41. An update on the arrival direction studies made with data from the Pierre Auger ObservatoryGeraldina Golup, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, published scientific conference contribution Abstract: The search for anisotropies in the arrival directions of ultra-high-energy cosmic rays plays a key role in the efforts to understand their origin. The observed first-harmonic modulation in right ascension above 8 EeV, detected by the Pierre Auger Observatory with a current significance of 6.9�, suggests an extragalactic origin above this energy. Furthermore, there are indications, at the ∼4� significance level, of anisotropies at intermediate angular scales, which are obtained when comparing the arrival directions against the distribution of potential sources from astrophysical catalogs, in particular that of nearby starburst galaxies, and around the Centaurus region. In this contribution, we present the status of the different searches for anisotropies at small, intermediate
and large angular scales. We use the latest available data set, with 19 years of operation that has yielded 135,000 km^2 yr sr of accumulated exposure, covering the sky at declinations from −90◦ to
45◦. At small and intermediate scales, we report updates of the all-sky blind search for localized excesses, the study around the Centaurus region, and the likelihood analysis with catalogs of
candidate sources. We have also studied the regions of the sky from which the Telescope Array Collaboration has reported hints of excesses in their data and we find no significant effects in
the same directions with a data set of comparable size. At large angular scales, the dipolar and quadrupolar amplitudes in energy bins are updated. We discuss the prospects of these searches,
both in regards to increases in statistics and in relation to the future inclusion of event-by-event mass estimators in these analyses through the upgrade of the Observatory, AugerPrime.
Keywords: anisotropies, Pierre Auger Observatory, ultra-high energy cosmic-rays, arrival directions
Published in RUNG: 22.01.2024; Views: 334; Downloads: 5
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42. Depth of maximum of air-shower profiles : testing the compatibility of the measurements at the Pierre Auger Observatory and the Telescope ArrayA. Abdul Halim, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, published scientific conference contribution Abstract: The Pierre Auger Observatory (Auger) and the Telescope Array (TA), located, respectively, in the Southern and Northern hemispheres, are the largest ultra-high-energy cosmic ray (UHECR) observatories. The Auger and TA Collaborations have collected unprecedented statistics providing us with a unique opportunity to search for the differences between the UHECR energy spectra and mass compositions in the complementary sky regions. To correctly attribute such differences to
the properties of the UHECR sources or propagation, the systematic effects in the measurements of each observatory should be considered properly. In this context, the task of the Auger – TA mass composition working group is to identify possible differences of astrophysical origin in the measurements of the depth of the maximum of air-shower profiles, X_max, performed at both observatories using the fluorescence technique. Due to distinct approaches to event selection and analysis atAuger and TA, theworking group uses a specially designed method to transfer the Auger X_max distributions into the TA detector. To this end, dedicated air-shower and detector simulations for the TA Black Rock Mesa and Long Ridge fluorescence detector stations were performed with the Sibyll 2.3d hadronic interaction model. From the comparison of the first two moments and the shapes of X_max distributions for energies above 10^18.2 eV, no significant differences between the Auger and TA measurements were found.
Keywords: Pierre Auger Observatory, Telescope Array, ultra-high energy cosmic rays, fluorescence detectors
Published in RUNG: 22.01.2024; Views: 388; Downloads: 5
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43. Constraining models for the origin of ultra-high-energy cosmic rays with a novel combined analysis of arrival directions, spectrum, and composition data measured at the Pierre Auger ObservatoryA. Abdul Halim, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2024, original scientific article Abstract: The combined fit of the measured energy spectrum and shower maximum depth
distributions of ultra-high-energy cosmic rays is known to constrain the parameters of
astrophysical models with homogeneous source distributions. Studies of the distribution of
the cosmic-ray arrival directions show a better agreement with models in which a fraction of
the flux is non-isotropic and associated with the nearby radio galaxy Centaurus A or with
catalogs such as that of starburst galaxies. Here, we present a novel combination of both
analyses by a simultaneous fit of arrival directions, energy spectrum, and composition data
measured at the Pierre Auger Observatory. The model takes into account a rigidity-dependent magnetic field blurring and an energy-dependent evolution of the catalog contribution shaped by interactions during propagation.
