1. The muon component of extensive air showers above 10[sup]17.5 eV measured with the Pierre Auger ObservatoryLukas Zehrer, Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Marta Trini, Samo Stanič, Gašper Kukec Mezek, Andrej Filipčič, Federico Sánchez, 2019, published scientific conference contribution Found in: ključnih besedah
Summary of found: ...ultra-high energy cosmic rays, Pierre Auger Observatory, extensive air showers,...
Keywords: ultra-high energy cosmic rays, Pierre Auger Observatory, extensive air showers, muon shower component
Published: 29.11.2020; Views: 1881; Downloads: 0
 Fulltext (784,63 KB) |
2. The flux of ultra-high energy cosmic rays after ten years of operation of the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Inés Valiño, 2015, published scientific conference contribution Abstract: The flux of ultra-high energy cosmic rays has been measured
with unprecedented precision at the Pierre Auger Observatory.
We report an update of the all-sky flux of cosmic rays above 3 x 10 [sup] 17 eV obtained by combining four
independent data sets. These measurements are based on data
from the surface detector arrays (divided into two sets according to the shower zenith angle), from a nested, denser,
detector array, and hybrid events measured simultaneously with
both the fluorescence detector and the surface detector array.
The spectral features are presented in detail and the
systematic uncertainties are addressed. The huge amount of data
collected to date, with a total exposure exceeding
50,000 km2 sr yr, together with the wide range of sky observed
(in declination from -90[deg] to 45[deg]) also allow us to
measure the energy spectrum from different regions of the sky.
We present the results of the search for a dependence of the
measured flux on the declination of the incoming directions.
Found in: ključnih besedah
Keywords: ultra-high energy cosmic rays
energy spectrum
Pierre Auger Observatory
Published: 02.03.2016; Views: 5019; Downloads: 221
Fulltext (755,08 KB) |
3. Arrival directions of the highest-energy cosmic rays detected with the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Julien Aublin, 2015, published scientific conference contribution Abstract: We present the results of a search for small to intermediate
scale anisotropies in the distribution of arrival directions
of ultra-high energy cosmic rays recorded at the Pierre Auger
Observatory. The data set, gathered in ten years of operation,
includes arrival directions with zenith angles up to 80◦,
and is about three times larger than that used in earlier
studies. We update the test based on correlations with active
galactic nuclei (AGNs) from the Véron-Cetty and Véron catalog,
which does not yield a significant indication of anisotropy
with the present data set. We perform a blind search for
localized excess fluxes and for self-clustering of arrival
directions at angular scales up to 30◦ and for different
energy thresholds between 40 EeV and 80 EeV. We also examine
the correlation of arrival directions with relatively nearby galaxies in the 2MRS catalog, AGNs detected by Swift-BAT,
and a sample of radio galaxies with jets and with the
Centaurus A galaxy. None of the searches shows a statistically
significant evidence of anisotropy. The two largest
departures from isotropy that were found have a post-trial
probability ≈ 1.4%. One is for cosmic rays with energy above
58 EeV that arrive within 15◦ of the direction toward
Centaurus A. The other is for arrival directions within 18◦
of Swift-BAT AGNs closer than 130 Mpc and brighter than
10[sup]44 erg/s, with the same energy threshold.
Found in: ključnih besedah
Keywords: ultra-high energy cosmic rays
anisotropy studies
active galactic nuclei
Pierre Auger Observatory
Published: 02.03.2016; Views: 4489; Downloads: 226
Fulltext (1,32 MB) |
4. Search for energy dependent patterns in the arrival direction of cosmic rays at the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Tobias Winchen, 2015, published scientific conference contribution Abstract: Energy-dependent patterns in the arrival directions of cosmic
rays are expected from deflections in galactic and extragalactic magnetic fields. We report on searches for such
patterns in the data of the surface detector of the Pierre
Auger Observatory at energies above E = 5 EeV in regions
within approximately 15◦ around events with energy E > 60
EeV. No significant patterns are found with this analysis which
can be used to constrain parameters in propagation scenarios.
Found in: ključnih besedah
Keywords: ultra-high energy cosmic rays
galactic and extragalactic magnetic fields
magnetic deflection patterns
Pierre Auger Observatory
Published: 02.03.2016; Views: 4381; Downloads: 225
Fulltext (1019,52 KB) |
5. Composition at the “ankle” measured by the Pierre Auger Observatory: pure or mixed?Marko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Alexey Yushkov, 2015, published scientific conference contribution Abstract: We report for the first time on the measurement of the
correlation between the depth of shower maximum and the signal
in water-Cherenkov stations for events reconstructed by both
the fluorescence and the surface detectors of the Pierre Auger Observatory. Such a correlated measurement is a unique feature
of a hybrid air-shower observatory and allows us to determine
the purity of the cosmic-ray composition. The observed
correlation in the energy range around the “ankle”
lg(E/eV) = 18.5−19.0 differs significantly from the expectations for pure beams, indicating that the primary composition in this range is mixed, unless the
hadronic interactions at these energies behave very
differently than in conventional, LHC-tuned event generators.
