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[show abstract]
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ABSTRACT: We consider the production of neutrinos in active galactic nuclei (AGN) through hadronic cascades. The initial, high energy nucleons are accelerated in a source above the accretion disk around the central black hole. From the source, the particles diffuse back to the disk and initiate hadronic cascades. The observable output from the cascade are electromagnetic radiation and neutrinos. We use the observed diffuse background X-ray luminosity, which presumably results {}from this process, to predict the diffuse neutrino flux close to existing limits from the Frejus experiment. The resulting neutrino spectrum is $E^{-2}$ down to the $\GeV$ region. We discuss modifications of this scenario which reduce the predicted neutrino flux.
12/1992;
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P. Abreu,
M. Aglietta,
M. Ahlers,
E. J. Ahn,
I. F. M. Albuquerque,
D. Allard,
I. Allekotte,
J. Allen,
P. Allison,
A. Almela, [......],
A. Yushkov,
B. Zamorano,
E. Zas,
D. Zavrtanik,
M. Zavrtanik,
I. Zaw,
A. Zepeda,
Y. Zhu,
M. Zimbres Silva,
M. Ziolkowski
[show abstract]
[hide abstract]
ABSTRACT: The Surface Detector of the Pierre Auger Observatory is sensitive to neutrinos of all flavors above 0.1 EeV. These interact through charged and neutral currents in the atmosphere giving rise to extensive air showers. When interacting deeply in the atmosphere at nearly horizontal incidence, neutrinos can be distinguished from regular hadronic cosmic rays by the broad time structure of their shower signals in the water-Cherenkov detectors. In this paper we present for the first time an analysis based on down-going neutrinos. We describe the search procedure, the possible sources of background, the method to compute the exposure and the associated systematic uncertainties. No candidate neutrinos have been found in data collected from 1 January 2004 to 31 May 2010. Assuming an E-2 differential energy spectrum the limit on the single-flavor neutrino is E2dN/dE<1.74×10-7GeVcm-2s-1sr-1 at 90% C.L. in the energy range 1×1017eV<E<1×1020eV.
Phys. Rev. D. 01/1970; 84(12).
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Pierre Auger The,
J Collaboration,
Abraham,
P Abreu,
M Aglietta,
C Aguirre,
E J Ahn,
D Allard,
I Allekotte,
J Allen, [......],
D Monnier Ragaigne,
F Montanet,
B Morales,
C Morello,
J C Moreno,
C Morris,
M Mostafá,
C A Moura,
S Mueller,
M A Muller
J. Coppens Hojvat K.H. Kampert T. Karova R.M. Kieckhafer J. Kleinfeller R. Knapik J. Knapp J.L. Navarro P. Necesal C. Newman-Holmes P.T. Nhung J. Oehlschläger V.M. Olmos-Gilbaja J. Pallotta. 01/1927; 27(27).
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[show abstract]
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ABSTRACT: The Standard Leaky Box model is based on an injection spectrum close to E −2 as a natural consequence of strong parallel shock acceleration. Accordingly, an empirical en-ergy dependence of E −0.6 for propagation distance in the Galaxy is invoked to interpret the observed spectrum below 10 5 GeV. There are strong arguments, on the other hand, that the interstellar propagation must be based on turbulent diffu-sion with an energy dependence of E −1/3 . A theory of origin and transport of cosmic-rays incorporating this concept has already been formulated. In this theory the bulk of cosmic-ray spallation takes place in the shell of stellar winds, and light and heavy nuclei have different propagation parame-ters. The diffusive parameters are obtained from the primary source spectra and are calculated from the measurement of observed secondary fluxes. The observational data on heavy secondaries such as Sc, Ti and V, and B, determine the pa-rameters of massive stellar wind shells, while measurement of light secondary elements such as ¯ p together with heavy secondary particles constrain the surrounding region of both low and high mass stars. The inferred propagation parame-ters also depend on the choice of the initial mass function of stars. Once these parameters are set, they can be checked by measurement of other secondaries such as 3 He, 2 H, and γ. In this report we discuss how this modeling is done.
