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 / 145
Na začetekNa prejšnjo stran12345678910Na naslednjo stranNa konec
11.
Combined fit of spectrum and composition data as measured by the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Andrea Di Matteo, 2015, objavljeni znanstveni prispevek na konferenci

Opis: We present a combined fit of both flux and composition of ultra-high energy cosmic rays as measured by the Pierre Auger Observatory. The fit has been performed for energies above 5 × 10[sup]18 eV, i.e. the region of the all-particle spectrum above the so-called “ankle” feature. A simple astrophysical model consisting of identical sources has been adopted, where nuclei are injected with a rigidity dependent mechanism and the sources are uniformly distributed in a comoving volume. The fit results suggest a source model characterized by relatively low maximum injection energies and hard spectral indices. The impact of different sources of systematic uncertainties in the above result is discussed.
Najdeno v: ključnih besedah
Povzetek najdenega: ...both flux and composition of ultra-high energy cosmic rays as measured by the Pierre Auger...
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, energy spectrum, elemental composition, combined data fit
Objavljeno: 03.03.2016; Ogledov: 1974; Prenosov: 164
.pdf Polno besedilo (704,98 KB)

12.
Solar Cycle Modulation of Cosmic Rays Observed with the Low Energy Modes of the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Jimmy Masías-Meza, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The low energy modes of the surface detector array of the Pierre Auger Observatory record variations in the flux of low energy secondary particles with extreme detail. These two modes consist of recording (1) the rate of signals for energies between ∼15 MeV and ∼100 MeV (the Scaler mode) and (2) the calibration charge histograms of the individual pulses detected by each water-Cherenkov station, covering different energy channels up to ∼1 GeV (the Histogram mode). Previous work has studied the flux of galactic cosmic rays on short and intermediate time scales (i.e. from minutes to weeks) using these low energy modes. In this work, after including a long- term correction to the response of the detectors, we present the first long-term analysis of the flux of cosmic rays using scalers and two energy bands of the calibration histograms. We show its sensitivity to the solar cycle variation and its relation to the solar modulation of cosmic rays for an 8-year period.
Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, Surface Detector, secondary cosmic rays, scaler mode, charge histogram mode, solar cycle modulation
Objavljeno: 03.03.2016; Ogledov: 2144; Prenosov: 132
.pdf Polno besedilo (533,18 KB)

13.
Upgrade of the Pierre Auger Observatory (AugerPrime)
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Ralph Engel, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The data collected with the Pierre Auger Observatory have led to a number of surprising discoveries. While a strong suppression of the particle flux at the highest energies has been established unambiguously, the dominant physics processes related to this suppression could not be identified. Within the energy range covered by fluorescence detector observations with sufficient statistics, an unexpected change of the depth of maximum distribution is found. Using LHC-tuned interaction models these observations can be understood as a correlated change of the fluxes of different mass groups. On the other hand, they could also indicate a change of hadronic interactions above the energy of the ankle. Complementing the water Cherenkov detectors of the surface array with scintillator detectors will, mainly through the determination of the muonic shower component, extend the composition sensitivity of the Auger Observatory into the flux suppression region. The upgrade of the Auger Observatory will allow us to estimate the primary mass of the highest energy cosmic rays on a shower-by-shower basis. In addition to measuring the mass composition the upgrade will open the possibility to search for light primaries at the highest energies, to perform composition-selected anisotropy studies, and to search for new phenomena including unexpected changes of hadronic interactions. After introducing the physics motivation for upgrading the Auger Observatory the planned detector upgrade is presented. In the second part of the contribution the expected performance and improved physics sensitivity of the upgraded Auger Observatory are discussed.
Najdeno v: ključnih besedah
Povzetek najdenega: ...the primary mass of the highest energy cosmic rays on a shower-by-shower basis. In addition...
Ključne besede: Pierre Auger Observatory, ultra-high energy cosmic rays, elemental composition sensitivity, Auger upgrade (AugerPrime), muonic shower component, scintillator detectors
Objavljeno: 03.03.2016; Ogledov: 1833; Prenosov: 147
.pdf Polno besedilo (659,02 KB)

