1-200 PeV using standardized extensive air shower responses from BASJE-MAS, Tibet, GAMMA and KASCADE scintillation shower arrays. Results point towards the two-component origin of observed cosmic ray energy spectra in the knee region (GAPS spectral model) consisting of a pulsar component superimposed upon rigidity-dependent power law diffuse galactic flux. The two-component energy spectral model accounts for both the sharp knee shower spectral phenomenon and observed irregularity of all-particle energy spectrum in the region of 50-100 PeV. Alternatively, tested multi-population primary energy spectra predicted by non-linear diffusive shock acceleration (DSA) models describe observed shower spectra in the knee region provided that the cutoff magnetic rigidities of accelerating particles are 6.0+/-0.3 PV and 45+/-2 PV for the first two populations respectively. Both tested spectral models confirm the predominant H-He primary nuclei origin of obser...

  20. The role of cosmic ray pressure in accelerating galactic outflows

    CERN Document Server

    Simpson, Christine M; Marinacci, Federico; Pfrommer, Christoph; Springel, Volker; Glover, Simon C O; Clark, Paul C; Smith, Rowan J

    2016-01-01

    We study the formation of galactic outflows from supernova explosions (SNe) with the moving-mesh code AREPO in a stratified column of gas with a surface density similar to the Milky Way disk at the solar circle. We compare different simulation models for SNe placement and energy feedback, including cosmic rays (CR), and find that models that place SNe in dense gas and account for CR diffusion are able to drive outflows with similar mass loading as obtained from a random placement of SNe with no CRs. Despite this similarity, CR-driven outflows differ in several other key properties including their overall clumpiness and velocity. Moreover, the forces driving these outflows originate in different sources of pressure, with the CR diffusion model relying on non-thermal pressure gradients to create an outflow driven by internal pressure and the random-placement model depending on kinetic pressure gradients to propel a ballistic outflow. CRs therefore appear to be non-negligible physics in the formation of outflows...

  1. The relation between post-shock temperature, cosmic-ray pressure, and cosmic-ray escape for non-relativistic shocks

    NARCIS (Netherlands)

    Vink, J.; Yamazaki, R.; Helder, E.A.; Schure, K.M.

    2010-01-01

    Supernova remnants (SNRs) are thought to be the dominant source of Galactic cosmic rays. This requires that at least 5% of the available energy is transferred to cosmic rays, implying a high cosmic-ray pressure downstream of SNR shocks. Recently, it has been shown that the downstream temperature in

  2. The Milagro anti-Center hot spots: cosmic rays from the Geminga Supernova ?

    CERN Document Server

    Salvati, M

    2008-01-01

    The Milagro experiment has announced the discovery of an excess flux of TeV cosmic rays from the general direction of the heliotail, also close to the Galactic anti--Center. We investigate the hypothesis that the excess cosmic rays were produced in the SN explosion which gave birth to the Geminga pulsar. The assumptions underlying our proposed scenario are that the Geminga Supernova occurred about 3.4 10^5 years ago (as indicated by the spin down timescale); that a burst of cosmic rays was injected with total energy ~10^49 erg (i.e., about 0.01 of a typical SN output); that the cosmic rays have since diffused according to the Bohm prescription (i.e., with a diffusion coefficient of the order of c r_L, with c the speed of light and r_L the Larmor radius); and that the Geminga pulsar was born with a positive radial velocity of at least 160 km s^-1. We find that our hypothesis is consistent with the available information. The assumption about the velocity of the Geminga pulsar was already proposed by previous in...

  3. Cosmic-ray acceleration during the impact of shocks on dense clouds

    Science.gov (United States)

    Jones, T. W.; Kang, Hyesung

    1993-01-01

    In order to elucidate the properties of diffusive shock acceleration in nonuniform environments, an extensive set of simulations of the dynamical interactions between plane nonradiative shocks and dense gas clouds was carried out initially in static equilibrium with their environments. These time-dependent calculations are based on the two-fluid model for diffusive cosmic ray transport, and include the dynamically active energetic proton component of the cosmic rays as well as passive electron and magnetic field components. Except when the incident shock is itself already dominated by cosmic ray pressure, it is found that the presence of the cloud adds little to the net acceleration efficiency of the original shock and can, in fact, reduce slightly the net amount of energy transferred to cosmic rays after a given time. It is found that, in 2D cloud simulations, the always-weak bow shock and the shock inside the cloud are less important to acceleration during the interaction than the tail shock.

  4. Cosmic-ray-induced dissociation and reactions in warm interstellar ices

    CERN Document Server

    Kalvans, Juris

    2014-01-01

    Context. Cosmic ray particles that hit interstellar grains in dark molecular cores may induce whole-grain heating. The high temperature of a CR-heated grain allows energy barriers for bulk diffusion and reactions to be overcome. Additionally, ice molecules are destroyed by direct cosmic-ray induced dissociation. Aims. We provide a justified estimate of the significance of cosmic-ray induced surface-mantle diffusion, chemical reactions in ice, and dissociation of ice species in a star-forming interstellar cloud core. Methods. We considered a gas clump in a collapsing low-mass prestellar core and during the initial stages of protostellar envelope heating with a three-phase chemical kinetics model. The model includes a proper treatment of the stochastic aspect of whole-grain heating and new experimental data for dissociation. Results. We found that the cosmic-ray-induced effects are mostly limited to an increase in abundance for carbon-chain species. The effect on major species abundances is a few percentage poi...

  5. Cosmic-Ray Small-scale Anisotropies and Local Turbulent Magnetic Fields

    Science.gov (United States)

    López-Barquero, V.; Farber, R.; Xu, S.; Desiati, P.; Lazarian, A.

    2016-10-01

    Cosmic-ray anisotropy has been observed in a wide energy range and at different angular scales by a variety of experiments over the past decade. However, no comprehensive or satisfactory explanation has been put forth to date. The arrival distribution of cosmic rays at Earth is the convolution of the distribution of their sources and of the effects of geometry and properties of the magnetic field through which particles propagate. It is generally believed that the anisotropy topology at the largest angular scale is adiabatically shaped by diffusion in the structured interstellar magnetic field. On the contrary, the medium- and small-scale angular structure could be an effect of nondiffusive propagation of cosmic rays in perturbed magnetic fields. In particular, a possible explanation for the observed small-scale anisotropy observed at the TeV energy scale may be the effect of particle propagation in turbulent magnetized plasmas. We perform numerical integration of test particle trajectories in low-β compressible magnetohydrodynamic turbulence to study how the cosmic rays’ arrival direction distribution is perturbed when they stream along the local turbulent magnetic field. We utilize Liouville’s theorem for obtaining the anisotropy at Earth and provide the theoretical framework for the application of the theorem in the specific case of cosmic-ray arrival distribution. In this work, we discuss the effects on the anisotropy arising from propagation in this inhomogeneous and turbulent interstellar magnetic field.

  6. Voyager 1 in the Local Interstellar Medium: Cosmic-ray Energy Density and Ionization Rate

    Science.gov (United States)

    Cummings, A. C.; Stone, E. C.; Heikkila, B. C.; Lal, N.; Webber, W. R.; Johannesson, G.; Moskalenko, I.; Orlando, E.; Porter, T.

    2015-12-01

    We present the energy spectra of cosmic ay nuclei and electrons in the local interstellar medium (LISM) from the Cosmic Ray Subsystem on Voyager 1 (V1). We use four models of the local interstellar spectra of nuclei and one of electrons that are constrained by the observations to compute the energy density and ionization rate of atomic H in the LISM above 3 MeV for electrons and protons and above 3 MeV/nuc for nuclei with Z > 1. We find that the total cosmic-ray energy density is in the range 0.82-0.97 eV/cm3, which includes a contribution of 0.023 eV/cm3 from electrons. We find the cosmic-ray ionization rate of atomic H to be in the range 1.45-1.58 x 10-17 s-1, which is a factor of more than 10 below the cosmic-ray ionization rate in diffuse interstellar clouds based on astrochemistry methods. We discuss possible reasons for this difference. Voyager data analysis is supported by NASA Grant NNN12AA012. GALPROP development is supported by NASA Grants NNX13AC47G and NNX10AE78G.

  7. Winds, Clumps, and Interacting Cosmic Rays in M82

    CERN Document Server

    Yoast-Hull, Tova M; Gallagher, J S; Zweibel, Ellen G

    2013-01-01

    We construct a family of models for the evolution of energetic particles in the starburst galaxy M82 and compare them to observations to test the calorimeter assumption that all cosmic ray energy is radiated in the starburst region. Assuming constant cosmic ray acceleration efficiency with Milky Way parameters, we calculate the cosmic-ray proton and primary and secondary electron/positron populations as a function of energy. Cosmic rays are injected with Galactic energy distributions and electron-to-proton ratio via type II supernovae at the observed rate of 0.07/yr. From the cosmic ray spectra, we predict the radio synchrotron and \\gamma-ray spectra. To more accurately model the radio spectrum, we incorporate a multiphase interstellar medium in the starburst region of M82. Our model interstellar medium is highly fragmented with compact dense molecular clouds and dense photoionized gas, both embedded in a hot, low density medium in overall pressure equilibrium. The spectra predicted by this one-zone model are...

