scholarly journals Cosmic Particle Accelerators

2020 ◽  
pp. 827-863
Author(s):  
W. Hofmann ◽  
J. A. Hinton
Keyword(s):  
Angular Distribution ◽  
Energy Spectrum ◽  
Cosmic Rays ◽  
Elemental Composition ◽  
Cosmic Ray ◽  
Particle Accelerators ◽  
The Galaxy ◽  
Cosmic Particle

AbstractIn the century since the measurements of Victor Hess [1]—considered as the discovery of cosmic rays—the properties of cosmic rays, as they arrive on Earth, have been studied in remarkable detail; we know their energy spectrum, extending to 1020 eV, their elemental composition, their angular distribution, and we understand the basic energetic requirements of cosmic ray production in the Galaxy.

scholarly journals The Origin and Dynamical Effects of the Magnetic Fields and Cosmic Rays in the Disk of the Galaxy

1970 ◽  
Vol 39 ◽  
pp. 168-183
Author(s):  
E. N. Parker
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Dynamical Behavior ◽  
Cosmic Ray ◽  
Interested Reader ◽  
Written Text ◽  
The Galaxy ◽  
Basic Ideas ◽  
The Magnetic Field

The topic of this presentation is the origin and dynamical behavior of the magnetic field and cosmic-ray gas in the disk of the Galaxy. In the space available I can do no more than mention the ideas that have been developed, with but little explanation and discussion. To make up for this inadequacy I have tried to give a complete list of references in the written text, so that the interested reader can pursue the points in depth (in particular see the review articles Parker, 1968a, 1969a, 1970). My purpose here is twofold, to outline for you the calculations and ideas that have developed thus far, and to indicate the uncertainties that remain. The basic ideas are sound, I think, but, when we come to the details, there are so many theoretical alternatives that need yet to be explored and so much that is not yet made clear by observations.

Influence of supernovae, gamma-ray bursts, solar flares, and cosmic rays on the terrestrial environment

2008 ◽  
Author(s):  
Arnon Dar
Keyword(s):  
Solar Activity ◽  
Cosmic Rays ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
Gamma Ray Bursts ◽  
The Sun ◽  
Terrestrial Environment ◽  
The Earth ◽  
The Galaxy ◽  
Threat To Life

Changes in the solar neighbourhood due to the motion of the sun in the Galaxy, solar evolution, and Galactic stellar evolution influence the terrestrial environment and expose life on the Earth to cosmic hazards. Such cosmic hazards include impact of near-Earth objects (NEOs), global climatic changes due to variations in solar activity and exposure of the Earth to very large fluxes of radiations and cosmic rays from Galactic supernova (SN) explosions and gamma-ray bursts (GRBs). Such cosmic hazards are of low probability, but their influence on the terrestrial environment and their catastrophic consequences, as evident from geological records, justify their detailed study, and the development of rational strategies, which may minimize their threat to life and to the survival of the human race on this planet. In this chapter I shall concentrate on threats to life from increased levels of radiation and cosmic ray (CR) flux that reach the atmosphere as a result of (1) changes in solar luminosity, (2) changes in the solar environment owing to the motion of the sun around the Galactic centre and in particular, owing to its passage through the spiral arms of the Galaxy, (3) the oscillatory displacement of the solar system perpendicular to the Galactic plane, (4) solar activity, (5) Galactic SN explosions, (6) GRBs, and (7) cosmic ray bursts (CRBs). The credibility of various cosmic threats will be tested by examining whether such events could have caused some of the major mass extinctions that took place on planet Earth and were documented relatively well in the geological records of the past 500 million years (Myr). A credible claim of a global threat to life from a change in global irradiation must first demonstrate that the anticipated change is larger than the periodical changes in irradiation caused by the motions of the Earth, to which terrestrial life has adjusted itself. Most of the energy of the sun is radiated in the visible range. The atmosphere is highly transparent to this visible light but is very opaque to almost all other bands of the electromagnetic spectrum except radio waves, whose production by the sun is rather small.

scholarly journals Atmospheric Muons Measured with IceCube

2019 ◽  
Vol 208 ◽  
pp. 08007 ◽  
Author(s):  
Dennis Soldin
Keyword(s):  
Angular Distribution ◽  
Energy Spectrum ◽  
Cosmic Ray ◽  
Cherenkov Detector ◽  
South Pole ◽  
Lateral Separation ◽  
Hadronic Interactions ◽  
Air Shower ◽  
Shower Development ◽  
Detector Volume