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J. Petrovic,
W.D. Apel,
F. Badea,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog, [......],
S. Valchierotti,
J. van Buren,
W. van Capellen,
W. Walkowiak,
A. Weindl,
S. Winjnholds,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D. Zimmermann
6:337.
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S. Nehls,
W.D. Apel,
F. Badea,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog, [......],
S. Valchierotti,
J. van Buren,
W. van Capellen,
W. Walkowiak,
A. Weindl,
S. Wijnholds,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D. Zimmermann
8:45.
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S. Lafebre,
A. Nigl,
W.D. Apel,
F. Badea,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer, [......],
S. Valchierotti,
J. van Buren,
W. van Capellen,
W. Walkowiak,
A. Weindl,
S. Wijnholds,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D. Zimmermann
8:245.
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A.F. Badea,
W.D. Apel,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog,
I.M. Brancus, [......],
S. Valchierotti,
J. van Buren,
W. van Capellen,
W. Walkowiak,
A. Weindl,
S. Wiknholds,
J. Wochele,
J. Zabierowski,
J.A. Zensuz,
D. Zimmermann
6:277.
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S. Buitink,
W.D. Apel,
F. Badea,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog, [......],
S. Valchierotti,
J. van Buren,
W. van Capellen,
W. Walkowiak,
A. Weindl,
S. Winjnholds,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D Zimmermann
6:333.
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A.F. Badea,
W.D. Apel,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog,
I.M. Brancus, [......],
S. Valchierotti,
J. van Buren,
W. van Capellen,
W. Walkowiak,
A. Weindl,
S. Wijnholds,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D. Zimmermann
6:273.
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A. Haungs,
W.D. Apel,
J.C. Arteaga,
T. Asch,
J. Auffenberg,
F. Badea,
L. Bähren,
K. Bekk,
M. Bertaina, P.L. Biermann, [......],
M. Stümpert,
G. Toma,
G.C. Trinchero,
H. Ulrich,
W. Walkowiak,
A. Weindl,
J. Wochele,
M. Wommer,
J. Zabierowski,
J.A. Zensus
[show abstract]
[hide abstract]
ABSTRACT: LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from extensive air showers. Since radio waves suffer very little attenuation, radio measurements allow the detection of very distant or highly inclined showers. These waves can be recorded day and night, and provide a bolometric measure of the leptonic shower component. LOPES is designed as a digital radio interferometer using high bandwidths and fast data processing and profits from the reconstructed air shower observables of KASCADE-Grande. The LOPES antennas are absolutely amplitude calibrated allowing to reconstruct the electric field strength which can be compared with predictions from detailed Monte-Carlo simulations. We report about the analysis of correlations present in the radio signals measured by the LOPES 30 antenna array. Additionally, LOPES operates antennas of a different type (LOPESSTAR) which are optimized for an application at the Pierre Auger Observatory. Status, recent results of the data analysis and further perspectives of LOPES and the possible large scale application of this new detection technique are discussed.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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T. Huege,
W.D. Apel,
T. Asch,
A.F. Badea,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer, [......],
G. Toma,
G.C. Trinchero,
H. Ulrich,
J. van Buren,
W. Walkowiak,
A. Weindl,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: In the last few years, radio detection of cosmic ray air showers has experienced a true renaissance, becoming manifest in a number of new experiments and simulation efforts. In particular, the LOPES project has successfully implemented modern interferometric methods to measure the radio emission from extensive air showers. LOPES has confirmed that the emission is coherent and of geomagnetic origin, as expected by the geosynchrotron mechanism, and has demonstrated that a large scale application of the radio technique has great potential to complement current measurements of ultra-high energy cosmic rays. We describe the current status, most recent results and open questions regarding radio detection of cosmic rays and give an overview of ongoing research and development for an application of the radio technique in the framework of the Pierre Auger Observatory.
Nuclear Physics B - Proceedings Supplements.
