scholarly journals Diffuse Galactic gamma-ray and neutrino fluxes at very high energy and the Galactic/extragalactic Cosmic Ray transition

2021 ◽  
Author(s):  
Silvia Vernetto ◽  
Paolo Lipari
Keyword(s):  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Very High Energy ◽  
Neutrino Fluxes ◽  
Very High

scholarly journals Performance optimization of the air shower simulation program for the Cherenkov Telescope Array

2019 ◽  
Vol 214 ◽  
pp. 05041 ◽  
Author(s):  
Luisa Arrabito ◽  
Konrad Bernlöhr ◽  
Johan Bregeon ◽  
Gernot Maier ◽  
Philippe Langlois ◽  
...  
Keyword(s):  
Performance Optimization ◽  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Telescope Array ◽  
Cherenkov Telescope ◽  
Cpu Time ◽  
Very High Energy ◽  
Under Construction ◽  
Very High

The Cherenkov Telescope Array (CTA), currently under construction, is the next-generation instrument in the field of very high energy gamma-ray astronomy. The first data are expected by the end of 2018, while the scientific operations will start in 2022 for a duration of about 30 years. In order to characterize the instrument response to the Cherenkov light emitted when cosmic ray showers develop in the atmosphere, detailed Monte Carlo simulations will be regularly performed in parallel to CTA operation. The estimated CPU time associated to these simulations is very high, of the order of 200 millions HS06 hours per year. Reducing the CPU time devoted to simulations would allow either to reduce infrastructure cost or to better cover the large phase space. In this paper, we focus on the main computing step (70% of the whole CPU time) implemented in the CORSIKA program, and specifically on the mod-ule responsible for the propagation of Cherenkov photons in the atmosphere. We present our preliminary studies about different options of code optimization, with a particular focus on vectorization facilities (SIMD instructions). Our proposals take care, as automatically as possible, of the hardware portability constraints introduced by the grid computing environment that hosts these simulations. Performance evaluation in terms of running-time and accuracy is provided.

scholarly journals Gamma-Ray Bursts at TeV Energies: Observational Status

Galaxies ◽  
2022 ◽  
Vol 10 (1) ◽  
pp. 7
Author(s):  
Koji Noda ◽  
Robert Daniel Parsons
Keyword(s):  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Gamma Ray Bursts ◽  
High Energy Gamma ◽  
Cosmic Ray Acceleration ◽  
Very High Energy ◽  
Energy Gamma ◽  
Observational Status ◽  
Very High

Gamma-ray bursts (GRBs) are some of the most energetic events in the Universe and are potential sites of cosmic ray acceleration up to the highest energies. GRBs have therefore been a target of interest for very high energy gamma-ray observatories for many years, leading to the recent discovery of a number of bursts with photons reaching energies above 100 GeV. We summarize the GRB observational campaigns of the current generation of very high energy gamma-ray observatories as well as describing the observations and properties of the GRBs discovered so far. We compare the properties of the very high energy bursts to the total GRB distribution and make predictions for the next generation of very high energy gamma-ray observations.

scholarly journals Comparison of the Measurement and Simulation with KM2A Prototype Array

2019 ◽  
Vol 208 ◽  
pp. 14006
Author(s):  
Zhe Li ◽  
Songzhan Chen ◽  
Huihai He ◽  
Cong Li ◽  
Hongkui Lv ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Stable Operation ◽  
Air Shower ◽  
Very High Energy ◽  
Energy Gamma ◽  
Many Sources ◽  
Very High ◽  
Monte Carlo Simulation Program

The Large High Altitude Air Shower Observatory (LHAASO) is a new hybrid array for very high energy gamma ray astronomy and cosmic ray physics. The KM2A array, one of the main parts of LHAASO, covers an area of 1.3 km2 to observe gamma rays above 10 TeV up to 1 PeV for many sources. A prototype with 1% the size of the whole KM2A has been in stable operation for more than two years. A Monte Carlo simulation program named G4KM2A was developed; based on this work, the trigger rate, hit multiplicity, angular and core reconstruction are compared with KM2A prototype data. Finally, the moon shadow with -6.5 significance was obtained. The G4KM2A simulation results are consistent with KM2A prototype data and can be used for the whole KM2A array in future.

scholarly journals Highlights from H.E.S.S.

2019 ◽  
Vol 209 ◽  
pp. 01025
Author(s):  
Mathieu de Naurois
Keyword(s):  
Gamma Ray ◽  
Cosmic Ray ◽  
High Energy ◽  
Physical Processes ◽  
Galactic Source ◽  
Very High Energy ◽  
Energy Gamma ◽  
Galactic Cosmic Ray ◽  
Fundamental Physical ◽  
Very High

In the 15 years since its construction, the H.E.S.S. gamma-ray observatory has allowed the study of the Very High Energy gamma-ray sky at resolutions and sensitivities which were never before possible. During this period H.E.S.S. has discovered a rich zoo of both galactic and extra galactic source classes, made measurements of the galactic cosmic ray spectrum and placed limits on fundamental physical processes. A summary of the latest H.E.S.S. results for these source classes has been presented at the conference, describing the most interesting new observations and their physical interpretation. Additionally the latest upgrades and improvements to the H.E.S.S. hardware and data analyses, and the future science prospects for the experiment have been described.

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