178 research outputs found
Radio galaxies of the local universe
No full textItem does not contain fulltextWe present the first catalog of radio-emitting galaxies that covers the entire sky. Our catalog allows the selection of volume-limited subsamples containing all low-power radio galaxies, similar to the prototypical low-power radio galaxies Cen A or M87, within some hundred Mpc. Over 30% of the galaxies in our catalog are not contained in existing large-area extra-galactic radio samples. We find that the local galaxy density in a sphere of 2Mpc centered on the radio galaxies is 1.7 times higher than around non-radio galaxies of the same luminosity and morphology. This significant enhancement suggests a causal relation between external galaxy properties, such as environment or merger history, and the formation of powerful jets in the present universe. Since the enhancement is observed with respect to galaxies of the same luminosity and Hubble type, it is not primarily driven by black hole mass. Our automated matching procedure is found to select radio-emitting galaxies with high efficiency (99%) and purity (91%)
Large-scale distribution of arrival directions of cosmic rays detected above 10(18) ev at the Pierre Auger observatory
No full textA thorough search for large-scale anisotropies in the distribution of arrival directions of cosmic rays detected above 10¹⁸ eV at the Pierre Auger Observatory is presented. This search is performed as a function of both declination and right ascension in several energy ranges above 10¹⁸ eV, and reported in terms of dipolar and quadrupolar coefficients. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Assuming that any cosmic-ray anisotropy is dominated by dipole and quadrupole moments in this energy range, upper limits on their amplitudes are derived. These upper limits allow us to test the origin of cosmic rays above 10¹⁸ eV from stationary Galactic sources densely distributed in the Galactic disk and predominantly emitting light particles in all directions.The Pierre Auger Collaboration, P. Abreu ... K. B. Barber ... J. A. Bellido ... R. W. Clay ... M. J. Cooper ... B. R. Dawson ... T. A. Harrison ... A. E. Herve, G. C. Hill ... V. C. Holmes ... J. Sorokin ... P. Wahrlich ... B. J. Whelan ... et al
The fluorescence detector of the Pierre Auger Observatory
No full textThe Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions. © 2010 Elsevier B.V. All rights reserved.J. Abraham... K.B. Barber... J.A. Bellido... R.W. Clay... B.R. Dawson... V.C. Holmes... A.G.K. Smith... J. Sorokin... P. Wahrlich... B.J. Whelan... N. Wild... M.G.Winnick... et al
Measurement of the cosmic ray energy spectrum using hybrid events of the Pierre Auger Observatory
No full textContains fulltext :
103511pub.pdf (Publisher’s version ) (Open Access)
Contains fulltext :
103511.pdf (Author’s version preprint ) (Open Access
Measurement of the proton-air cross section at root s=57 TeV with the Pierre Auger Observatory
No full textWe report a measurement of the proton-air cross section for particle production at the center-of-mass energy per nucleon of 57 TeV. This is derived from the distribution of the depths of shower maxima observed with the Pierre Auger Observatory: systematic uncertainties are studied in detail. Analyzing the tail of the distribution of the shower maxima, a proton-air cross section of [505±22(stat)₋₃₆⁺²⁸(syst)] mb is found.K. B Barber.... J.A. Bellido.... R.W. Clay.... M.J. Cooper.... B.R. Dawson.... T.A. Harrison.... A.E. Herve.... V.C. Holmes.... J. Sorokin.... P. Wahrlich.... B.J. Whelan.... M. G. Winnick... et al.(The Pierre Auger Collaboration
Interpretation of the depths of maximum of extensive air showers measured by the Pierre Auger Observatory
No full textCollaboration members: K.B. Barber, J.A. Bellido, R.W. Clay, M.J. Cooper, B.R. Dawson, T.D. Grubb, T.A. Harrison, A.E. Herve, G.C. Hill, V.C. Holmes, M. Malacari, S.J. Saffi, and P. Wahrlich of the University of Adelaide, Adelaide, South Australia, AustraliaTo interpret the mean depth of cosmic ray air shower maximum and its dispersion, we parametrize those two observables as functions of the first two moments of the ln A distribution. We examine the goodness of this simple method through simulations of test mass distributions. The application of the parameterization to Pierre Auger Observatory data allows one to study the energy dependence of the mean ln A and of its variance under the assumption of selected hadronic interaction models. We discuss possible implications of these dependences in term of interaction models and astrophysical cosmic ray sources.The Pierre Auger collaboratio
Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory
No full textContribution Members: K.B. Barber, J.A. Bellido, R.W. Clay, M.J. Cooper, B.R. Dawson, T.A. Harrison, A.E. Herve, G.C. Hill, V.C. Holmes, M. Malacari, S.J. Saffi, J. Sorokin, P. Wahrlich for the University of Adelaide, Adelaide, S.A., AustraliaWe derive lower bounds on the density of sources of ultra-high energy cosmic rays from the lack of significant clustering in the arrival directions of the highest energy events detected at the Pierre Auger Observatory. The density of uniformly distributed sources of equal intrinsic intensity was found to be larger than ~ (0.06−5) × 10⁻⁴ Mpc⁻³ at 95% CL, depending on the magnitude of the magnetic deflections. Similar bounds, in the range (0.2−7) × 10⁻⁴ Mpc⁻³, were obtained for sources following the local matter distribution.The Pierre Auger collaboratio
The Pierre Auger Observatory scaler mode for the study of solar activity modulation of galactic cosmic rays
No full textSince data-taking began in January 2004, the Pierre Auger Observatory has been recording the count rates of low energy secondary cosmic ray particles for the self-calibration of the ground detectors of its surface detector array. After correcting for atmospheric effects, modulations of galactic cosmic rays due to solar activity and transient events are observed. Temporal variations related with the activity of the heliosphere can be determined with high accuracy due to the high total count rates. In this study, the available data are presented together with an analysis focused on the observation of Forbush decreases, where a strong correlation with neutron monitor data is found.Comision Nacional de Energia Atomica, ArgentinaFundacion AntorchasGobierno De La Provincia de Mendoza, Municipalidad de Malargue, ArgentinaNDM HoldingsValle Las Lenas, ArgentinaAustralian Research Council (ARC)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Financiadora de Estudos e Projetos (FINEP)Fundação de Amparo à Pesquisa do Estado do Rio de Janeiro (FAPERJ)Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Ministério da Ciência, Tecnologia e Inovação do Brasil (MCTI)Academy of Sciences of the Czech Republic (AVCR) [AV0Z10100502] [AV0Z10100522] [GAAV KJB300100801] [KJB100100904] [MSMT-CR LA08016] [LC527] [1M06002] [MSM0021620859]Centre National de la Recherche Scientifique (CNRS), Centre de Calcul IN2P3/CNRSConseil Regional Ile-de-France, Departement Physique Nucleaire et Corpusculaire [PNC-IN2P3/CNRS]Departement Sciences de l`Univers (SDU-INSU/CNRS), FranceBundesministerium fur Bildung und Forschung (BMBF)Deutsche Forschungsgemeinschaft (DFG)Finanzministerium Baden-WurttembergHelmholtz-Gemeinschaft Deutscher Forschungszentren (HGF)Ministerium fur Wissenschaft und Forschung, Nordrhein-Westfalen, GermanyMinisterium fur Wissenschaft, Forschung und Kunst, Baden-Wurttemberg, GermanyIstituto Nazionale di Fisica Nucleare (INFN)Istituto Nazionale di Astrofisica (INAF)Ministero dell Istruzione, dell Universita e della Ricerca (MIUR), ItalyConsejo Nacional de Ciencia y Tecnologia (CONACYT), MexicoMinisterie van Onderwijs, Cultuur en Wetenschap, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO)Stichting voor Fundamenteel Onderzoek der Materie (FOM), NetherlandsMinistry of Science and Higher Education, Poland [1 P03 D 014 30] [N N202 207238]Fundacao para a Ciencia e a Tecnologia (FCT), PortugalMinistry for Higher Education, Science, and Technology, Slovenian Research Agency, SloveniaComunidad de Madrid, SpainConsejeria de Educacion de la Comunidad de Castilla La ManchaFondo Europeo de Desarrollo Regional (FEDER)Ministerio de Ciencia e Innovacion, Consolider-Ingenio, SpainGeneralitat ValencianaJunta de AndaluciaXunta de Galicia, SpainScience and Technology Facilities Council, United KingdomU.S. Department of Energy (DOE) [DE-AC02-07CH11359] [DE-FR02-04ER41300]National Science Foundation (NSF) [0450696]Grainger Foundation USAALFA-EC / HELENEuropean Union [MEIF-CT-2005-025057] [PIEF-GA-2008-220240]United Nations Educational, Scientific and Cultural Organization (UNESCO
Description of atmospheric conditions at the Pierre Auger Observatory using the Global Data Assimilation System (GDAS)
