Limits to the diffuse flux of UHE tau neutrinos at EeV energies from the Pierre Auger Observatory

With the Pierre Auger Observatory we have the capability of detecting ultra-high energy neutrinos by searching for very inclined showers with a significant electromagnetic component. In this work we discuss the discrimination power of the instrument for earth skimming tau neutrinos with ultra-high energies. Based on the data collected since January 2004 an upper limit to the diffuse flux of neutrinos atEeV energies is presented and systematic uncertainties are discussed.Comment: To be published in Proceedings of the 30th International Cosmic Ray Conference, July 3 - 11, 2007, Merida, Yucatan, Mexico. 4 pages, 5 figure

Exploring the Gamma Ray Horizon with the next generation of Gamma Ray Telescopes. Part 1: Theoretical predictions

The physics potential of the next generation of Gamma Ray Telescopes in exploring the Gamma Ray Horizon is discussed. It is shown that the reduction in the Gamma Ray detection threshold might open the window to use precise determinations of the Gamma Ray Horizon as a function of the redshift to either put strong constraints on the Extragalactic Background Light modeling or to obtain relevant independent constraints in some fundamental cosmological parameters.Comment: Updated contents, 19 pages, 8 figure

A modified Lax-Wendroff correction for wave propagation in media described by Zener elements

A modified Lax-Wendroff correction for wave propagation in attenuating and dispersive media described by Zener elements is presented. As opposed to the full correction, this new technique is explicit and offers large computational savings. The technique may be applied to a wide variety of hyperbolic problems. Here, the concept is illustrated for wave propagation in visco-acoustic medi

Ultra High Energy neutrinos with the Pierre Auger Observatory

texte intégral disponible sur http://proc.sf2a.asso.fr/2006/2006sf2a.conf..0115B.pdfInternational audienceThe Pierre Auger Observatory was designed to observe cosmic rays of ultra-high energy. It has also the capability to observe rare neutrino-induced showers. An evaluation of the sensitivity of the Surface Detector is presented and a procedure to discriminate them from the background is described

Exploring the Gamma Ray Horizon with the next generation of Gamma Ray Telescopes. Part 3: Optimizing the observation schedule of gamma-ray sources for the extraction of cosmological parameters

The optimization of the observation schedule of gamma-ray emitters by the new generation of Cherenkov Telescopes to extract cosmological parameters from the measurement of the Gamma Ray Horizon at different redshifts is discussed. It is shown that improvements over 30% in the expected cosmological parameter uncertainties can be achieved if instead of equal-observation time, dedicated observation schedules are applied.Comment: 13 pages, 3 figure