25 research outputs found
Update on the correlation of the highest energy cosmic rays with nearby extragalactic matter
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, \nobreak{eV}. The
anisotropy was measured by the fraction of arrival directions that are less
than from the position of an active galactic nucleus within 75 Mpc
(using the V\'eron-Cetty and V\'eron 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 , compared
with expected for isotropic cosmic rays. This is down from the early
estimate of . 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.Comment: Accepted for publication in Astroparticle Physics on 31 August 201
Advanced functionality for radio analysis in the Offline software framework of the Pierre Auger Observatory
The advent of the Auger Engineering Radio Array (AERA) necessitates the
development of a powerful framework for the analysis of radio measurements of
cosmic ray air showers. As AERA performs "radio-hybrid" measurements of air
shower radio emission in coincidence with the surface particle detectors and
fluorescence telescopes of the Pierre Auger Observatory, the radio analysis
functionality had to be incorporated in the existing hybrid analysis solutions
for fluoresence and surface detector data. This goal has been achieved in a
natural way by extending the existing Auger Offline software framework with
radio functionality. In this article, we lay out the design, highlights and
features of the radio extension implemented in the Auger Offline framework. Its
functionality has achieved a high degree of sophistication and offers advanced
features such as vectorial reconstruction of the electric field, advanced
signal processing algorithms, a transparent and efficient handling of FFTs, a
very detailed simulation of detector effects, and the read-in of multiple data
formats including data from various radio simulation codes. The source code of
this radio functionality can be made available to interested parties on
request.Comment: accepted for publication in NIM A, 13 pages, minor corrections to
author list and references in v
Search for First Harmonic Modulation in the Right Ascension Distribution of Cosmic Rays Detected at the Pierre Auger Observatory
We present the results of searches for dipolar-type anisotropies in different
energy ranges above eV with the surface detector array of
the Pierre Auger Observatory, reporting on both the phase and the amplitude
measurements of the first harmonic modulation in the right-ascension
distribution. Upper limits on the amplitudes are obtained, which provide the
most stringent bounds at present, being below 2% at 99% for EeV
energies. We also compare our results to those of previous experiments as well
as with some theoretical expectations.Comment: 28 pages, 11 figure
Depth Of Maximum Of Air-shower Profiles At The Pierre Auger Observatory. I. Measurements At Energies Above 1017.8ev
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Synaptic vesicle pool size, release probability and synaptic depression are sensitive to Ca2+ buffering capacity in the developing rat calyx of Held
Atmospheric Radiation Monitor
The Atmospheric Radiation Monitor (MonRAt) is a compact experiment aiming to measure the fluorescence radiation in the atmosphere initiated by cosmic rays with energies between 100 PeV and 100 EeV. It is composite by a mirror focusing on a multianodic photomultiplier with an ultraviolet filter - selecting photons with wavelengths between 300 and 450 nm - And the data acquisition boards. The monitor is intended to contribute in problems such as the study of fluorescence radiation yield in the atmosphere parameterized with atmospheric conditions.Hara, T., (1970) Acta Phys. Acad. Sci. Hung., 29 (SUPPL. 3), p. 361Baltrusaitus, R.M., (1985) Nucl. Instr. and Meth. in Phys. Res., A240, p. 410Abu-Zayyad, T., (2000) Nucl. Instr. and Meth. in Phys. Res., A450, p. 253Abraham, J., (2004) Nucl. Instr. and Meth. in Phys. Res., A523, p. 50Fukushima, M., (2003) Prog. Theo. Phys. Suppl., 151, p. 206Scarsi, L., (2001) Proc. 27th Int. Cosmic Ray Conf., p. 839. , HamburgStecker, F.W., (2004) Nucl. Phys., B139, p. 433Bunner, A.N., (1967) Cosmic Ray Detection by Atmospheric Fluorescence, , PhD Thesis, Cornell Univ. (FebDavidson, G., O'Neil, R., (1964) J. Chem. Phys., 41, p. 3946Kakimoto, K., (1996) Nucl. Instr. and Meth. in Phys. Res., A372, p. 527Nagano, M., (2003) Astropart. Phys., 20, p. 293Nagano, M., (2004) Astropart. Phys., 22, p. 235Beltz, J.W., (2006) Astropart. Phys., 25, p. 129P. Collin et al. astroph/06121110De Souza, V., Medina-Tanco, G., Ortiz, J.A., (2006) Astropart. Phys., 25, p. 129Leigui De Oliveira, M.A., (2008) Monitor de Radiacao Atmosferica, , XXIX ENFPC, SBF, Sao Lourenco, BrazilHamamatsu Photonics K.K., , http://www.hamamatsu.comHeck, D., Knapp, J., Capdevielle, J.N., Schatz, G., Thouw, T., (1998) Report FZKA 6019, , http://www-ik.fzk.de/heck/publications/fzka6019.pdfFletcher, R.S., (1994) Phys. Rev. D, D50, p. 5710(2001) IPCC Report, , http://www.ipcc.chLeigui De Oliveira, M.A., Peixoto, C.J.T., Leao, M.S.A.B., The ionization energy deposit in the atmosphere and the fluorescence light generation at shower axis (2009) 31stICRC, , Lodz, Session: HE.1.4 . ID=98Flowers, E.C., McCormick, R.A., Kurfis, J., (1969) J. Appl. Meteorology, 8, p. 955Sokolsky, P., (1996) Proc. of Int. Sym. on EHECRs: Astrophysics and Future Observatories, p. 253. , Ed. M. Nagan