No full textAtmospheric conditions at the site of a cosmic ray observatory must be known for reconstructing observed extensive air showers. The Global Data Assimilation System (GDAS) is a global atmospheric model predicated on meteorological measurements and numerical weather predictions. GDAS provides altitude-dependent profiles of the main state variables of the atmosphere like temperature, pressure, and humidity. The original data and their application to the air shower reconstruction of the Pierre Auger Observatory are described. By comparisons with radiosonde and weather station measurements obtained on-site in Malargüe and averaged monthly models, the utility of the GDAS data is shown. © 2012 Elsevier B.V. All rights reserved.The Pierre Auger Collaboration... K. B. Barber... J. A. Bellido... R. W. Clay... M. J. Cooper... B. R. Dawson... T. A. Harrison... A. E. Herve... V. C. Holmes... J. Sorokin... P. Wahrlich... B. J. Whelan... et al
The fluorescence detector of the Pierre Auger Observatory
No full textThe Pierre Auger Observatory is a hybrid detector for ultra-high energy cosmic rays. It combines a surface array to measure secondary particles at ground level together with a fluorescence detector to measure the development of air showers in the atmosphere above the array. The fluorescence detector comprises 24 large telescopes specialized for measuring the nitrogen fluorescence caused by charged particles of cosmic ray air showers. In this paper we describe the components of the fluorescence detector including its optical system, the design of the camera, the electronics, and the systems for relative and absolute calibration. We also discuss the operation and the monitoring of the detector. Finally, we evaluate the detector performance and precision of shower reconstructions.The successful installation and commissioning of the Pierre Auger Observatory would not have been possible without the strong commitment and effort from the technical and administrative staff in Malargue. ¨ We are very grateful to the following agencies and organizations for financial support: Comisio´n Nacional de Energ?´a Ato´mica, Fundacio´n Antorchas, Gobierno De La Provincia de Mendoza, Municipalidad de Malargue, NDM Holdings and Valle Las Len ¨ ˜as, in gratitude for their continuing cooperation over land access, Argentina; the Australian Research Council; Conselho Nacional de Desenvolvimento Cient?´fico e Tecnolo´ gico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundac-ao de Amparo ~ a Pesquisa do Estado de Rio de Janeiro (FAPERJ), Fundac-ao de Amparo ~ a Pesquisa do Estado de Sao Paulo (FAPESP), Ministe ~ ´ rio de Ciencia e ˆ Tecnologia (MCT), Brazil; AVCR AV0Z10100502 and AV0Z10100522, GAAV KJB300100801 and KJB100100904, GACR 202/06/P006, MSMT-CR LA08016, LC527, 1M06002 and MSM0021620859, Czech Republic; Centre de Calcul IN2P3/CNRS, Centre National de la Recherche Scientifique (CNRS), Conseil Re´gional Ile-de-France, De´partement Physique Nucle´aire et Corpusculaire (PNC-IN2P3/CNRS), De´partement Sciences de l’Univers (SDU-INSU/CNRS), France; Bundesministerium fur Bildung ¨ und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DFG), Finanzministerium Baden-Wurttemberg, Helmholtz-Ge- ¨ meinschaft Deutscher Forschungs- zentren (HGF), Ministerium fur Wissenschaft und Forschung, Nordrhein-Westfalen, Minister- ¨ ium fur Wissenschaft, Forschung und Kunst, Baden-W ¨ u rttem- ¨ berg, Germany; Istituto Nazionale di Fisica Nucleare (INFN), Ministero dell’Istruzione, dell’Universita e della Ricerca (MIUR), Italy; Consejo Nacional de Ciencia y Tecnolog?´a (CONACYT), Mexico; Ministerie van Onderwijs, Cultuur en Wetenschap, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Stichting voor Fundamenteel Onderzoek der Materie (FOM), Netherlands; Ministry of Science and Higher Education, Grant nos. 1 P03 D 014 30, N202 090 31/0623, and PAP/218/2006, Poland; Fundac-ao~ para a Ciencia e a Tecnologia, Portugal; Ministry ˆ for Higher Education, Science, and Technology, Slovenian Research Agency, Slovenia; Comunidad de Madrid, Consejer?´a de Educacio´n de la Comunidad de Castilla La Mancha, FEDER funds, Ministerio de Ciencia e Innovacio´n, Xunta de Galicia, Spain; Science and Technology Facilities Council, UK; Department of Energy, Contract no. DE-AC02-07CH11359, National Science Foundation, Grant no. 0450696, The Grainger Foundation USA; ALFA-EC/HELEN, European Union Sixth Framework Program, Grant no. MEIF-CT-2005-025057, European Union Seventh Framework Program, Grant no. PIEF-GA-2008-220240 and UNESCO.https://www.sciencedirect.com/science/article/pii/S016890021000872
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