1. Multimessenger studies with the Pierre Auger ObservatoryJon Paul Lundquist, Andrej Filipčič, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2025, published scientific conference contribution Abstract: 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.
Keywords: high-energy particle physics, astrophysics, ultra-high energy cosmic rays, neutrinos, gravitional waves
Published in RUNG: 22.04.2025; Views: 300; Downloads: 0
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2. Orography‐induced atmospheric small‐scale waves during Bora using lidar observations and numerical simulationsLonglong Wang, Marija Bervida, Samo Stanič, Luca Patruno, Wenjun Dong, Daru Chen, 2025, original scientific article Abstract: Atmospheric flow of cold air over mountain barriers in the Alpine region often gives a rise to
strong and gusty downslope wind, Bora. Such flows are often accompanied by atmospheric waves, generated by
the flow passing an elevated barrier. Such phenomenon can only rarely be observed visually and can generally
not be reliably reproduced by simplified numerical models. Orography‐induced atmospheric small‐scale waves
were experimentally observed on 25 January 2019 during a Bora outbreak in the Vipava valley, Slovenia. A
vertical scanning lidar, positioned at the lee side of the Trnovski gozd mountain and a fixed direction lidar, 5 km
apart in the Vipava valley, were used to characterize the density field. The flow exhibited a stationary jump after
the mountain ridge and, superimposed, an oscillatory flow pattern. High‐resolution numerical simulations
complemented the observations and supported experimental results on the flow periodicity but also on the wave
structures and propagation characteristics.
Keywords: Bora, wind, lidar, numerical simulation, Vipava valley, atmospheric waves
Published in RUNG: 18.02.2025; Views: 617; Downloads: 6
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3. Multi-messenger and transient astrophysics with the Cherenkov Telescope ArrayŽ. Bošnjak, Anthony M. Brown, Alessandro Carosi, M. Chernyakova, Pierre Cristofari, F. Longo, A. López Oramas, M. Santander, Serguei Vorobiov, Danilo Zavrtanik, 2021, other component parts Abstract: The discovery of gravitational waves, high-energy neutrinos or the very-high-energy counterpart of gamma-ray bursts has revolutionized the high-energy and transient astrophysics community. The development of new instruments and analysis techniques will allow the discovery and/or follow-up of new transient sources. We describe the prospects for the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory, for multi-messenger and transient astrophysics in the decade ahead. CTA will explore the most extreme environments via very-high-energy observations of compact objects, stellar collapse events, mergers and cosmic-ray accelerators.
Keywords: multi-messenger astrophysics, gravitational waves, very-high-energy (VHE) gamma rays, cosmic rays, VHE neutrinos, transient astrophysical phenomena, Cherenkov Telescope Array Observatory
Published in RUNG: 13.01.2025; Views: 671; Downloads: 7
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4. The gravitational wave follow-up program of the Cherenkov Telescope ArrayMonica Seglar-Arroyo, 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 birth of gravitational-wave / electromagnetic astronomy was heralded by the joint observation of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo, GW170817, and of gamma-rays from the short gamma-ray burst GRB170817A by the Fermi Gamma-ray Burst Monitor (GBM) and INTEGRAL. This detection provided the first direct evidence that at least a fraction of BNSs are progenitors of short GRBs. GRBs are now also known to emit very-high-energy (VHE, > 100 GeV) photons as has been shown by recent independent detections of the GRBs 1901114C and 180720B by the ground-based gamma-ray detectors MAGIC and H.E.S.S. In the next years, the Cherenkov Telescope Array (CTA) will boost the searches for VHE counterparts thanks to its unprecedented sensitivity, rapid response and
capability to monitor large sky areas via survey-mode operation. In this contribution, we present the CTA program of observations following the detection of GW events. We discuss various follow-up strategies and links to multi-wavelength and multi-messenger observations. Finally we outline the capabilities and prospects of detecting VHE emission from GW counterparts.
Keywords: multi-messenger astrophysics, the Cherenkov Telescope Array (CTA) Observatory, gravitational waves, very-high-energy photons, gravitational-wave follow-up program
Published in RUNG: 08.11.2024; Views: 890; Downloads: 5
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5. A gamma-ray pulsar timing array constrains the nanohertz gravitational wave backgroundM. Ajello, W. B. Atwood, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, R. Bellazzini, A. Berretta, B. Bhattacharyya, Gabrijela Zaharijas, 2022, original scientific article Keywords: pulsar timing array, gravitational waves
Published in RUNG: 15.01.2024; Views: 1946; Downloads: 0
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6. Follow-up Search for UHE Photons from Gravitational Wave Sources with the Pierre Auger ObservatoryP. Ruehl, Andrej Filipčič, Jon Paul Lundquist, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Lukas Zehrer, 2022, published scientific conference contribution Abstract: Multimessenger astronomy has become increasingly important during the past decade. Some astronomical objects have already been successfully observed in the light of multiple messenger signals, allowing for a much deeper understanding of their physical properties. The Pierre Auger Observatory has taken part in multimessenger astronomy with an exhaustive exploration of the ultra-high-energy sky. In this contribution, for the first time, a search for UHE photons from the sources of gravitational waves is presented. Interactions with the cosmic background radiation fields are expected to attenuate any possible flux of ultra-high-energy photons from distant sources and a non-negligible background of air shower events with hadronic origin makes an unambiguous identification of primary photons a challenging task. In the analysis presented here, a selection strategy is applied to both GW sources and air shower events aiming to provide maximum sensitivity to a possible photon signal. At the same time, a window is kept open for hypothetical new-physics processes, which might allow for much larger interaction lengths of photons in the extragalactic medium. Preliminary results on the UHE photon fluence from a selection of GW sources, including the binary neutron star merger GW170817 are presented.
