scholarly journals Measurement of knees of the spectra of heavy nuclei above 10 PeV with LHAASO

2019 ◽  
Vol 208 ◽  
pp. 14002
Author(s):  
Z. Cao ◽  
L.L. Ma ◽  
S.S. Zhang ◽  
C. Wang ◽  
L.Q. Yin ◽  
...  
Keyword(s):  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Individual Species ◽  
Heavy Nuclei ◽  
Detector Arrays ◽  
Simulation Tools ◽  
Variate Analysis ◽  
Important Approach ◽  
Selection For

Measuring the knees of the cosmic ray spectra for individual species is a very important approach to solve the problem of the origin of ultra high energy galactic cosmic rays. The knee of the iron spectrum is implied to be above 10 PeV from previous experiments, such as ARGO-YBJ and LHAASO-WFCTA. LHAASO is a suitable size for measurements with the required precision. The key is to separate iron nuclei from all cosmic ray samples. In this paper, we identify a couple of variables that are sensitive to the composition of showers recorded by the detector arrays in LHAASO. A multi variate analysis is proposed for the separation. The efficiency and purity of the selection for demanded species are optimized by well configuring the LHAASO array using the LHAASO simulation tools.

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 ACTIVE GALACTIC NUCLEI: SOURCES FOR ULTRA HIGH ENERGY COSMIC RAYS

2009 ◽  
Vol 18 (10) ◽  
pp. 1577-1581 ◽  
Author(s):  
P. L. BIERMANN ◽  
J. K. BECKER ◽  
L. CARAMETE ◽  
L. GERGELY ◽  
I. C. MARIŞ ◽  
...  
Keyword(s):  
Cosmic Rays ◽  
Radio Galaxy ◽  
Galactic Nuclei ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Ultra High Energy ◽  
Heavy Nuclei ◽  
High Energy Cosmic Rays ◽  
Relativistic Jet

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

scholarly journals The Phenomena of High Energy Astrophysics

2003 ◽  
Vol 214 ◽  
pp. 3-20 ◽  
Author(s):  
R. D. Blandford
Keyword(s):  
Supernova Remnants ◽  
New Technology ◽  
Low Frequency ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
High Energy Astrophysics ◽  
Physical Conditions ◽  
Hot Gas ◽  
Neutrino Astronomy

A brief summary of some highlights in the study of high energy astrophysical sources over the past decade is presented. It is argued that the great progress that has been made derives largely from the application of new technology to observation throughout all of the electromagnetic and other spectra and that, on this basis, the next decade should be even more exciting. However, it is imperative to observe cosmic sources throughout these spectra in order to obtain a full understanding of their properties. In addition, it is necessary to learn the universal laws that govern the macroscopic and the microscopic behavior of cosmic plasma over a great range of physical conditions by combining observations of different classes of source. These two injunctions are illustrated by discussions of cosmology, hot gas, supernova remnants and explosions, neutron stars, black holes and ultrarelativistic outflows. New interpreations of the acceleration of Galactic cosmic rays, the cooling of hot gas in rich clusters and the nature of ultrarelativistic outflows are outlined. The new frontiers of VHE γ-ray astronomy, low frequency radio astronomy, neutrino astronomy, UHE cosmic ray physics and gravitational wave astronomy are especially promising.

scholarly journals The Origin of the Most Energetic Galactic Cosmic Rays: Supernova Explosions into Massive Star Plasma Winds

Galaxies ◽  
2019 ◽  
Vol 7 (2) ◽  
pp. 48 ◽  
Author(s):  
Peter L. Biermann ◽  
Philipp P. Kronberg ◽  
Michael L. Allen ◽  
Athina Meli ◽  
Eun-Suk Seo
Keyword(s):  
Magnetic Field ◽  
Cosmic Rays ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
Space Station ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Starburst Galaxy ◽  
Supergiant Star

