71. Extraction of the muon signals recorded with the surface detector of the Pierre Auger Observatory using recurrent neural networksMarko Zavrtanik, Lukas Zehrer, Danilo Zavrtanik, Serguei Vorobiov, Samo Stanič, Marta Trini, A. Aab, Andrej Filipčič, Jon Paul Lundquist, 2021, original scientific article Found in: osebi
Keywords: Statistične metode, Čerenkov detektor, kalibracije in metode prilagajanja, Observatorij Pierre Auger
Published: 19.07.2021; Views: 835; Downloads: 124
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72. Evidence of Intermediate-Scale Energy Spectrum Anisotropy in the Northern Hemisphere from Telescope ArrayJ. P. Lundquist, 2018, published scientific conference contribution Abstract: Evidence of an energy dependent intermediate-scale anisotropy has been found in the arrival directions of ultra-high energy cosmic rays in the northern hemisphere, using 7 years of TA surface detector data. The previously reported ``hot spot" excess E ≥ 10^19.75 EeV is found to correspond to a deficit, or ``cold spot," of events for 10^19.2≤ E < 10^19.75 EeV. This feature suggests energy dependent magnetic deflection of cosmic-rays. The global post-trial significance of the energy spectrum deviation is found to be 3.74σ.
Found in: osebi
Keywords: UHECR, cosmic rays, energy spectrum, anisotropy, magnetic deflection
Published: 28.04.2020; Views: 1509; Downloads: 49
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73. Search for correlations between the arrival directions of IceCube neutrino events and ultrahigh-energy cosmic rays detected by the Pierre Auger Observatory and the Telescope ArrayJ. P. Lundquist, M. G. Aartsen, 2016, original scientific article Abstract: This paper presents the results of different searches for correlations between very high-energy neutrino candidates detected by IceCube and the highest-energy cosmic rays measured by the Pierre Auger Observatory and the Telescope Array. We first consider samples of cascade neutrino events and of high-energy neutrino-induced muon tracks, which provided evidence for a neutrino flux of astrophysical origin, and study their cross-correlation with the ultrahigh-energy cosmic ray (UHECR) samples as a function of angular separation. We also study their possible directional correlations using a likelihood method stacking the neutrino arrival directions and adopting different assumptions on the size of the UHECR magnetic deflections. Finally, we perform another likelihood analysis stacking the UHECR directions and using a sample of through-going muon tracks optimized for neutrino point-source searches with sub-degree angular resolution. No indications of correlations at discovery level are obtained for any of the searches performed. The smallest of the p-values comes from the search for correlation between UHECRs with IceCube high-energy cascades, a result that should continue to be monitored.
Found in: osebi
Keywords: UHECR, cosmic rays, neutrinos, multi-messenger physics, anisotropy
Published: 30.04.2020; Views: 1411; Downloads: 0
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74. The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and at the Telescope ArrayLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Jon Paul Lundquist, Gašper Kukec Mezek, Andrej Filipčič, Olivier Deligny, 2019, published scientific conference contribution Found in: osebi
Keywords: ultra-high energy cosmic rays (UHECR), UHECR energy spectrum, Pierre Auger Observatory, Telescope Array
Published: 10.05.2021; Views: 736; Downloads: 31
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75. Search for Correlations of High-energy Neutrinos and Ultra-high Energy Cosmic RaysLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Jon Paul Lundquist, Gašper Kukec Mezek, Andrej Filipčič, A.M. Barbano, 2019, published scientific conference contribution Found in: osebi
Keywords: ultra-high energy cosmic rays (UHECR), high-energy neutrinos, arrival directions, correlation search, IceCube neutrino
observatory, Pierre Auger Observatory, Telescope Array, ANTARES neutrino observatory
Published: 22.12.2020; Views: 1154; Downloads: 48
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76. Extrapolating FR-0 radio galaxy source properties from propagation of multi-messenger ultra-high energy cosmic raysChiara Righi, Giacomo Bonnoli, Fabrizio Tavecchio, Paolo Da Vela, Anita Reimer, Margot Boughelilba, Serguei Vorobiov, Lukas Merten, Jon Paul Lundquist, 2021, published scientific conference contribution Abstract: Recently, it has been shown that relatively low luminosity Fanaroff-Riley type 0 (FR-0) radio galaxies are a good candidate source class for a predominant fraction of cosmic rays (CR) accelerated to ultra-high energies (UHE, E>10[sup]18 eV). FR-0s can potentially provide a significant fraction
of the UHECR energy density as they are much more numerous in the local universe than more energetic radio galaxies such as FR-1s or FR-2s (up to a factor of ∼5 with z≤0.05 compared to
FR-1s).