Keywords: Pierre Auger Observatory, indirect detection, fluorescence detection, ultra-high energy, photons, cosmic rays, anisotropy, gravitational waves, multimessenger
Published in RUNG: 29.09.2023; Views: 2156; Downloads: 7
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7. Searching for very-high-energy electromagnetic counterparts to gravitational-wave events with the Cherenkov Telescope ArrayBarbara Patricelli, Saptashwa Bhattacharyya, Barbara MARČUN, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Gabrijela Zaharijas, Marko Zavrtanik, Danilo Zavrtanik, Miha Živec, 2021, published scientific conference contribution Abstract: The detection of electromagnetic (EM) emission following the gravitational wave (GW) event GW170817 opened the era of multi-messenger astronomy with GWs and provided the first direct evidence that at least a fraction of binary neutron star (BNS) mergers are progenitors of short Gamma-Ray Bursts (GRBs). GRBs are also expected to emit very-high energy (VHE, > 100 GeV) photons, as proven by the recent MAGIC and H.E.S.S. observations. One of the challenges for future multi-messenger observations will be the detection of such VHE emission from GRBs in association with GWs. In the next years, the Cherenkov Telescope Array (CTA) will be a key instrument for the EM follow-up of GW events in the VHE range, owing to its unprecedented sensitivity, rapid response, and capability to monitor a large sky area via scan-mode operation. We present the CTA GW follow-up program, with a focus on the searches for short GRBs possibly associated with BNS mergers. We investigate the possible observational strategies and we outline the prospects for the detection of VHE EM counterparts to transient GW events.
Keywords: Cherenkov Telescope Array, very-high energy photons, gravitational waves, gravitational wave counterparts
Published in RUNG: 19.09.2023; Views: 3034; Downloads: 7
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8. Chasing gravitational waves with the Cherenkov Telescope ArrayJ. G. Green, Saptashwa Bhattacharyya, Judit Pérez Romero, Samo Stanič, Veronika Vodeb, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, Miha Živec, 2023, published scientific conference contribution Abstract: The detection of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced
LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts
of this GW event, ushered in a new era of multimessenger astronomy, providing the first
direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events
may also produce very-high-energy (VHE, > 100 GeV) photons which have yet to be detected
in coincidence with a GW signal. The Cherenkov Telescope Array (CTA) is a next-generation
VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity
and ability to slew anywhere on the sky within a few tens of seconds. Achieving such a feat
will require a comprehensive real-time strategy capable of coordinating searches over potentially
very large regions of the sky. This work will evaluate and provide estimations on the number of
GW-CTA events determined from simulated BNS systems and short GRBs, considering both on and
off-axis emission. In addition, we will present and discuss the prospects of potential follow-up
strategies with CTA.
Keywords: gravitational waves, binary neutron star merger, short gamma-ray bursts
Published in RUNG: 15.09.2023; Views: 2503; Downloads: 13
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9. Business-information system for smart homes based on Z-Wave technology : diploma thesisDavid Manchevski, 2021, undergraduate thesis Abstract: The goal of this thesis is to show how to create a system, that can be implemented in today’s market of smart home modules.
This will be done by introducing how the Z-Wave technology works, how it can be implemented in the user’s home. Furthermore, the functionalities of the Z-Wave technology will be presented together with the Z-Wave modules and their everyday uses. In addition, the business-information system can put on display how a smart home company operates, how the data is distributed between the departments of said smart home company. The business-information system is shown with the help of a data flow diagrams, entity relationship diagrams and a database of the data that is stored inside the particular database. This system will be used by a user interested in the buying the smart home technology products, partners, Z-wave certifiers, reclamation department.
Keywords: Z-Waves, smart homes, business-information systems, entity-relationship, processes, data flows, data stores, modules, diploma thesis
Published in RUNG: 24.01.2022; Views: 3840; Downloads: 94
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10. Gravity wave instability structures and turbulence from more than 1.5 years of OH[ast] airglow imager observations in SloveniaRené Sedlak, Patrick Hannawald, Carsten Schmidt, Sabine Wüst, Michael Bittner, Samo Stanič, 2021, original scientific article Abstract: We analyzed 286 nights of data from the OH* airglow imager FAIM 3 (Fast Airglow IMager) acquired at Otlica Observatory, Slovenia, between 26 October 2017 and 6 June 2019. Measurements were performed with a spatial resolution of 24 m per pixel and a temporal resolution of 2.8 s. Multiple turbulence episodes were observed and the energy dissipation rate in the upper mesosphere/lower thermosphere region was estimated from image sequences in 25 cases. Values range around 0.08 and 9.03 W/kg and would lead to an approximated localized maximum heating of 0.03–3.02 K per turbulence event.
Keywords: upper mesosphere, lower thermosphere, remote sensing, gravity waves, turbulence, Bora episodes
Published in RUNG: 25.10.2021; Views: 3160; Downloads: 0
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