We propose that the high energy Cosmic Ray particles up to the upturn commonly called the ankle, from around the spectral turn-down commonly called the knee, mostly come from Blue Supergiant star explosions. At the upturn, i.e., the ankle, Cosmic Rays probably switch to another source class, most likely extragalactic sources. To show this we recently compiled a set of Radio Supernova data where we compute the magnetic field, shock speed and shock radius. This list included both Blue and Red Supergiant star explosions; both data show the same magnetic field strength for these two classes of stars despite very different wind densities and velocities. Using particle acceleration theory at shocks, those numbers can be transformed into characteristic ankle and knee energies. Without adjusting any free parameters both of these observed energies are directly indicated by the supernova data. In the next step in the argument, we use the Supernova Remnant data of the starburst galaxy M82. We apply this analysis to Blue Supergiant star explosions: The shock will race to their outer edge with a magnetic field that is observed to follow over several orders of magnitude B ( r ) × r ∼ c o n s t . , with in fact the same magnetic field strength for such stellar explosions in our Galaxy, and other galaxies including M82. The speed is observed to be ∼0.1 c out to about 10 16 cm radius in the plasma wind. The Supernova shock can run through the entire magnetic plasma wind region at full speed all the way out to the wind-shell, which is of order parsec scale in M82. We compare and identify the Cosmic Ray spectrum in other galaxies, in the starburst galaxy M82 and in our Galaxy with each other; we suggest how Blue Supergiant star explosions can provide the Cosmic Ray particles across the knee and up to the ankle energy range. The data from the ISS-CREAM (Cosmic Ray Energetics and Mass Experiment at the International Space Station) mission will test this cosmic ray concept which is reasonably well grounded in two independent radio supernova data sets. The next step in developing our understanding will be to obtain future more accurate Cosmic Ray data near to the knee, and to use unstable isotopes of Cosmic Ray nuclei at high energy to probe the “piston” driving the explosion. We plan to incorporate these data with the physics of the budding black hole which is probably forming in each of these stars.

scholarly journals Hydrogen isotopic anomalies in extraterrestrial organic matter: role of cosmic ray irradiation and implications for UCAMMs

2019 ◽  
Vol 627 ◽  
pp. A122 ◽  
Author(s):  
B. Augé ◽  
E. Dartois ◽  
J. Duprat ◽  
C. Engrand ◽  
G. Slodzian ◽  
...  
Keyword(s):  
Organic Matter ◽  
Infrared Spectroscopy ◽  
Spatial Scale ◽  
Secondary Ion Mass Spectrometry ◽  
Isotopic Fractionation ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Ex Situ

Context. Micrometeorites represent, at timescales shorter than a few million years, the dominant source of extraterrestrial matter at the surface of the Earth. Analyses of ultracarbonaceous micrometeorites recovered from Antarctica, known as UCAMMs reveal an exceptionally N-rich organic matter associated with spatially extended high D enrichments. Experiments show that this specific organic matter might have been formed in the outer solar system by energetic irradiation of N-rich icy surfaces. Aims. We experimentally investigate the hydrogen isotopic fractionation resulting from irradiation of normal and D-rich N2-CH4 ices by high energy ions, simulating the exposition to Galactic cosmic rays of icy bodies surfaces orbiting at large heliocentric distances. Methods. Films of N2-CH4 ices and a N2-CH4/CD4/N2-CH4 “sandwich” ice were exposed to 129Xe13+ ion beams at 92 and 88 MeV. The chemical evolution of the samples was monitored using in situ Fourier transform infrared spectroscopy. After irradiation, targets were annealed to room temperature. The solid residues of the whole process left after ice sublimation were characterized in situ by infrared spectroscopy, and the hydrogen isotopic composition measured ex situ by imaging secondary ion mass spectrometry at the sub-micron scale (NanoSIMS). Results. Irradiation leads to the formation of new molecules and radicals. After annealing, the resulting poly-HCN-like macro-molecular residue exhibits an infrared spectrum close to that of UCAMMs. The residue resulting from irradiation of N2-CH4 ices does not exhibit a significant deuterium enrichment comparable to that found in extraterrestrial organic matter. The residue formed by irradiation of D-rich ices shows the formation of isotopic heterogeneities with localised hotspots and an extended contribution likely due to the diffusion of the radiolytic products from the D-rich layer. Conclusions. These results show that high-energy cosmic ray irradiation does not induce the large hydrogen isotopic fractionation observed at small spatial scale in interplanetary organics. By contrast, large D/H ratio heterogeneities at the sub-micron spatial scale in extraterrestrial organic matter can result from isotopically heterogeneous ices mixtures (i.e. condensed with different D/H ratios), which were transformed into refractory organic matter upon irradiation.

