1. Investigation of multi-messenger properties of FR0 radio galaxy emitted ultra-high energy cosmic raysJon Paul Lundquist, Lukas Merten, Serguei Vorobiov, Margot Boughelilba, Albert Reimer, Paolo Da Vela, F. Tavecchio, G. Bonnoli, C. Righi, 2023, objavljeni znanstveni prispevek na konferenci Opis: Low luminosity Fanaroff-Riley type 0 (FR0) radio galaxies are amongst potential contributors to the observed flux of ultra-high energy cosmic rays (UHECRs). Due to FR0s’ much higher abundance in the local universe than more powerful radio galaxies (e.g., about five times more ubiquitous at redshifts z≤0.05 than FR1s), they could provide a substantial fraction of the total UHECR energy density.
In the presented work, we determine the mass composition and energy spectrum of UHECRs emitted by FR0 sources by fitting simulation results from the CRPropa3 framework to the recently published Pierre Auger Observatory data. The resulting emission spectral characteristics (spectral indices, rigidity cutoffs) and elemental group fractions are compared to the Auger results. The FR0 simulations include the approximately isotropic distribution of FR0s extrapolated from the measured FR0 galaxy properties and various extragalactic magnetic field configurations, including random and large-scale structured fields. We predict the fluxes of secondary photons and neutrinos produced during UHECR propagation through cosmic photon backgrounds. The presented results allow for probing the properties of the FR0 radio galaxies as cosmic-ray sources using observational high-energy multi-messenger data.
Ključne besede: ultra-high energy cosmic rays, UHECRs, Pierre Auger Observatory, UHECR propagation, UHECR interactions, UHECR energy spectrum, UHECR mass composition, UHECR sources, Fanaroff-Riley (FR) radio galaxies, FR0 galaxies
Objavljeno v RUNG: 24.01.2024; Ogledov: 456; Prenosov: 6
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2. Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger ObservatoryOlena Tkachenko, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci Opis: In this work, we present an estimate of the cosmic-ray mass composition from the distributions of the depth of the shower maximum (�max) measured by the fluorescence detector of the Pierre Auger Observatory. We discuss the sensitivity of the mass composition measurements to the uncertainties in the properties of the hadronic interactions, particularly in the predictions of the particle interaction cross-sections. For this purpose, we adjust the fractions of cosmic-ray mass groups to fit the data with �max distributions from air shower simulations. We modify the proton-proton cross-sections at ultra-high energies, and the corresponding air shower simulations with rescaled nucleus-air cross-sections are obtained via Glauber theory. We compare the energydependent composition of ultra-high-energy cosmic rays obtained for the different extrapolations
of the proton-proton cross-sections from low-energy accelerator data.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, extensive air shower, hadronic interactions, cross-section, Xmax
Objavljeno v RUNG: 23.01.2024; Ogledov: 347; Prenosov: 5
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3. Studies of the UHECR Mass Composition and Hadronic Interactions with the FD and SD of the Pierre Auger ObservatoryJ.M. Carceller, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Samo Stanič, Marta Trini, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, objavljeni znanstveni prispevek na konferenci 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: 669; Prenosov: 8
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5. CR-ENTREES - Cosmic-Ray ENergy TRansport in timE-Evolving astrophysical SettingsAnita Reimer, Lukas Merten, Margot Boughelilba, Paolo Da Vela, Serguei Vorobiov, Jon Paul Lundquist, 2023, objavljeni znanstveni prispevek na konferenci Opis: In order to understand observable signatures from putative cosmic-ray (CR) sources in-source
acceleration of particles, their energy and time-dependent transport including interactions in an
evolving environment and their escape from source have to be considered, in addition to sourceto-
Earth propagation.
We present the code CR-ENTREES (Cosmic-Ray ENergy TRansport in timE-Evolving astrophysical
Settings) that evolves the coupled time- and energy-dependent kinetic equations for cosmicray
nucleons, pions, muons, electrons, positrons, photons and neutrinos in a one-zone setup of
(possibly) non-constant size, with user-defined particle and photon injection laws. All relevant
interactions, particle/photon escape and adiabatic losses are considered in a radiation-dominated,
magnetized astrophysical environment that is itself evolving in time. Particle and photon interactions
are pre-calculated using event generators assuring an accurate interactions and secondary
particle production description. We use the matrix multiplication method for fast radiation and
particle energy transport which allows also an efficient treatment of transport non-linearities due
to the produced particles/photons being fed back into the simulation chain.
