Repozitorij Univerze v Novi Gorici

Iskanje po repozitoriju
A+ | A- | Pomoč | SLO | ENG

Iskalni niz: išči po
išči po
išči po
išči po
* po starem in bolonjskem študiju

Opcije:
  Ponastavi


11 - 20 / 468
Na začetekNa prejšnjo stran12345678910Na naslednjo stranNa konec
11.
Investigating the UHECR characteristics from cosmogenic neutrino limits with the measurements of the Pierre Auger Observatory
Camilla Petrucci, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: Cosmogenic neutrinos are expected to originate in the extragalactic propagation of ultra-highenergy cosmic rays (UHECRs), as a result of their interactions with background photons. Due to these reactions, the visible Universe in UHECRs is more limited than in neutrinos, which instead could reach us without interacting after traveling cosmological distances. In this contribution, we exploit a multimessenger approach by computing the expected energy spectrum and mass composition of UHECRs at Earth corresponding to combinations of spectral parameters and mass composition at their sources, as well as parameters related to the UHECR source distribution, and by determining, at the same time, the associated cosmogenic neutrino fluxes. By comparing the expected UHECR observables to the energy spectrum and mass composition measured at the Pierre Auger Observatory above 10^17.8 eV and the expected neutrino fluxes to the most updated neutrino limits, we show the dependence of the neutrino fluxes on the characteristics of the the properties of the potential sources of UHECRs, such as their cosmological evolution and maximum redshift. In addition, the fraction of protons compatible with the data is also investigated in terms of expected neutrino fluxes.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays
Objavljeno v RUNG: 24.01.2024; Ogledov: 788; Prenosov: 4
.pdf Celotno besedilo (647,90 KB)
Gradivo ima več datotek! Več...

12.
International Masterclasses as part of the Pierre Auger Observatory program of Outreach and Education
R. Sarmento, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The Pierre Auger Observatory is committed to bringing education and knowledge of cosmic rays to the public, with a strong focus on schools and students. Over the last few years, initiatives have been developed, such as the Science Fair, virtual visits, and participation in international activities on the subject of cosmic rays, including collaborations with external groups. Modern digital tools bringing novel ways of interacting with the public have been explored at these initiatives and also locally at a renewed Visitor Center in Malargüe. The development of tools for the public release of the Auger data, including standardized data formats, analysis notebooks, and a 3D interactive event display, led to the creation of a new activity directed to high-school students called Masterclasses. The participants are challenged to perform the reconstruction and selection of events using a graphical interface with 3D effects, then combined into a smoothed, exposure-corrected sky map of arrival directions. A final discussion takes place in which the students engage with peers and scientists, looking for answers about the origin of ultra-high-energy cosmic rays. The concept had a successful debut in 2022 and was included in the 2023 edition of the International Masterclasses on Particle Physics, reaching students worldwide.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays
Objavljeno v RUNG: 24.01.2024; Ogledov: 941; Prenosov: 5
.pdf Celotno besedilo (12,06 MB)
Gradivo ima več datotek! Več...

13.
Portals to data of the Pierre Auger Observatory
P. L. Ghia, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The Pierre Auger Collaboration has embraced the concept of open access to their data from its foundation. As early as 2007, when the Observatory was almost complete, a portal to 1% of the data from the surface detector was created and updated every year for over ten years. Meant for educational purposes, the portal was the first step towards making data public by the FAIR (Findable, Accessible, Interoperable, and Reusable) principles. A new portal was opened in February 2021, at the end of the first phase of operation. Presented for the first time at the ICRC 2021, it includes not only 10% of the data–raw and processed–from the different instruments of the Observatory, but also a visualisation tool, documentation to make the data user-friendly, and analyses codes that can be readily used and modified. Since 2021, the portal has been updated three times: new data, documentation, and codes have been added. Moreover, the portal has become dual, with one part dedicated to scientists and the other to educational users. Furthermore, a catalog containing details of the 100 highest-energy cosmic rays has been included. At this conference we will discuss these new features, as well as our intentions for the future. We will also share our approach and methods for making data public and understandable to external users, from simplifying the data structure to translating codes from in-house computing architecture into popular available software.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, portals to data
Objavljeno v RUNG: 24.01.2024; Ogledov: 831; Prenosov: 6
.pdf Celotno besedilo (2,23 MB)
Gradivo ima več datotek! Več...

