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Author |
Pierre Auger Collaboration (Abreu, P. et al); Pastor, S. |
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Title |
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter |
Type |
Journal Article |
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Year |
2010 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
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Volume |
34 |
Issue |
5 |
Pages |
314-326 |
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Keywords |
Cosmic rays; UHECR; Anisotropy; Pierre Auger Observatory; Extra-galactic; GZK |
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Abstract |
Data collected by the Pierre Auger Observatory through 31 August 2007 showed evidence for anisotropy in the arrival directions of cosmic rays above the Greisen-Zatsepin-Kuz'min energy threshold, 6 x 10(19) eV. The anisotropy was measured by the fraction of arrival directions that are less than 3.1 degrees from the position of an active galactic nucleus within 75 Mpc (using the Veron-Cetty and Veron 12th catalog). An updated measurement of this fraction is reported here using the arrival directions of cosmic rays recorded above the same energy threshold through 31 December 2009. The number of arrival directions has increased from 27 to 69, allowing a more precise measurement. The correlating fraction is (38(-6)(+7))%, compared with 21% expected for isotropic cosmic rays. This is down from the early estimate of (69-(+11)(13))%. The enlarged set of arrival directions is examined also in relation to other populations of nearby extragalactic objects: galaxies in the 2 Microns All Sky Survey and active galactic nuclei detected in hard X-rays by the Swift Burst Alert Telescope. A celestial region around the position of the radiogalaxy Cen A has the largest excess of arrival directions relative to isotropic expectations. The 2-point autocorrelation function is shown for the enlarged set of arrival directions and compared to the isotropic expectation. |
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Address |
[Allekotte, I.; Asorey, H.; Bertou, X.; Golup, G.; Gomez Berisso, M.; Harari, D.; Mollerach, S.; Ponce, V. H.; Roulet, E.] Ctr Atom Bariloche, San Carlos De Bariloche, Rio Negro, Argentina |
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Publisher |
Elsevier Science Bv |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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0927-6505 |
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Conference |
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Notes |
ISI:000284669100007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
320 |
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Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Dornic, D.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
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Title |
Zenith distribution and flux of atmospheric muons measured with the 5-line ANTARES detector |
Type |
Journal Article |
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Year |
2010 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
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Volume |
34 |
Issue |
3 |
Pages |
179-184 |
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Keywords |
Atmospheric muons; Neutrino telescope; Depth-intensity relation |
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Abstract |
The ANTARES high-energy neutrino telescope is a three-dimensional array of about 900 photomultipliers distributed over 12 mooring lines installed in the Mediterranean Sea. Between February and November 2007 it acquired data in a 5-line configuration. The zenith angular distribution of the atmospheric muon flux and the associated depth-intensity relation are measured and compared with previous measurements and Monte Carlo expectations. An evaluation of the systematic effects due to uncertainties on environmental and detector parameters is presented. |
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Address |
[Bazzotti, M.; Biagi, S.; Carminati, G.; Giacomelli, G.; Margiotta, A.; Spurio, M.] Dipartimento Fis Univ, I-40127 Bologna, Italy, Email: Annarita.Margiotta@bo.infn.it |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-6505 |
ISBN |
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Expedition |
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Conference |
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Notes |
ISI:000282496000005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
373 |
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Author |
ANTARES Collaboration (Aguilar, J.A. et al); Bigongiari, C.; Emanuele, U.; Gomez-Gonzalez, J.P.; Hernandez-Rey, J.J.; Mangano, S.; Salesa, F.; Toscano, S.; Yepes, H.; Zornoza, J.D.; Zuñiga, J. |
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Title |
Measurement of the atmospheric muon flux with a 4 GeV threshold in the ANTARES neutrino telescope |
Type |
Journal Article |
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Year |
2010 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
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Volume |
33 |
Issue |
2 |
Pages |
86-90 |
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Keywords |
Atmospheric muons; Depth intensity relation; Potassium-40 |
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Abstract |
