P.Auger, a major step: Need high statistics large detection area : 2 x3000 km²

1. Data from Agasa: 100km² x 10 years Auger sky after 3 years of Auger running: ( E>1019 , 15 sources randomly distributed ) 20 months of Auger running: (Cosmologically distributed sources, E-2 spectrum, GZK cut off) The World's Largest Cosmic Ray Detector The Pierre Auger Observatory is designed to detect and study cosmic rays around and above the GZK cutoff, i.e. at energies exceeding 1019 eV, with an unprecedented quality and precision. Within our present knowledge, there is no standard explanation to the production and acceleration of any particle in the universe at such macroscopic energies. To solve this astrophysical puzzle of more than 30 years, an international scientific collaboration has designed and is building Auger. The puzzle of UHECR (Ultra High Energy Cosmic Rays) E>1019eV, “ particles which do exist... But perhaps shouldn’t!”Ludwik M. Celnikier • Physics issues with Auger: • Where does the spectrum end ?Is there a GZK cutoff? Are the sources local (<150 Mly)? • Primary nature (composition) ? • Nuclei? Protons ? • Gamma rays? Neutrinos? Or...? • What is the source of UHECR ? • Bottom-Up or Top-Down scenario ? Auger in 1 year :(existing data) E > 10 EeV 6000 events E > 40 EeV 500 events(100)E > 100 EeV 60 events(9) • P.Auger, a major step: • Need high statistics • large detection area : 2 x3000 km² • Uniform sky coverage • 2 sites located in each hemisphere Argentina and USA • Hybrid detector : • surface array (water Cerenkov tanks) • + fluorescence detector Good energy and pointing resolution, Improved sensitivity to composition • Energy cross calibration On each site: 1600 SD (surface detectors) 4 FD stations (fluorescence detectors) Duty Cycle: Efficiency: SD 100% >90% above 10 EeV FD 10% Energy resolution: SD alone Hybrid mode 100 EeV 15%10% 10 EeV 30%20% Angular resolution: SD alone Hybrid mode 100 EeV 0.5° 0.20° 10 EeV 1.0° 0.35° Northern hemisphere Millard county Utah, USA Southern hemisphere: Malargüe Provincia de Mendoza Argentina Collaboration: >250 researchers from 56 institutions and 20 countries: Argentina, Armenia, Australia, Bolivia, Brazil, Chile, China, Czech Republic, France, Germany, Greece, Italy, Japan, Mexico, Poland, Russia, Slovenia, United Kingdom, United States of America, Vietnam US Auger groups: Colorado, Colorado State, Chicago, Fermilab, LSU, Michigan Tech, Mississippi, Nebraska, New Mexico, Northeastern, Penn State, UCLA, Utah

2. Tanks arriving by truck from Brazil Unloading the tanks Solar panel and electronic box GPSantenna Commantenna Three 8” PM Tubes Battery box White light diffusing liner First tank deployed: Priscila, Queen of the Desert De-ionized water Plastic tank Official ribbon cutting, Nov. 2000 SD tank with a view of the Andes Each detector is powered by a solar panel 2 bays equipped overlooking the EA SD Mirrors 440 PMTs camera Window and filters Auger collaborators march in the Malargue 50th Anniversary parade (with flamenco dancers), Nov. 2000 Installing electronics boxes Building the Engineering Array at the Southern Site 2001: Engineering Array 15 april 38 SD detectors covering 70km² 15 june 2 FD camera (each 30 x30°) 2004: Southern site completed The surface detector array is on a flat plane at 1400 m altitude • Surface Detector status: • Water purification plant operational • Detector assembly building at Central Site is completed and in use. Data acquisition equipment (CDAS) has been installed and is operating. • Brackets for the solar panels and electronics now include the 3 m communications antenna mast (improved previous design). • All solar panels and battery boxes have been delivered. • 18 tanks have been deployed into the field; 13 are filled with water. • Installation of the electronics and the mounting of PMT’s has started • By end of March, all 40 EA tanks (38 in field + 2 control) will be deployed and filled with water. The pampa amarilla, 3000 km2 of grassland 38 tanks of the Engineering Array • Fluorescence Detector status: • Auger now has access to the Los Leones fluorescence building. • The telescope alignment reference points are being installed. • The mirror support systems for both telescopes and one set of mirrors are on site and ready for installation. • Data link from Los Leones to Central Campus is now operational. Central campus and Assembly Hall Los Leones: the first 2 fluorescence detectors overlooking the EA Filter window detail View from one of the telescope bays Open house for the public Town of Malargüe Completing the comms tower The completed FD building will house 6 telescope/ camera arrays