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Opis: Taking data stably since 2004, the Pierre Auger Observatory has published numerous results regarding the properties of ultra-high-energy cosmic rays with unprecedented statistics. However, questions about their origin and mass composition remain unanswered, motivating us to build AugerPrime, a major upgrade of our surface detector array with improved electronics and new detectors. The upgrade is swiftly approaching its completion. Phase II of the Pierre Auger Observatory has begun, which called for an update of the Offline software Framework and modules to handle the additional detectors and the new electronics. Thanks to its modular structure, Offline has proved flexible enough to accommodate all the changes required to handle AugerPrime data reconstruction and event simulation. Additionally, new reference libraries of shower and detector simulations, including dedicated libraries envisaging the searches for neutral particles, such as ultra-high-energy photons and neutrinos, profiting from the new AugerPrime detectors with the upgraded electronics, are in the pipeline. In this contribution, we report on the current status and prospects for the Auger Off line Framework and the production of reference Monte Carlo libraries for AugerPrime.
Ključne besede: AugerPrime, Pierre Auger Observatory, cosmic rays, surface detectors
Objavljeno v RUNG: 16.01.2024; Ogledov: 1814; Prenosov: 8
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Opis: Astrophysical neutral particles, such as neutrons, can point directly to their sources since they are not affected by magnetic fields. We expect neutron production in the immediate vicinity of the acceleration sites due to cosmic ray interactions. Hence, a high-energy neutron flux could help to identify sources of cosmic rays in the EeV range. Free neutrons, although unstable, can travel a mean distance of 9.2 kpc times their energy in EeV. Due to the neutron instability, we limit the searches to Galactic candidate sources. Since air showers initiated by a neutron are indistinguishable from those generated by a proton, we would recognize a neutron flux as an excess of events from the direction of its source. Previous searches using events with a zenith angle up to 60^◦ and energies above 1 EeV found no surplus of events that would indicate a neutron flux. We present the results of the search for evidence of high-energy neutron fluxes using a data set about three times larger than the previous work. We investigate the sky in the field of view of the Pierre Auger Observatory, narrowing down to specific directions of candidate sources. With respect to previous works, we extend the angular range up to zenith angles of 80^◦ , reaching declinations from −90^◦ to +45^◦ , and the energy range going as low as 0.1 EeV. The extension in the field of view provides exposure to the Crab Nebula for the first time.
Ključne besede: neutrons, cosmic ray, Pierre Auger Observatory, Crab Nebula, proton, high-energy neutron flux
Objavljeno v RUNG: 14.11.2023; Ogledov: 2238; Prenosov: 6
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Opis: The Cherenkov Telescope Array (CTA) is the major ground-based gamma-ray observatory planned for the next decade and beyond. Consisting of two large atmospheric Cherenkov telescope arrays (one in the southern hemisphere and one in the northern hemisphere), CTA will have superior angular resolution, a much wider energy range, and approximately an order of magnitude improvement in sensitivity, as compared to existing instruments. The CTA science programme will be rich and diverse, covering cosmic particle acceleration, the astrophysics of extreme environments, and physics frontiers beyond the Standard Model. This paper outlines the science goals for CTA and covers the current status of the project.
Ključne besede: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array (CTA), cosmic particle acceleration, astrophysics of extreme environments, physics beyond the Standard Model
Objavljeno v RUNG: 11.10.2023; Ogledov: 2029; Prenosov: 14
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Opis: With data on the depth of maximum Xmax collected during more than a decade of operation of the Pierre Auger Observatory, we report on the inferences on the mass composition of UHECRs in the energy range E = 10[sup]17.2 − 10[sup]19.6 eV and on the measurements of the proton-air cross section for energies up to 10[sup]18.5 eV. We also present the results on Xmax obtained using the information on the particle arrival times recorded by the SD stations allowing us to extend the Xmax measurements up to 10[sup]20 eV. The inferences on mass composition, in particular using the data of the SD, are subject to systematic uncertainties due to uncertainties in the description of hadronic interactions at ultra-high energies. We discuss this problem with respect to the properties of the muonic component of extensive air-showers as derived from the SD data.
Ključne besede: ultra-high-energy cosmic rays (UHECRs), extensive air showers (EAS), EAS muonic component, EAS electromagnetic component, Pierre Auger Observatory, UHECR mass composition, UHECR hadronic interactions
Objavljeno v RUNG: 11.10.2023; Ogledov: 2251; Prenosov: 12
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Opis: The Pierre Auger Observatory has been very successful in determining many aspects of the highest-energy cosmic rays including, among others, the flux suppression at energies above 4 × 10[sup]19 eV, stringent upper limits on photon and neutrino fluxes at ultra-high energies and an unexpected evolution of the mass composition with energy. We expect an extension of the frontiers of our knowledge on these aspects from a major upgrade of the Observatory. The upgrade, known as AugerPrime, will include an addition of a 4 sq. m Surface Scintillator Detector atop each water-Cherenkov station of the Surface array. The new detectors will provide us with an unprecedented opportunity to perform a complementary measurement of the shower particles and thus determine the primary mass composition with good accuracy on an event-by-event basis. AugerPrime will also include an upgrade of electronics, installation of the AMIGA Underground Muon Detector and a change of observation mode of the Fluorescence Detector, which will increase its current duty cycle by about 50%. Current status of the upgrade with the main focus on the Surface Scintillator Detectors will be presented, following a brief description of the physics motivation for the upgrade.
Ključne besede: ultra-high-energy cosmic rays (UHECRs), Pierre Auger Observatory, AugerPrime upgrade
Objavljeno v RUNG: 11.10.2023; Ogledov: 3472; Prenosov: 13
Celotno besedilo (2,05 MB)
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