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W.D. Apel,
J.C. Arteaga,
T. Asch,
A.F. Badea,
L. Bähren,
K. Bekk,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog, [......],
O. Sima,
K. Singh,
G. Toma,
G.C. Trinchero,
H. Ulrich,
A. Weindl,
J. Wochele,
M. Wommer,
J. Zabierowski,
J.A. Zensus
[show abstract]
[hide abstract]
ABSTRACT: The antenna array LOPES is set up at the location of the KASCADE-Grande extensive air shower experiment in Karlsruhe, Germany and aims to measure and investigate radio pulses from extensive air showers. The coincident measurements allow us to reconstruct the electric field strength at observation level in dependence of general EAS parameters. In the present work, the lateral distribution of the radio signal in air showers is studied in detail. It is found that the lateral distributions of the electric field strengths in individual EAS can be described by an exponential function. For about 20% of the events a flattening towards the shower axis is observed, preferentially for showers with large inclination angle. The estimated scale parameters R0, describing the slope of the lateral profiles range between 100 and 200 m. No evidence for a direct correlation of R0 with shower parameters like azimuth angle, geomagnetic angle, or primary energy can be found. This indicates that the lateral profile is an intrinsic property of the radio emission during the shower development which makes the radio detection technique suitable for large scale applications.
Astroparticle Physics.
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T. Huege,
W.D. Apel,
J.C. Arteaga,
T. Asch,
L. Bähren,
K. Bekk,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog, [......],
A. Schmidt,
F.G. Schröder,
O. Sima,
G. Toma,
G.C. Trinchero,
A. Weindl,
J. Wochele,
M. Wommer,
J. Zabierowski,
J.A. Zensus
[show abstract]
[hide abstract]
ABSTRACT: The LOPES experiment at the Karlsruhe Institute of Technology has been taking radio data in the frequency range from 40 to 80 MHz in coincidence with the KASCADE-Grande air shower detector since 2003. Various experimental configurations have been employed to study aspects such as the energy scaling, geomagnetic dependence, lateral distribution, and polarization of the radio emission from cosmic rays. The high quality per-event air shower information provided by KASCADE-Grande has been the key to many of these studies and has even allowed us to perform detailed per-event comparisons with simulations of the radio emission. In this article, we give an overview of results obtained by LOPES, and present the status and perspectives of the ever-evolving experiment.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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J.R. Hörandel,
W.D. Apel,
J.C. Arteaga,
T. Asch,
F. Badea,
L. Bähren,
K. Bekk,
M. Bertaina, P.L. Biermann,
J. Blümer, [......],
O. Sima,
K. Singh,
G. Toma,
G.C. Trinchero,
H. Ulrich,
A. Weindl,
J. Wochele,
M. Wommer,
J. Zabierowski,
J.A. Zensus
[show abstract]
[hide abstract]
ABSTRACT: A new method is explored to detect extensive air showers: the measurement of radio waves emitted during the propagation of the electromagnetic shower component in the magnetic field of the Earth. Recent results of the pioneering experiment LOPES are discussed. It registers radio signals in the frequency range between 40 and 80 MHz. The intensity of the measured radio emission is investigated as a function of different shower parameters, such as shower energy, angle of incidence, and distance to shower axis. In addition, new antenna types are developed in the framework of LOPESstar and new methods are explored to realize a radio self-trigger algorithm in real time.
Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.
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[show abstract]
[hide abstract]
ABSTRACT: In this second paper, in a series of two, we determine the properties of the stellar torus that we showed in the first paper to result as a product of two merging black holes. If the surrounding stellar cluster is as massive as the binary black hole, the torque acting on the stars ejects a fraction which extracts the binary's angular momentum. After the black holes coalesced on scales of similar to10(7) yr, a geometrically thick torus remained. In the present article we show that a certain fraction of the stars has winds, shaped into elongated tails by the central radiation pressure, which are optically thick for line of sights aligned with them. These stars are sufficiently numerous to achieve a covering factor of 1, so that the complete torus is optically thick. This patchy structured torus is then compared with observations. We find the parameters of such a torus to be just in the right range in order to explain the observed large column densities in AGN and their temporal variations on time scales of about a decade. Within this model the broad absorption line quasars can be interpreted as quasars seen at intermediate inclination angles, with the line of sight grazing the edge of the torus. The half- opening angle of the torus is wider for major mergers and thus correlates with the central luminosity, as has been suggested previously. In this picture the spin of the merged black hole is possibly dominated by the orbital angular momentum of the binary. Thus the spin of the merged black hole points into a new direction, and consequently the jet experiences a spin-flip according to the spin-paradigm. This re-orientation could be an explanation for the X-shaped radio galaxies, and the advancing of a new jet through the ambient medium for Compact Symmetric Objects.