We find that a model containing a flux contribution from the starburst galaxy catalog
of around 20% at 40 EeV with a magnetic field blurring of around 20◦ for a rigidity of
10EV provides a fair simultaneous description of all three observables. The starburst galaxy
model is favored with a significance of 4.5σ (considering experimental systematic effects)
compared to a reference model with only homogeneously distributed background sources.
By investigating a scenario with Centaurus A as a single source in combination with the
homogeneous background, we confirm that this region of the sky provides the dominant
contribution to the observed anisotropy signal. Models containing a catalog of jetted active
galactic nuclei whose flux scales with the γ-ray emission are, however, disfavored as they
cannot adequately describe the measured arrival directions.
Keywords: ultra high energy cosmic rays, cosmic ray experiments, Pierre Auger Observatory, active galactic nuclei
Published in RUNG: 19.01.2024; Views: 391; Downloads: 7
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45. The Cherenkov Telescope ArrayDaniel Mazin, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Abstract: The Cherenkov Telescope Array (CTA) is the next generation ground-based observatory
for gamma-ray astronomy at very-high energies. It will be capable of detecting gamma rays in the energy range from 20 GeV to more than 300 TeV with unprecedented precision in energy and directional reconstruction. With more than 100 telescopes of three different types it will be located in the northern hemisphere at La Palma, Spain, and in the southern
at Paranal, Chile. CTA will be one of the largest astronomical infrastructures in the world with open data access and it will address questions in astronomy, astrophysics and fundamental physics in the next decades. In this presentation we will focus on the status
of the CTA construction, the status of the telescope prototypes and highlight some of the physics perspectives.
Keywords: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array, CTA sensitivity, gamma-ray bursts, POpulation Synthesis Theory Integrated project for very high-energy emission
Published in RUNG: 04.12.2023; Views: 513; Downloads: 3
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46. POSyTIVE : a GRB population study for the Cherenkov Telescope ArrayMaria Grazia Bernardini, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Abstract: One of the central scientific goals of the next-generation Cherenkov Telescope Array
(CTA) is the detection and characterization of gamma-ray bursts (GRBs). CTA will be sensitive to gamma rays with energies from about 20 GeV, up to a few hundred TeV.
The energy range below 1 TeV is particularly important for GRBs. CTA will allow exploration of this regime with a ground-based gamma-ray facility with unprecedented sensitivity.
As such, it will be able to probe radiation and particle acceleration mechanisms at work in GRBs. In this contribution, we describe POSyTIVE, the POpulation Synthesis Theory Integrated project for very high-energy emission. The purpose of the project is to make realistic predictions for the detection rates of GRBs with CTA, to enable studies
of individual simulated GRBs, and to perform preparatory studies for time-resolved
spectral analyses. The mock GRB population used by POSyTIVE is calibrated using the entire 40-year dataset of multi-wavelength GRB observations. As part of this project we explore theoretical models for prompt and afterglow emission of long and short GRBs,
and predict the expected radiative output. Subsequent analyses are performed
in order to simulate the observations with CTA, using the publicly available ctools and Gammapy frameworks. We present preliminary results of the design and implementation
of this project.
Keywords: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array, CTA sensitivity, gamma-ray bursts, population Synthesis Theory, very high-energy emission
Published in RUNG: 04.12.2023; Views: 677; Downloads: 1
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47. Cherenkov Telescope Array Science : a multi-wavelength and multi-messenger perspectiveUlisses Barres de Almeida, Christopher Eckner, Gašper Kukec Mezek, Samo Stanič, Serguei Vorobiov, Lili Yang, Gabrijela Zaharijas, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2019, published scientific conference contribution Abstract: The Cherenkov Telescope Array (CTA) will be the major global observatory for
VHE gamma-ray astronomy over the next decade and beyond. It will be an explorer
of the extreme universe, with a broad scientific potential: from understanding the role of relativistic cosmic particles, to the search for dark matter. Covering photon energies from 20 GeV to 300 TeV, and with an angular resolution unique in the field, of about 1 arc min, CTA will improve on all aspects of the performance with respect to current instruments, surveying the high energy sky hundreds of times faster than previous TeV telescopes,
and with a much deeper view. The very large collection area of CTA makes it an important probe of transient phenomena. The first CTA telescope has just been inaugurated in the Canary Islands, Spain, and as more telescopes are added in the coming years, scientific operation will start. It is evident that CTA will have important synergies with many of the
new generation astronomical and astroparticle observatories. In this talk we will review
the CTA science case from the point of view of its synergies with other instruments and
facilities, highlighting the CTA needs in terms of external data, as well as the opportunities and strategies for cooperation to achieve the basic CTA science goals.