  8. Propagation of cosmic rays in the Earth's atmosphere

    Energy Technology Data Exchange (ETDEWEB)

    Putze, Antje [LPSC-CNRS-IN2P3, 53, avenue des Martyrs, 38021 Grenoble cedex (France)

    2006-06-15

    Cosmic rays are composed of charged particles, which arrive after a long travel through the Galaxy on Earth. Supernova explosions are considered to be galactic sources, which accelerate these particles up to energies around 10{sup 18} eV. Beyond this energy, one supposes that the extragalactic sources, like active galaxy nuclei (AGN), gamma ray bursts or pulsars, are the origin of the ultra high energy cosmic rays. The spectral index of the elemental energy distributions of cosmic rays reflects the dynamic of its propagation, particularly the conjugation of the effects connected to the cosmic ray source spectrum and those connected to its propagation (acceleration, absorption and escape). The evolution of the spectral index with the cosmic-ray particle energy constitutes a sensitive test of the components, which determine this evolution. The precise index measurement of individual elemental spectra of the cosmic rays by AMS up to TeV and by the experiment CREAM beyond it, from TeV to PeV, will permit to proceed in this problematic. One of the difficulties on this measurement is to take well into account the systematic errors. During the data analysis we have to take into account in particular the interaction (diffusion and fragmentation) of the ions while their travel through the Earth's atmosphere. The study of the interaction and the fragmentation of these ions in the atmosphere is hence indispensable and described in this work. The study is based on a matrix calculation, which had been successfully implemented and tested and which has permitted to analyse the effects, caused by the experimental uncertainties on the cross sections, on the spectral index measurement. (author)

  9. WINDS, CLUMPS, AND INTERACTING COSMIC RAYS IN M82

    Energy Technology Data Exchange (ETDEWEB)

    Yoast-Hull, Tova M.; Everett, John E.; Zweibel, Ellen G. [Department of Physics, University of Wisconsin-Madison, WI (United States); Gallagher, J. S. III, E-mail: yoasthull@wisc.edu [Department of Astronomy, University of Wisconsin-Madison, WI (United States)

    2013-05-01

    We construct a family of models for the evolution of energetic particles in the starburst galaxy M82 and compare them to observations to test the calorimeter assumption that all cosmic ray energy is radiated in the starburst region. Assuming constant cosmic ray acceleration efficiency with Milky Way parameters, we calculate the cosmic-ray proton and primary and secondary electron/positron populations as a function of energy. Cosmic rays are injected with Galactic energy distributions and electron-to-proton ratio via Type II supernovae at the observed rate of 0.07 yr{sup -1}. From the cosmic ray spectra, we predict the radio synchrotron and {gamma}-ray spectra. To more accurately model the radio spectrum, we incorporate a multiphase interstellar medium in the starburst region of M82. Our model interstellar medium is highly fragmented with compact dense molecular clouds and dense photoionized gas, both embedded in a hot, low density medium in overall pressure equilibrium. The spectra predicted by this one-zone model are compared to the observed radio and {gamma}-ray spectra of M82. {chi}{sup 2} tests are used with radio and {gamma}-ray observations and a range of model predictions to find the best-fit parameters. The best-fit model yields constraints on key parameters in the starburst zone of M82, including a magnetic field strength of {approx}250 {mu}G and a wind advection speed in the range of 300-700 km s{sup -1}. We find that M82 is a good electron calorimeter but not an ideal cosmic-ray proton calorimeter and discuss the implications of our results for the astrophysics of the far-infrared-radio correlation in starburst galaxies.

  10. Cosmic Rays from Heavy Dark Matter from the Galactic Center

    CERN Document Server

    Cembranos, Jose A R; Maroto, Antonio L

    2013-01-01

    The gamma-ray fluxes observed by the High Energy Stereoscopic System (HESS) from the J1745-290 Galactic Center source is well fitted by the secondary photons coming from Dark Matter (DM) annihilation in particle-antiparticle standard model pairs over a diffuse power-law background. The spectral features of the signal are consistent with different channels: light quarks, electro-weak gauge bosons and top-antitop production. The amount of photons and morphology of the signal localized within a region of few parsecs, require compressed DM profiles as those resulting from baryonic contraction, which offer large enhancements in the signal over DM alone simulations. The fits return a heavy WIMP, with a mass above 10 TeV, but well below the unitarity limit for thermal relic annihilation. The fitted background spectral index is compatible with the Fermi-Large Area Telescope (LAT) data from the same region. This possibility can be potentially tested with the observations of other high energy cosmic rays.

  11. Magnetic fields and cosmic rays in clusters of galaxies

    CERN Document Server

    Kushnir, Doron; Waxman, Eli

    2009-01-01

    We argue that the observed correlation between the radio luminosity and the X-ray luminosity in radio emitting galaxy clusters implies that the radio emission is due to secondary electrons that are produced by p-p interactions and lose their energy by emitting synchrotron radiation in a strong magnetic field, B>(8\\pi a T_{CMB}^4)^{1/2}\\simeq 3\\muG. We construct a simple model that naturally explains the correlation, and show that the observations provide stringent constraints on cluster magnetic fields and cosmic rays (CRs): Within the cores of clusters, the ratio beta_{core} between the CR energy (per logarithmic particle energy interval) and the thermal energy is beta_{core}\\sim 10^{-4}; The source of these CRs is most likely the cluster accretion shock, which is inferred to deposit in CRs ~ a few percent of the thermal energy it generates; The diffusion time of 100 GeV CRs over scales \\gtrsim100 kpc is not short compared to the Hubble time; Cluster magnetic fields are enhanced by mergers to \\gtrsim 1 % of ...

  12. Cosmic-ray Propagation and Interactions in the Galaxy

    Energy Technology Data Exchange (ETDEWEB)

    Strong, Andrew W.; /Garching, Max Planck Inst., MPE; Moskalenko, Igor V.; /Stanford U., HEPL /KIPAC, Menlo Park; Ptuskin, Vladimir S.; /Troitsk, IZMIRAN

    2007-01-22

    We survey the theory and experimental tests for the propagation of cosmic rays in the Galaxy up to energies of 10{sup 15} eV. A guide to the previous reviews and essential literature is given, followed by an exposition of basic principles. The basic ideas of cosmic-ray propagation are described, and the physical origin of its processes are explained. The various techniques for computing the observational consequences of the theory are described and contrasted. These include analytical and numerical techniques. We present the comparison of models with data including direct and indirect--especially gamma-ray--observations, and indicate what we can learn about cosmic-ray propagation. Some particular important topics including electrons and antiparticles are chosen for discussion.

  13. Cosmic rays, geomagnetic field and climate changes

    Science.gov (United States)

    Shea, M.; Smart, D.

    The possibility of a connection between cosmic radiation and climate has intrigued scientists for the past several decades. The recent studies of Friis -Christensen and Svensmark has shown an observed variation of 3-4% of the global cloud cover between 1980 and 1995 that appeared to be directly correlated with the change in galactic cosmic radiation flux over the solar cycle. However, in studies of this type, not only the solar cycle modulation of cosmic radiation must be considered, but also the changes in the cosmic radiation impinging at the top of the atmosphere as a result of the long term evolution of the geomagnetic field. We present preliminary results of an on-going study of geomagnetic cutoff rigidities over a 400-year interval. These results show (1) the change in cutoff rigidity is sufficient large so that the change in cosmic radiation flux impacting the earth is approximately equal to the relative change in flux over a solar cycle, and (2) the changes in cutoff rigidity are non- uniform over the globe with both significant increases and decreases at mid-latitude locations.

  14. Cosmic-ray induced gamma-ray emission from the starburst galaxy NGC 253

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xilu; Fields, Brian D. [Department of Astronomy, MC-221, 1002 W. Green Street, University of Illinois at Urbana-Champaign, Urbana, IL 61801 (United States)

    2014-05-09

    Cosmic rays in galaxies interact with the interstellar medium and give us a direct view of nuclear and particle interactions in the cosmos. For example, cosmic-ray proton interactions with interstellar hydrogen produce gamma rays via PcrPism→π{sup 0}→γγ. For a 'normal' star-forming galaxy like the Milky Way, most cosmic rays escape the Galaxy before such collisions, but in starburst galaxies with dense gas and huge star formation rate, most cosmic rays do suffer these interactions [1,2]. We construct a 'thick-target' model for starburst galaxies, in which cosmic rays are accelerated by supernovae, and escape is neglected. This model gives an upper limit to the gamma-ray emission. Only two free parameters are involved in the model: cosmic-ray proton acceleration energy rate from supernova and the proton injection spectral index. The pionic gamma-radiation is calculated from 10 MeV to 10 TeV for the starburst galaxy NGC 253, and compared to Fermi and HESS data. Our model fits NGC 253 well, suggesting that cosmic rays in this starburst are in the thick target limit, and that this galaxy is a gamma-ray calorimeter.

  15. Ultra High Energy Comic Rays in the Cosmic Microwave Background

    CERN Document Server

    Hwang, W-Y Pauchy

    2011-01-01

    We consider the propagation of ultra high energy cosmic rays (UHECR), for energies greater than E > 10^{14} eV but less than E < 10^{26} eV, in the cosmic medium of the Cosmic Microwave Background (CMB). We find that the CMB plays a pivot role in this energy range. As example, the observed "knee(s)" and the "ankle" could be understood in reasonable terms. What we may observe at energy near 10^{25} eV (W^\\pm bursts or Z^0 bursts) is also briefly discussed.

  16. The Eddington Limit in Cosmic Rays: An Explanation for the Observed Faintness of Starbursting Galaxies

    CERN Document Server

    Socrates, A; Ramirez-Ruiz, E; Socrates, Aristotle; Davis, Shane W.; Ramirez-Ruiz, Enrico

    2006-01-01

    We show that the luminosity of a star forming galaxy is capped by the production and subsequent expulsion of cosmic rays from its interstellar medium. By defining an Eddington luminosity in cosmic rays, we show that the star formation rate of a given galaxy is limited by its mass content and the cosmic ray mean free path. When the cosmic ray luminosity and pressure reaches a critical value as a result of vigorous star formation, hydrostatic balance is lost, a cosmic ray-driven wind develops, and star formation is choked off. Cosmic ray pressure-driven winds are likely to produce wind velocities significantly in excess of the galactic escape velocity. It is possible that cosmic ray feedback results in the Faber-Jackson relation for a plausible set of input parameters that describe cosmic ray production and transport, which are calibrated by observations of the Milky Way's interstellar cosmic rays.

  17. A general detector testing system using cosmic rays

    CERN Document Server

    Zhu, Chengguang

    2013-01-01

    A cosmic ray hodoscope with two-dimensional spacial sensitivity and good time resolution has been developed. The system is designed to use the cosmic muons as probes to test the performances of charged particle sensitive detectors. This paper will present the structure of this system, the timing calibration and the resulted performance of this system. The results of the test of the prototype electron detector for LHAASO project are presented as well.

