Bursts of extensive air showers: chaos vs. stochasticity

Bursts of the count rate of extensive air showers (EAS) lead to the appearance of clusters in time series that represent EAS arrival times. We apply methods of nonlinear time series analysis to twenty EAS cluster events found in the data set obtained with the EAS-1000 prototype array. In particular, we use the Grassberger-Procaccia algorithm to compute the correlation dimension of the time series in the vicinity of the clusters. We find that four cluster events produce signs of chaos in the corresponding time series. By applying a number of supplementary methods we assess that the nature of the observed behaviour of the correlation dimension is likely to be deterministic. We suggest a simple qualitative model that might explain an origin of clusters in general and "possibly chaotic" clusters in particular. Finally, we compare our conclusions with the results of similar investigations performed by the EAS-TOP and LAAS groups.Comment: An extended version of the paper to be submitted to Astroparticle Physics. Version 2: 22 pages, discussion extended, the main part shortened, accepted for publication. Version 1 is still valid (up to a number of typos

Singularities inside nonAbelian black holes

Singularities inside static spherically symmetric black holes in the SU(2) Einstein-Yang-Mills and Einstein-Yang-Mills-dilaton theories are investigated. Analytical formulas are presented describing oscillatory and power law metric behavior near spacelike singularities in generic solutions

EUSO-Offline: A comprehensive simulation and analysis framework

International audienceThe complexity of modern cosmic ray observatories and therich data sets they capture often require a sophisticated softwareframework to support the simulation of physical processes, detectorresponse, as well as reconstruction and analysis of real andsimulated data. Here we present the EUSO-Offline framework. Thecode base was originally developed by the Pierre AugerCollaboration, and portions of it have been adopted by othercollaborations to suit their needs. We have extended this softwareto fulfill the requirements of Ultra-High Energy Cosmic Raydetectors and very high energy neutrino detectors developed for theJoint Exploratory Missions for an Extreme Universe Observatory(JEM-EUSO). These path-finder instruments constitute a program tochart the path to a future space-based mission like POEMMA. Forcompleteness, we describe the overall structure of the frameworkdeveloped by the Auger collaboration and continue with a descriptionof the JEM-EUSO simulation and reconstruction capabilities. Theframework is written predominantly in modern C++ (compliled againstC++17) and incorporates third-party libraries chosen based onfunctionality and our best judgment regarding support andlongevity. Modularity is a central notion in the framework design, arequirement for large collaborations in which many individualscontribute to a common code base and often want to compare differentapproaches to a given problem. For the same reason, the framework isdesigned to be highly configurable, which allows us to contend witha variety of JEM-EUSO missions and observation scenarios. We alsodiscuss how we incorporate broad, industry-standard testing coveragewhich is necessary to ensure quality and maintainability of arelatively large code base, and the tools we employ to support amultitude of computing platforms and enable fast, reliableinstallation of external packages. Finally, we provide a fewexamples of simulation and reconstruction applications usingEUSO-Offline

EUSO-Offline: A comprehensive simulation and analysis framework

International audienceThe complexity of modern cosmic ray observatories and therich data sets they capture often require a sophisticated softwareframework to support the simulation of physical processes, detectorresponse, as well as reconstruction and analysis of real andsimulated data. Here we present the EUSO-Offline framework. Thecode base was originally developed by the Pierre AugerCollaboration, and portions of it have been adopted by othercollaborations to suit their needs. We have extended this softwareto fulfill the requirements of Ultra-High Energy Cosmic Raydetectors and very high energy neutrino detectors developed for theJoint Exploratory Missions for an Extreme Universe Observatory(JEM-EUSO). These path-finder instruments constitute a program tochart the path to a future space-based mission like POEMMA. Forcompleteness, we describe the overall structure of the frameworkdeveloped by the Auger collaboration and continue with a descriptionof the JEM-EUSO simulation and reconstruction capabilities. Theframework is written predominantly in modern C++ (compliled againstC++17) and incorporates third-party libraries chosen based onfunctionality and our best judgment regarding support andlongevity. Modularity is a central notion in the framework design, arequirement for large collaborations in which many individualscontribute to a common code base and often want to compare differentapproaches to a given problem. For the same reason, the framework isdesigned to be highly configurable, which allows us to contend witha variety of JEM-EUSO missions and observation scenarios. We alsodiscuss how we incorporate broad, industry-standard testing coveragewhich is necessary to ensure quality and maintainability of arelatively large code base, and the tools we employ to support amultitude of computing platforms and enable fast, reliableinstallation of external packages. Finally, we provide a fewexamples of simulation and reconstruction applications usingEUSO-Offline