Astronomy & Astrophysics, v.396, 91-108 (2002).
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J. Abraham,
P. Abreu,
M. Aglietta,
C. Aguirre,
E.J. Ahn,
D. Allard,
I. Allekotte,
J. Allen,
P. Allison,
J. Alvarez-Muñiz, [......],
H. Wu,
B. Wundheiler,
P. Younk,
G. Yuan,
E. Zas,
D. Zavrtanik,
M. Zavrtanik,
I. Zaw,
A. Zepeda,
M. Ziolkowski
[show abstract]
[hide abstract]
ABSTRACT: From direct observations of the longitudinal development of ultra-high energy air showers performed with the Pierre Auger Observatory, upper limits of 3.8%, 2.4%, 3.5% and 11.7% (at 95% c.l.) are obtained on the fraction of cosmic-ray photons above 2, 3, 5 and 10 EeV , respectively. These are the first experimental limits on ultra-high energy photons at energies below 10 EeV. The results complement previous constraints on top–down models from array data and they reduce systematic uncertainties in the interpretation of shower data in terms of primary flux, nuclear composition and proton-air cross-section.
Astroparticle Physics.
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J. Abraham,
P. Abreu,
M. Aglietta,
C. Aguirre,
E.J. Ahn,
D. Allard,
I. Allekotte,
J. Allen,
P. Allison,
J. Alvarez-Muñiz, [......],
B. Wundheiler,
T. Yamamoto,
P. Younk,
G. Yuan,
E. Zas,
D. Zavrtanik,
M. Zavrtanik,
I. Zaw,
A. Zepeda,
M. Ziolkowski
[show abstract]
[hide abstract]
ABSTRACT: Atmospheric parameters, such as pressure (P), temperature (T) and density (ρ∝P/T), affect the development of extensive air showers initiated by energetic cosmic rays. We have studied the impact of atmospheric variations on extensive air showers by means of the surface detector of the Pierre Auger Observatory. The rate of events shows a ∼10% seasonal modulation and ∼2% diurnal one. We find that the observed behaviour is explained by a model including the effects associated with the variations of P and ρ. The former affects the longitudinal development of air showers while the latter influences the Molière radius and hence the lateral distribution of the shower particles. The model is validated with full simulations of extensive air showers using atmospheric profiles measured at the site of the Pierre Auger Observatory.
Astroparticle Physics.
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Encyclopedia of Physical Science and Technology, Vol. 3, 823-835 (2002).
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W.D. Apel,
T. Asch,
A.F. Badea,
L. Bähren,
K. Bekk,
A. Bercuci,
M. Bertaina, P.L. Biermann,
J. Blümer,
H. Bozdog, [......],
G. Toma,
G.C. Trinchero,
H. Ulrich,
J. van Buren,
W. Walkowiak,
A. Weindl,
J. Wochele,
J. Zabierowski,
J.A. Zensus,
D. Zimmermann
[show abstract]
[hide abstract]
ABSTRACT: Data taken during half a year of operation of 10 LOPES antennas (LOPES-10), triggered by EAS observed with KASCADE-Grande have been analysed. We report about the analysis of correlations of radio signals measured by LOPES-10 with extensive air shower events reconstructed by KASCADE-Grande, including shower cores at large distances. The efficiency of detecting radio signals induced by air showers up to distances of 700 m from the shower axis has been investigated. The results are discussed with special emphasis on the effects of the reconstruction accuracy for shower core and arrival direction on the coherence of the measured radio signal. In addition, the correlations of the radio pulse amplitude with the primary cosmic ray energy and with the lateral distance from the shower core are studied.
Astroparticle Physics.
