Search for point-like sources of ultra-high energy neutrinos at the Pierre Auger Observatory and improved limit on the diffuse flux of tau neutrinos

THE PIERRE AUGER COLLABORATION: SON 511 AUTORES, A.C. ROVERO

Astrophysical Journal Letters

The American Astronomical Society

Lugar: Londres; Año: 2012 vol. 755 p. 1 - 21

2041-8205

The surface detector array of the Pierre Auger Observatory can detect neutrinos with energy E_nu between 10^17 eV and 10^20 eV from point-like sources across the sky south of +55° and north of -65° declinations. A search has been performed for highly inclined extensive air showers produced by the interaction of neutrinos of all flavors in the atmosphere (downward-going neutrinos), and by the decay of tau leptons originating from tau neutrino interactions in Earth´s crust (Earth-skimming neutrinos). No candidate neutrinos have been found in data up to 2010 May 31. This corresponds to an equivalent exposure of approx 3.5 years of a full surface detector array for the Earth-skimming channel and approx. 2 years for the downward-going channel. An improved upper limit on the diffuse flux of tau neutrinos has been derived. Upper limits on the neutrino flux from point-like sources have been derived as a function of the source declination. Assuming a differential neutrino flux k_ps E_nu^-2 from a point-like source, 90% confidence level upper limits for k_ps at the level of 5 × 10^-7 and 2.5 × 10^-6 GeV cm^-2 s^-1 have been obtained over a broad range of declinations from the searches for Earth-skimming and downward-going neutrinos, respectively.