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 1 - 6 / 61 1.Evidence for Declination Dependence of Ultrahigh Energy Cosmic Ray Spectrum in the Northern HemisphereJ. P. Lundquist, R.U. Abbasi, 2018, other component partsAbstract: The energy of the ultrahigh energy spectral cutoff was measured, integrating over the northern hemisphere sky, by the Telescope Array (TA) collaboration, to be 10^19.78±0.06 eV, in agreement with the High Resolution Fly's Eye (HiRes) experiment, whereas the Pierre Auger experiment, integrating over the southern hemisphere sky, measured the cutoff to be at 10^19.62±0.02 eV. An 11% energy scale difference between the TA and Auger does not account for this difference. However, in comparing the spectra of the Telescope Array and Pierre Auger experiments in the band of declination common to both experiments ( −15.7∘<δ<24.8∘ ) we have found agreement in the energy of the spectral cutoff. While the Auger result is essentially unchanged, the TA cutoff energy has changed to 10^19.59±0.06 eV. In this paper we argue that this is an astrophysical effect.Found in: ključnih besedahSummary of found: ...The energy of the ultra high energy spectral cutoff was measured, integrating over... ...paper we argue that this is an astrophysical effect.... ...Astrophysics, High Energy Astrophysical Phenomena, UHECR, Cosmic Rays, Anisotropy, Energy Spectrum...Keywords: Astrophysics, High Energy Astrophysical Phenomena, UHECR, Cosmic Rays, Anisotropy, Energy SpectrumPublished: 27.04.2020; Views: 1780; Downloads: 60 Fulltext (687,87 KB) 2.Magnetic Fields and Afterglows of BdHNe: Inferences from GRB 130427A, GRB 160509A, GRB 160625B, GRB 180728A, and GRB 190114CJorge Armando Rueda, Remo Ruffini, Mile Karlica, Rahim Moradi, Yu Wang, 2020, original scientific articleAbstract: GRB 190114C is the first binary-driven hypernova (BdHN) fully observed from initial supernova (SN) appearance to the final emergence of the optical SN signal. It offers an unprecedented testing ground for the BdHN theory, which is here determined and further extended to additional gamma-ray bursts (GRBs). BdHNe comprise two subclasses of long GRBs, with progenitors a binary system composed of a carbon–oxygen star (COcore) and a neutron star (NS) companion. The COcore explodes as an SN, leaving at its center a newborn NS (νNS). The SN ejecta hypercritically accretes on both the νNS and the NS companion. BdHNe I are very tight binaries, where the accretion leads the companion NS to gravitationally collapse into a black hole (BH). In BdHN II, the accretion rate onto the NS is lower, so there is no BH formation. We observe the same afterglow structure for GRB 190114C and other selected examples of BdHNe I (GRB 130427A, GRB 160509A, GRB 160625B) and for BdHN II (GRB 180728A). In all cases, the afterglows are explained via the synchrotron emission powered by the νNS, and their magnetic field structures and their spin are determined. For BdHNe I, we discuss the properties of the magnetic field embedding the newborn BH, which was inherited from the collapsed NS and amplified during the gravitational collapse process, and surrounded by the SN ejecta.Found in: ključnih besedahSummary of found: ...Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and...Keywords: Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Cosmology and Nongalactic Astrophysics, General Relativity and Quantum CosmologyPublished: 20.07.2020; Views: 1462; Downloads: 0 Fulltext (1,37 MB) 3.On the GeV Emission of the Type I BdHN GRB 130427ALaura Beccera, She Sheng Xue, Yu Wang, Narek Sahakyan, Mile Karlica, Yen-Chen Chen, Simonetta Filippi, Christian Cherubini, Carlo Luciano Bianco, Jorge Armando Rueda, Rahim Moradi, Remo Ruffini, 2019, original scientific articleAbstract: We propose that the inner engine of a type I binary-driven hypernova (BdHN) is composed of Kerr black hole (BH) in a non-stationary state, embedded in a uniform magnetic field B_0 aligned with the BH rotation axis and surrounded by an ionized plasma of extremely low density of 10^−14 g cm−3. Using GRB 130427A as a prototype, we show that this inner engine acts in a sequence of elementary impulses. Electrons accelerate to ultrarelativistic energy near the BH horizon, propagating along the polar axis, θ = 0, where they can reach energies of ~10^18 eV, partially contributing to ultrahigh-energy cosmic rays. When propagating with $\theta \ne 0$ through the magnetic field B_0, they produce GeV and TeV radiation