  18. Experimental Summary: Very High Energy Cosmic Rays and their Interactions

    Science.gov (United States)

    Kampert, Karl-Heinz

    2013-06-01

    The XVII International Symposium on Very High Energy Cosmic Ray Interactions, held in August of 2012 in Berlin, was the first one in the history of the Symposium,where a plethora of high precision LHC data with relevance for cosmic ray physics was presented. This report aims at giving a brief summary of those measurements andit discusses their relevance for observations of high energy cosmic rays. Enormous progress has been made also in air shower observations and in direct measurements of cosmic rays, exhibiting many more structure in the cosmic ray energy spectrum than just a simple power law with a knee and an ankle. At the highest energy, the flux suppression may not be dominated by the GZK-effect but by the limiting energy of a nearby source or source population. New projects and application of new technologies promise further advances also in the near future. We shall discuss the experimental and theoretical progress in the field and its prospects for coming years.

  19. COSMOS: The COsmic-ray Soil Moisture Observing System

    Directory of Open Access Journals (Sweden)

    M. Zreda

    2012-04-01

    Full Text Available Area-average soil moisture at the sub-kilometer scale is needed but until the advent of the cosmic-ray method (Zreda et al., 2008, it was difficult to measure. This new method is now being implemented routinely in the COsmic-ray Soil Moisture Observing System (or COSMOS. The stationary cosmic-ray soil moisture probe (sometimes called "neutronavka" measures the neutrons that are generated by cosmic rays within air and soil, moderated by mainly hydrogen atoms located primarily in soil water, and emitted to the atmosphere where they mix instantaneously at a scale of hundreds of meters and whose density is inversely correlated with soil moisture. COSMOS has already deployed 53 of the eventual 500 neutronavkas distributed mainly in the USA, each generating a time series of average soil moisture over its hectometer horizontal footprint, with similar networks coming into existence around the world. This paper is written to serve a community need to better understand this novel method and the COSMOS project. We describe the cosmic-ray soil moisture measurement method, the instrument and its calibration, the design, data processing and dissemination used in COSMOS, and give example time series of soil moisture obtained from COSMOS probes.

  20. Experimental Summary: Very High Energy Cosmic Rays and their Interactions

    Directory of Open Access Journals (Sweden)

    Kampert Karl-Heinz

    2013-06-01

    Full Text Available The XVII International Symposium on Very High Energy Cosmic Ray Interactions, held in August of 2012 in Berlin, was the first one in the history of the Symposium,where a plethora of high precision LHC data with relevance for cosmic ray physics was presented. This report aims at giving a brief summary of those measurements andit discusses their relevance for observations of high energy cosmic rays. Enormous progress has been made also in air shower observations and in direct measurements of cosmic rays, exhibiting many more structure in the cosmic ray energy spectrum than just a simple power law with a knee and an ankle. At the highest energy, the flux suppression may not be dominated by the GZK-effect but by the limiting energy of a nearby source or source population. New projects and application of new technologies promise further advances also in the near future. We shall discuss the experimental and theoretical progress in the field and its prospects for coming years.

  1. Cosmic rays and terrestrial life: A brief review

    Science.gov (United States)

    Atri, Dimitra; Melott, Adrian L.

    2014-01-01

    “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.

  2. The Transport of Cosmic Rays Across Magnetic Fieldlines

    CERN Document Server

    Desiati, Paolo

    2014-01-01

    The long residence times and small anisotropies of cosmic rays suggest that they are well confined and well scattered by the Galactic magnetic field. Due to the disklike shape of the confinement volume, transport in the vertical direction, perpendicular to the mean Galactic magnetic field, is key to cosmic ray escape. It has long been recognized that this vertical transport depends both on the vertical component of the fieldlines themselves and on the extent to which the cosmic rays are tied to the fieldlines. In this paper we use magnetic fields with very simple spatial and temporal structure to isolate some important features of cross field transport. We show that even simple magnetic nonuniformities combined with pitch angle scattering can enhance cross field transport by several orders of magnitude, while pitch angle scattering is unnecessary for enhanced transport if the field is chaotic. Nevertheless, perpendicular transport is much less than parallel transport in all the cases we study. We apply the re...

  3. A Cosmic Ray Resolution to the Superbubble Energy-Crisis

    CERN Document Server

    Butt, Yousaf M

    2008-01-01

    Superbubbles (SBs) are amongst the greatest injectors of energy into the Galaxy, and have been proposed to be the acceleration site of Galactic cosmic rays. They are thought to be powered by the fast stellar winds and powerful supernova explosions of massive stars in dense stellar clusters and associations. Observations of the SB 'DEM L192' in the neighboring Large Magellenic Cloud (LMC) galaxy show that it contains only about one-third the energy injected by its constituent stars via fast stellar winds and supernovae. It is not yet understood where the excess energy is going, thus, the so-called 'energy crisis'. We show here that it is very likely that a significant fraction of the unaccounted for energy is being taken up in accelerating cosmic rays, thus bolstering the argument for the SB origin of cosmic rays.

  4. Investigation of cosmic ray-cloud connections using MISR

    CERN Document Server

    Krissansen-Totton, Joshua

    2013-01-01

    Numerous empirical studies have analyzed International Satellite Cloud Climatology Project data and reached contradictory conclusions regarding the influence of solar-modulated galactic cosmic rays on cloud fraction and cloud properties. The Multiangle Imaging Spectroradiometer (MISR) instrument on the Terra satellite has been in continuous operation for 13 years and thus provides an independent (and previously unutilized) cloud data set to investigate purported solar-cloud links. Furthermore, unlike many previous solar-climate studies that report cloud fraction MISR measures albedo, which has clearer climatological relevance. Our long-term analysis of MISR data finds no statistically significant correlations between cosmic rays and global albedo or globally averaged cloud height, and no evidence for any regional or lagged correlations. Moreover, epoch superposition analysis of Forbush decreases reveals no detectable albedo response to cosmic ray decreases, thereby placing an upper limit on the possible influ...

  5. Can Cosmic Ray Catalysed Vacuum Decay Dominate Over Tunnelling?

    CERN Document Server

    Enqvist, Kari; Enqvist, Kari; Donald, John Mc

    1997-01-01

    We consider the question of whether cosmic ray catalysed false vacuum decay can be phenomenologically more important than spontaneous decay via quantum tunnelling. We extend the zero bubble wall width Landau-WKB analysis of catalysed false vacuum decay to include the leading order effects of finite wall width and derive an expression for the thin-wall bubble action. Using this we calculate the exponential suppression factor for the catalysed decay rate at the critical bubble energy, corresponding to the largest probability of catalysed decay. We show that, in general, cosmic ray catalysed decay is likely to be more important than spontaneous decay for sufficiently thin-walled bubbles (wall thickness less than about 30 % of the initial bubble radius), but that spontaneous decay will dominate for the case of thick-walled bubbles. Since any perturbative model with a cosmologically significant false vacuum decay rate will almost certainly produce thick-walled bubbles, we can conclude that cosmic ray catalysed fal...

  6. Restrictions from Lorentz invariance violation on cosmic ray propagation

    Science.gov (United States)

    Martínez-Huerta, H.; Pérez-Lorenzana, A.

    2017-03-01

    Lorentz invariance violation introduced as a generic modification to particle dispersion relations is used to study high energy cosmic ray attenuation processes. It is shown to reproduce the same physical effects for vacuum Cherenkov radiation, as in some particular models with spontaneous breaking of Lorentz symmetry. This approximation is also implemented for the study of photon decay in vacuum, where stringent limits to the violation scale are derived from the direct observation of very high energy cosmic ray photon events on gamma telescopes. Photo production processes by cosmic ray primaries on photon background are also addressed, to show that Lorentz violation may turn off this attenuation process at energies above a well-defined secondary threshold.

  7. Radio detection of cosmic ray air showers with LOPES

    Energy Technology Data Exchange (ETDEWEB)

    Huege, T.; Apel, W.D. [IK, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Asch, T. [IPE, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Badea, A.F. [IK, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Baehren, L. [ASTRON, 7990 AA Dwingeloo (Netherlands); Bekk, K. [IK, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Bercuci, A. [Nat. Inst. of Physics and Nuclear Eng., 7690 Bucharest (Romania); Bertaina, M. [Dipartimento di Fisica Generale dell' Universita, 10125 Torino (Italy); Biermann, P.L. [Max-Planck-Institut fuer Radioastronomie, 53121 Bonn (Germany); Bluemer, J. [IK, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); IEKP, Universitaet Karlsruhe, 76021 Karlsruhe (Germany); Bozdog, H. [IK, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Brancus, I.M. [Nat. Inst. of Physics and Nuclear Eng., 7690 Bucharest (Romania); Buitink, S. [Dpt. Astrophysics, Radboud Univ., 6525 ED Nijmegen (Netherlands); Brueggemann, M.; Buchholz, P. [Fachbereich Physik, Universitaet Siegen, 57072 Siegen (Germany); Butcher, H. [ASTRON, 7990 AA Dwingeloo (Netherlands); Chiavassa, A. [Dipartimento di Fisica Generale dell' Universita, 10125 Torino (Italy); Cossavella, F. [IEKP, Universitaet Karlsruhe, 76021 Karlsruhe (Germany); Daumiller, K. [IK, Forschungszentrum Karlsruhe, 76021 Karlsruhe (Germany); Di Pierro, F. [Dipartimento di Fisica Generale dell' Universita, 10125 Torino (Italy)] (and others)

    2007-03-15

    In the last few years, radio detection of cosmic ray air showers has experienced a true renaissance, becoming manifest in a number of new experiments and simulation efforts. In particular, the LOPES project has successfully implemented modern interferometric methods to measure the radio emission from extensive air showers. LOPES has confirmed that the emission is coherent and of geomagnetic origin, as expected by the geosynchrotron mechanism, and has demonstrated that a large scale application of the radio technique has great potential to complement current measurements of ultra-high energy cosmic rays. We describe the current status, most recent results and open questions regarding radio detection of cosmic rays and give an overview of ongoing research and development for an application of the radio technique in the framework of the Pierre Auger Observatory.

