131. Long Term Performance of the Pierre Auger ObservatoryKoun Choi, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Keywords: ultra-high energy cosmic rays, Pierre Auger Observatory, long term performance Published in RUNG: 16.06.2020; Views: 2517; Downloads: 82 Full text (1,14 MB) |
132. Anisotropies of the highest energy cosmic-ray events recorded by the Pierre Auger Observatory in 15 years of operationLorenzo Caccianiga, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Keywords: ultra-high energy cosmic rays (UHECR), UHECR anisotropies, Pierre Auger Observatory Published in RUNG: 16.06.2020; Views: 2586; Downloads: 100 Full text (1,65 MB) |
133. The AMIGA underground muon detector of the Pierre Auger Observatory - performance and event reconstructionAna Martina Botti, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Keywords: Pierre Auger Observatory, muon detector, event reconstruction Published in RUNG: 16.06.2020; Views: 2778; Downloads: 78 Full text (1,02 MB) |
134. Test benches for the upgrade of the Pierre AugerObservatory electronicsMartina Boháčová, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Keywords: Pierre Auger Observatory, surface detector station, electronics, test benches Published in RUNG: 16.06.2020; Views: 2511; Downloads: 77 Full text (735,82 KB) |
135. Highlights from the Pierre Auger ObservatoryAntonella Castellina, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Keywords: ultra-high energy cosmic rays, extensive air showers, Pierre Auger Observatory Published in RUNG: 16.06.2020; Views: 3026; Downloads: 101 Full text (4,92 MB) |
136. Multi-Messenger Physics With the Pierre Auger ObservatoryKarl-Heinz Kampert, Andrej Filipčič, Gašper Kukec Mezek, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, original scientific article Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, photons, neutrinos, protons, multi-messenger physics and astrophysics Published in RUNG: 06.05.2019; Views: 3282; Downloads: 107 Full text (2,46 MB) |
137. Mass composition of ultra-high energy cosmic rays at the Pierre Auger ObservatoryGašper Kukec Mezek, 2019, doctoral dissertation Abstract: Cosmic rays with energies above 10^18 eV, usually referred to as ultra-high energy cosmic rays (UHECR), have been a mystery from the moment they have been discovered. Although we have now more information on their extragalactic origin, their direct sources still remain hidden due to deviations caused by galactic magnetic fields. Another mystery, apart from their production sites, is their nature. Their mass composition, still uncertain at these energies, would give us a better understanding on their production, acceleration, propagation and capacity to produce extensive air showers in the Earth's atmosphere. Mass composition studies of UHECR try to determine their nature from the difference in development of their extensive air showers.
In this work, observational parameters from the hybrid detection system of the Pierre Auger Observatory are used in a multivariate analysis to obtain the mass composition of UHECR. The multivariate analysis (MVA) approach combines a number of mass composition sensitive variables and tries to improve the separation between different UHECR particle masses. Simulated distributions of different primary particles are fitted to measured observable distributions in order to determine individual elemental fractions of the composition. When including observables from the surface detector, we find a discrepancy in the estimated mass composition between a mixed simulation sample and the Pierre Auger data. Our analysis results from the Pierre Auger data are to a great degree independent on hadronic interaction models. Although they differ at higher primary masses, the different models are more consistent, when combining fractions of oxygen and iron. Compared to previously published results, the systematic uncertainty from hadronic interaction models is roughly four times smaller. Our analysis reports a predominantly heavy composition of UHECR, with more than a 50% fraction of oxygen and iron at low energies. The composition is then becoming heavier with increasing energy, with a fraction of oxygen and iron above 80% at the highest energies. Keywords: astroparticle physics, ultra-high energy cosmic rays, extensive air showers, mass composition, Pierre Auger Observatory, machine learning, multivariate analysis Published in RUNG: 03.04.2019; Views: 4915; Downloads: 186 Full text (17,53 MB) |
138. All-sky search for correlations in the arrival directions of astrophysical neutrino candidates and ultrahigh-energy cosmic raysI. Al Samarai, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, published scientific conference contribution Keywords: correlations, astrophysical neutrino, ultrahigh-energy cosmic rays Published in RUNG: 19.02.2018; Views: 3461; Downloads: 166 Full text (3,07 MB) |
139. Testing the agreement between the Xmax distributions measured by the Pierre Auger and Telescope Array ObservatoriesV. De Souza, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, published scientific conference contribution Keywords: Xmax distributions, Pierre Auger Observatory, Telescope Array Published in RUNG: 19.02.2018; Views: 3741; Downloads: 179 Full text (266,09 KB) |
140. Report of the Telescope Array - Pierre Auger Observatory Working Group on Energy SpectrumDmitri Ivanov, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Darko Veberič, Serguei Vorobiov, Marta Trini, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, published scientific conference contribution Keywords: Telescope Array, Pierre Auger Observatory, Energy Spectrum Published in RUNG: 19.02.2018; Views: 3386; Downloads: 172 Full text (398,98 KB) |