through synchroton emission. The mass of BH, M = 2.31M ⊙, its spin, α = 0.47, and the value of magnetic field B_0 = 3.48 × 10^10 G, are determined self consistently to fulfill the energetic and the transparency requirement. The repetition time of each elementary impulse of energy ${ \mathcal E }\sim {10}^{37}$ erg is ~10^−14 s at the beginning of the process, then slowly increases with time evolution. In principle, this "inner engine" can operate in a gamma-ray burst (GRB) for thousands of years. By scaling the BH mass and the magnetic field, the same inner engine can describe active galactic nuclei.Found in: ključnih besedahSummary of found: ...gamma-ray burst, neutron stars, supernovae, Astrophysics - High Energy Astrophysical Phenomena...Keywords: black hole physics, binaries, gamma-ray burst, neutron stars, supernovae, Astrophysics - High Energy Astrophysical PhenomenaPublished: 20.07.2020; Views: 1601; Downloads: 0 Fulltext (1,09 MB) 4.Electromagnetic emission of white dwarf binary mergersJorge Armando Rueda, Remo Ruffini, Yu Wang, Carlo Luciano Bianco, J.M. Blanco-Iglesias, Mile Karlica, P. Lorén-Aguilar, Rahim Moradi, Narek Sahakyan, 2019, original scientific articleAbstract: It has been recently proposed that the ejected matter from white dwarf (WD) binary mergers can produce transient, optical and infrared emission similar to the "kilonovae" of neutron star (NS) binary mergers. To confirm this we calculate the electromagnetic emission from WD-WD mergers and compare with kilonova observations. We simulate WD-WD mergers leading to a massive, fast rotating, highly magnetized WD with an adapted version of the smoothed-particle-hydrodynamics (SPH) code Phantom. We thus obtain initial conditions for the ejecta such as escape velocity, mass and initial position and distribution. The subsequent thermal and dynamical evolution of the ejecta is obtained by integrating the energy-conservation equation accounting for expansion cooling and a heating source given by the fallback accretion onto the newly-formed WD and its magneto-dipole radiation. We show that magnetospheric processes in the merger can lead to a prompt, short gamma-ray emission of up to ≈ 1046 erg in a timescale of 0.1-1 s. The bulk of the ejecta initially expands non-relativistically with velocity 0.01 c and then it accelerates to 0.1 c due to the injection of fallback accretion energy. The ejecta become transparent at optical wavelengths around ~ 7 days post-merger with a luminosity 1041-1042 erg s-1. The X-ray emission from the fallback accretion becomes visible around ~ 150-200 day post-merger with a luminosity of 1039 erg s-1. We also predict the post-merger time at which the central WD should appear as a pulsar depending on the value of the magnetic field and rotation period.Found in: ključnih besedahSummary of found: ...Astrophysics - High Energy Astrophysical Phenomena... ...the ejecta is obtained by integrating the energy-conservation equation accounting for expansion cooling and a...Keywords: Astrophysics - High Energy Astrophysical PhenomenaPublished: 20.07.2020; Views: 1488; Downloads: 0 Fulltext (8,22 MB) 5.Dark Matter science in the era of LSSTKeith Bechtol, Alex Drlica-Wagner, Kevork N. Abazajian, Muntazir Abidi, Susmita Adhikari, Yacine Ali-Haïmoud, James Annis, Behzad Ansarinejad, Christopher Eckner, Gabrijela Zaharijas, 2019, project documentation (preliminary design, working design)Found in: ključnih besedahSummary of found: ...cosmology, nongalactic astrophysics, high energy astrophysical phenomena, high energy physics, experiments...Keywords: cosmology, nongalactic astrophysics, high energy astrophysical phenomena, high energy physics, experimentsPublished: 03.05.2022; Views: 268; Downloads: 8 Fulltext (0,00 KB)This document has many files! More... 6.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 contributionAbstract: 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: ključnih besedahSummary of found: ...discipline, providing unique insights into the properties of high-energy phenomena in the Universe. The Pierre Auger Observatory,... ...high-energy cosmic phenomena, multi-messenger astrophysical studies, cosmic rays, gamma-rays, neutrinos, Pierre Auger...Keywords: high-energy cosmic phenomena, multi-messenger astrophysical studies, cosmic rays, gamma-rays, neutrinos, Pierre Auger ObservatoryPublished: 06.05.2022; Views: 270; Downloads: 0 Fulltext (1,06 MB)
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