  8. Radio detection of cosmic ray air showers with LOPES

    CERN Document Server

    Huege, T; Asch, T; Badea, A F; Bähren, L; Bekk, K; Bercuci, A; Bertaina, M; Biermann, P L; Blumer, J; Bozdog, H; Brancus, I M; Buitink, S; Bruggemann, M; Buchholz, P; Butcher, H; Chiavassa, A; Cossavella, F; Daumiller, K; Di Pierro, F; Doll, P; Engel, R; Falcke, H; Gemmeke, H; Ghia, P L; Glasstetter, R; Grupen, C; Hakenjos, A; Haungs, A; Heck, D; Hörandel, J R; Horneffer, A; Isar, P G; Kampert, K H; Kolotaev, Yu; Krömer, O; Kuijpers, J; Lafebre, S; Mathes, H J; Mayer, H J; Meurer, C; Milke, J; Mitrica, B; Morello, C; Navarra, G; Nehls, S; Nigl, A; Obenland, R; Oehlschläger, J; Ostapchenko, S; Over, S; Petcu, M; Petrovic, J; Pierog, T; Plewnia, S; Rebel, H; Risse, A; Roth, M; Schieler, H; Sima, O; Singh, K; Stumpert, M; Toma, G; Trinchero, G C; Ulrich, H; Van Buren, J; Walkowiak, W; Weindl, A; Wochele, J; Zabierowski, J; Zensus, J A; Zimmermann, D; Huege, Tim; al, et

    2006-01-01

    In the last few years, radio detection of cosmic ray air showers has experienced a true renaissance, becoming manifest in a number of new experiments and simulation efforts. In particular, the LOPES project has successfully implemented modern interferometric methods to measure the radio emission from extensive air showers. LOPES has confirmed that the emission is coherent and of geomagnetic origin, as expected by the geosynchrotron mechanism, and has demonstrated that a large scale application of the radio technique has great potential to complement current measurements of ultra-high energy cosmic rays. We describe the current status, most recent results and open questions regarding radio detection of cosmic rays and give an overview of ongoing research and development for an application of the radio technique in the framework of the Pierre Auger Observatory.

  9. Testing the proposed link between cosmic rays and cloud cover

    CERN Document Server

    Sloan, T

    2008-01-01

    A decrease in the globally averaged low level cloud cover, deduced from the ISCCP infra red data, as the cosmic ray intensity decreased during the solar cycle 22 was observed by two groups. The groups went on to hypothesise that the decrease in ionization due to cosmic rays causes the decrease in cloud cover, thereby explaining a large part of the presently observed global warming. We have examined this hypothesis to look for evidence to corroborate it. None has been found and so our conclusions are to doubt it. From the absence of corroborative evidence, we estimate that less than 23%, at the 95% confidence level, of the 11-year cycle change in the globally averaged cloud cover observed in solar cycle 22 is due to the change in the rate of ionization from the solar modulation of cosmic rays.

  10. Regional cosmic ray induced ionization and geomagnetic field changes

    Directory of Open Access Journals (Sweden)

    G. A. Kovaltsov

    2007-08-01

    Full Text Available Cosmic ray induced ionization (CRII is an important factor of outer space influences on atmospheric properties. Variations of CRII are caused by two different processes – solar activity variations, which modulate the cosmic ray flux in interplanetary space, and changes of the geomagnetic field, which affects the cosmic ray access to Earth. Migration of the geomagnetic dipole axis may greatly alter CRII in some regions on a time scale of centuries and longer. Here we present a study of CRII regional effects of the geomagnetic field changes during the last millennium for two regions: Europe and the Far East. We show that regional effects of the migration of the geomagnetic dipole axis may overcome global changes due to solar activity variations.

  11. Cosmic rays,Climate and the CERN CLOUD Experiment

    CERN Document Server

    CERN. Geneva

    2011-01-01

    For more than two centuries, scientists have been puzzled by observations of solar-climate variability yet the lack of any established physical mechanism. Some recent observations, although disputed, suggest that clouds may be influenced by cosmic rays, which are modulated by the solar wind. The CLOUD experiment aims to settle the question of whether or not cosmic rays have a climatically-significant effect on clouds by carrying out a series of carefully-controlled measurements in a large cloud chamber exposed to a beam from the CERN PS. This talk will present the scientific motivation for CLOUD and the first results, which have recently been published in Nature (Kirkby et al. (2011). Role of sulphuric acid, ammonia and galactic cosmic rays in atmospheric aerosol nucleation. Nature 476, 429-433).

  12. Identifying Galactic Cosmic Ray Origins With Super-TIGER

    Science.gov (United States)

    deNolfo, Georgia; Binns, W. R.; Israel, M. H.; Christian, E. R.; Mitchell, J. W.; Hams, T.; Link, J. T.; Sasaki, M.; Labrador, A. W.; Mewaldt, R. A.; Stone, E. C.; Waddington, C. J.; Wiedenbeck, M. E.

    2009-01-01

    Super-TIGER (Super Trans-Iron Galactic Element Recorder) is a new long-duration balloon-borne instrument designed to test and clarify an emerging model of cosmic-ray origins and models for atomic processes by which nuclei are selected for acceleration. A sensitive test of the origin of cosmic rays is the measurement of ultra heavy elemental abundances (Z > or equal 30). Super-TIGER is a large-area (5 sq m) instrument designed to measure the elements in the interval 30 TIGER builds on the heritage of the smaller TIGER, which produced the first well-resolved measurements of elemental abundances of the elements Ga-31, Ge-32, and Se-34. We present the Super-TIGER design, schedule, and progress to date, and discuss the relevance of UH measurements to cosmic-ray origins.

  13. Precision Cosmic Ray physics with space-born experiment

    Science.gov (United States)

    Incagli, Marco

    2016-07-01

    More than 100 years after their discoveries, cosmic rays have been extensively studied, both with balloon experiments and with ground observatories. More recently, the possibility of mounting detectors on satellites or on the International Space Station has allowed for a long duration (several years) continuous observation of primary cosmic rays, i.e. before their interaction with the earth atmosphere, thus opening a new regime of precision measurements. In this review, recent results from major space experiments, as Pamela, AMS02 and Fermi, as well as next generation experiments proposed for the International Space Station, for standalone satellites or for the yet to come Chinese Space Station, will be presented. The impact of these experiment on the knowledge of Cosmic Ray propagation will also be discussed.

  14. High-energy cosmic rays measured with KASCADE-Grande

    CERN Document Server

    Haungs, A; Arteaga-Velazquez, J C; Bekk, K; Bertaina, M; Bluemer, J; Bozdog, H; Brancus, I M; Cantoni, E; Chiavassa, A; Cossavella, F; Curcio, C; Daumiller, K; de Souza, V; Di Pierro, F; Doll, P; Engel, R; Engler, J; Fuchs, B; Fuhrmann, D; Gils, H J; Glasstetter, R; Grupen, C; Heck, D; Hoerandel, J R; Huber, D; Huege, T; Kampert, K -H; Kang, D; Klages, H O; Link, K; Luczak, P; Ludwig, M; Mathes, H J; Mayer, H J; Melissas, M; Milke, J; Mitrica, B; Morello, C; Oehlschlaeger, J; Ostapchenko, S; Palmieri, N; Petcu, M; Pierog, T; Rebel, H; Roth, M; Schieler, H; Schoo, S; Schroeder, F G; Sima, O; Toma, G; Trinchero, G C; Ulrich, H; Weindl, A; Wochele, D; Wochele, J

    2013-01-01

    The detection of high-energy cosmic rays above a few hundred TeV is realized by the observation of extensive air-showers. By using the multi-detector setup of KASCADE-Grande, energy spectrum, elemental composition, and anisotropies of high-energy cosmic rays in the energy range from below the knee up to 2 EeV are investigated. In addition, the large high-quality data set permits distinct tests of the validity of hadronic interaction models used in interpreting air-shower measurements. After more than 16 years, the KASCADE-Grande experiment terminated measurements end of 2012. This contribution will give an overview of the main results of the data analysis achieved so far, and will report about the status of KCDC, the KASCADE Cosmic-ray Data Center, where via a web-based interface the data will be made available for the interested public.

  15. Long-term modulation of the cosmic ray fluctuation spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Starodubtsev, S.A.; Grigoryev, A.V. [Yu.G. Shafer Inst. of Cosmophysical Research and Aeronomy, SB RAS, Yakutsk (Russian Federation); Usoskin, I.G. [Sodankylae Geophysical Observatory, Univ. of Oulu (Finland); Mursula, K. [Dept. of Physical Sciences, Univ of Oulu (Finland)

    2006-07-01

    Here we study the power level of rapid cosmic ray fluctuations in the frequency range of 10{sup -4}-1.67 . 10{sup -3} Hz (periods from 10 min to about 3h), using measurements by space-borne instruments for the period since 1974. We find that the power level of these fluctuations varies over the solar cycle, but the phase of this variation depends on the energy of cosmic ray particles. While the power level of these fluctuations in the higher energy channels (corresponding to galactic cosmic rays) changes in phase with the solar cycle, the fluctuation level for lower energy channels (predominantly of solar/interplanetary origin) is roughly in an opposite phase with the solar cycle. The results prove conclusively that these fluctuations originate in the near-Earth space, excluding their atmospheric or magnetospheric origin. We present these new results and discuss a possible scenario explaining the observed energy-dependence. (orig.)

  16. Long-term modulation of the cosmic ray fluctuation spectrum

    Directory of Open Access Journals (Sweden)

    S. A. Starodubtsev

    2006-03-01

    Full Text Available Here we study the power level of rapid cosmic ray fluctuations in the frequency range of 10-4-1.67·10-3 Hz (periods from 10 min to about 3 h, using measurements by space-borne instruments for the period since 1974. We find that the power level of these fluctuations varies over the solar cycle, but the phase of this variation depends on the energy of cosmic ray particles. While the power level of these fluctuations in the higher energy channels (corresponding to galactic cosmic rays changes in phase with the solar cycle, the fluctuation level for lower energy channels (predominantly of solar/interplanetary origin is roughly in an opposite phase with the solar cycle. The results prove conclusively that these fluctuations originate in the near-Earth space, excluding their atmospheric or magnetospheric origin. We present these new results and discuss a possible scenario explaining the observed energy-dependence.