High-energy galactic cosmic-ray composition measured in Gemini XI

1968 ◽  
Vol 46 (10) ◽  
pp. S569-S571 ◽  
Author(s):  
F. W. O'Dell ◽  
M. M. Shapiro ◽  
R. Silberberg ◽  
B. Stiller ◽  
C. H. Tsao ◽  
...  
Keyword(s):  
Time Resolution ◽  
Chemical Elements ◽  
Relative Number ◽  
Cosmic Ray ◽  
High Energy ◽  
Heavy Nuclei ◽  
Earth’S Atmosphere ◽  
Nuclear Emulsion Detector ◽  
Earth's Atmosphere ◽  
Galactic Cosmic Ray

An oriented nuclear-emulsion detector capable of time resolution was exposed in Gemini Flight XI to investigate the primary cosmic-ray nuclei above the earth's atmosphere. This was the first satellite exposure of an emulsion apparatus designed to collect 103 high-quality tracks of heavy nuclei under a negligible thickness of matter (0.07 g/cm2). Time resolution was obtained by moving a lower stack, consisting of emulsions of various sensitivities, with respect to a shallower, sensitive upper stack at the rate of 25 microns/minute. It was thus possible to separate the "useful" tracks–formed during the oriented portion of the flight–from those formed at other times. Preliminary data are presented on the relative abundances of individual chemical elements in the high-energy cosmic radiation above the earth's atmosphere. These measurements are compared to published results obtained on balloon flights at similar latitudes. When sufficient data become available in a later phase of this experiment, particular attention will be directed towards the Be and B abundances, the N and F content relative to C and O, and the relative number of iron-group nuclei compared to the lighter ones.

scholarly journals Cosmic-Ray Transport and Acceleration

1994 ◽  
Vol 142 ◽  
pp. 926-936
Author(s):  
Reinhard Schlickeiser
Keyword(s):  
Cosmic Rays ◽  
Decisive Role ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Diffusion Term ◽  
Solar Particle Events ◽  
High Energy Cosmic Rays ◽  
Propagation Parameters ◽  
And Diffusion

AbstractWe review the transport and acceleration of cosmic rays concentrating on the origin of galactic cosmic rays. Quasi-linear theory for the acceleration rates and propagation parameters of charged test particles combined with the plasma wave viewpoint of modeling weak cosmic electromagnetic turbulence provides a qualitatively and quantitatively correct description of key observations. Incorporating finite frequency effects, dispersion, and damping of the plasma waves are essential in overcoming classical discrepancies with observations as the Kfit - Kql discrepancy of solar particle events. We show that the diffusion-convection transport equation in its general form contains spatial convection and diffusion terms as well as momentum convection and diffusion terms. In particular, the latter momentum diffusion term plays a decisive role in the acceleration of cosmic rays at super-Alfvénic supernova shock fronts, and in the acceleration of ultra-high-energy cosmic rays by distributed acceleration in our own galaxy.Subject headings: acceleration of particles — convection — cosmic rays — diffusion — shock waves

scholarly journals DIFFUSIVE PROPAGATION OF HIGH ENERGY COSMIC RAYS IN GALAXY: EFFECT OF HALL DRIFT

2011 ◽  
Vol 26 (05) ◽  
pp. 911-923 ◽  
Author(s):  
HIDEYOSHI ARAKIDA ◽  
SHUICHI KURAMATA
Keyword(s):  
Cosmic Rays ◽  
Diffusion Tensor ◽  
Galactic Disk ◽  
Cosmic Ray ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Propagation Model ◽  
High Energy Cosmic Rays ◽  
Semi Empirical ◽  
Symmetric Diffusion

We phenomenologically developed a propagation model of high energy galactic cosmic rays. We derived the analytical solutions by adopting the semi-empirical diffusion equation, proposed by Berezinskii et al. (1990) and the diffusion tensor proposed by Ptuskin et al. (1993). This model takes into account both the symmetric diffusion and the antisymmetric diffusion due to the particle Hall drift. Our solutions are an extension of the model developed by Ptuskin et al. to a two-dimensional two-layer (galactic disk and halo) model, and they coincide completely with the solution derived by Berezinskii et al. in the absence of antisymmetric diffusion due to Hall drift. We showed that this relatively simple toy model can be used to explain the variation in the exponent of the cosmic ray energy spectrum, γ, around the knee E ≈1015 eV .

scholarly journals Heavy nuclei enrichment of the galactic cosmic rays at high energy: astrophysical interpretation

2003 ◽  
Vol 18 (5) ◽  
pp. 471-486 ◽  
Author(s):  
David Maurin ◽  
Michel Cassé ◽  
Elisabeth Vangioni-Flam
Keyword(s):  
Cosmic Rays ◽  
High Energy ◽  
Galactic Cosmic Rays ◽  
Heavy Nuclei
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