1. The UHECR-FR0 Radio Galaxy Connection: A Multi-Messenger Study of Energy Spectra/Composition Emission and Intergalactic Magnetic Field PropagationJon Paul Lundquist, Lukas Merten, Serguei Vorobiov, Margot Boughelilba, Anita Reimer, Paolo Da Vela, Fabrizio Tavecchio, Giacomo Bonnoli, Chiara Righi, 2023, published scientific conference contribution Abstract: This study investigates low luminosity Fanaroff-Riley Type 0 (FR0) radio galaxies as a potentially
significant source of ultra-high energy cosmic rays (UHECRs). Due to their much higher prevalence
in the local universe compared to more powerful radio galaxies (about five times more than
FR-1s), FR0s may provide a substantial fraction of the total UHECR energy density. To determine
the nucleon composition and energy spectrum of UHECRs emitted by FR0 sources, simulation
results from CRPropa3 are fit to Pierre Auger Observatory data. The resulting emission spectral
indices, rigidity cutoffs, and nucleon fractions are compared to recent Auger results. The FR0 simulations
include the approximately isotropic distribution of FR0 galaxies and various intergalactic
magnetic field configurations (including random and structured fields) and predict the fluxes of
secondary photons and neutrinos produced during UHECR propagation through cosmic photon
backgrounds. This comprehensive simulation allows for investigating the properties of the FR0
sources using observational multi-messenger data.
Keywords: ultra-high energy cosmic rays (UHECRs), UHECR propagation, CRPropa, active galactic nuclei (AGN), jetted AGN, FR0 radio galaxies, Pierre Auger Observatory, UHECR energy spectrum, UHECR mass composition
Published in RUNG: 24.08.2023; Views: 182; Downloads: 2
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2. Constraining the sources of ultra-high-energy cosmic rays across and above the ankle with the spectrum and composition data measured at the Pierre Auger ObservatoryA. Abdul Halim, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, original scientific article Abstract: In this work we present the interpretation of the energy spectrum and mass composition data as measured by the Pierre Auger Collaboration above 6 × 10[sup]17 eV. We use an astrophysical model with two extragalactic source populations to model the hardening of the cosmic-ray flux at around 5 × 10[sup]18 eV (the so-called "ankle" feature) as a transition between these two components. We find our data to be well reproduced if sources above the ankle emit a mixed composition with a hard spectrum and a low rigidity cutoff. The component below the ankle is required to have a very soft spectrum and a mix of protons and intermediate-mass nuclei. The origin of this intermediate-mass component is not well constrained and it could originate from either Galactic or extragalactic sources. To the aim of evaluating our capability to constrain astrophysical models, we discuss the impact on the fit results of the main experimental systematic uncertainties and of the assumptions about quantities affecting the air shower development as well as the propagation and redshift distribution of injected ultra-high-energy cosmic rays (UHECRs).
Keywords: ultra-high-energy cosmic rays (UHECRs), Pierre Auger Observatory, extensive air showers, UHECR propagation, UHECR energy spectrum, UHECR mass composition
Published in RUNG: 18.08.2023; Views: 175; Downloads: 3
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3. Recent results from the Pierre Auger ObservatorySerguei Vorobiov, 2022, published scientific conference contribution abstract (invited lecture) Abstract: Ultra-high-energy cosmic rays (UHECRs) are mostly protons and heavier nuclei arriving on Earth from space and producing particle cascades in the atmosphere, ”extensive air showers”. As of today, the most precise and high-statistics data set of the rare (≤ 1 particle per sq.km per year above 10[sup]19 eV) UHECR events is obtained by the Pierre Auger Observatory, a large area (~3000 sq.km) hybrid detector in Argentina. The Auger Observatory determines the arrival directions and energies of the primary UHECR particles and provides constraints for their masses.
In this talk, I will present and discuss the recent results, including the detailed measurements of the cosmic-ray energy spectrum features, the study of the anisotropies in the UHECR arrival directions at large and intermediate angular scales, the multi-messenger searches, and the inferred cosmic-ray mass composition. Finally, the progress of the current upgrade of the Observatory, "AugerPrime" which is aimed at improving the sensitivity to the mass composition of ultra-high-energy cosmic rays, will be presented.