  17. Cosmic Rays from the Knee to the Ankle

    CERN Document Server

    Haungs, Andreas

    2015-01-01

    Investigations of the energy spectrum as well as the mass composition of cosmic rays in the energy range of PeVto EeV are important for understanding both, the origin of the galactic and the extragalactic cosmic rays. Recently, three modern experimental installations (KASCADE-Grande, IceTop, Tunka-133), dedicated to investigate this primary energy range, have published new results on the all-particle energy spectrum. In this short review these results are presented and the similarities and differences discussed. In addition, the effects of using different hadronic interaction models for interpreting the measured air-shower data will be examined. Finally, a brief discussion on the question if the present results are in agreement or in contradiction with astrophysical models for the transition from galactic to 10 pagesextragalactic origin of cosmic rays completes this paper.

  18. Indirect dark matter searches in gamma and cosmic rays

    Science.gov (United States)

    Conrad, Jan; Reimer, Olaf

    2017-03-01

    Dark matter candidates such as weakly interacting massive particles are predicted to annihilate or decay into Standard Model particles, leaving behind distinctive signatures in gamma rays, neutrinos, positrons, antiprotons, or even antinuclei. Indirect dark matter searches, and in particular those based on gamma-ray observations and cosmic-ray measurements, could detect such signatures. Here we review the strengths and limitations of this approach and look into the future of indirect dark matter searches.

  19. Ultrahigh Energy Cosmic Rays: Facts, Myths, and Legends

    CERN Document Server

    Anchordoqui, Luis Alfredo

    2013-06-27

    This is a written version of a series of lectures aimed at graduate students in astrophysics/particle theory/particle experiment. In the first part, we explain the important progress made in recent years towards understanding the experimental data on cosmic rays with energies > 10^8 GeV. We begin with a brief survey of the available data, including a description of the energy spectrum, mass composition, and arrival directions. At this point we also give a short overview of experimental techniques. After that, we introduce the fundamentals of acceleration and propagation in order to discuss the conjectured nearby cosmic ray sources, and emphasize some of the prospects for a new (multi-particle) astronomy. Next, we survey the state of the art regarding the ultrahigh energy cosmic neutrinos which should be produced in association with the observed cosmic rays. In the second part, we summarize the phenomenology of cosmic ray air showers. We explain the hadronic interaction models used to extrapolate results from ...

  20. Analysis of cosmic-ray events with ALICE at LHC

    Directory of Open Access Journals (Sweden)

    Rodríguez Cahuantzi M.

    2015-01-01

    Full Text Available ALICE is one of the four main experiments of the LHC at CERN. Located 40 meters underground, with 30 m of overburden rock, it can also operate to detect muons produced by cosmic-ray interactions in the atmosphere. An analysis of the data collected with cosmic-ray triggers from 2010 to 2013, corresponding to about 31 days of live time, is presented. Making use of the ability of the Time Projection Chamber (TPC to track large numbers of charged particles, a special emphasis is given to the study of muon bundles, and in particular to events with high-muon density.

  1. Atmospheric ionization and cosmic rays: studies and measurements before 1912

    CERN Document Server

    De Angelis, Alessandro

    2012-01-01

    The discovery of cosmic rays, a milestone in science, was based on the work by scientists in Europe and the New World and took place during a period characterised by nationalism and lack of communication. Many scientists that took part in this research a century ago were intrigued by the penetrating radiation and tried to understand the origin of it. Several important contributions to the discovery of the origin of cosmic rays have been forgotten; historical, political and personal facts might have contributed to their substantial disappearance from the history of science.

  2. Light Elements and Cosmic Rays in the Early Galaxy

    CERN Document Server

    Ramaty, R; Lingenfelter, R E

    1996-01-01

    We derive constraints on the cosmic rays responsible for the Be and part of the B observed in stars formed in the early Galaxy: the cosmic rays cannot be accelerated from the ISM; their energy spectrum must be relatively hard (the bulk of the nuclear reactions should occur at $>$30 MeV/nucl); and only 10$^{49}$ erg/SNII in high metallicity, accelerated particle kinetic energy could suffice to produce the Be and B. The reverse SNII shock could accelerate the particles.

  3. Primary Cosmic-Ray Spectra in the Knee Region

    Science.gov (United States)

    Ter-Antonyan, Samvel V.; Biermann, P. L.

    2003-07-01

    Using EAS inverse approach and KASCADE EAS data the primary energy spectra for different primary nuclei at energies 1015 - 1017 eV are obtained in the framework of multi-comp onent model of primary cosmic ray origin and QGSJET and SIBYLL interaction models. The rigidity-dep endent behavior of spectra is the same for two interaction models. The extrap olation of the obtained primary spectra in a 1017 - 1018 eV energy range displays a presence of the extragalactic component of primary cosmic rays.

  4. An orientable time of flight detector for cosmic rays

    CERN Document Server

    Iori, M

    2007-01-01

    Cosmic ray studies, in particular UHECR, can be in general supported by a directional, easy deployable, simple and robust detector. The design of this detector is based on the time of flight between two parallel tiles of scintillator, to distinguish particle passing through in opposite directions; by fine time resolution and pretty adjustable acceptance it is possible to select upward(left)/downward(right) cosmic rays. It has been developed for an array of detectors to measure upward $\\tau$ from Earth-Skimming neutrino events with energy above $10^8 GeV$. The properties and performances of the detector are discussed. Test results from a high noise environment are presented.

  5. Cosmic Ray Sun Shadow in Soudan 2 Underground Muon Flux

    CERN Document Server

    Allison, W W M; Ayres, D S; Barrett, W L; Bode, C; Border, P M; Brooks, C B; Cobb, J H; Cotton, R J; Courant, H; Demuth, D M; Fields, T H; Gallagher, H R; García-García, C; Goodman, M C; Gran, R; Joffe-Minor, T M; Kafka, T; Kasahara, S M; Leeson, W; Lichtfield, P J; Longley, N P; Mann, W A; Marshak, M L; Milburn, R H; Miller, W H; Mualem, L M; Napier, A; Oliver, W P; Pearce, G F; Peterson, E A; Petyt, D A; Price, L E; Ruddick, K; Sánchez, M; Schneps, J; Schub, M H; Seidlein, R; Stassinakis, A; Thron, J L; Vasilev, V; Villaume, G; Wakely, S P; West, N; Wall, D

    1999-01-01

    The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. We report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a $3.3\\sigma$ shadow observed during the years 1995 to 1998.

  6. Observations of cosmic-ray modulations in the fall, 1984

    Science.gov (United States)

    Torsti, J. J.; Nieminen, M.; Valtonen, E.; Arvela, H.; Lumme, M.; Peltonen, J.; Vainikka, E.

    1985-01-01

    Modulation of cosmic-ray energy spectrum was studied by using the Turku double neutron monitor. The multiplicity region of detected neutrons produced by cosmic ray hadrons in the monitor was divided into seven categories corresponding to mean energies 0.1, 0.3, 1.0, 3.2, 8.6, 21, and 94 GeV of hadrons at sea level. Based on 24-hour frequencies, a statistical analysis showed that modulation of the intensity in all categories occurred during several periods in the fall 1984. The magnitude of the variation was a few per cent.

  7. Are EeV cosmic rays isotropic at intermediate scales?

    CERN Document Server

    Zotov, M Yu

    2014-01-01

    We study anisotropy of cosmic rays in the energy range 0.2-1.4 EeV at intermediate angular scales using the public data set of the Pierre Auger Observatory. At certain scales, the analysis reveals a number of deviations from the isotropic distribution with the statistical significance above three standard deviations. It also demonstrates that the anisotropy evolves with energy. If confirmed with the complete Auger or Telescope Array data sets, the result can shed new light on the structure of galactic magnetic fields and the problem of transition from galactic to extragalactic cosmic rays.

  8. Response of the D0 calorimeter to cosmic ray muons

    Energy Technology Data Exchange (ETDEWEB)

    Kotcher, Jonathan [New York Univ. (NYU), NY (United States)

    1992-10-01

    The D0 Detector at the Fermi National Accelerator Laboratory is a large multi-purpose detector facility designed for the study of proton-antiproton collision products at the center-of-mass energy of 2 TeV. It consists of an inner tracking volume, hermetic uranium/liquid argon sampling calorimetry, and an outer 4π muon detector. In preparation for our first collider run, the collaboration organized a Cosmic Ray Commissioning Run, which took place from February - May of 1991. This thesis is a detailed study of the response of the central calorimeter to cosmic ray muons as extracted from data collected during this run.

  9. Response of the D0 calorimeter to cosmic ray muons

    Energy Technology Data Exchange (ETDEWEB)

    Kotcher, Jonathan [New York Univ. (NYU), NY (United States)

    1992-10-01

    The D0 Detector at the Fermi National Accelerator Laboratory is a large multipurpose detector facility designed for the study of proton-antiproton collision products at the center-of-mass energy of 2 TeV. It consists of an inner tracking volume, hermetic uranium/liquid argon sampling calorimetry, and an outer 4π muon detector. In preparation for our first collider run, the collaboration organized a Cosmic Ray Commissioning Run, which took place from February -May of 1991. This thesis is a detailed study of the response of the central calorimeter to cosmic ray muons as extracted from data collected during this run.

  10. Ultrahigh Energy Cosmic Rays and Black Hole Mergers

    CERN Document Server

    Kotera, Kumiko

    2016-01-01

    The recent detection of the gravitational wave source GW150914 by the LIGO collaboration motivates a speculative source for the origin of ultrahigh energy cosmic rays as a possible byproduct of the immense energies achieved in black hole mergers, provided that the black holes have spin as seems inevitable and there are relic magnetic fields and disk debris remaining from the formation of the black holes or from their accretion history. We argue that given the modest efficiency $< 0.01$ required per event per unit of gravitational wave energy release, merging black holes potentially provide an environment for accelerating cosmic rays to ultrahigh energies.

  11. Searching for ultra-high energy cosmic rays with smartphones

    Science.gov (United States)

    Whiteson, Daniel; Mulhearn, Michael; Shimmin, Chase; Cranmer, Kyle; Brodie, Kyle; Burns, Dustin

    2016-06-01

    We propose a novel approach for observing cosmic rays at ultra-high energy (>1018 eV) by repurposing the existing network of smartphones as a ground detector array. Extensive air showers generated by cosmic rays produce muons and high-energy photons, which can be detected by the CMOS sensors of smartphone cameras. The small size and low efficiency of each sensor is compensated by the large number of active phones. We show that if user adoption targets are met, such a network will have significant observing power at the highest energies.