Found in: ključnih besedah
Summary of found: ...us to determine
the purity of the cosmic-ray composition. The observed
correlation in the energy... ...ultra-high energy cosmic rays,
elemental composition,
depth of shower maximum,
secondary cosmic rays,
Pierre Auger...
Keywords: ultra-high energy cosmic rays, elemental composition, depth of shower maximum, secondary cosmic rays, Pierre Auger Observatory
Published: 02.03.2016; Views: 4501; Downloads: 233
Fulltext (388,00 KB) |
6. Update of the neutrino and photon limits from the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Carla Bleve, 2015, published scientific conference contribution Abstract: Ultra-high energy neutrinos and photons, with energies above
1 EeV and 10 EeV respectively, can be detected with the Surface
Detector array (SD) of the Pierre Auger Observatory. Downward-
going neutrinos of all flavours interacting in the atmosphere
at zenith angles θ > 60◦, upward-going tau neutrinos (“Earth-
skimming”), as well as photons in the zenith range 30◦ − 60◦
can be identified through the broad time-structure of the
signals expected to be induced in the SD stations. An
additional signature for photon-induced air showers is the
steeper lateral distribution of secondary particles at ground
with respect to the nucleonic showers. Stringent limits are set
to the diffuse flux of ultra-high energy (UHE) neutrinos and
photons, using data collected between 2004 and mid-2013, under
the hypothesis of an E[sup]−2 spectrum for signal primaries.
Found in: ključnih besedah
Summary of found: ...ultra-high energy neutrinos,
ultra-high energy photons,
cosmic rays, elemental composition,
Pierre Auger Observatory...
Keywords: ultra-high energy neutrinos, ultra-high energy photons, cosmic rays, elemental composition, Pierre Auger Observatory
Published: 03.03.2016; Views: 4066; Downloads: 223
Fulltext (398,21 KB) |
7. Measurement of the muon content in air showers at the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Laura Collica, 2015, published scientific conference contribution Abstract: The muon content of extensive air showers is an
observable sensitive to the primary composition and to
the hadronic interaction properties. We present here
different methods which allow us to estimate the muon number
at the ground level and the muon production depth by
exploiting the measurement of the longitudinal, lateral and
temporal distribution of particles in air showers recorded at
the Pierre Auger Observatory. The results, obtained at about
10[sup]19 eV (E[inf]CM ∼ 140 TeV center-of-mass energy for
proton primaries), are compared to the predictions
of LHC-tuned hadronic interaction models with different primary
masses and suggest a deficit in the muon content at the
ground predicted by simulations. The Pierre Auger Observatory
uses water-Cherenkov detectors to measure particle
densities at the ground and therefore has a good
sensitivity to the muon content of air showers. Moreover, due
to its hybrid design, the combination of muon measurements with
other independent mass composition analyses such as Xmax
provides additional constraints on hadronic interaction models.
Found in: ključnih besedah
Summary of found: ...Pierre Auger Observatory,
ultra-high energy cosmic rays,
muons, mass composition,
hadronic interactions...
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, muons, mass composition, hadronic interactions
Published: 03.03.2016; Views: 3934; Downloads: 212
Fulltext (298,46 KB) |
8. Combined fit of spectrum and composition data as measured by the Pierre Auger ObservatoryMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Andrea Di Matteo, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Summary of found: ...both flux and composition of
ultra-high energy cosmic rays as measured by the Pierre Auger...
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, energy spectrum, elemental composition, combined data fit
Published: 03.03.2016; Views: 3751; Downloads: 227
Fulltext (704,98 KB) |
9. 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, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Summary of found: ...the primary mass of the highest energy
cosmic rays on a shower-by-shower basis. In addition...
Keywords: Pierre Auger Observatory, ultra-high energy cosmic rays, elemental composition sensitivity, Auger upgrade (AugerPrime), muonic shower component, scintillator detectors
Published: 03.03.2016; Views: 3642; Downloads: 217
Fulltext (659,02 KB) |
10. Search for a correlation between the UHECRs measured by the Pierre Auger Observatory and the Telescope Array and the neutrino candidate events from IceCubeMarko Zavrtanik, Danilo Zavrtanik, Lili Yang, Serguei Vorobiov, Darko Veberič, Marta Trini, Samo Stanič, Ahmed Saleh, Gašper Kukec Mezek, Andrej Filipčič, Asen Christov, 2015, published scientific conference contribution Abstract: 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.
Found in: ključnih besedah
Summary of found: ...three searches for correlations between
ultra-high energy cosmic rays detected by the Telescope Array
and...
Keywords: ultra-high energy cosmic rays, Pierre Auger Observatory, Telescope Array, high-energy neutrinos, IceCube, correlation search
Published: 08.03.2016; Views: 4158; Downloads: 187
Fulltext (1,11 MB) |