14.
Constraints on upward-going air showers using the Pierre Auger Observatory data
Emanuele De Vito, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The fluorescence detector (FD) of the Pierre Auger Observatory is sensitive to upward-going air showers with energies above 1017 eV. Given its operation time and wide field of view, the FD has the potential to support or constrain the “anomalous” observations by the ANITA detector, interpreted as upward-going air showers that would be indicative of Beyond Standard Model (BSM) physics. To this end, a search for upward-going air showers with the FD has been performed applying selection criteria that were optimized using 10% of FD data. Dedicated background simulations (downward-going events) have been performed to estimate our capability to distinguish candidates from false positives. Also dedicated signal simulations (upward-going events) have been used to estimate our sensitivity to such showers with a focus on the energy region close to the ANITA observations. Improved and updated results of the Pierre Auger Observatory exposure to upward-going showers will be presented after the unblinding of 14 years of FD data. Extensive simulations allow the FD exposure to be obtained at lower energies which are particularly relevant for the comparison with the ANITA results. A refinement of the method for signal discrimination and background rejection has also been applied. The implications are discussed under the assumption that the ANITA events were due to upward-going events.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, air showers, beyond standard model, fluorescence detectors, ANITA
Objavljeno v RUNG: 23.01.2024; Ogledov: 706; Prenosov: 6
.pdf Celotno besedilo (2,95 MB)
Gradivo ima več datotek! Več...

15.
Possible interpretations of the joint observations of UHECR arrival directions using data recorded at the Telescope Array and the Pierre Auger Observatory
Mikhail Kuznetsov, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: Various hints for anisotropies in the distribution of arrival directions of ultra-high-energy cosmic rays (UHECRs) have been reported. Still, our poor knowledge about extragalactic and Galactic magnetic fields and about the UHECR mass composition makes it non-trivial to interpret such results in terms of possible models of UHECR sources. In this work, we apply the same analyses that have been performed on the Pierre Auger Observatory and the Telescope Array UHECR data to a variety of Monte Carlo simulations generated according to many different combinations of hypotheses about the sources, composition and magnetic deflections of UHECRs. We find that only some of these models can yield results similar to those obtained with the real data.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, anisotropy, galactic magnetic fields, telescope array, arrival directions
Objavljeno v RUNG: 23.01.2024; Ogledov: 738; Prenosov: 6
.pdf Celotno besedilo (1,30 MB)
Gradivo ima več datotek! Več...

16.
Update on the searches for anisotropies in UHECR arrival directions with the Pierre Auger Observatory and the Telescope Array
Lorenzo Caccianiga, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The origin of ultra-high-energy cosmic rays (UHECRs), particles from outer space with energies �≥1 EeV, is still unknown, though the near-isotropy of their arrival direction distribution excludes a dominant Galactic contribution, and interactions with background photons prevent them from travelling cosmologically large distances. This suggests that their sources must be searched for in nearby galaxy groups and clusters. Deflections by intergalactic and Galactic magnetic fields are expected to hinder such searches but not preclude them altogether. So far, the only anisotropy detected with statistical significance ≥ 5� is a modulation in right ascension in the data from the Pierre Auger Observatory at �≥8 EeV interpretable as a 7% dipole moment. Various hints for higher-energy, smaller-scale anisotropies have been reported. UHECR arrival direction data from both the Pierre Auger Observatory and the Telescope Array experiment have been searched for anisotropies by a working group with members from both collaborations; combining the two datasets requires a cross-calibration procedure due to the different systematic uncertainties on energy measurements but allows us to perform analyses that are less model-dependent than what can be done with partial sky coverage. We report a significant dipole pointing away from the Galactic Center and a ∼4.6� anisotropy found when comparing the directions of UHECRs with a catalog of starburst galaxies.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, anisotropy, galactic magnetic fields, telescope array, arrival directions
Objavljeno v RUNG: 23.01.2024; Ogledov: 717; Prenosov: 5
.pdf Celotno besedilo (4,36 MB)
Gradivo ima več datotek! Več...