14.
Measurement of the water-Cherenkov detector response to inclined muons using an RPC hodoscope
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Pedro Assis, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The Pierre Auger Observatory operates a hybrid detector composed of a Fluorescence Detector and a Surface Detector array. Water-Cherenkov detectors (WCD) are the building blocks of the array and as such play a key role in the detection of secondary particles at the ground. A good knowledge of the detector response is of paramount importance to lower systematic uncertainties and thus to increase the capability of the experiment in determining the muon content of the extensive air showers with a higher precision. In this work we report on a detailed study of the detector response to single muons as a function of their trajectories in the WCD. A dedicated Resistive Plate Chambers (RPC) hodoscope was built and installed around one of the detectors. The hodoscope is formed by two stand-alone low gas flux segmented RPC detectors with the test water-Cherenkov detector placed in between. The segmentation of the RPC detectors is of the order of 10 cm. The hodoscope is used to trigger and select single muon events in different geometries. The signal recorded in the water-Cherenkov detector and performance estimators were studied as a function of the trajectories of the muons and compared with a dedicated simulation. An agreement at the percent level was found, showing that the simulation correctly describes the tank response.
Najdeno v: ključnih besedah
Povzetek najdenega: ...Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope...
Ključne besede: Pierre Auger Observatory, Water-Cherenkov detectors, detector calibration, inclined cosmic ray muons, Resistive Plate Chambers (RPC) hodoscope
Objavljeno: 03.03.2016; Ogledov: 2173; Prenosov: 128
.pdf Polno besedilo (1,27 MB)

15.
AugerNext: R&D studies at the Pierre Auger Observatory for a next generation ground-based ultra-high energy cosmic-ray experiment
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Andreas Haungs, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The findings so far of the Pierre Auger Observatory and those of the Telescope Array define some requirements for a possible next generation global cosmic ray observatory: it needs to be considerably increased in size, it needs enhanced sensitivity to composition, and it has to cover the full sky. At the Pierre Auger Observatory, AugerNext aims to conduct some innovative initial research studies on a design of a sophisticated hybrid detector fulfilling these demands. Within a European supported ASPERA/APPEC (Astroparticle Physics European Consortium) project for the years 2011-2014, such R&D studies primarily focused on the following areas: i) consolidation of the detection of cosmic rays using MHz radio antennas; ii) proof- of-principle of cosmic ray microwave detection; iii) test of the large-scale application of new generation photo sensors; iv) generalization of data communication techniques; and v) development of new schemes for muon detection with surface arrays. The AugerNext Consortium consists of 14 principal investigators from 9 countries. This contribution summarizes some achievements of the R&D studies within the AugerNext project.
Najdeno v: ključnih besedah
Ključne besede: ultra-high energy cosmic-ray experiments, Pierre Auger Observatory, Telescope Array, AugerNext research and development study
Objavljeno: 03.03.2016; Ogledov: 2022; Prenosov: 130
.pdf Polno besedilo (594,23 KB)

16.
Education, Outreach and Public Relations of the Pierre Auger Observatory
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Charles Timmermans, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The scale and scope of the physics studied at the Pierre Auger Observatory continue to offer significant opportunities for original outreach work. Education, outreach and public relations of the Auger Collaboration are coordinated in a dedicated task whose goals are to encourage and support a wide range of efforts that link schools and the public with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. We focus on the impact of the Collaboration in Mendoza Province, Argentina and beyond. The Auger Visitor Center in Malargüe has hosted over 95,000 visitors since 2001, and a fifth Collaboration-sponsored science fair was held on the Observatory campus in November 2014. The Rural Schools Program, which is run by Observatory staff and which brings cosmic-ray science and infrastructure improvements to remote schools, continues to broaden its reach. Numerous online resources, video documentaries, and animations of extensive air showers have been created for wide public release. Increasingly, collaborators draw on these resources to develop Auger related displays and outreach events at their institutions and in public settings to disseminate the science and successes of the Observatory worldwide. We also highlight education and outreach activities associated with the planned upgrade of the Observatory’s detector systems and future physics goals.
Najdeno v: ključnih besedah
Povzetek najdenega: ...with the Auger scientists and the science of cosmic rays, particle physics, and associated technologies. We...
Ključne besede: Pierre Auger Observatory, cosmic rays physics, education, outreach, public relations
Objavljeno: 03.03.2016; Ogledov: 2128; Prenosov: 116
.pdf Polno besedilo (4,12 MB)

17.
Search for a correlation between the UHECRs measured by the Pierre Auger Observatory and the Telescope Array and the neutrino candidate events from IceCube
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Asen Christov, 2015, objavljeni znanstveni prispevek na konferenci

Opis: We have conducted three searches for correlations between ultra-high energy cosmic rays detected by the Telescope Array and the Pierre Auger Observatory, and high-energy neutrino candidate events from IceCube. Two cross-correlation analyses with UHECRs are done: one with 39 cascades from the IceCube ‘high-energy starting events’ sample and the other with 16 high-energy ‘track events’. The angular separation between the arrival directions of neutrinos and UHECRs is scanned over. The same events are also used in a separate search using a maximum likelihood approach, after the neutrino arrival directions are stacked. To estimate the significance we assume UHECR magnetic deflections to be inversely proportional to their energy, with values 3◦, 6◦ and 9◦ at 100 EeV to allow for the uncertainties on the magnetic field strength and UHECR charge. A similar analysis is performed on stacked UHECR arrival directions and the IceCube sample of through-going muon track events which were optimized for neutrino point- source searches.
Najdeno v: ključnih besedah
Povzetek najdenega: ...three searches for correlations between ultra-high energy cosmic rays detected by the Telescope Array and...
Ključne besede: ultra-high energy cosmic rays, Pierre Auger Observatory, Telescope Array, high-energy neutrinos, IceCube, correlation search
Objavljeno: 08.03.2016; Ogledov: 2233; Prenosov: 114
.pdf Polno besedilo (1,11 MB)