Examples for the temporal evolution of the non-thermal emission from AGN jet-like systems with
focus on proton-initiated pair cascades inside an expanding versus straight jet emission region, are
further presented.
Ključne besede: cosmic rays, CR energy transport, CR interactions
Objavljeno v RUNG: 24.08.2023; Ogledov: 656; Prenosov: 3
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6. Efficient modeling of heavy cosmic rays propagation in evolving astrophysical environmentsLukas Merten, Paolo Da Vela, Anita Reimer, Jon Paul Lundquist, Margot Boughelilba, Serguei Vorobiov, J. Becker Tjus, 2023, objavljeni znanstveni prispevek na konferenci Opis: We present a new energy transport code that models the time dependent and non-linear evolution
of spectra of cosmic-ray nuclei, their secondaries, and photon target fields. The software can inject
an arbitrary chemical composition including heavy elements up to iron nuclei. Energy losses and
secondary production due to interactions of cosmic ray nuclei, secondary mesons, leptons, or
gamma-rays with a target photon field are available for all relevant processes, e.g., photo-meson
production, photo disintegration, synchrotron radiation, Inverse Compton scattering, and more.
The resulting x-ray fluxes can be fed back into the simulation chain to correct the initial photon
targets, resulting in a non-linear treatment of the energy transport. The modular structure of the
code facilitates simple extension of interaction or target field models.
We will show how the software can be used to improve predictions of observables in various
astrophysical sources such as jetted active galactic nuclei (AGN). Since the software can model
the propagation of heavy ultrahigh-energy cosmic rays inside the source it can precisely predict
the chemical composition at the source. This will also refine predictions of neutrino emissions
–– they strongly depend on the chemical composition. This helps in the future to optimize the
selection and analyses of data from the IceCube neutrino observatory with the aim to enhance the
sensitivity of IceCube and reduce the number of trial factors.
Ključne besede: cosmic rays, low-luminosity jetted AGNCR energy transport, CR interactions
Objavljeno v RUNG: 24.08.2023; Ogledov: 669; Prenosov: 4
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7. Potts spins, protein conformations and implicit water modelArtem Badasyan, 2023, objavljeni povzetek znanstvenega prispevka na konferenci (vabljeno predavanje) Opis: I will summarize past and current achievements in the field of spin model applications to protein conformations. Using classical Statistical Mechanics scheme and 1D many-body Hamiltonian, exact partition function can be estimated, giving access to the free energy, order parameter and specific heat. I will introduce a simplified water model as an additive term at the level of Hamiltonian, and will show how the solvent degrees of freedom can be summed out. The suggested procedure results in the effective Hamiltonian with the temperature dependent hydrogen bonding energy. If the many-body range is reduced to the nearest neighbour, the approach reduces to the Zimm-Bragg model. Obtained expressions for the order parameter and the specific heat nicely fit to the corresponding experiments for protein folding, providing an alternative or complementary scheme for the processing of experimental data.
Ključne besede: protein folding, Zimm-Bragg, protein-water interactions
Objavljeno v RUNG: 19.06.2023; Ogledov: 1073; Prenosov: 6
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8. Non-covalent ligand-oxide interaction promotes oxygen evolutionQianbao Wu, Junwu Liang, Mengjun Xiao, Chang Long, Lei Li, Zhenhua Zeng, Andraž Mavrič, Xia Zheng, Jing Zhu, Matjaž Valant, 2023, izvirni znanstveni članek Opis: Strategies to generate high-valence metal species capable of oxidizing water often employ composition and coordination tuning of oxide-based catalysts, where strong covalent interactions with metal sites are crucial. However, it remains unexplored whether a relatively weak “non-bonding” interaction between ligands and oxides can mediate the electronic states of metal sites in oxides. Here we present an unusual non-covalent phenanthroline-CoO2 interaction that substantially elevates the population of Co4+ sites for improved water oxidation. We find that phenanthroline only coordinates with Co2+ forming soluble Co(phenanthroline)2(OH)2 complex in alkaline electrolytes, which can be deposited as amorphous CoOxHy film containing non-bonding phenanthroline upon oxidation of Co2+ to Co3+/4+. This in situ deposited catalyst demonstrates a low overpotential of 216 mV at 10 mA cm−2 and sustainable activity over 1600 h with Faradaic efficiency above 97%. Density functional theory calculations reveal that the presence of phenanthroline can stabilize CoO2 through the non-covalent interaction and generate polaron-like electronic states at the Co-Co center.