17.
Study of downward Terrestrial Gamma-ray Flashes with the surface detector of the Pierre Auger Observatory
Roberta Colalillo, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The surface detector (SD) of the Pierre Auger Observatory, consisting of 1660 water-Cherenkov detectors (WCDs), covers 3000 km2 in the Argentinian pampa. Thanks to the high efficiency of WCDs in detecting gammarays, it represents a unique instrument for studying downward Terrestrial Gamma-ray Flashes (TGFs) over a large area. Peculiar events, likely related to downward TGFs, were detected at the Auger Observatory. Their experimental signature and time evolution are very different from those of a shower produced by an ultrahigh-energy cosmic ray. They happen in coincidence with low thunderclouds and lightning, and their large deposited energy at the ground is compatible with that of a standard downward TGF with the source a few kilometers above the ground. A new trigger algorithm to increase the TGF-like event statistics was installed in the whole array. The study of the performance of the new trigger system during the lightning season is ongoing and will provide a handle to develop improved algorithms to implement in the Auger upgraded electronic boards. The available data sample, even if small, can give important clues about the TGF production models, in particular, the shape of WCD signals. Moreover, the SD allows us to observe more than one point in the TGF beam, providing information on the emission angle.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, surface detectors, extensive air shower, terrestrial gamma-ray flashes
Objavljeno v RUNG: 23.01.2024; Ogledov: 728; Prenosov: 6
.pdf Celotno besedilo (1,04 MB)
Gradivo ima več datotek! Več...

18.
Measurement of UHECR energy spectrum with the Pierre Auger Observatory and the Telescope Array
Douglas R. Bergman, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The measurement of the energy spectrum of ultra-high-energy cosmic rays (UHECRs) is of crucial importance to clarify their origin, acceleration mechanisms, and propagation processes in inter-Galactic and Galactic space. The Pierre Auger Observatory in Argentina and the Telescope Array (TA) in the US have reported their measurements of UHECR energy spectra observed in the southern and northern hemisphere, respectively. The Auger–TA energy spectrum working group was established in 2012 and has been working to understand the uncertainties in energy scale in both experiments, their systematic differences, and differences in the shape of the spectra. In previous works, we reported that there was an overall agreement of the energy spectra measured by the two observatories below 10 EeV while at higher energies, a remaining significant difference was observed in the common declination band. This time we revisit the energy scales of both experiments, including the fluorescence yield and the invisible energy corrections. Another new approach to investigate a possible source of energy systematic difference is to reconstruct simulated showers of common energy and zenith angle using the detector simulation and reconstruction programs of both experiments that are independently tuned and optimized for data from their own detectors. The results will be presented at the conference.
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, Telescope Array, energy spectrum
Objavljeno v RUNG: 23.01.2024; Ogledov: 820; Prenosov: 5
.pdf Celotno besedilo (731,82 KB)
Gradivo ima več datotek! Več...

19.
Studies of the mass composition of cosmic rays and proton-proton interaction cross-sections at ultra-high energies with the Pierre Auger Observatory
Olena 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: 783; Prenosov: 5
.pdf Celotno besedilo (917,40 KB)
Gradivo ima več datotek! Več...

20.
The second knee in the cosmic ray spectrum observed with the surface detector of the Pierre Auger Observatory
Gabriel Brichetto Orquera, Andrej Filipčič, Jon Paul Lundquist, Shima Ujjani Shivashankara, Samo Stanič, Serguei Vorobiov, Danilo Zavrtanik, Marko Zavrtanik, 2023, objavljeni znanstveni prispevek na konferenci

Opis: The determination of the energy spectrum features with low systematic uncertainty is crucial for interpreting the nature of cosmic rays. In this study, we conducted a measurement of the energy spectrum at the Pierre Auger Observatory using a surface detector with a calorimetric energy scale indirectly set by a fluorescence detector. The surface detector consists of an array of water-Cherenkov detectors that extends over 3000 km^2 with 1500m spacing. Additionally, two nested arrays of the same kind with 750m and 433m spacing were utilized to lower the energy threshold of the measurements. This contribution presents, for the first time, the spectrum measured with the 433m array, which reduces the energy threshold down to 63 PeV, nearly half the energy at which we previously published a steepening using the 750m array. Our measurements include a characterization of the spectral features of the flux steepening around 230 PeV, known as the second-knee. The study benefits from a nearly 100% duty cycle and geometrical exposure. Notably, this is the first simultaneous measurement of the second knee energy and spectral indexes before and after the break, using a surface detector with an energy scale predominantly independent of air shower simulations and assumptions regarding hadronic interaction models.
Ključne besede: ultra-high energy cosmic rays, Pierre Auger Observatory, hadronic interaction model, water-Cherenkov detectors
Objavljeno v RUNG: 23.01.2024; Ogledov: 721; Prenosov: 4
.pdf Celotno besedilo (1,48 MB)
Gradivo ima več datotek! Več...

Iskanje izvedeno v 0.07 sek.
Na vrh