1. Azimuthal asymmetry in the risetime of the Surface Detector signals 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, Ignacio Minaya, 2015, published scientific conference contribution Abstract: The azimuthal asymmetry in the risetime of signals in Auger
surface detector stations is a source of information on shower
development. The azimuthal asymmetry is due to a combination of
the longitudinal evolution of the shower and geometrical
effects related to the angles of incidence of the particles
into the detectors. The magnitude of the effect depends upon
the zenith angle and state of development of the shower and
thus provides a novel observable sensitive to the mass
composition of cosmic rays above 3 × 10[sup]18 eV. By comparing
measurements with predictions from shower simulations, we find
for both of our adopted models of hadronic physics (QGSJetII-
04 and Epos-LHC) an indication that the mean cosmic-ray mass
increases with energy, as has been inferred from other studies.
However the absolute values derived for the mass are dependent
on the shower model and on the range of distance from the
shower core selected. Thus the method has uncovered further
deficiencies in our understanding of shower modelling that must
be resolved before the mass composition can be inferred from
(sec θ)max. Found in: ključnih besedah Keywords: Pierre Auger Observatory, Surface Detector, risetime of detector signal, azimuthal asymmetry, extensive air showers Published: 03.03.2016; Views: 4017; Downloads: 192
Fulltext (243,04 KB) |
2. Solar Cycle Modulation of Cosmic Rays Observed with the Low Energy Modes 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, Jimmy Masías-Meza, 2015, published scientific conference contribution Abstract: 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. Found in: ključnih besedah Summary of found: ...The low energy modes of the surface detector array of the
Pierre Auger Observatory record... Keywords: Pierre Auger Observatory, Surface Detector, secondary cosmic rays, scaler mode, charge histogram mode, solar cycle modulation Published: 03.03.2016; Views: 4066; Downloads: 198
Fulltext (533,18 KB) |
3. Improved limits to point-like sources of ultrahigh energy neutrinos with the Pierre Auger ObservatoryLili Yang, Marta Trini, Pablo Pieroni, Jaime Alvarez-Muniz, 2016, treatise, preliminary study, study Found in: ključnih besedah Summary of found: ...ultrahigh energy neutrinos,
Pierre Auger Observatory,
surface detector... Keywords: ultrahigh energy neutrinos, Pierre Auger Observatory, surface detector Published: 07.04.2016; Views: 4447; Downloads: 0
Fulltext (307,54 KB) |
4. Azimuthal asymmetry in the risetime of the surface detector signals 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, A. Aab, 2016, original scientific article Abstract: The azimuthal asymmetry in the risetime of signals in Auger surface detector stations is a source of information on shower development. The azimuthal asymmetry is due to a combination of the longitudinal evolution of the shower and geometrical effects related to the angles of incidence of the particles into the detectors. The magnitude of the effect depends upon the zenith angle and state of development of the shower and thus provides a novel observable, (secθ)max, sensitive to the mass composition of cosmic rays above 3×1018 eV. By comparing measurements with predictions from shower simulations, we find for both of our adopted models of hadronic physics (QGSJETII-04 and EPOS-LHC) an indication that the mean cosmic-ray mass increases slowly with energy, as has been inferred from other studies. However, the mass estimates are dependent on the shower model and on the range of distance from the shower core selected. Thus the method has uncovered further deficiencies in our understanding of shower modeling that must be resolved before the mass composition can be inferred from (secθ)max. Found in: ključnih besedah Keywords: ultra-high energy cosmic rays (UHECR), UHECR mass composition, Pierre Auger Observatory, extensive air showers, Auger Surface Detector signals risetime, azimuthal symmetry Published: 15.04.2016; Views: 4661; Downloads: 0
Fulltext (698,19 KB) |
5. Impact of atmospheric effects on the energy reconstruction of air showers observed by the surface detectors 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, A. Aab, 2017, original scientific article Found in: ključnih besedah Summary of found: ...Pierre Auger Observatory (PAO),
PAO Surface Detector,
energy reconstruction,
atmospheric effects... Keywords: Pierre Auger Observatory (PAO), PAO Surface Detector, energy reconstruction, atmospheric effects Published: 16.02.2017; Views: 3715; Downloads: 0
Fulltext (4,52 MB) |
6. Peculiar lightning-related events observed by the surface detector 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, Roberta Colalillo, 2017, published scientific conference contribution Found in: ključnih besedah Keywords: Pierre Auger Observatory, surface detector, peculiar lightning-related events Published: 16.02.2018; Views: 2791; Downloads: 182
Fulltext (3,10 MB) |
