Gamma-rays above 100 GeV

1981 ◽  
Vol 301 (1462) ◽  
pp. 615-628 ◽  
Keyword(s):  
Gamma Rays ◽  
High Energy ◽  
Cherenkov Light ◽  
Ultra High Energy ◽  
Future Work

The Cherenkov light technique for the ground-based detection of ultra-high energy y-rays is described and some of the most significant measurements are reported. Improvements in experiments leading to increases in sensitivity are outlined and the aims of future work are discussed.

scholarly journals Broadband RF Phased Array Design with MEEP: Comparisons to Array Theory in Two and Three Dimensions

Electronics ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 415
Author(s):  
Jordan C. Hanson
Keyword(s):  
Phased Array ◽  
High Energy ◽  
Index Of Refraction ◽  
Three Dimensions ◽  
Ultra High Energy ◽  
Array Design ◽  
Radar Systems ◽  
Array Detectors ◽  
5 Ghz ◽  
Future Work

Phased array radar systems have a wide variety of applications in engineering and physics research. Phased array design usually requires numerical modeling with expensive commercial computational packages. Using the open-source MIT Electrogmagnetic Equation Propagation (MEEP) package, a set of phased array designs is presented. Specifically, one and two-dimensional arrays of Yagi-Uda and horn antennas were modeled in the bandwidth [0.1–5] GHz, and compared to theoretical expectations in the far-field. Precise matches between MEEP simulation and radiation pattern predictions at different frequencies and beam angles are demonstrated. Given that the computations match the theory, the effect of embedding a phased array within a medium of varying index of refraction is then computed. Understanding the effect of varying index on phased arrays is critical for proposed ultra-high energy neutrino observatories which rely on phased array detectors embedded in natural ice. Future work will develop the phased array concepts with parallel MEEP, in order to increase the detail, complexity, and speed of the computations.

scholarly journals Ultra High Energy Cosmic Rays: Origin, Composition and Spectrum

2019 ◽  
Vol 209 ◽  
pp. 01018
Author(s):  
Roberto Aloisio
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Theoretical Models ◽  
High Energy ◽  
Experimental Results ◽  
Mass Composition ◽  
Ultra High Energy ◽  
High Energy Cosmic Rays ◽  
Secondary Particles

The physics of Ultra High Energy Cosmic Rays will be reviewed, discussing the latest experimental results and theoretical models aiming at explaining the observations in terms of spectra, mass composition and possible sources. It will be also discussed the emission of secondary particles such as neutrinos and gamma rays produced by the interaction of Ultra High Energy Cosmic Rays with astrophysical photon backgrounds. The content of the present proceeding paper is mainly based on the review papers [1, 2].

A search for diffuse sources of ultra high energy gamma-rays

1996 ◽  
Vol 48 (1-3) ◽  
pp. 483-484
Author(s):  
A. Borione ◽  
C.E. Covault ◽  
J.W. Cronin ◽  
B.E. Fick ◽  
L.F. Fortson ◽  
...  
Keyword(s):  
Gamma Rays ◽  
High Energy ◽  
Ultra High Energy ◽  
Diffuse Sources ◽  
High Energy Gamma ◽  
Energy Gamma

scholarly journals The Status of Ultra-High-Energy Gamma-Ray Observations

1994 ◽  
Vol 142 ◽  
pp. 883-888
Author(s):  
R. J. Protheroe
Keyword(s):  
Gamma Rays ◽  
Gamma Ray ◽  
Crab Nebula ◽  
Statistical Significance ◽  
High Energy ◽  
Archival Data ◽  
Ultra High Energy ◽  
Air Shower ◽  
The Galaxy ◽  
The Status

AbstractIn 1983 Samorski and Stamm found evidence of ultra-high-energy (UHE) gamma-ray emission from Cygnus X-3 in archival data from the Kiel air shower array. The emission appeared to be emitted only at one phase in the binary orbit. The Kiel array was sensitive to air showers generated by particles with energies above 3 × 1015 eV. Their discovery led to searches in archival data from other arrays for evidence of UHE emission from Cygnus X-3 and other potential sources in the Galaxy, and to the construction of new air shower arrays dedicated to UHE astronomy.In the mid 1980s many groups around the world claimed detections of Cygnus X-3, Hercules X-1, Vela X-1, and other objects. Cygnus X-3 is strongly variable at all wavelengths, and so it would be surprising if this variability did not extend to UHE gamma-rays also. This indeed appeared to be the case, and in the mid to late 1980s the UHE gamma-ray output showed a steady decline apart from transient UHE emission following giant radio flares. With the exception of possible detections above 1017 eV by the Fly’s Eye and Akeno Array, I am unaware of any statistically compelling claimed detections of this source reported over the past 4 years. The new arrays—CASA-MIA and SPASE—have not detected any of the claimed sources, and it seems likely that at least some of these early claims may have been premature. However, although none of the observations taken alone was of extremely high statistical significance, the observations of Cygnus X-3 by different groups showed a consistency which I feel cannot be ascribed to chance alone. The observations of Cygnus X-3 and the Crab Nebula/Pulsar are reviewed with particular reference to the results published during the last 5 years.Subject headings: gamma rays: observations — pulsars: individual (Crab Nebula) — stars: individual (Cygnus X-3)

scholarly journals Searches for Ultra–High‐Energy Gamma Rays from SN 1987A and Centaurus X‐3

1996 ◽  
Vol 472 (2) ◽  
pp. 800-805 ◽  
Author(s):  
H. Yoshii ◽  
T. Baba ◽  
T. Kaneko ◽  
K. Suga ◽  
F. Kakimoto ◽  
...  
Keyword(s):  
Gamma Rays ◽  
High Energy ◽  
Ultra High Energy ◽  
High Energy Gamma ◽  
Sn 1987A ◽  
Energy Gamma

scholarly journals ULTRA HIGH ENERGY COSMIC RAYS: ORIGIN AND PROPAGATION

2010 ◽  
Vol 25 (18) ◽  
pp. 1467-1481 ◽  
Author(s):  
TODOR STANEV
Keyword(s):  
Cosmic Rays ◽  
Gamma Rays ◽  
Cosmic Ray ◽  
High Energy ◽  
Ultra High Energy ◽  
Ultrahigh Energy ◽  
High Energy Cosmic Rays ◽  
Astrophysical Objects ◽  
Ultrahigh Energy Cosmic Rays ◽  
The Universe

We introduce the highest energy cosmic rays and briefly review the powerful astrophysical objects where they could be accelerated. We then introduce the interactions of different cosmic ray particles with the photon fields of the Universe and the formation of the cosmic ray spectra observed at Earth. The last topic is the production of secondary gamma rays and neutrinos in the interactions of the ultrahigh energy cosmic rays.

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