IceCube is a cubic-kilometer Cherenkov detector in the deep ice at the geographic South Pole. The dominant event yield is produced by penetrating atmospheric muons with energies above several 100 GeV. Due to its large detector volume, IceCube provides unique opportunities to study atmospheric muons with large statistics in detail. Measurements of the energy spectrum and the lateral separation distribution of muons offer insights into hadronic interactions during the air shower development and can be used to test hadronic models. We will present an overview of various measurements of atmospheric muons in IceCube, including the energy spectrum of muons between 10 TeV and 1 PeV. This is used to derive an estimate of the prompt contribution of muons, originating from the decay of heavy (mainly charmed) hadrons and unflavored mesons. We will also present measurements of the lateral separation distributions of TeV muons between 150m and 450m for several initial cosmic ray energies between 1 PeV and 16 PeV. Finally, the angular distribution of atmospheric muons in IceCube will be discussed.

scholarly journals Composition and Galactic Confinement of Cosmic Rays

1971 ◽  
Vol 2 ◽  
pp. 740-756
Author(s):  
Maurice M. Shapiro
Keyword(s):  
Cosmic Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Interstellar Space ◽  
Heavy Nuclei ◽  
High Energy Astrophysics ◽  
Transit Times ◽  
The Galaxy ◽  
Path Lengths

The ‘Galactic’ cosmic rays impinging on the Earth come from afar over tortuous paths, traveling for millions of years. These particles are the only known samples of matter that reach us from regions of space beyond the solar system. Their chemical and isotopic composition and their energy spectra provide clues to the nature of cosmic-ray sources, the properties of interstellar space, and the dynamics of the Galaxy. Various processes in high-energy astrophysics could be illuminated by a more complete understanding of the arriving cosmic rays, including the electrons and gamma rays.En route, some of theprimordialcosmic-ray nuclei have been transformed by collision with interstellar matter, and the composition is substantially modified by these collisions. A dramatic consequence of the transformations is the presence in the arriving ‘beam’ of considerable fluxes of purely secondary elements (Li, Be, B), i.e., species that are, in all probability, essentially absent at the sources. We shall here discuss mainly the composition of the arriving ‘heavy’ nuclei -those heavier than helium - and what they teach us about thesourcecomposition, the galactic confinement of the particles, their path lengths, and their transit times.

scholarly journals On the correlation of the highest energy cosmic rays with AGNs

2009 ◽  
Vol 5 (H15) ◽  
pp. 251-253
Author(s):  
Vitor de Souza ◽  
Peter L. s Biermman
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Magnetic Fields ◽  
Present Status ◽  
Cosmic Ray ◽  
Radio Galaxies ◽  
Pierre Auger Observatory ◽  
Heavy Nuclei ◽  
Measured Energy

AbstractIn this paper we briefly discuss the present status of the cosmic ray astrophysics under the light of the new data from the Pierre Auger Observatory. The measured energy spectrum is used to test the scenario of production in nearby radio galaxies. Within this framework the AGN correlation would require that most of the cosmic rays are heavy nuclei and are widely scattered by intergalactic magnetic fields.

scholarly journals Radio haloes around galaxies and in clusters

1978 ◽  
Vol 79 ◽  
pp. 161-163
Author(s):  
V. L. Ginzburg
Keyword(s):  
Cosmic Rays ◽  
Radio Emission ◽  
Cosmic Ray ◽  
Relativistic Electrons ◽  
Radio Halo ◽  
Normal Galaxies ◽  
Extended Region ◽  
The Galaxy ◽  
Nuclear Component ◽  
Galactic Sources

The question of whether or not our and other normal galaxies have some sort of halo - an extended region containing, in particular, cosmic rays - has been discussed for no less than 25 years. Such a “cosmic ray halo” (CRH) appears as a radio-halo, although the absence of the latter is not evidence against the presence of CRH. the point is that the relativistic electrons responsible for the radio emission from the radio-halo undergo synchrotron and Compton losses which are practically absent in the case of the cosmic-ray proton-nuclear component. Possibly because the discussion concerning the existence of the radio-halo in the Galaxy has lasted for years it has acquired a particular character. the latter is clearly reflected in the report by Baldwin (1976) who emphasized that: ȜIn this discussion so far I have avoided the use of the phrase Ȝradio-haloȝ. It arouses antagonism in otherwise placid astronomers and many sought to deny its existence …ȝ Such a situation evidently reflects the difficulties that arise in detecting the radio-halo of our own Galaxy when account is taken of other confusing galactic sources as well as of the metagalactic background.

scholarly journals The Pierre Auger Observatory: Review of Latest Results and Perspectives

