121 research outputs found
Cardiac Complications in Patients with Community-Acquired Pneumonia: A Systematic Review and Meta-Analysis of Observational Studies
Vicente Corrales-Medina and colleagues report estimates of the risk of cardiac complications among patients with community-acquired pneumonia from a systematic review and meta-analysis
Measurement of the cosmic ray spectrum above eV using inclined events detected with the Pierre Auger Observatory
A measurement of the cosmic-ray spectrum for energies exceeding
eV is presented, which is based on the analysis of showers
with zenith angles greater than detected with the Pierre Auger
Observatory between 1 January 2004 and 31 December 2013. The measured spectrum
confirms a flux suppression at the highest energies. Above
eV, the "ankle", the flux can be described by a power law with
index followed by
a smooth suppression region. For the energy () at which the
spectral flux has fallen to one-half of its extrapolated value in the absence
of suppression, we find
eV.Comment: Replaced with published version. Added journal reference and DO
Energy Estimation of Cosmic Rays with the Engineering Radio Array of the Pierre Auger Observatory
The Auger Engineering Radio Array (AERA) is part of the Pierre Auger
Observatory and is used to detect the radio emission of cosmic-ray air showers.
These observations are compared to the data of the surface detector stations of
the Observatory, which provide well-calibrated information on the cosmic-ray
energies and arrival directions. The response of the radio stations in the 30
to 80 MHz regime has been thoroughly calibrated to enable the reconstruction of
the incoming electric field. For the latter, the energy deposit per area is
determined from the radio pulses at each observer position and is interpolated
using a two-dimensional function that takes into account signal asymmetries due
to interference between the geomagnetic and charge-excess emission components.
The spatial integral over the signal distribution gives a direct measurement of
the energy transferred from the primary cosmic ray into radio emission in the
AERA frequency range. We measure 15.8 MeV of radiation energy for a 1 EeV air
shower arriving perpendicularly to the geomagnetic field. This radiation energy
-- corrected for geometrical effects -- is used as a cosmic-ray energy
estimator. Performing an absolute energy calibration against the
surface-detector information, we observe that this radio-energy estimator
scales quadratically with the cosmic-ray energy as expected for coherent
emission. We find an energy resolution of the radio reconstruction of 22% for
the data set and 17% for a high-quality subset containing only events with at
least five radio stations with signal.Comment: Replaced with published version. Added journal reference and DO
Measurement of the Radiation Energy in the Radio Signal of Extensive Air Showers as a Universal Estimator of Cosmic-Ray Energy
We measure the energy emitted by extensive air showers in the form of radio
emission in the frequency range from 30 to 80 MHz. Exploiting the accurate
energy scale of the Pierre Auger Observatory, we obtain a radiation energy of
15.8 \pm 0.7 (stat) \pm 6.7 (sys) MeV for cosmic rays with an energy of 1 EeV
arriving perpendicularly to a geomagnetic field of 0.24 G, scaling
quadratically with the cosmic-ray energy. A comparison with predictions from
state-of-the-art first-principle calculations shows agreement with our
measurement. The radiation energy provides direct access to the calorimetric
energy in the electromagnetic cascade of extensive air showers. Comparison with
our result thus allows the direct calibration of any cosmic-ray radio detector
against the well-established energy scale of the Pierre Auger Observatory.Comment: Replaced with published version. Added journal reference and DOI.