In the present work, UHECR mass composition and energy spectra at the FR-0 sources are estimated by fitting simulation results to the published Pierre Auger Observatory data. This fitting is done using a simulated isotropic sky distribution extrapolated from the measured FR-0 galaxy properties and propagating CRs in plausible extragalactic magnetic field configurations using the CRPropa3 framework. In addition, we present estimates of the fluxes of secondary photons and neutrinos created in UHECR interactions with cosmic photon backgrounds during
CR propagation. With this approach, we aim to investigate the properties of the sources with the help of observational multi-messenger data.
Found in: osebi
Keywords: jetted active galaxies, FR-0 radiogalaxies, ultra-high energy cosmic rays, extragalactic magnetic fields, UHECR propagation, UHECR interactions, cosmogenic photons, cosmogenic neutrinos
Published: 16.08.2021; Views: 610; Downloads: 0
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77. FR-0 jetted active galaxiesChiara Righi, Jon Paul Lundquist, Giacomo Bonnoli, Fabrizio Tavecchio, Serguei Vorobiov, Paolo Da Vela, Anita Reimer, Margot Boughelilba, Lukas Merten, 2021, published scientific conference contribution Abstract: Fanaroff-Riley (FR) 0 radio galaxies form a low-luminosity extension to the well-established ultra-high-energy cosmic-ray (UHECR) candidate accelerators FR-1 and FR-2 galaxies. Their much higher number density — up to a factor five times more numerous than FR-1 with z ≤ 0.05 — makes them good candidate sources for an isotropic contribution to the observed UHECR flux.
Here, the acceleration and survival of UHECR in prevailing conditions of the FR-0 environment are discussed.
First, an average spectral energy distribution (SED) is compiled based on the FR0CAT. These photon fields, composed of a jet and a host galaxy component, form a minimal target photon field for the UHECR, which will suffer from electromagnetic pair production, photo-disintegration, photo-meson production losses, and synchrotron radiation. The two most promising acceleration scenarios based on Fermi-I order and gradual shear acceleration are discussed as well as different
escape scenarios.
When an efficient acceleration mechanism precedes gradual shear acceleration, e.g., Fermi-I orothers, FR-0 galaxies are likely UHECR accelerators. Gradual shear acceleration requires a jet
Lorentz factor of Gamma>1.6, to be faster than the corresponding escape. In less optimistic models, a contribution to the cosmic-ray flux between the knee and ankle is expected to be relatively independent of the realized turbulence and acceleration.
Found in: osebi
Keywords: jetted active galaxies, FR-0 radiogalaxies, ultra-high energy cosmic rays, cosmic ray acceleration, cosmic ray energy losses
Published: 16.08.2021; Views: 562; Downloads: 0
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78. The energy spectrum of cosmic rays beyond the turn-down around 10[sup]17 eV as measured with the surface detector of the Pierre Auger ObservatorySamo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, P. Abreu, Andrej Filipčič, Jon Paul Lundquist, Lukas Zehrer, 2021, original scientific article Found in: osebi
Keywords: kozmični žarki, spektertalni detektor, Observatorij Pierre Auger
Published: 08.11.2021; Views: 424; Downloads: 0
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79. Testing effects of Lorentz invariance violation in the propagation of astroparticles with the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Serguei Vorobiov, Samo Stanič, Jon Paul Lundquist, Andrej Filipčič, P. Abreu, Lukas Zehrer, 2022, original scientific article Found in: osebi
Keywords: cosmic ray experiments, ultra high energy, cosmic rays, physics of the early universe, Pierre Auger Observatory, Lorentz invariance violation effects
Published: 18.01.2022; Views: 377; Downloads: 9
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80. Multi-messenger studies with the Pierre Auger ObservatoryLukas Zehrer, Andrej Filipčič, Gašper Kukec Mezek, Jon Paul Lundquist, Samo Stanič, Marta Trini, Serguei Vorobiov, Marko Zavrtanik, Danilo Zavrtanik, 2021, published scientific conference contribution Abstract: Over the past decade the multi-messenger astrophysics has emerged as a distinct discipline,
providing unique insights into the properties of high-energy phenomena in the Universe. The
Pierre Auger Observatory, located in Malargüe, Argentina, is the world’s largest cosmic ray
detector sensitive to photons, neutrinos, and hadrons at ultra-high energies. Using its data, stringent
limits on photon and neutrino fluxes at EeV energies have been obtained. The collaboration uses
the excellent angular resolution and the neutrino identification capabilities of the Observatory
for follow-up studies of events detected in gravitational waves or other messengers, through
cooperation with global multi-messenger networks. We present a science motivation together
with an overview of the multi-messenger capabilities and results of the Pierre Auger Observatory.
Found in: osebi
Keywords: high-energy cosmic phenomena, multi-messenger astrophysical studies, cosmic rays, gamma-rays, neutrinos, Pierre Auger Observatory
Published: 06.05.2022; Views: 135; Downloads: 0
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