  12. Cosmic ray decreases affect atmospheric aerosols and clouds

    DEFF Research Database (Denmark)

    Svensmark, Henrik; Bondo, Torsten; Svensmark, J.

    2009-01-01

    Close passages of coronal mass ejections from the sun are signaled at the Earth's surface by Forbush decreases in cosmic ray counts. We find that low clouds contain less liquid water following Forbush decreases, and for the most influential events the liquid water in the oceanic atmosphere can...... diminish by as much as 7%. Cloud water content as gauged by the Special Sensor Microwave/Imager (SSM/I) reaches a minimum ≈7 days after the Forbush minimum in cosmic rays, and so does the fraction of low clouds seen by the Moderate Resolution Imaging Spectroradiometer (MODIS) and in the International...

  13. The response of clouds and aerosols to cosmic ray decreases

    DEFF Research Database (Denmark)

    Svensmark, J.; Enghoff, Martin Andreas Bødker; Shaviv, N. J.;

    2016-01-01

    A method is developed to rank Forbush Decreases (FDs) in the galactic cosmic ray radiation according to their expected impact on the ionization of the lower atmosphere. Then a Monte Carlo bootstrap based statistical test is formulated to estimate the significance of the apparent response in physi......A method is developed to rank Forbush Decreases (FDs) in the galactic cosmic ray radiation according to their expected impact on the ionization of the lower atmosphere. Then a Monte Carlo bootstrap based statistical test is formulated to estimate the significance of the apparent response...

  14. Gamma-ray emission from Cassiopeia A produced by accelerated cosmic rays

    CERN Document Server

    Berezhko, E G; Völk, H J

    2003-01-01

    The nonlinear kinetic model of cosmic ray (CR) acceleration in supernova remnants (SNRs) is used to describe the relevant properties of Cassiopeia A (Cas A). In order to reproduce the SNR's observed size, expansion rate and thermal X-ray emission we employ a piecewise homogeneous model for the progenitor's circumstellar medium developed by Borkowski et al. (1996). It consists of a tenuous inner wind bubble, a dense shell of swept-up red supergiant wind material, and a subsequent red supergiant wind region. A quite large SNR interior magnetic field B_d approx 1 mG is required to give a good fit for the radio and X-ray synchrotron emission. The steep radio spectrum is consistent with efficient proton acceleration which produces a significant shock modification and leads to a steep electron spectrum at energies E_e < 1 GeV. The calculated integral gamma-ray flux from Cas A, F propto E_gamma^-1, is dominated by pi^0-decay gamma-rays due to relativistic protons. It extends up to roughly 30 TeV if CR diffusion i...

  15. An absence of neutrinos associated with cosmic-ray acceleration in γ-ray bursts

    Science.gov (United States)

    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.; Hülβ, 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

    Very energetic astrophysical events are required to accelerate cosmic rays to above 1018electronvolts. GRBs (γ-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 γ-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.

  16. An Absence of Neutrinos Associated with Cosmic Ray Acceleration in Gamma-Ray Bursts

    CERN Document Server

    Abbasi, R; 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; Alba, J L Bazo; 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; Besson, D Bertrand 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; Silva, A H Cruz; 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; Ismail, A Haj; 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; Hülβ, 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; Heros, C Pérez de los; 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

    2012-01-01

    Gamma-Ray Bursts (GRBs) have been proposed as a leading candidate for acceleration of ultra high-energy cosmic rays, which would be accompanied by emission of TeV neutrinos produced in proton-photon interactions during acceleration in the GRB fireball. Two analyses using data from two years of the IceCube detector produced no evidence for this neutrino emission, placing strong constraints on models of neutrino and cosmic-ray production in these sources.

  17. Modelling the cosmic ray electron propagation in M 51

    CERN Document Server

    Mulcahy, D D; Beck, R; Mitra, D; Scaife, A M M

    2016-01-01

    Cosmic ray electrons (CREs) are a crucial part of the ISM and are observed via synchrotron emission. While much modelling has been carried out on the CRE distribution and propagation of the Milky Way, little has been done on normal external star-forming galaxies. Recent spectral data from a new generation of radio telescopes enable us to find more robust estimations of the CRE propagation. We model the synchrotron spectral index of M 51 using the time-dependent diffusion energy-loss equation and to compare the model results with the observed spectral index determined from recent low-frequency observations with LOFAR. This is the first time that this model for CRE propagation has been solved for a realistic distribution of CRE sources, which we derive from the observed star formation rate, in an external galaxy. The radial variation of the synchrotron spectral index and scale-length produced by the model are compared to recent LOFAR and older VLA observational data and also to new observations of M 51 at 325MH...

  18. A solution to the cosmic ray anisotropy problem

    CERN Document Server

    Mertsch, Philipp

    2014-01-01

    In the standard diffusive picture for transport of cosmic rays (CRs), a gradient in the CR density induces a typically small, dipolar anisotropy in their arrival directions. This has been widely advertised as a tool for finding nearby sources. However, the predicted dipole amplitude at TeV and PeV energies exceeds the measured one by almost two orders of magnitude. Here, we critically examine the validity of this prediction which is based on averaging over an ensemble of turbulent magnetic fields. We focus (1) on the deviations of the dipole in a particular random realisation from the ensemble average and (2) the possibility of a misalignment between the regular magnetic field and the CR gradient. We find that if the field direction and the gradient direction are close to $\\sim 90^\\circ$, the dipole amplitude is considerably suppressed and can be reconciled with observations, thus solving a long-standing problem. Furthermore, we show that the dipole direction in general does not coincide with the gradient dir...

  19. Simulations of disk galaxies with cosmic ray driven galactic winds

    CERN Document Server

    Booth, C M; Kravtsov, Andrey V; Gnedin, Nickolay Y

    2013-01-01

    We present results from high-resolution hydrodynamic simulations of isolated SMC- and Milky Way-sized galaxies that include a model for feedback from galactic cosmic rays (CRs). We find that CRs are naturally able to drive winds with mass loading factors of up to ~10 in dwarf systems. The scaling of the mass loading factor with circular velocity between the two simulated systems is consistent with \\propto v_c^{1-2} required to reproduce the faint end of the galaxy luminosity function. In addition, simulations with CR feedback reproduce both the normalization and the slope of the observed trend of wind velocity with galaxy circular velocity. We find that winds in simulations with CR feedback exhibit qualitatively different properties compared to SN driven winds, where most of the acceleration happens violently in situ near star forming sites. In contrast, the CR-driven winds are accelerated gently by the large-scale pressure gradient established by CRs diffusing from the star-forming galaxy disk out into the h...

  20. Propagation and Signatures of Ultra High Energy Cosmic Rays

    CERN Document Server

    Berezinsky, Vladimir; Grigorieva, S

    2004-01-01

    We study the extragalactic protons with universal spectrum, which is independent of mode of propagation, when distance between sources is less than the propagation lengths, such as energy attenuation length or diffusion length (for propagation in magnetic fields). The propagation features in this spectrum, the GZK cutoff, dip and bump, are studied with help of modification factor, which weakly depends on the generation spectrum index $\\gamma_g$. We argue that from the above features the dip is the most model-independent one. For the power-law generation spectrum with $\\gamma_g=2.7$ the dip is very well confirmed by the data of all existing detectors, which gives the strong evidence for extragalactic protons propagating through CMB. We develop the AGN model for origin of UHECR, which successfully explains the observed spectra up to $1\\times 10^{20}$ eV and transition from galactic to extragalactic cosmic rays. The calculated spectrum has the GZK cutoff, and the AGASA excess of events at $E \\gsim 1\\times 10^{20...

  1. Positron Anomaly in Galactic Cosmic Rays: Constraining Dark Matter Contribution

    Science.gov (United States)

    Sagdeev, Roald; Malkov, Mikhail; Diamond, Patrick

    2016-10-01

    An explanation of the unexpected rise in the positron fraction of the cosmic ray (CR) leptonic energy spectrum, is proposed. It is argued that the e+/- spectra are different because they are accelerated by a charge-sign selective mechanism. This premise was hinted at by a recent result from the AMS-02 spectrometer that revealed a difference between e+ and antiproton spectra, which both are secondary CRs but of the opposite charges. The new mechanism extends the diffusive shock acceleration (DSA) to make it charge-sign selective. The DSA, operating in Galactic supernova remnant (SNR) shocks, is held responsible for the production of the bulk of the CRs. The new mechanism was found to account for the positron data with an excellent agreement, except in a limited energy range between 100-300 GeV. In this range, the data exceed the theoretical prediction systematically, thus opening a window for a contribution from dark matter decay or annihilation as well as nearby pulsars. The charge-sign selectivity of the DSA arises from an electric field induced by the CR protons illuminating the neutral gas clumps in the SNR surroundings. The electric field expels positrons from the clump but traps electrons and secondary antiprotons, thus suppressing their acceleration in such SNRs. Work supported by NASA ATP-program under Grant NNX14AH36G, and by the US Department of Energy under Award No. DE-FG02-04ER54738.

  2. Explanation of the local galactic cosmic ray energy spectra measured by Voyager 1. I. Protons

    Energy Technology Data Exchange (ETDEWEB)

    Schlickeiser, R.; Kempf, A. [Institut für Theoretische Physik, Lehrstuhl IV: Weltraum- und Astrophysik, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Webber, W. R., E-mail: rsch@tp4.rub.de, E-mail: ank@tp4.rub.de, E-mail: bwebber@nmsu.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States)

    2014-05-20

    Almost exactly 100 yr after the original discovery of cosmic rays, the V1 spacecraft has observed, for the first time, the local interstellar medium energy spectra of cosmic ray H, He, C/O nuclei at nonrelativistic kinetic energies, after leaving the heliosphere modulation region on 2012 August 25. We explain these observations by modeling the propagation of these particles in the local Galactic environment with an updated steady-state spatial diffusion model including all particle momentum losses with the local interstellar gas (Coulomb/ionization, pion production, adiabatic deceleration, and fragmentation interactions). Excellent agreement with the V1 cosmic ray H observations is obtained if the solar system resides within a spatially homogeneous layer of distributed cosmic ray sources injecting the same momentum power law ∝p {sup –s} with s = 2.24 ± 0.12. The best fit to the V1 H observations also provides an estimate of the characteristic break kinetic energy T{sub C} = 116 ± 27 MeV, representing the transition from ionization/Coulomb energy losses at low energies to pion production and adiabatic deceleration losses in a Galactic wind at high energies. As the determined value is substantially smaller than 217 MeV in the absence of adiabatic deceleration, our results prove the existence of a Galactic wind in the local Galactic environment.