18.
Report of the Working Group on the Composition of Ultra-High Energy Cosmic Rays
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Michael Unger, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The atmospheric depth, Xmax, at which the particle number of an air shower reaches its maximum is a good indicator for the mass of the primary particle. We present a comparison of the energy evolution of the mean of Xmax as measured by the Telescope Array and c Collaborations. After accounting for the different resolutions, acceptances and analysis strategies of the two experiments, the two results are found to be in good agreement within systematic uncertainties.
Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, Telescope Array, Ultra-High Energy Cosmic Rays, elemental composition, extensive air showers, the atmospheric depth of the air shower maximum
Objavljeno: 08.03.2016; Ogledov: 2117; Prenosov: 165
.pdf Polno besedilo (329,86 KB)

19.
Large-Scale Distribution of Arrival Directions of Cosmic Rays Detected at the Pierre Auger Observatory and the Telescope Array above 10[sup]19 eV
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Olivier Deligny, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The large-scale distribution of arrival directions of high-energy cosmic rays is a key observable in attempts to understanding their origin. The dipole and quadrupole moments are of special interest in revealing potential anisotropies. An unambiguous measurement of these moments as well as of the full set of spherical harmonic coefficients requires full-sky coverage. This can be achieved by combining data from observatories located in both the northern and southern hemispheres. To this end, a joint analysis using data recorded at the Pierre Auger Observatory and the Telescope Array above 10[sup]19 eV has been performed. Thanks to the full-sky coverage, the measurement of the dipole moment reported in this study does not rely on any assumption on the underlying flux of cosmic rays. As well, the resolution on the quadrupole and higher order moments is the best ever obtained. The resulting multipolar expansion of the flux of cosmic rays allows a series of anisotropy searches to be performed, and in particular to report on the first angular power spectrum of cosmic rays. This allows a comprehensive description of the angular distribution of cosmic rays above 10[sup]19 eV.
Najdeno v: ključnih besedah
Ključne besede: Pierre Auger Observatory, Telescope Array, high-energy cosmic rays, large-scale anisotropies, angular power spectrum
Objavljeno: 08.03.2016; Ogledov: 2004; Prenosov: 121
.pdf Polno besedilo (462,61 KB)

20.
Initial results of a direct comparison between the Surface Detectors of the Pierre Auger Observatory and the Telescope Array
Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, R. Takeishi, 2015, objavljeni znanstveni prispevek na konferenci

Opis: The Pierre Auger Observatory (Auger) in Mendoza, Argentina and the Telescope Array (TA) in Utah, USA aim at unraveling the origin and nature of Ultra-High Energy Cosmic Rays (UHECR). At present, there appear to be subtle differences between Auger and TA results and interpretations. Joint working groups have been established and have already reported preliminary findings. From an experimental standpoint, the Surface Detectors (SD) of both experiments make use of different detection processes not equally sensitive to the components of the extensive air showers making it to the ground. In particular, the muonic component of the shower measured at ground level can be traced back to the primary composition, which is critical for understanding the origin of UHECRs. In order to make direct comparisons between the SD detection techniques used by Auger and TA, a joint SD experimental research program is being developed. In the first phase, two Auger SD stations were deployed at the TA Central Laser Facility to compare station-level responses. This paper concentrates on the results obtained with the first Auger SD station (an “Auger North” design), which has been operating since October 2014. The second Auger SD station, identical to the ones being operated at Auger in Argentina (an “Auger South” design), was just deployed in June 2015. The second phase of this research program will be to co-locate six Auger North SD stations with TA stations in the field to compare event-level responses.
Najdeno v: ključnih besedah
Povzetek najdenega: ...the origin and nature of Ultra-High Energy Cosmic Rays (UHECR). At present, there appear to be...
Ključne besede: Ultra-High Energy Cosmic Rays, Pierre Auger Observatory, Telescope Array, extensive air showers, secondary cosmic rays, muonic shower component, surface detectors
Objavljeno: 08.03.2016; Ogledov: 2032; Prenosov: 120
.pdf Polno besedilo (1,42 MB)

Iskanje izvedeno v 0 sek.
Na vrh