Universe ◽  
2018 ◽  
Vol 4 (11) ◽  
pp. 128 ◽  
Author(s):  
Dariusz Góra ◽  
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Detection System ◽  
Cosmic Ray ◽  
High Energy ◽  
Pierre Auger Observatory ◽  
Mass Composition ◽  
Ultra High Energy ◽  
Energy Limitation ◽  
Arrival Directions

The Pierre Auger Observatory is the world’s largest operating detection system for the observation of ultra high energy cosmic rays (UHECRs), with energies above 10 17 eV. The detector allows detailed measurements of the energy spectrum, mass composition and arrival directions of primary cosmic rays in the energy range above 10 17 eV. The data collected at the Auger Observatory over the last decade show the suppression of the cosmic ray flux at energies above 4 × 10 19 eV. However, it is still unclear if this suppression is caused by the energy limitation of their sources or by the Greisen–Zatsepin–Kuzmin (GZK) cut-off. In such a case, UHECRs would interact with the microwave background (CMB), so that particles traveling long intergalactic distances could not have energies greater than 5 × 10 19 eV. The other puzzle is the origin of UHECRs. Some clues can be drawn from studying the distribution of their arrival directions. The recently observed dipole anisotropy has an orientation that indicates an extragalactic origin of UHECRs. The Auger surface detector array is also sensitive to showers due to ultra high energy neutrinos of all flavors and photons, and recent neutrino and photon limits provided by the Auger Observatory can constrain models of the cosmogenic neutrino production and exotic scenarios of the UHECRs origin, such as the decays of super heavy, non-standard-model particles. In this paper, the recent results on measurements of the energy spectrum, mass composition and arrival directions of cosmic rays, as well as future prospects are presented.

scholarly journals Gamma Rays from Cosmic Rays

1981 ◽  
Vol 94 ◽  
pp. 309-319 ◽  
Author(s):  
A. W. Wolfendale
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Molecular Clouds ◽  
Cosmic Ray ◽  
Cosmic Ray Intensity ◽  
Cosmic Ray Interactions ◽  
The Galaxy ◽  
Γ Rays ◽  
Γ Ray

It is shown that there is evidence favouring molecular clouds being sources of γ-rays, the fluxes being consistent with expectation for ambient cosmic rays interacting with the gas in the clouds for the clouds considered. An estimate is made of the fraction of the apparently diffuse γ-ray flux which comes from cosmic ray interactions in the I.S.M. as distinct from unresolved discrete sources. Finally, an examination is made of the possibility of gradients of cosmic ray intensity in the Galaxy.

The change in the energy spectrum of galactic cosmic rays over the 11-year solar activity cycle

1968 ◽  
Vol 46 (10) ◽  
pp. S927-S929
Author(s):  
Yu. Stozhkov ◽  
T. N. Charakhchyan
Keyword(s):  
Diffusion Coefficient ◽  
Solar Activity ◽  
Energy Spectrum ◽  
Cosmic Rays ◽  
Cosmic Ray ◽  
Activity Cycle ◽  
Solar Activity Cycle ◽  
Galactic Cosmic Rays ◽  
Ray Diffusion

The energy spectrum of galactic cosmic rays has been investigated for various periods of the solar activity. In the framework of commonly used ideas about the mechanism of the 11-year variation according to Parker the dependence of the cosmic-ray diffusion coefficient, D, on the particle rigidity, P, was determined. For the form D ≈ vpα the parameter α is found to change during the cycle of the solar activity.[Formula: see text]

The effects of the nature of matter traversed by cosmic rays on their composition and energy spectrum

1968 ◽  
Vol 46 (10) ◽  
pp. S512-S514
Author(s):  
M. V. K. Apparao ◽  
S. Ramadurai
Keyword(s):  
Energy Spectrum ◽  
Cosmic Rays ◽  
Neutral Hydrogen ◽  
Cosmic Ray ◽  
The State ◽  
Energy Spectra ◽  
Ionization Loss ◽  
Usual Assumption ◽  
Considerable Portion ◽  
Nature Of Matter

The effects of the state of ionization of the matter traversed by cosmic rays, and those due to the presence of helium in it, have been studied. The amount of matter traversed by cosmic rays expressed in g/cm2 deduced by the usual assumption that the matter traversed is all neutral hydrogen can be erroneous. The presence of helium increases this value, and a considerable portion of the matter is helium. The ionized (partial) nature of the matter increases the ionization loss of cosmic-ray nuclei. The effect of this on energy spectra has been demonstrated.

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