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Opis: The Pierre Auger Observatory, the world’s largest ultra-high-energy (UHE) cosmic ray (CR) detector, plays a crucial role in multi-messenger astroparticle physics with its high sensitivity to UHE photons and neutrinos. Recent Auger Observatory studies have set stringent limits on the diffuse and point-like fluxes of these particles, enhancing constraints on dark-matter models and UHECR sources. Although no temporal coincidences of neutrinos or photons with LIGO/Virgo gravitational wave events have been observed, competitive limits on the energy radiated in these particles have been established, particularly from the GW170817 binary neutron star merger. Additionally, correlations between the arrival directions of UHECRs and high-energy neutrinos have been explored using data from the IceCube Neutrino Observatory, ANTARES, and the Auger Observatory, providing additional neutrino flux constraints. Efforts to correlate UHE neutron fluxes with gamma-ray sources within our galaxy continue, although no significant excesses have been found. These collaborative and multi-faceted efforts underscore the pivotal role of the Auger Observatory in advancing multi-messenger astrophysics and probing the most extreme environments of the Universe.
Ključne besede: high-energy particle physics, astrophysics, ultra-high energy cosmic rays, neutrinos, gravitional waves
Objavljeno v RUNG: 22.04.2025; Ogledov: 305; Prenosov: 0
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Opis: We present the results of our analysis of Gaia19dke, an extraordinary microlensing event in the Cygnus constellation that the Gaia satellite discovered. This event featured a strong microlensing parallax effect, resulting in multiple light curve peaks. We conducted extensive photometric, spectroscopic, and high-resolution imaging follow-up observations to determine the mass and nature of the invisible lensing object. Using the Milky Way priors on the density and proper motion of lenses, we found that the lens is likely to be located at a distance of DL=3.3(+2.1, -1.7) kpc, and has a mass of ML=0.50(+0.82, -0.27) M☉. Based on its low luminosity and mass, we propose that the lens in the Gaia19dke event is either a main sequence star or an isolated white dwarf. Due to its brightness, longevity, and lack of blending, Gaia19dke is a target for which the forthcoming Gaia Data Release 4 data will help to constrain the parameters of the lens.
Ključne besede: gravitational lensing, micro stars, fundamental parameters, white dwarfs, astrophysics, solar astrophysics, stellar astrophysics, astrophysics of galaxies, instrumentation for astrophysics, methods for astrophysics
Objavljeno v RUNG: 13.01.2025; Ogledov: 708; Prenosov: 2
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Opis: In this presentation, the existing open data practices in high energy astro-, particle and astroparticle physics are presented. Open data has become fundamental in astrophysics, particle, and astroparticle physics, enhancing collaboration, reproducibility, and transparency, while accelerating innovation. A recent shift toward openness, marked by data-sharing initiatives and accessible resources, is driving breakthroughs like the multi-messenger observation of GW170817, a neutron star merger detected in both gravitational waves and gamma rays, and the identification of blazar TXS 0506+056 as a high-energy neutrino source. Across these fields, robust efforts are underway to develop and implement FAIR-compliant data policies, with a wide array of supportive tools, standards, protocols, and software already in use (Virtual Observatory in astrophysics, CERN’s Open Data Portal in particle physics, ...). The challenges of astroparticle physics data, often more complex than traditional astrophysics or particle physics data, call for additional coordination and technical advancements to meet FAIR principles effectively. Machine learning also plays a transformative role in these domains, enhancing the analysis of both proprietary and open data to reveal new insights and optimize research methodologies.
Ključne besede: open data, FAIR data, astrophysics, high-energy particle physics, astroparticle physics, multi-messenger astronomy
Objavljeno v RUNG: 06.01.2025; Ogledov: 822; Prenosov: 2
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Opis: We report discovering an exoplanet from following up a microlensing event alerted by Gaia. The event Gaia22dkv is toward a disk source rather than the traditional bulge microlensing fields. Our primary analysis yields a Jovian planet with M_p = 0.59 (+0.15, -0.05) M_J at a projected orbital separation r_perpendicular = 1.4 (+0.8, -0.3) au, and the host is a ∼1.1 M⊙ turnoff star at ∼1.3 kpc. At r' ~= 14, the host is far brighter than any previously discovered microlensing planet host, opening up the opportunity to test the microlensing model with radial velocity (RV) observations. RV data can be used to measure the planet's orbital period and eccentricity, and they also enable searching for inner planets of the microlensing cold Jupiter, as expected from the "inner–outer correlation" inferred from Kepler and RV discoveries. Furthermore, we show that Gaia astrometric microlensing will not only allow precise measurements of its angular Einstein radius θ_E but also directly measure the microlens parallax vector and unambiguously break a geometric light-curve degeneracy, leading to the definitive characterization of the lens system.
Ključne besede: gravitational microlensing exoplanet detection, planetary astrophysics, astrophysics of galaxies, instrumentation astrophysics, methods for astrophysics, solar astrophysics, stellar astrophysics
Objavljeno v RUNG: 23.08.2024; Ogledov: 1452; Prenosov: 10
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Ključne besede: gamma-ray astrophysics, dark matter, galactic center
Objavljeno v RUNG: 15.01.2024; Ogledov: 2299; Prenosov: 7
Celotno besedilo (7,22 MB)
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