A5051263948- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- Astrophysics and Cosmic Phenomena
- Dark Matter and Cosmic Phenomena
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Radio Astronomy Observations and Technology
- Particle Detector Development and Performance
- Computational Physics and Python Applications
- Gamma-ray bursts and supernovae
- Particle Accelerators and Free-Electron Lasers
- Atmospheric Ozone and Climate
- Black Holes and Theoretical Physics
- Atmospheric aerosols and clouds
- History and Developments in Astronomy
- Medical Imaging Techniques and Applications
- Ionosphere and magnetosphere dynamics
- Cosmology and Gravitation Theories
- Radiation Detection and Scintillator Technologies
- Solar and Space Plasma Dynamics
- Pulsars and Gravitational Waves Research
- Astronomical Observations and Instrumentation
- Photocathodes and Microchannel Plates
- Atomic and Subatomic Physics Research
- Radiation Therapy and Dosimetry
University of Lisbon
2016-2025
Universidade Federal de Goiás
2025
LIP - Laboratory of Instrumentation and Experimental Particle Physics
2015-2024
University of Buenos Aires
2011-2023
Consejo Nacional de Investigaciones Científicas y Técnicas
2011-2023
Instituto de Tecnologías en Detección y Astropartículas
2021-2023
National University of General San Martín
2021-2023
Pierre Auger Observatory
2007-2023
Institute of Scientific and Technical Research for Defense
2021-2023
Institute of Astronomy and Space Physics
2011-2023
Using data collected at the Pierre Auger Observatory during past 3.7 years, we demonstrated a correlation between arrival directions of cosmic rays with energy above 6 × 10 19 electron volts and positions active galactic nuclei (AGN) lying within ∼75 megaparsecs. We rejected hypothesis an isotropic distribution these least 99% confidence level from prescribed priori test. The observed is compatible that highest-energy particles originate nearby extragalactic sources whose flux has not been...
The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world's largest cosmic ray observatory. objectives of Observatory are to probe origin and characteristics rays above $10^{17}$ eV study interactions these, most energetic particles observed nature. design features an array 1660 water-Cherenkov particle detector stations spread over 3000 km$^2$ overlooked by 24 air fluorescence telescopes. In addition, three elevation telescopes overlook 23.5 km$^2$,...
The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. spectral index gamma particle flux, J proportional, variantE;{-gamma}, energies between 4 eV and 10;{19} 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) higher energies. hypothesis a single power law rejected with significance greater than 6 standard deviations. data are consistent prediction by Greisen Zatsepin Kuz'min.
We describe the measurement of depth maximum, X{max}, longitudinal development air showers induced by cosmic rays. Almost 4000 events above 10;{18} eV observed fluorescence detector Pierre Auger Observatory in coincidence with at least one surface station are selected for analysis. The average shower maximum was found to evolve energy a rate (106{-21}{+35}) g/cm{2}/decade below 10{18.24+/-0.05} eV, and (24+/-3) this energy. measured shower-to-shower fluctuations decrease from about 55 26...
We report a study of the distributions depth maximum, ${X}_{\mathrm{max}}$, extensive air-shower profiles with energies above $1{0}^{17.8}\text{ }\text{ }\mathrm{eV}$ as observed fluorescence telescopes Pierre Auger Observatory. The analysis method for selecting data sample minimal sampling bias is described in detail well experimental cross-checks and systematic uncertainties. Furthermore, we discuss detector acceptance resolution ${X}_{\mathrm{max}}$ measurement provide parametrizations...
Cosmic rays are atomic nuclei arriving from outer space that reach the highest energies observed in nature. Clues to their origin come studying distribution of arrival directions. Using 3 × 104 cosmic with above 8 1018 electron volts, recorded Pierre Auger Observatory a total exposure 76,800 km2 sr year, we determined existence anisotropy The anisotropy, detected at more than 5.2σ level significance, can be described by dipole an amplitude [Formula: see text] percent toward right ascension...
We present a combined fit of simple astrophysical model UHECR sources to both the energy spectrum and mass composition data measured by Pierre Auger Observatory. The has been performed for energies above 5 ⋅ 1018 eV, i.e. region all-particle so-called "ankle" feature. we adopted consists identical uniformly distributed in comoving volume, where nuclei are accelerated through rigidity-dependent mechanism. results suggest characterized relatively low maximum injection energies, hard spectra...
Using the data taken at Pierre Auger Observatory between December 2004 and 2012, we have examined implications of distributions depths atmospheric shower maximum (Xmax), using a hybrid technique, for composition hadronic interaction models. We do this by fitting with predictions from variety models variations in primary cosmic rays examining quality fit. Regardless what model is assumed, find that our are not well described mix protons iron nuclei over most energy range. Acceptable fits can...
We report a measurement of the proton-air cross section for particle production at center-of-mass energy per nucleon 57 TeV. This is derived from distribution depths shower maxima observed with Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing tail maxima, $[505\ifmmode\pm\else\textpm\fi{}22(\mathrm{stat}{)}_{\ensuremath{-}36}^{+28}(\mathrm{syst})]\text{ }\text{ }\mathrm{mb}$ found.
We present the first hybrid measurement of average muon number in air showers at ultra-high energies, initiated by cosmic rays with zenith angles between $62^\circ$ and $80^\circ$. The is based on 174 events recorded simultaneously Surface Detector array Fluorescence Pierre Auger Observatory. for each shower derived scaling a simulated reference profile lateral density distribution ground until it fits data. A $10^{19}$~eV angle $67^\circ$, which arrives an altitude 1450 m above sea level,...
Abstract A new analysis of the data set from Pierre Auger Observatory provides evidence for anisotropy in arrival directions ultra-high-energy cosmic rays on an intermediate angular scale, which is indicative excess arrivals strong, nearby sources. The consist 5514 events above with zenith angles up to 80° recorded before 2017 April 30. Sky models have been created two distinct populations extragalactic gamma-ray emitters: active galactic nuclei second catalog hard Fermi -LAT sources (2FHL)...
Ultrahigh energy cosmic ray air showers probe particle physics at energies beyond the reach of accelerators. Here we introduce a new method to test hadronic interaction models without relying on absolute calibration, and apply it events with primary 6–16 EeV (ECM=110–170 TeV), whose longitudinal development lateral distribution were simultaneously measured by Pierre Auger Observatory. The average shower is 1.33±0.16 (1.61±0.21) times larger than predicted using leading LHC-tuned EPOS-LHC...
We analyze the distribution of arrival directions ultra-high energy cosmic rays recorded at Pierre Auger Observatory in 10 years operation. The data set, about three times larger than that used earlier studies, includes with zenith angles up to $80^\circ$, thus covering from $-90^\circ$ $+45^\circ$ declination. After updating fraction events correlating active galactic nuclei (AGNs) V\'eron-Cetty and V\'eron catalog, we subject energies excess 40 EeV different tests for anisotropy. search...
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,"...
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,...