A new method for the measurement of the muon flux in the deep-sea ANTARES neutrino telescope and its dependence on the depth is presented. The method is based oil the observation of coincidence signals in adjacent storeys of the detector. This yields an energy threshold of about 4 GeV. The main sources of optical background are the decay of K-40 and the bioluminescence in the sea water. The K-40 background is used to calibrate the efficiency of the photo-multiplier tubes. |
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Address |
[Zaborov, D.] Inst Theoret & Expt Phys, Moscow 117218, Russia, Email: Dmitry.Zaborov@itep.ru |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-6505 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000275514800004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
485 |
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| Permanent link to this record |
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Author |
Pierre Auger Collaboration (Abraham, J. et al); Pastor, S. |
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Title |
A study of the effect of molecular and aerosol conditions in the atmosphere on air fluorescence measurements at the Pierre Auger Observatory |
Type |
Journal Article |
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Year |
2010 |
Publication |
Astroparticle Physics |
Abbreviated Journal |
Astropart Phys. |
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Volume |
33 |
Issue |
2 |
Pages |
108-129 |
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Keywords |
Cosmic rays; Extensive air showers; Air fluorescence method; Atmosphere; Aerosols; Lidar; Bi-static lidar |
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Abstract |
The air fluorescence detector of the Pierre Auger Observatory is designed to perforin calorimetric measurements of extensive air showers created by Cosmic rays of above 10(18) eV. To correct these measurements for the effects introduced by atmospheric fluctuations, the Observatory contains a group Of monitoring instruments to record atmospheric conditions across the detector site, ail area exceeding 3000 km(2). The atmospheric data are used extensively in the reconstruction of air showers, and are particularly important for the correct determination of shower energies and the depths of shower maxima. This paper contains a summary of the molecular and aerosol conditions measured at the Pierre Auger Observatory since the start of regular operations in 2004, and includes a discussion of the impact of these measurements oil air shower reconstructions. Between 10(18) and 10(20) eV, the systematic Uncertainties due to all atmospheric effects increase from 4% to 8% in measurements of shower energy, and 4 g cm(-2) to 8 g cm(-2) in measurements of the shower maximum. |
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Address |
[BenZvi, S.; Pfendner, C.; Westerhoff, S.] Univ Wisconsin, Madison, WI 53706 USA, Email: sybenzvi@icecube.wisc.cdu |
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Corporate Author |
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Thesis |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0927-6505 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000275514800007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
486 |
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Author |
Rodriguez-Alvarez, M.J.; Sanchez, F.; Soriano, A.; Iborra, A. |
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Title |
Sparse Givens resolution of large system of linear equations: Applications to image reconstruction |
Type |
Journal Article |
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Year |
2010 |
Publication |
Mathematical and Computer Modelling |
Abbreviated Journal |
Math. Comput. Model. |
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Volume |
52 |
Issue |
7-8 |
Pages |
1258-1264 |
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Keywords |
Givens rotations; QR-factorization; Computed tomography; Image reconstruction |
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Abstract |
In medicine, computed tomographic images are reconstructed from a large number of measurements of X-ray transmission through the patient (projection data). The mathematical model used to describe a computed tomography device is a large system of linear equations of the form AX = B. In this paper we propose the QR decomposition as a direct method to solve the linear system. QR decomposition can be a large computational procedure. However, once it has been calculated for a specific system, matrices Q and R are stored and used for any acquired projection on that system. Implementation of the QR decomposition in order to take more advantage of the sparsity of the system matrix is discussed. |
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Address |
[Rodriguez-Alvarez, Maria-Jose; Iborra, Amadeo] Univ Politecn Valencia, Inst Matemat Multidisciplinar, E-46022 Valencia, Spain, Email: mjrodri@imm.upv.es |
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Corporate Author |
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Thesis |
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Publisher |
Pergamon-Elsevier Science Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0895-7177 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000280933700043 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
no |
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Call Number |
IFIC @ elepoucu @ |
Serial |
395 |
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| Permanent link to this record |