Keywords: very-high-energy gamma-ray astronomy, Cherenkov Telescope Array, CTA performances, transient VHE sources, CTA science
Published in RUNG: 04.12.2023; Views: 616; Downloads: 4
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48. Defining worst-performing buildings in Slovenia based on EPCsMarjana Šijanec-Zavrl, Henrik Gjerkeš, 2023, published scientific conference contribution Abstract: The 2021 EC proposal for EPBD recast planned inter alia the harmonization of energy performance certificates (EPCs) across EU and definition of minimum energy performance (MEP) standards to support the renovation of worst-performing buildings. Rescaling of EPCs to a common EU ranking and consequently setting MEP standards is a task for the near future, but current planning of building renovation to meet decarbonization by 2050 may only relay on data in Slovenian EPCs from 2013-2022 data base. The paper presents the analysis of energy related indicators in existing Slovenian EPCs in order to demonstrate that existing EPCs issued in last decade can be used to define 15% of worst-performing buildings prioritized for deep and NZEB renovation, if combined with other indicators, like heat demand.
Keywords: energy performance indicators, decarbonization, energy efficiency, building renovation
Published in RUNG: 27.11.2023; Views: 495; Downloads: 4
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49. Search for evidence of neutron fluxes using Pierre Auger Observatory dataDanelise De Oliveira Franco, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, published scientific conference contribution Abstract: 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.
Keywords: neutrons, cosmic ray, Pierre Auger Observatory, Crab Nebula, proton, high-energy neutron flux
Published in RUNG: 14.11.2023; Views: 584; Downloads: 5
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50. Implementation of the EPBD in Slovenia – Status in 2020Marjana Šijanec Zavrl, Miha Tomšič, Henrik Gjerkeš, Erik Potočar, 2021, final research report Abstract: The Concerted Action EPBD (CA EPBD) addresses the Energy Performance of Buildings Directive (EPBD). It aims to contribute to the reduction of energy use in European buildings, through the exchange of knowledge and best practices in the field of energy efficiency and energy savings between all 28 EU Member States plus Norway.
The CA EPBD is a joint initiative between the EU Member States and the European Commission. It involves representatives of national ministries or their affiliated institutions who are in charge of preparing the technical, legal and administrative framework for the Energy Performance of Buildings Directive in each EU Member State, plus Norway. The objective is to enhance the sharing of information and experiences from national adoption and implementation of this important European legislation.
The transposition of the EPBD in Slovenia is the overall responsibility of the Ministry of Infrastructure and was primarily transposed by the Energy Act (EZ-1), covering the topics of NZEB, energy performance certification, inspection of heating and AC systems and energy efficiency information programmes. The Act on Energy Efficiency (ZURE) integrates the EZ-1 articles related to the EPBD.
The revision of the building codes (PURES) is still in progress and planned for publication in late 2021. It will contain detailed technical requirements for NZEB based on the technical definition given in the national NZEB action plan, and the revision of the calculation methodology according to a new set of CEN EPBD standards.
Important recent steps in EPBD implementation are the application of the central national electronic register of EPCs and associated software, the independent control system for EPCs, first steps in the cross-linking of e-registries for EPCs, inspections and public buildings, as well as wide information activities implemented by the Eco Fund concerning financial instruments available for the energy renovation of buildings.
Keywords: Concerted Action, Energy Performance of Buildings Directive, Act on Energy Efficiency, Slovenia
Published in RUNG: 02.11.2023; Views: 565; Downloads: 8
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