  3. New fermionic dark matters, extended Standard Model and cosmic rays

    Science.gov (United States)

    Hwang, Jae-Kwang

    2017-08-01

    Three generations of leptons and quarks correspond to the lepton charges (LCs) in this work. Then, the leptons have the electric charges (ECs) and LCs. The quarks have the ECs, LCs and color charges (CCs). Three heavy leptons and three heavy quarks are introduced to make the missing third flavor of EC. Then the three new particles which have the ECs are proposed as the bastons (dark matters) with the rest masses of 26.121 eV/c2, 42.7 GeV/c2 and 1.9 × 1015 eV/c2. These new particles are applied to explain the origins of the astrophysical observations like the ultra-high energy cosmic rays and supernova 1987A anti-neutrino data. It is concluded that the 3.5 keV X-ray peak observed from the cosmic X-ray background spectra is originated not from the pair annihilations of the dark matters but from the X-ray emission of the Q1 baryon atoms which are similar in the atomic structure to the hydrogen atom. The presence of the 3.5 keV cosmic X-ray supports the presence of the Q1 quark with the EC of ‑4/3. New particles can be indirectly seen from the astrophysical observations like the cosmic ray and cosmic gamma ray. In this work, the systematic quantized charges of EC, LC and CC for the elementary particles are used to consistently explain the decay and reaction schemes of the elementary particles. Also, the strong, weak and dark matter forces are consistently explained.

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

    Directory of Open Access Journals (Sweden)

    J. Shuttleworth

    2013-08-01

    Full Text Available 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

  5. Cosmic ray composition investigations using ICE/ISEE-3

    Science.gov (United States)

    Wiedenbeck, Mark E.

    1992-01-01

    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.

  6. Cosmic ray muon study with the NEVOD-DECOR experiment

    Science.gov (United States)

    Saavedra San Martin, Oscar

    2017-06-01

    The experiment NEVOV-DECOR, which is desinged to study the cosmic muons at very inclined directions, is running under the collaboration of the Moscow Engineering Physics Institute, Moscow, Russia, and the Instituto Nazionale di Astrofisica and the Dipartimento di Fisica, Università di Torino, Italy. The main purpose of this experiment is to study the characteristics of the high multiplicity muons in muon bundles and their angular distributions. The result has shown the observation of the second knee at 1017 eV in the primary cosmic ray spectrum. In addition, we found that the number of high energy muons in EAS is more than 30% of what is predicted by the Monte Carlo models. This effect was found also by other experiments like Auger, but at primary cosmic ray energies higher than 1018 eV. We will present and discuss the main results of these investigations.

  7. Cosmic Rays Induced Background Radiation on Board of Commercial Flights

    CERN Document Server

    Pinilla, S; Núñez, L A

    2015-01-01

    The aim of this work is to determine the total integrated flux of cosmic radiation which a commercial aircraft is exposed to along specific flight trajectories. To study the radiation background during a flight and its modulation by effects such as altitude, latitude, exposure time and transient magnetospheric events, we perform simulations based on Magnetocosmics and CORSIKA codes, the former designed to calculate the geomagnetic effects on cosmic rays propagation and the latter allows us to simulate the development of extended air showers in the atmosphere. In this first work, by considering the total flux of cosmic rays from 5 GeV to 1 PeV, we obtained the expected integrated flux of secondary particles on board of a commercial airplane during the Bogot\\'a-Buenos Aires trip by point-to-point numerical integration.

  8. Ultra high energy cosmic rays: the highest energy frontier

    CERN Document Server

    Neto, João R T de Mello

    2015-01-01

    Ultra-high energy cosmic rays (UHECRs) are the highest energy messengers of the present universe, with energies up to $10^{20}$ eV. Studies of astrophysical particles (nuclei, electrons, neutrinos and photons) at their highest observed energies have implications for fundamental physics as well as astrophysics. The primary particles interact in the atmosphere and generate extensive air showers. Analysis of those showers enables one not only to estimate the energy, direction and most probable mass of the primary cosmic particles, but also to obtain information about the properties of their hadronic interactions at an energy more than one order of magnitude above that accessible with the current highest energy human-made accelerator. In this contribution we will review the state-of-the-art in UHECRs detection. We will present the leading experiments Pierre Auger Observatory and Telescope Array and discuss the cosmic ray energy spectrum, searches for directional anisotropy, studies of mass composition, the determ...

  9. X-Ray Emission from Star-Forming Galaxies - Signatures of Cosmic Rays and Magnetic Fields

    CERN Document Server

    Schober, Jennifer; Klessen, Ralf S

    2014-01-01

    The evolution of magnetic fields in galaxies is still an open problem in astrophysics. In nearby galaxies the far-infrared-radio correlation indicates the coupling between magnetic fields and star formation. The correlation arises from the synchrotron emission of cosmic ray electrons traveling through the interstellar magnetic fields. However, with an increase of the interstellar radiation field (ISRF), inverse Compton scattering becomes the dominant energy loss mechanism of cosmic ray electrons with a typical emission frequency in the X-ray regime. The ISRF depends on the one hand on the star formation rate and becomes stronger in starburst galaxies, and on the other hand increases with redshift due to the evolution of the cosmic microwave background. With a model for the star formation rate of galaxies, the ISRF, and the cosmic ray spectrum, we can calculate the expected X-ray luminosity resulting from the inverse Compton emission. Except for galaxies with an active galactic nucleus the main additional cont...

  10. Cosmic rays and the search for a Lorentz Invariance Violation

    Energy Technology Data Exchange (ETDEWEB)

    Bietenholz, Wolfgang [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany). John von Neumann-Inst. fuer Computing NIC

    2008-11-15

    This is an introductory review about the on-going search for a signal of Lorentz Invariance Violation (LIV) in cosmic rays. We first summarise basic aspects of cosmic rays, focusing on rays of ultra high energy (UHECRs). We discuss the Greisen-Zatsepin-Kuz'min (GZK) energy cutoff for cosmic protons, which is predicted due to photopion production in the Cosmic Microwave Background (CMB). This is a process of modest energy in the proton rest frame. It can be investigated to a high precision in the laboratory, if Lorentz transformations apply even at factors {gamma} {proportional_to} O(10{sup 11}). For heavier nuclei the energy attenuation is even faster due to photo-disintegration, again if this process is Lorentz invariant. Hence the viability of Lorentz symmetry up to tremendous {gamma}-factors - far beyond accelerator tests - is a central issue. Next we comment on conceptual aspects of Lorentz Invariance and the possibility of its spontaneous breaking. This could lead to slightly particle dependent ''Maximal Attainable Velocities''. We discuss their effect in decays, Cerenkov radiation, the GZK cutoff and neutrino oscillation in cosmic rays. We also review the search for LIV in cosmic {gamma}-rays. For multi TeV {gamma}-rays we possibly encounter another puzzle related to the transparency of the CMB, similar to the GZK cutoff, due to electron/positron creation and subsequent inverse Compton scattering. The photons emitted in a Gamma Ray Burst occur at lower energies, but their very long path provides access to information not far from the Planck scale. We discuss conceivable non-linear photon dispersions based on non-commutative geometry or effective approaches. No LIV has been observed so far. However, even extremely tiny LIV effects could change the predictions for cosmic ray physics drastically. An Appendix is devoted to the recent hypothesis by the Pierre Auger Collaboration, which identifies nearby Active Galactic Nuclei - or objects

  11. ESA's Integral detects closest cosmic gamma-ray burst

    Science.gov (United States)

    2004-08-01

    5 August 2004 A gamma-ray burst detected by ESA's Integral gamma-ray observatory on 3 December 2003 has been thoroughly studied for months by an armada of space and ground-based observatories. Astronomers have now concluded that this event, called GRB 031203, is the closest cosmic gamma-ray burst on record, but also the faintest. This also suggests that an entire population of sub-energetic gamma-ray bursts has so far gone unnoticed... Gamma ray burst model hi-res Size hi-res: 22 KB Credits: CXC/M. Weiss Artist impression of a low-energy gamma-ray burst This illustration describes a model for a gamma-ray burst, like the one detected by Integral on 3 December 2003 (GRB 031203). A jet of high-energy particles from a rapidly rotating black hole interacts with surrounding matter. Observations with Integral on 3 December 2003 and data on its afterglow, collected afterwards with XMM-Newton, Chandra and the Very Large Array telescope, show that GRB 031203 radiated only a fraction of the energy of normal gamma-ray bursts. Like supernovae, gamma-ray bursts are thought to be produced by the collapse of the core of a massive star. However, while the process leading to supernovae is relatively well understood, astronomers still do not know what happens when a core collapses to form a black hole. The discovery of 'under-energetic' gamma-ray bursts, like GRB 031203, should provide valuable clues as to links between supernovae, black holes and gamma-ray bursts. Lo-res JPG (22 Kb) Hi-res TIFF (5800 Kb) Cosmic gamma-ray bursts (GRBs) are flashes of gamma rays that can last from less than a second to a few minutes and occur at random positions in the sky. A large fraction of them is thought to result when a black hole is created from a dying star in a distant galaxy. Astronomers believe that a hot disc surrounding the black hole, made of gas and matter falling onto it, somehow emits an energetic beam parallel to the axis of rotation. According to the simplest picture, all GRBs

  12. THE MYSTERY OF THE COSMIC DIFFUSE ULTRAVIOLET BACKGROUND RADIATION

    Energy Technology Data Exchange (ETDEWEB)