7. The dynamic range of the AugerPrime Surface Detector: technical solution and physics reachAntonella Castellina, Andrej Filipčič, Gašper Kukec Mezek, Ahmed Saleh, Marta Trini, Darko Veberič, Serguei Vorobiov, Lili Yang, Danilo Zavrtanik, Marko Zavrtanik, 2017, published scientific conference contribution Found in: ključnih besedah Keywords: AugerPrime, Surface Detector, Pierre Auger Observatory Published: 16.02.2018; Views: 2765; Downloads: 166
Fulltext (1,96 MB) |
8. Search for Anisotropy in the Ultra High Energy Cosmic Ray Spectrum using the Telescope Array Surface DetectorJ. P. Lundquist, R.U. Abbasi, 2017, other component parts Abstract: The Telescope Array (TA) experiment is located in the western desert of Utah, USA, and observes ultra high energy cosmic rays (UHECRs) in the Northern hemisphere. At the highest energies, E>10~EeV, the shape of cosmic ray energy spectrum may carry an imprint of the source density distribution along the line of sight different in different directions of the sky. In this study, we search for such directional variations in the shape of the energy spectrum using events observed with the Telescope Array's surface detector. We divide the TA field of view into two nearly equal-exposure regions: the "on-source" region which we define as ±30∘ of the supergalactic plane containing mostly nearby structures, and the complementary "off-source" region where the sources are further away on average. We compare the UHECR spectra in these regions by fitting them to the broken power law and comparing the resulting parameters. We find that the off-source spectrum has an earlier break at highest energies. The chance probability to obtain such or larger difference in statistically equivalent distributions is estimated as 6.2±1.1×10−4 (3.2σ) by a Monte-Carlo simulation. The observed difference in spectra is in a reasonable quantitative agreement with a simplified model that assumes that the UHECR sources trace the galaxy distribution from the 2MRS catalogue, primary particles are protons and the magnetic deflections can be neglected. Found in: ključnih besedah Keywords: cosmic radiation: UHE, detector: surface, cosmic radiation: spectrum, cosmic radiation: energy spectrum, deflection: magnetic, numerical calculations: Monte Carlo, anisotropy Published: 27.04.2020; Views: 2134; Downloads: 84
Fulltext (169,05 KB) |
9. TA Anisotropy SummaryJ. P. Lundquist, K. Kawata, 2019, published scientific conference contribution Abstract: The Telescope Array (TA) is the largest ultra-high-energy cosmic-ray (UHECR) detector in the northern hemisphere. It consists of an array of 507 surface detectors (SD) covering a total 700 km^2 and three fluorescence detector stations overlooking the SD array. In this proceedings, we summarize recent results on the search for directional anisotropy of UHECRs using the latest dataset collected by the TA SD array. We obtained hints of the anisotropy of the UHECRs in the northern sky from the various analyses. Found in: ključnih besedah Summary of found: ...It consists of an array of 507 surface detectors (SD) covering a total 700 km^2... Keywords: cosmic radiation, UHE detector, fluorescence detector, surface, Telescope Array Experiment, anisotropy, experimental results Published: 28.04.2020; Views: 2149; Downloads: 73
Fulltext (1,88 MB) |
10. Gamma Ray Showers Observed at Ground Level in Coincidence With Downward Lightning LeadersJ. P. Lundquist, R.U. Abbasi, 2018, original scientific article Abstract: Bursts of gamma ray showers have been observed in coincidence with downward propagating negative leaders in lightning flashes by the Telescope Array Surface Detector (TASD). The TASD is a 700‐km^2 cosmic ray observatory located in southwestern Utah, USA. In data collected between 2014 and 2016, correlated observations showing the structure and temporal development of three shower‐producing flashes were obtained with a 3‐D lightning mapping array, and electric field change measurements were obtained for an additional seven flashes, in both cases colocated with the TASD. National Lightning Detection Network information was also used throughout. The showers arrived in a sequence of 2–5 short‐duration (≤10 μs) bursts over time intervals of several hundred microseconds and originated at an altitude of ≃3–5 km above ground level during the first 1–2 ms of downward negative leader breakdown at the beginning of cloud‐to‐ground lightning flashes. The shower footprints, associated waveforms and the effect of atmospheric propagation indicate that the showers consist primarily of downward‐beamed gamma radiation. This has been supported by GEANT simulation studies, which indicate primary source fluxes of ≃10^12–10^14 photons for 16° half‐angle beams. We conclude that the showers are terrestrial gamma ray flashes, similar to those observed by satellites, but that the ground‐based observations are more representative of the temporal source activity and are also more sensitive than satellite observations, which detect only the most powerful terrestrial gamma ray flashes. Found in: ključnih besedah Summary of found: ...in lightning flashes by the Telescope Array Surface Detector (TASD). The TASD is a 700‐km^2... Keywords: gamma rays, lightning, gamma ray bursts, surface detector Published: 30.04.2020; Views: 2404; Downloads: 0
Fulltext (1,14 MB) |