Supplemental material in the ancillary file
Bounds on the density of sources of ultra-high energy cosmic rays from the Pierre Auger Observatory
We 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 similar to (0.06 – 5) x 10(-4) Mpc(-3) at 95% CL, depending on the magnitude of the magnetic defections. Similar bounds, in the range (0.2 – 7) x 10(-4) Mpc(-3), were obtained for sources following the local matter distribution.We are very grateful to the following agencies and organizations for financial support,: Comision Nacional de Energia Atomica, Fundacion Antorchas, Gobierno De La, Provincia de Ailendoza. Municipalidad de Malargile. INDM floldings and Valle Las Lenas, in gratitude for their continuing cooperation over land access. Argentina; the Australian Research Council; Conselho Nacional de Desenvolvimento Cientifico e 'Tecnologico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundacdo de Amparo a Pesquisa do Est ado de Rio de Janeiro (FAP HRJ), Fundacdo de Amparo Pesquisa do Estado de Sdo Paulo (FAPESP), Ministerio de Ciencia e Tecnologia (IVICT), Brazil; AVCR AVOZ10100502 and AVOZ10100522, GAAV KJB100100904, AISMT-CR LA08016, LG11044, 1VIEB111003, MSAI0021620859, LA08015, TACR TA01010517 and GA U.K. 119810, Czech Republic; Centre de Calcul I-N2P3/CNRS, Centre National de la -Recherche Scientifique ((1 NRS), Conseil Regional Ile-de-France, f)epartement, Physique Nuclealre et Corpusculaire (I N( Departement Sciences de l'Univers (SDU-INSU/CNRS), France; Bundesministerium fur Bildung und Forschung (BMBF), Deutsche Forschungsgemeinschaft (DITG), Finanzministerium Baden-Wurttemberg, flelmholtz-Gemeinschaft Deutscher Forschungszentren Ministerium fur Wissenschaft und Forschung, Nordrhein-Westfalen, Ministerimn fur Wissenschaft, Forschung und Kunst, Baden-WUrttemberg, Germany; Istituto Nazion ale di Fisica Nucleare (INFN), Ministero dell'Istruzione, delhLniversita e della Ricerca (MIUR), Italy: Consejo Nacional de Ciencia y Tecnologia (CONACYT), Mexico; Ministerie van Onden s Cultuur on NVetenschap Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Stichting voor Rmdamenteel Onderzoek der Materie (FOM), Netherlands; Ministry of Science and Higher Education, Grant Nos. N N202 200239 and N N202 207238, Poland; Portuguese national funds and FEDER funds within COMPETE - Programa Operacional Factores de Competitividade through Fundacao para a Ciencia e a Tecnologia, Portugal; Romanian Authority for Scientific Research ANCS, CNDI-UEFISETD1 partnership projects nr.20/2012 and nr.194/2012, project nr.1 /ASPERA2/20I2 ERA-NET and PN-IIRU-PD-2011-3-0145-17, Romania; Ministry for Higher Education, Science, and 'Technology, Slovenian Research Agency, Slovenia; Comunidad de Madrid, FEDER funds, Ministerio de Ciencia e Innovacion and Consolider-Ingenio 2010 (( PAN), X unta de Galicia Spain; Science and Technology Facilities Council, United kingdom; Department of Luergy, Contract Nos. DE-ACO2-07(11-111359, DE-FR02-04E1(41300, DE-FG02-99E1(41107, National Science Foundation, Grant No. 0450696, The Grainger Foundation U.S.A.; NAFOSTED, Vietnam; Marie Curie-IRSES/HPLANET, European Particle Physics Latin American Network, European Union 7th Frarneworlc Program. Grant No. IIRSES-2009-GA-246806; and UNESCO.Peer reviewe
Identifying clouds over the Pierre Auger Observatory using infrared satellite data
We describe a new method of identifying night-time clouds over the Pierre Auger Observatory using infrared data from the Imager instruments on the GOES-12 and GOES-13 satellites. We compare cloud. identifications resulting from our method to those obtained by the Central Laser Facility of the Auger Observatory. Using our new method we can now develop cloud probability maps for the 3000 km(2) of the Pierre Auger Observatory twice per hour with a spatial resolution of similar to 2.4 km by similar to 5.5 km. Our method could also be applied to monitor cloud cover for other ground-based observatories and for space-based observatories. (C) 2013 Elsevier B.V. All rights reserved.The successful installation, commissioning, and operation of the
Pierre Auger Observatory would not have been possible without
the strong commitment and effort from the technical and adminis-
trative staff in Malargüe.