    Henry, Richard Conn [Henry A. Rowland Department of Physics and Astronomy, The Johns Hopkins University, Baltimore, MD 21218 (United States); Murthy, Jayant [Indian Institute of Astrophysics, Bengaluru (India); Overduin, James; Tyler, Joshua, E-mail: henry@jhu.edu, E-mail: jmurthy@yahoo.com, E-mail: joverduin@towson.edu, E-mail: 97tyler@cardinalmail.cua.edu [Department of Physics, Astronomy and Geosciences, Towson University, Towson, MD 21252 (United States)

    2015-01-01

    The diffuse cosmic background radiation in the Galaxy Evolution Explorer far-ultraviolet (FUV, 1300-1700 Å) is deduced to originate only partially in the dust-scattered radiation of FUV-emitting stars: the source of a substantial fraction of the FUV background radiation remains a mystery. The radiation is remarkably uniform at both far northern and far southern Galactic latitudes and increases toward lower Galactic latitudes at all Galactic longitudes. We examine speculation that this might be due to interaction of the dark matter with the nuclei of the interstellar medium, but we are unable to point to a plausible mechanism for an effective interaction. We also explore the possibility that we are seeing radiation from bright FUV-emitting stars scattering from a ''second population'' of interstellar grains—grains that are small compared with FUV wavelengths. Such grains are known to exist, and they scatter with very high albedo, with an isotropic scattering pattern. However, comparison with the observed distribution (deduced from their 100 μm emission) of grains at high Galactic latitudes shows no correlation between the grains' location and the observed FUV emission. Our modeling of the FUV scattering by small grains also shows that there must be remarkably few such ''smaller'' grains at high Galactic latitudes, both north and south; this likely means simply that there is very little interstellar dust of any kind at the Galactic poles, in agreement with Perry and Johnston. We also review our limited knowledge of the cosmic diffuse background at ultraviolet wavelengths shortward of Lyα—it could be that our ''second component'' of the diffuse FUV background persists shortward of the Lyman limit and is the cause of the reionization of the universe.

  13. Are gamma-ray bursts the sources of ultra-high energy cosmic rays?

    CERN Document Server

    Baerwald, Philipp; Winter, Walter

    2014-01-01

    We reconsider the possibility that gamma-ray bursts (GRBs) are the sources of the ultra-high energy cosmic rays (UHECRs) within the internal shock model, assuming a pure proton composition of the UHECRs. For the first time, we combine the information from gamma-rays, cosmic rays, prompt neutrinos, and cosmogenic neutrinos quantitatively in a joint cosmic ray production and propagation model, and we show that the information on the cosmic energy budget can be obtained as a consequence. In addition to the neutron model, we consider alternative scenarios for the cosmic ray escape from the GRBs, i.e., that cosmic rays can leak from the sources. We find that the dip model, which describes the ankle in UHECR observations by the pair production dip, is strongly disfavored in combination with the internal shock model because a) unrealistically high baryonic loadings (energy in protons versus energy in electrons/gamma-rays) are needed for the individual GRBs and b) the prompt neutrino flux easily overshoots the corres...

  14. Further delays hit troubled $2bn cosmic-ray detector

    CERN Multimedia

    Cartlidge, Edwin

    2010-01-01

    "A $2bn mission to study cosmic rays will have to wait another few months before being sent to the International Space Station (ISS) after NASA announced last month that it was pushing back the launch of the Space Shuttle Endeavour until 26 February 2011" (0.5 page)

  15. Concerning the Nature of the Cosmic Ray Power Law Exponents

    CERN Document Server

    Widom, A; Srivastava, Y N

    2014-01-01

    We have recently shown that the cosmic ray energy distributions as detected on earthbound, low flying balloon or high flying satellite detectors can be computed by employing the heats of evaporation of high energy particles from astrophysical sources. In this manner, the experimentally well known power law exponents of the cosmic ray energy distribution have been theoretically computed as 2.701178 for the case of ideal Bose statistics, 3.000000 for the case of ideal Boltzmann statistics and 3.151374 for the case of ideal Fermi statistics. By "ideal" we mean virtually zero mass (i.e. ultra-relativistic) and noninteracting. These results are in excellent agreement with the experimental indices of 2.7 with a shift to 3.1 at the high energy ~ PeV "knee" in the energy distribution. Our purpose here is to discuss the nature of cosmic ray power law exponents obtained by employing conventional thermal quantum field theoretical models such as quantum chromodynamics to the cosmic ray sources in a thermodynamic scheme w...

  16. Measurement of camera image sensor depletion thickness with cosmic rays

    CERN Document Server

    Vandenbroucke, J; Bravo, S; Jensen, K; Karn, P; Meehan, M; Peacock, J; Plewa, M; Ruggles, T; Santander, M; Schultz, D; Simons, A L; Tosi, D

    2015-01-01

    Camera image sensors can be used to detect ionizing radiation in addition to optical photons. In particular, cosmic-ray muons are detected as long, straight tracks passing through multiple pixels. The distribution of track lengths can be related to the thickness of the active (depleted) region of the camera image sensor through the known angular distribution of muons at sea level. We use a sample of cosmic-ray muon tracks recorded by the Distributed Electronic Cosmic-ray Observatory to measure the thickness of the depletion region of the camera image sensor in a commercial smart phone, the HTC Wildfire S. The track length distribution prefers a cosmic-ray muon angular distribution over an isotropic distribution. Allowing either distribution, we measure the depletion thickness to be between 13.9~$\\mu$m and 27.7~$\\mu$m. The same method can be applied to additional models of image sensor. Once measured, the thickness can be used to convert track length to incident polar angle on a per-event basis. Combined with ...

  17. 1912 – 2012: a century of studying cosmic rays

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    One year ago, the Alpha Magnetic Spectrometer was docked to the International Space Station. This state-of-the-art tool for studying cosmic rays has revolutionised methods of detecting cosmic radiation, which was discovered barely a century ago.   Victor Francis Hess (in the basket), back from his balloon flight in August 1912. Source: American Physical Society. Exactly one hundred years ago, the Austrian-American physicist Victor Francis Hess discovered cosmic rays. The researcher observed the phenomenon while on board a balloon; he found that at an altitude of 1,000 to 5,000 metres, the wires of his Wulf electrometer (a tool used to measure radiation) showed an increase in electrical charge. Hess had just proven the existence of ionising radiation coming from outside the Earth’s atmosphere. Twenty years or so later, the invention of the Geiger-Müller counter enabled physicists to study the properties of the rays more precisely. One century later, cosmic rays and the ques...

  18. Excesses of Cosmic Ray Spectra from A Single Nearby Source

    CERN Document Server

    Liu, Wei; Lin, Su-Jie; Wang, Bing-Bing; Yin, Peng-Fei

    2016-01-01

    Growing evidence reveals universal hardening on various cosmic ray spectra, e.g. proton, positron, as well as antiproton fraction. Such universality may indicate they have a common origin. In this paper, we argue that these widespread excesses can be accounted for by a nearby supernova remnant surrounded by a giant molecular cloud. Secondary cosmic rays ($\\rm p$, $\\rm e^+$) are produced through the collisions between the primary cosmic ray nuclei from this supernova remnant and the molecular gas. Different from the background, which is produced by the ensemble of large amount of sources in the Milky Way, the local injected spectrum can be harder. The time-dependent transport of particles would make the propagated spectrum even harder. Under this scenario, the anomalies of both primary ($\\rm p$, $\\rm e^-$) and secondary ($\\rm e^+$, $\\rm \\bar{p}/p$) cosmic rays can be properly interpreted. We further show that the TeV to sub-PeV anisotropy of proton is consistent with the observations if the local source is rel...

  19. Observing The Cosmic Ray Moon Shadow With VERITAS

    CERN Document Server

    Bird, Ralph

    2015-01-01

    The Earth is subjected to a uniform flux of very-high-energy (VHE, E > 100 GeV) cosmic rays unless they are obscured by an object, such as the Moon, in which case a deficit or shadow is created. Since cosmic rays are charged this deficit is deflected by the Earth's magnetic field, enabling the rigidity of the obstructed cosmic rays to be determined. Measurement of the relative deficits of different species enables the positron fraction and the antiproton ratio to be measured. The April 15, 2014 lunar eclipse was visible with the VERITAS Cherenkov telescopes, which allowed (with special UV bandpass filters) 74 minutes of direct observations of the Moon and the associated deficit in the cosmic-ray flux. The results of this observation are presented. In addition VERITAS has been conducting a series of observations by pointing close to a partially illuminated Moon, with a reduced photomultiplier tube high voltage and UV bandpass filters. We present the technique developed for these observations and their current ...

  20. Discrepant hardening observed in cosmic-ray elemental spectra

    CERN Document Server

    Ahn, H S; Bagliesi, M G; Beatty, J J; Bigongiari, G; Childers, J T; Conklin, N B; Coutu, S; DuVernois, M A; Ganel, O; Han, J H; Jeon, J A; Kim, K C; Lee, M H; Lutz, L; Maestro, P; Malinin, A; Marrocchesi, P S; Minnick, S; Mognet, S I; Nam, J; Nam, S; Nutter, S L; Park, I H; Park, N H; Seo, E S; Sina, R; Wu, J; Yang, J; Yoon, Y S; Zei, R; Zinn, S Y; 10.1088/2041-8205/714/1/L89

    2010-01-01

    The balloon-borne Cosmic Ray Energetics And Mass (CREAM) experiment launched five times from Antarctica has achieved a cumulative flight duration of about 156 days above 99.5% of the atmosphere. The instrument is configured with complementary and redundant particle detectors designed to extend direct measurements of cosmic-ray composition to the highest energies practical with balloon flights. All elements from protons to iron nuclei are separated with excellent charge resolution. Here we report results from the first two flights of ~70 days, which indicate hardening of the elemental spectra above ~200 GeV/nucleon and a spectral difference between the two most abundant species, protons and helium nuclei. These results challenge the view that cosmic-ray spectra are simple power laws below the so-called knee at ~1015 eV. This discrepant hardening may result from a relatively nearby source, or it could represent spectral concavity caused by interactions of cosmic rays with the accelerating shock. Other possible ...