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Opis: The Pierre Auger Observatory, sited in Malargüe, Argentina, is the largest observatory available for measuring ultra-high-energy cosmic rays (UHECR). The Auger Collaboration has measured and analysed an unprecedented number of UHECRs. Along with making important scientific discoveries, for example, the demonstration that cosmic rays above 8 EeV are of extragalactic origin and the observation of a new feature in the energy spectrum at around 13 EeV, outreach work has been carried out across the 18 participating countries and online. This program ranges from talks to a varied audience, to the creation of a local Visitor Center, which attracts 8000 visitors annually, to initiating masterclasses. Permanent and temporary exhibitions have been prepared both in reality and virtually. Science fairs for elementary- and high-school students have been organised, together with activities associated with interesting phenomena such as eclipses. In addition, we participate in international events such as the International Cosmic Day, Frontiers from H2020, and the International Day of Women and Girls in Science. Part of the Collaboration website is aimed at the general public. Here the most recent articles published are summarised. Thus the Collaboration informs people about work in our field, which may seem remote from everyday life. Furthermore, the Auger Observatory has been a seed for scientific and technological activities in and around Malargüe. Different outreach ventures that already have been implemented and others which are foreseen will be described.
Ključne besede: Pierre Auger Observatory, indirect detection, ultra-high energy, cosmic rays, outreach, open data
Objavljeno v RUNG: 26.09.2023; Ogledov: 612; Prenosov: 5
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Opis: The Fluorescence Detector (FD) of the Pierre Auger Observatory has a large exposure to search for upward-going showers. Constraints have been recently obtained by using 14 years of FD data searching for upward-going showers in the zenith angle range [110◦, 180◦]. In this work, we translate these bounds to upper limits of a possible flux of ultra high energy tau-leptons escaping from the Earth into the atmosphere. Such a mechanism could explain the observation of "anomalous pulses" made by ANITA, that indicated the existence of upward-going air showers with energies above 10[sup]17 eV. As tau neutrinos would be absorbed within the Earth at the deduced angles and energies, a flux of upward-going taus could only be resulted from an unknown type of ultra high energy Beyond Standard Model particle penetrating the Earth with little attenuation, and then creating tau-leptons through interactions within a maximum depth of about 50 km before exiting. We test classes of such models in a generic way and determine upper flux limits of ultra high energy BSM particles as a function of their unknown cross section with matter.
Ključne besede: ultra-high energy cosmic rays, Pierre Auger Observatory, fluorescence detector, upward-going air showers, Beyond Standard Model particles
Objavljeno v RUNG: 26.09.2023; Ogledov: 585; Prenosov: 6
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Opis: Nature is providing particles with energies exceeding 100 EeV. Their existence imposes immediate questions: Are they ordinary particles, accelerated in extreme astrophysical environments, or are they annihilation or decay products of super-heavy dark matter or other exotic objects? If the particles are accelerated in extreme astrophysical environments, are their sources related to those of high-energy neutrinos, gamma rays, and/or gravitational waves, such as the recently observed mergers of compact objects? The particles can also be used to study physics processes at extreme energies; is Lorentz invariance still valid? Are the particles interacting according to the Standard Model or are there new physics processes? The particles can be used to study hadronic interactions (QCD) in the kinematic forward direction; what is the cross section of protons at center-of-mass energies sqrt(s) > 100 TeV? These questions are addressed at present by installations like the Telescope Array and the Pierre Auger Observatory. After the year 2030, a next-generation observatory will be needed to study the physics and properties of the highest-energy particles in Nature, building on the knowledge harvested from the existing observatories. It should have an aperture at least an order of magnitude bigger than the existing observatories. Recently, more than 200 scientists from around the world came together to discuss the future of the field of multi-messenger astroparticle physics beyond the year 2030. Ideas have been discussed towards the physics case and possible scenarios for detection concepts of the Global Cosmic Ray Observatory - GCOS. A synopsis of the key results discussed during the brainstorming workshop will be presented.
Ključne besede: ultra-high-energy cosmic rays, Pierre Auger Observatory, Telescope Array, Global Cosmic Ray Observatory (GCOS) project
Objavljeno v RUNG: 13.09.2023; Ogledov: 557; Prenosov: 6
Celotno besedilo (5,89 MB)
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Opis: 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.
Ključne besede: ultra-high energy cosmic rays, UHECR propagation, CRPropa, active galactic nuclei, jetted AGN, FR0 radio galaxies, Pierre Auger Observatory, UHECR energy spectrum
Objavljeno v RUNG: 24.08.2023; Ogledov: 676; Prenosov: 4
Celotno besedilo (1,12 MB)
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Opis: We use the surface detector of the Pierre Auger Observatory to search for air showers initiated by photons with an energy above 10[sup]19 eV. Photons in the zenith angle range from 30 deg. to 60 deg. can be identified in the overwhelming background of showers initiated by charged cosmic rays through the broader time structure of the signals induced in the water-Cherenkov detectors of the array and the steeper lateral distribution of shower particles reaching ground. Applying the search method to data collected between January 2004 and June 2020, upper limits at 95% CL are set to an E[sup]-2 diffuse flux of ultra-high energy photons above 10[sup]19 eV, 2 × 10[sup]19 eV and 4 × 10[sup]19 eV amounting to 2.11 × 10[sup]-3, 3.12 × 10[sup]-4 and 1.72 × 10[sup]-4 km-2 sr-1 yr-1, respectively. While the sensitivity of the present search around 2 × 10[sup]19 eV approaches expectations of cosmogenic photon fluxes in the case of a pure-proton composition, it is one order of magnitude above those from more realistic mixed-composition models. The inferred limits have also implications for the search of super-heavy dark matter that are discussed and illustrated.
Ključne besede: ultra-high-energy cosmic rays, UHE photons, Pierre Auger Observatory, extensive air showers, water Cherenkov detectors
Objavljeno v RUNG: 18.08.2023; Ogledov: 694; Prenosov: 8
Celotno besedilo (2,46 MB)
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