Ključne besede: water oxidation, cobalt hydroxide, ligand-metal interactions
Objavljeno v RUNG: 23.02.2023; Ogledov: 1422; Prenosov: 15
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9. Extrapolating FR-0 radio galaxy source properties from propagation of multi-messenger ultra-high energy cosmic raysJon Paul Lundquist, Lukas Merten, Serguei Vorobiov, Margot Boughelilba, Anita Reimer, Paolo Da Vela, Fabrizio Tavecchio, Giacomo Bonnoli, Chiara Righi, 2021, objavljeni znanstveni prispevek na konferenci Opis: Recently, it has been shown that relatively low luminosity Fanaroff-Riley type 0 (FR-0) radio galaxies are a good candidate source class for a predominant fraction of cosmic rays (CR) accelerated to ultra-high energies (UHE, E>10[sup]18 eV). FR-0s can potentially provide a significant fraction
of the UHECR energy density as they are much more numerous in the local universe than more energetic radio galaxies such as FR-1s or FR-2s (up to a factor of ∼5 with z≤0.05 compared to
FR-1s).
In the present work, UHECR mass composition and energy spectra at the FR-0 sources are estimated by fitting simulation results to the published Pierre Auger Observatory data. This fitting is done using a simulated isotropic sky distribution extrapolated from the measured FR-0 galaxy properties and propagating CRs in plausible extragalactic magnetic field configurations using the CRPropa3 framework. In addition, we present estimates of the fluxes of secondary photons and neutrinos created in UHECR interactions with cosmic photon backgrounds during
CR propagation. With this approach, we aim to investigate the properties of the sources with the help of observational multi-messenger data.
Ključne besede: jetted active galaxies, FR-0 radiogalaxies, ultra-high energy cosmic rays, extragalactic magnetic fields, UHECR propagation, UHECR interactions, cosmogenic photons, cosmogenic neutrinos
Objavljeno v RUNG: 16.08.2021; Ogledov: 1939; Prenosov: 3
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10. Pollutant removal with organic macrocycle-based covalent organic polymers and frameworksTina Škorjanc, Dinesh Shetty, Ali Trabolsi, 2021, pregledni znanstveni članek Opis: Air, water, and soil pollution devastate countless ecosystems and deteriorate human health. Adsorption has commonly been used as a pollutant removal technique, but ongoing materials science research is still searching for more efficient, cheaper, and scalable sorbent materials. Herein, we discuss the synthesis and pollutant-capturing abilities of covalent polymeric structures, including covalent organic polymers and covalent organic frameworks that contain organic macrocycles in the backbone of their structures. These organic macrocycles (cyclodextrin, calixarene, cucurbituril, pillararene, and porphyrin) possess cavities and functional groups that can sequester pollutants by forming supramolecular interactions. The insolubility of these materials prominently aids in their regeneration and recyclability potentials. Following a discussion on the synthetic strategies used in the polymerization of each type of macrocycle, environmental applications of these materials are presented. Here, we focus on the removal of micropollutants, charged species, metal ions, oils and organic solvents, perfluorinated substances, iodine, and volatile organic compounds.
Ključne besede: supramolecular interactions, host-guest chemistry, organic macrocycles, covalent polymers, covalent organic frameworks, environmental remediation, adsorption
Objavljeno v RUNG: 09.04.2021; Ogledov: 2204; Prenosov: 65
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