Keywords: ultra-high-energy cosmic rays, Pierre Auger Observatory, UHECR mass composition, energy spectrum, anisotropies, AugerPrime upgrade
Published in RUNG: 23.12.2022; Views: 780; Downloads: 6
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4. The energy spectrum of ultra-high energy cosmic rays measured at the Pierre Auger Observatory and at the Telescope ArrayOlivier Deligny, Andrej Filipčič, Gašper Kukec Mezek, Jon Paul Lundquist, 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 energy spectrum, Pierre Auger Observatory, Telescope Array
Published in RUNG: 10.05.2021; Views: 1547; Downloads: 63
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5. Measurement of the energy spectrum of ultra-high energy cosmic rays using the Pierre Auger ObservatoryValerio Verzi, 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, ultra-high energy cosmic rays (UHECR), UHECR energy spectrum
Published in RUNG: 21.12.2020; Views: 1772; Downloads: 59
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6. Measurement of the spectrum of cosmic rays above 10^16.5 eV with Cherenkov–dominated events at the Pierre Auger ObservatoryVladimír Novotný, 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 (UHECRs), Pierre Auger Observatory, UHECR energy spectrum, Cherenkov–dominated UHECR events
Published in RUNG: 24.07.2020; Views: 1989; Downloads: 71
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7. Measurement of the cosmic ray flux near the second knee with the Pierre Auger ObservatoryAlan Coleman, 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 energy spectrum, second knee, Pierre Auger Observatory
Published in RUNG: 16.06.2020; Views: 2171; Downloads: 75
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8. The energy spectrum of ultra-high-energy cosmic rays measured by the Telescope Array FADC fluorescence detectors in monocular modeT. Abu-Zayyad, J. P. Lundquist, 2013, original scientific article Abstract: We present a measurement of the energy spectrum of ultra-high-energy cosmic rays performed by the Telescope Array experiment using monocular observations from its two new FADC-based fluorescence detectors. After a short description of the experiment, we describe the data analysis and event reconstruction procedures. Since the aperture of the experiment must be calculated by Monte Carlo simulation, we describe this calculation and the comparisons of simulated and real data used to verify the validity of the aperture calculation. Finally, we present the energy spectrum calculated from the merged monocular data sets of the two FADC-based detectors, and also the combination of this merged spectrum with an independent, previously published monocular spectrum measurement performed by Telescope Array’s third fluorescence detector [T. Abu-Zayyad et al., The energy spectrum of Telescope Array’s middle drum detector and the direct comparison to the high resolution fly’s eye experiment, Astroparticle Physics 39 (2012) 109-119, http://dx.doi.org/10.1016/j.astropartphys.2012.05.012, Available from: ]. This combined spectrum corroborates the recently published Telescope Array surface detector spectrum [T. Abu-Zayyad, et al., The cosmic-ray energy spectrum observed with the surface detector of the Telescope Array experiment, ApJ 768 (2013) L1, http://dx.doi.org/10.1088/2041-8205/768/1/L1, Available from: ] with independent systematic uncertainties.
Keywords: UHECR, Energy spectrum, Fluorescence, Monocular
Published in RUNG: 19.05.2020; Views: 2116; Downloads: 0
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9. The Cosmic Ray Energy Spectrum between 2 PeV and 2 EeV Observed with the TALE Detector in Monocular ModeR.U. Abbasi, J. P. Lundquist, 2018, original scientific article Abstract: We report on a measurement of the cosmic ray energy spectrum by the Telescope Array Low-Energy Extension (TALE) air fluorescence detector (FD). The TALE air FD is also sensitive to the Cherenkov light produced by shower particles. Low-energy cosmic rays, in the PeV energy range, are detectable by TALE as Cherenkov events. Using these events, we measure the energy spectrum from a low energy of ~2 PeV to an energy greater than 100 PeV. Above 100 PeV, TALE can detect cosmic rays using air fluorescence. This allows for the extension of the measurement to energies greater than a few EeV. In this paper, we describe the detector, explain the technique, and present results from a measurement of the spectrum using ~1000 hr of observation. The observed spectrum shows a clear steepening near 10^17.1 eV, along with an ankle-like structure at 10^16.2 eV. These features present important constraints on the origin of galactic cosmic rays and on propagation models. The feature at 10^17.1 eV may also mark the end of the galactic cosmic ray flux and the start of the transition to extragalactic sources.
Keywords: astroparticle physics, cosmic rays, UHECR, energy spectrum
Published in RUNG: 30.04.2020; Views: 2215; Downloads: 0
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