Justin M. Albury
A5015857333- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Particle physics theoretical and experimental studies
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Gamma-ray bursts and supernovae
- Cosmology and Gravitation Theories
- Atmospheric Ozone and Climate
- Pulsars and Gravitational Waves Research
- Noncommutative and Quantum Gravity Theories
- Lightning and Electromagnetic Phenomena
- Ionosphere and magnetosphere dynamics
- Astronomical Observations and Instrumentation
- Atmospheric aerosols and clouds
- Galaxies: Formation, Evolution, Phenomena
- Radiation Detection and Scintillator Technologies
- Solar and Space Plasma Dynamics
- Earthquake Detection and Analysis
- Quantum and Classical Electrodynamics
- Adaptive optics and wavefront sensing
- History and Developments in Astronomy
- Astrophysical Phenomena and Observations
- Computational Physics and Python Applications
- Optical Wireless Communication Technologies
The University of Adelaide
2017-2023
Pierre Auger Observatory
2021
Universidad Nacional de La Plata
2021
Institute of Astronomy and Space Physics
2021
Consejo Nacional de Investigaciones Científicas y Técnicas
2021
National University of General San Martín
2021
National Technological University
2021
Czech Academy of Sciences
2021
Czech Academy of Sciences, Institute of Physics
2021
Palacký University Olomouc
2021
We report a measurement of the energy spectrum cosmic rays for energies above 2.5×1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature work is that estimates are independent assumptions about unknown hadronic physics or primary mass composition. The most precise made hitherto accumulated exposure being so large measurements flux dominated by systematic uncertainties except at 5×1019 eV. principal conclusions (1) flattening near 5×1018 eV, so-called "ankle,"...
We report a measurement of the energy spectrum cosmic rays above 2.5×1018 eV based on 215 030 events. New results are presented: at about 1.3×1019 eV, spectral index changes from 2.51±0.03(stat)±0.05(syst) to 3.05±0.05(stat)±0.10(syst), evolving 5.1±0.3(stat)±0.1(syst) beyond 5×1019 while no significant dependence features declination is seen in accessible range. These can be reproduced models with energy-dependent mass composition. The density 5×1018 [5.66±0.03(stat)±1.40(syst)]×1053 erg...
Neutrinos with energies above $10^{17}$ eV are detectable the Surface Detector Array of Pierre Auger Observatory. The identification is efficiently performed for neutrinos all flavors interacting in atmosphere at large zenith angles, as well Earth-skimming $\tau$ nearly tangential trajectories relative to earth. No neutrino candidates were found $\sim\,14.7$ years data taken up 31 August 2018. This leads restrictive upper bounds on their flux. $90\%$ C.L. single-flavor limit diffuse flux...
We present a detailed study of the large-scale anisotropies cosmic rays with energies above 4 EeV measured using Pierre Auger Observatory. For energy bins [4,8] and $E\geq 8$ EeV, most significant signal is dipolar modulation in right ascension at 8 as previously reported. In this paper we further scrutinize highest-energy bin by splitting it into three ranges. find that amplitude dipole increases EeV. The growth can be fitted power law index $\beta=0.79\pm 0.19$. directions dipoles are...
We present a measurement of the cosmic-ray spectrum above 100\,PeV using part surface detector Pierre Auger Observatory that has spacing 750~m. An inflection is observed, confirming presence so-called \emph{second-knee} feature. The then combined with 1500\,m array to produce single flux, linking this spectral feature three additional breaks at highest energies. spectrum, an energy scale set calorimetrically via fluorescence telescopes and type, results in most statistically systematically...
We present the first measurement of fluctuations in number muons extensive air showers produced by ultrahigh energy cosmic rays. find that measured are good agreement with predictions from shower simulations. This observation provides new insights into origin previously reported deficit simulations and constrains models hadronic interactions at energies. Our is compatible muon originating small deviations interaction particle production accumulate as develop.
A promising energy range to look for angular correlation between cosmic rays of extragalactic origin and their sources is at the highest energies, above few tens EeV ($1\:{\rm EeV}\equiv 10^{18}\:$eV). Despite flux these particles being extremely low, area ${\sim}\:3{,}000 \: \text{km}^2$ covered Pierre Auger Observatory, 17-year data-taking period Phase 1 its operations, have enabled us measure arrival directions more than 2,600 ultra-high $32\:\text{EeV}$. We publish this data set, largest...
We present measurements of the large-scale cosmic-ray anisotropies in right ascension, using data collected by surface detector array Pierre Auger Observatory over more than 14 years. determine equatorial dipole component, $\vec{d}_\perp$, through a Fourier analysis ascension that includes weights for each event so as to account main detector-induced systematic effects. For energies at which trigger efficiency is small, ``East-West'' method employed. Besides from with detectors separated...
Abstract The hybrid design of the Pierre Auger Observatory allows for measurement properties extensive air showers initiated by ultra-high energy cosmic rays with unprecedented precision. By using an array prototype underground muon detectors, we have performed first direct measurement, Collaboration, content between $$2\times 10^{17}$$ <mml:math...
Ultra-high-energy photons with energies exceeding $10^{17}$ eV offer a wealth of connections to different aspects cosmic-ray astrophysics as well gamma-ray and neutrino astronomy. The recent observations in the $10^{15}$ range further motivate searches for even higher-energy photons. In this paper, we present search $2{\times}10^{17}$ using about 5.5 years hybrid data from low-energy extensions Pierre Auger Observatory. upper limits on integral photon flux derived here are most stringent...