We are very grateful to the following agencies and organiza-
tions for financial support: Comisión Nacional de Energía Atómica,
Fundación Antorchas, Gobierno De La Provincia de Mendoza,
Municipalidad de Malargüe, NDM Holdings and Valle Las Leñas,
in gratitude for their continuing cooperation over land access,
Argentina; the Australian Research Council; Conselho Nacional de
Desenvolvimento Científico e Tecnológico (CNPq), Financiadora
de Estudos e Projetos (FINEP), Fundação de Amparo à Pesquisa do
Estado de Rio de Janeiro (FAPERJ), Fundação de Amparo à Pesquisa
do Estado de São Paulo (FAPESP), Ministério de Ciência e Tecnolo-
gia (MCT), Brazil; AVCR AV0Z10100502 and AV0Z10100522, GAAV
KJB100100904, MSMT-CR LA08016, LG11044, MEB111003,
MSM0021620859, LA08015, TACR TA01010517 and GA UK
119810, Czech Republic; Centre de Calcul IN2P3/CNRS, Centre Na-
tional de la Recherche Scientifique (CNRS), Conseil Régional Ile-de-
France, Département Physique Nucléaire et Corpusculaire (PNC-
IN2P3/CNRS), Département Sciences de l’Univers (SDU-INSU/
CNRS), France; Bundesministerium für Bildung und Forschung
(BMBF), Deutsche Forschungsgemeinschaft (DFG), Finanzministeri-
um Baden-Württemberg, Helmholtz-Gemeinschaft Deutscher
Forschungszentren (HGF), Ministerium für Wissenschaft und
Forschung, Nordrhein-Westfalen, Ministerium für Wissenschaft,
Forschung und Kunst, Baden-Württemberg, Germany; Istituto
Nazionale di Fisica Nucleare (INFN), Ministero dell’Istruzione,
dell’Università e della Ricerca (MIUR), Italy; Consejo Nacional de Ciencia y Tecnología (CONACYT), Mexico; Ministerie van Ond-
erwijs, Cultuur en Wetenschap, Nederlandse Organisatie voor Wet-
enschappelijk Onderzoek (NWO), Stichting voor Fundamenteel
Onderzoek der Materie (FOM), Netherlands; Ministry of Science
and Higher Education, Grant Nos. N N202 200239 and N N202
207238, Poland; Portuguese national funds and FEDER funds with-
in COMPETE - Programa Operacional Factores de Competitividade
through Fundação para a Ciência e a Tecnologia, Portugal; Roma-
nian Authority for Scientific Research ANCS, CNDI-UEFISCDI part-
nership projects nr.20/2012 and nr.194/2012, project nr.1/
ASPERA2/2012 ERA-NET and PN-II-RU-PD-2011-3-0145-17, Roma-
nia; Ministry for Higher Education, Science, and Technology, Slove-
nian Research Agency, Slovenia; Comunidad de Madrid, FEDER
funds, Ministerio de Ciencia e Innovación and Consolider-Ingenio
2010 (CPAN), Xunta de Galicia, Spain; The Leverhulme Foundation,
Science and Technology Facilities Council, United Kingdom;
Department of Energy, Contract Nos. DE-AC02-07CH11359, DE-
FR02-04ER41300, DE-FG02-99ER41107, National Science Founda-
tion, Grant No. 0450696, The Grainger Foundation USA; NAFO-
STED, Vietnam; Marie Curie-IRSES/EPLANET, European Particle
Physics Latin American Network, European Union 7th Framework
Program, Grant No. PIRSES-2009-GA-246806; and UNESCO.
We would like to thank the former Michigan Tech students:
Nathan Kelley-Hoskins, Kyle Luck and Arin Nelson for their impor-
tant contribution to the development of this paper. We would like
to thank NOAA for the GOES satellite data that we freely down-
loaded from their website. Also, we would like to mention in these
acknowledgments Dr. Steve Ackerman and Dr. Tony Schreiner for
very valuable conversationsPeer reviewe
Antennas for the detection of radio emission pulses from cosmic-ray induced air showers at the Pierre Auger Observatory
The Pierre Auger Observatory is exploring the potential of the radio detection technique to study extensive air showers induced by ultra-high energy cosmic rays. The Auger Engineering Radio Array (AERA) addresses both technological and scientific aspects of the radio technique. A first phase of AERA has been operating since September 2010 with detector stations observing radio signals at frequencies between 30 and 80 MHz. In this paper we present comparative studies to identify and optimize the antenna design for the final configuration of AERA consisting of 160 individual radio detector stations. The transient nature of the air shower signal requires a detailed description of the antenna sensor. As the ultra-wideband reception of pulses is not widely discussed in antenna literature, we review the relevant antenna characteristics and enhance theoretical considerations towards the impulse response of antennas including polarization effects and multiple signal reflections. On the basis of the vector effective length we study the transient response characteristics of three candidate antennas in the time domain. Observing the variation of the continuous galactic background intensity we rank the antennas with respect to the noise level added to the galactic signal
Constraints on the origin of cosmic rays above eV from large scale anisotropy searches in data of the Pierre Auger Observatory
A thorough search for large scale anisotropies in the distribution of arrival directions of cosmic rays detected above eV at the Pierre Auger Observatory is reported. For the first time, these large scale anisotropy searches are performed as a function of both the right ascension and the declination and expressed in terms of dipole and quadrupole moments. Within the systematic uncertainties, no significant deviation from isotropy is revealed. Upper limits on dipole and quadrupole amplitudes are derived under the hypothesis that any cosmic ray anisotropy is dominated by such moments in this energy range. These upper limits provide constraints on the production of cosmic rays above eV, since they allow us to challenge an origin from stationary galactic sources densely distributed in the galactic disk and emitting predominantly light particles in all directions.Peer Reviewe
- …