Paulo Ricardo Araújo Ferreira
A5103950218- 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
- Atmospheric Ozone and Climate
- Ionosphere and magnetosphere dynamics
- Gamma-ray bursts and supernovae
- History and Developments in Astronomy
- Atmospheric and Environmental Gas Dynamics
- High-Energy Particle Collisions Research
- Pulsars and Gravitational Waves Research
- Radiation Detection and Scintillator Technologies
- Cosmology and Gravitation Theories
- Astronomical Observations and Instrumentation
- Computational Physics and Python Applications
- Particle Accelerators and Free-Electron Lasers
- Noncommutative and Quantum Gravity Theories
- Atmospheric aerosols and clouds
- Solar and Space Plasma Dynamics
- Calibration and Measurement Techniques
- Earthquake Detection and Analysis
- Precipitation Measurement and Analysis
- Lightning and Electromagnetic Phenomena
RWTH Aachen University
2019-2025
Istituto Nazionale di Fisica Nucleare, Sezione di Lecce
2023
Abstract In this work we present the interpretation of energy spectrum and mass composition data as measured by Pierre Auger Collaboration above 6 × 10 17 eV. We use an astrophysical model with two extragalactic source populations to hardening cosmic-ray flux at around 5 18 eV (the so-called “ankle” feature) a transition between these components. find our be well reproduced if sources ankle emit mixed hard low rigidity cutoff. The component below is required have very soft mix protons...
Abstract The combined fit of the measured energy spectrum and shower maximum depth distributions ultra-high-energy cosmic rays is known to constrain parameters astrophysical models with homogeneous source distributions. Studies distribution cosmic-ray arrival directions show a better agreement in which fraction flux non-isotropic associated nearby radio galaxy Centaurus A or catalogs such as that starburst galaxies. Here, we present novel combination both analyses by simultaneous directions,...
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...
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...
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...
We use the surface detector of Pierre Auger Observatory to search for air showers initiated by photons with an energy above $10^{19}$ eV. Photons in zenith angle range from 30$^\circ$ 60$^\circ$ can be identified overwhelming background charged cosmic rays through broader time structure signals induced water-Cherenkov detectors array and steeper lateral distribution shower particles reaching ground. Applying method data collected between January 2004 June 2020, upper limits at 95\% CL are...
The (AERA), part of the Pierre Auger Observatory, is currently largest array radio antenna stations deployed for detection cosmic rays, spanning an area <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mn>17</a:mn><a:mtext> </a:mtext><a:mtext> </a:mtext><a:msup><a:mrow><a:mi>km</a:mi></a:mrow><a:mn>2</a:mn></a:msup></a:math> with 153 stations. It detects emission extensive air showers produced by rays in 30–80 MHz band. Here, we report AERA measurements (<c:math...
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) $X_{\mathrm{max}}$....
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...
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 origin of ultra-high-energy cosmic rays (UHECRs), particles from outer space with energies~$E \geq 1\;$EeV, is still unknown, though the near-isotropy their arrival direction distribution excludes a dominant Galactic contribution, and interactions background photons prevent them travelling cosmologically large distances. This suggests that sources must be searched for in nearby galaxy groups clusters. Deflections by intergalactic magnetic fields are expected to hinder such searches but...
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...
The search for anisotropies in the arrival directions of ultra-high-energy cosmic rays plays a key role efforts to understand their origin. observed first-harmonic modulation right ascension (R.A.) above $8\,$EeV, detected by Pierre Auger Observatory with current significance $6.9\sigma$, suggests an extragalactic origin this energy. Furthermore, there are indications, at $\sim$$4\sigma$ level, intermediate angular scales, which obtained when comparing against distribution potential sources...
A dedicated search for upward-going air showers at zenith angles exceeding $110^\circ$ and energies $E>0.1$ EeV has been performed using the Fluorescence Detector of Pierre Auger Observatory. The is motivated by two "anomalous" radio pulses observed ANITA flights I III which appear inconsistent with Standard Model particle physics. Using simulations both regular cosmic ray events, a selection procedure defined to separate potential candidate events corresponding exposure calculated in energy...
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...
The Pierre Auger Observatory, being the largest air-shower experiment in world, offers an unprecedented exposure to neutral particles at highest energies. Since start of data taking more than 18 years ago, various searches for ultra-high-energy (UHE, $E\gtrsim10^{17}\,\text{eV}$) photons have been performed: either a diffuse flux UHE photons, point sources or associated with transient events like gravitational wave events. In present paper, we summarize these and review current results...
A catalog containing details of the highest-energy cosmic rays recorded through detection extensive air-showers at Pierre Auger Observatory is presented with aim opening data to detailed examination. Descriptions 100 showers created by particles between 1 January 2004 and 31 December 2020 are given for that have energies in range 78 EeV 166 EeV. Details also a further nine very-energetic events been used calibration procedure adopted determine energy each primary. sky plot arrival directions...
After nearly 20 years of data-taking, the measurements made with Pierre Auger Observatory represent largest collection ultra-high-energy cosmic ray (UHECR) data so far assembled from a single instrument. Exploring this set led to deeper understanding UHECR flux and many surprises. In particular, studies aiming investigate leverage mass composition UHECRs have played an important role in empowering discovery. This contribution will present overview analyses primary carried out during first...
We present a new analysis for estimating the depth of maximum air-shower profiles, $X_\mathrm{max}$, to investigate evolution ultra-high-energy cosmic ray mass composition from 3 100 EeV. use recently developed deep-learning-based technique reconstruction $X_\mathrm{max}$ data surface detector Pierre Auger Observatory. To avoid systematic uncertainties arising hadronic interaction models in simulation data, we calibrate with observations fluorescence detector. Using novel analysis, have...
We report a measurement of the energy spectrum cosmic rays above $2.5{\times} 10^{18}$ eV based on $215,030$ events. New results are presented: at about $1.3{\times} 10^{19}$ eV, spectral index changes from $2.51 \pm 0.03 \textrm{ (stat.)} 0.05 (sys.)}$ to $3.05 (stat.)}\pm 0.10\textrm{ (sys.)}$, evolving $5.1\pm0.3\textrm{ 0.1\textrm{ beyond $5{\times} while no significant dependence features declination is seen in accessible range. These can be reproduced models with energy-dependent mass...
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 Pierre Auger Observatory (Auger) and the Telescope Array (TA), located, respectively, in Southern Northern hemispheres, are largest ultra-high-energy cosmic ray (UHECR) observatories. TA Collaborations have collected unprecedented statistics providing us with a unique opportunity to search for differences between UHECR energy spectra mass compositions complementary sky regions. To correctly attribute such properties of sources or propagation, systematic effects measurements each...