With the Auger Engineering Radio Array (AERA) of Pierre Observatory, we have observed radio emission from 561 extensive air showers with zenith angles between 60$^\circ$ and 84$^\circ$. In contrast to more vertical incidence, these inclined illuminate large ground areas several km$^2$ signals detectable in 30 80\,MHz band. A comparison measured radio-signal amplitudes Monte Carlo simulations a subset 50 events for which reconstruct energy using surface detector shows agreement within...
Cosmic rays arriving at Earth collide with the upper parts of atmosphere, thereby inducing extensive air showers. When secondary particles from cascade arrive ground, they are measured by surface detector arrays. We describe methods applied to measurements Pierre Auger Observatory reconstruct events zenith angles less than $60^\circ$ using timing and signal information recorded water-Cherenkov stations. In addition, we assess accuracy these in reconstructing arrival directions primary cosmic...
The atmospheric depth of the air shower maximum $X_{\mathrm{max}}$ is an observable commonly used for determination nuclear mass composition ultra-high energy cosmic rays. Direct measurements are performed using observations longitudinal development with fluorescence telescopes. At same time, several methods have been proposed indirect estimation from characteristics particles registered surface detector arrays. In this paper, we present a deep neural network (DNN) $X_{\mathrm{max}}$....
Instantons, which are non-perturbative solutions to Yang-Mills equations, provide a signal for the occurrence of quantum tunneling between distinct classes vacua. They can give rise decays particles otherwise forbidden. Using data collected at Pierre Auger Observatory, we search signatures such instanton-induced processes that would be suggestive super-heavy decaying in Galactic halo. These could have been produced during post-inflationary epoch and match relic abundance dark matter inferred...
Using the data of Pierre Auger Observatory, we report on a search for signatures that would be suggestive super-heavy particles decaying in Galactic halo. From lack signal, present upper limits different energy thresholds above ≳108 GeV secondary by-product fluxes expected from decay particles. Assuming density these matches dark matter observed today, translate bounds particle into tight constraints couplings governing process as function mass. Instantons, which are nonperturbative...
The determination of the primary energy extensive air showers using fluorescence detection technique requires an estimation carried away by particles that do not deposit all their in atmosphere. This is typically made Monte Carlo simulations and thus depends on assumed particle mass model predictions for neutrino muon production. In this work we present a new method to obtain invisible from events detected Pierre Auger Observatory. uses measurements number at ground level, it allows us...
The Pierre Auger Observatory is the most sensitive detector to primary photons with energies above $\sim 0.2$ EeV. It measures extensive air showers using a hybrid technique that combines fluorescence (FD) ground array of particle detectors (SD). signatures photon-induced shower are larger atmospheric depth at maximum ($X_{max}$) and steeper lateral distribution function, along lower number muons respect bulk hadron-induced background. Using observables measured by FD SD, three photon...
Abstract Lorentz invariance violation (LIV) is often described by dispersion relations of the form E i 2 = m + p +δ i,n 2+n with delta different based on particle type , energy momentum and rest mass . Kinematics thresholds interactions are modified once LIV terms become comparable to squared masses particles involved. Thus, strongest constraints coefficients δ tend come from highest energies. At sufficiently high energies, photons produced cosmic ray as they propagate through Universe could...
The Pierre Auger Observatory, at present the largest cosmic-ray observatory ever built, is instrumented with a ground array of 1600 water-Cherenkov detectors, known as Surface Detector (SD). SD samples secondary particle content (mostly photons, electrons, positrons and muons) extensive air showers initiated by cosmic rays energies ranging from $10^{17}~$eV up to more than $10^{20}~$eV. Measuring independent contribution muon component total registered signal crucial enhance capability...
Abstract Elves are a class of transient luminous events, with radial extent typically greater than 250 km, that occur in the lower ionosphere above strong electrical storms. We report observation 1,598 elves, from 2014 to 2016, recorded unprecedented time resolution (100 ns) using fluorescence detector (FD) Pierre Auger Cosmic‐Ray Observatory. The Observatory is located Mendoza province Argentina viewing footprint for elve observations km , reaching areas Pacific and Atlantic Oceans, as well...
The distribution of ultra-high-energy cosmic-ray arrival directions appears to be nearly isotropic except for a dipole moment order $6 \times (E/10~\mathrm{EeV})$ per cent. Nonetheless, at the highest energies, as number possible candidate sources within propagation horizon and magnetic deflections both shrink, smaller-scale anisotropies might expected emerge. On other hand, flux suppression reduces statistics available searching such anisotropies. In this work, we consider two different...
AMIGA (Auger Muons and Infill for the Ground Array) is an upgrade of Pierre Auger Observatory to complement study ultra-high-energy cosmic rays (UHECR) by measuring muon content extensive air showers (EAS). It consists array 61 water Cherenkov detectors on a denser spacing in combination with underground scintillation used density measurement. Each detector composed three modules, 10 m2 detection area per module, buried at 2.3 m depth, resulting total 30 m2. Silicon photomultiplier sensors...
More than half a century after the discovery of ultra-high energy cosmic rays (UHECRs), their origin is still an open question. The study anisotropies in arrival directions such particles essential ingredient to solve this puzzle. We update our previous analysis large-scale observed by Pierre Auger Observatory using latest data collected before AugerPrime upgrade. select events with zenith angles up 80 degrees, implying sky coverage 85$\%$, and energies above 4 EeV, for which surface...
The combined fit of the energy spectrum and mass composition data above 5 EeV suggested presence extragalactic sources ejecting ultra-high-energy cosmic rays with relatively low maximum energies, hard spectral indices mixed chemical compositions, dominated by contribution intermediate groups. Here we present an extension to lower include feature observed near in all-particle spectrum, so-called ankle. We show that it is possible generate such a change slope assuming flux below ankle provided...