Pierre Auger Observatory Present and Future Ruben Conceição Jornadas LIP 2010 – Braga

Extensive Air Showers (EAS) Cosmic ray spectrum Ultra High Energy Cosmic Rays What are they? Where do they come from? What can we learn with them? Rare events Impossible to detect directly Interact with Earth’s atmosphere creating huge particle showers Tevatron (p-p) LHC (p-p)

Pierre Auger Observatory The Auger Observatory is a "hybrid detector," employing two independent methods to detect and study high-energy cosmic rays: Surface detector (SD) 3000 km2 in the Pampa Argentina 1600 pure water tanks Fluorescence Detector (FD) 4 “eyes” each with 6 telescopes Several systems to monitor the atmosphere Auger is now completed Very high statistics up to 50 EeV Above 50 EeV we get 30 events per year

Energy Spectrum FD Lower energy range SD higher exposure Enough statistics to see GZK cut-off like feature

UHECR Propagation GZK cut-off effect Interaction with CMB photons degrades energy Sources must be nearer than 100 MPc Magnetic fields don’t bend very high energy particles Charged Particle Astronomy!! Access Galactic and Extra-Galatic magnetic fields

Where do they come from? Top energy CR data is anisotropic!! CR energy above 55 EeV Probability of being isotropic is less than 1% Some correlation with AGN distribution is observed The small deviation from AGNs suggests that the particle is a proton?!

What are they? Elongation Rate <Xmax> as a function of the primary energy Iron  56 nucl (E/56) Smaller fluctuactions Smaller Xmax Data goes to a heavier composition as energy increases But elongation rate is also sensitive to hadronic models p-Air Cross-Section Muon excess seen from SD!!! Anisotropy Proton Iron Data Anisotropy

Also a gamma and neutrino detector!! Photons Neutrinos No candidate found yet!!

Next steps… Fully explore the data Reduce systematic uncertainty Auger South Enhancements Auger North

Auger South Enhancements Extension to lower energies High Elevation Auger Telescopes Upgrades Present 2nd knee Ankle AMIGA detectors Auger Muons and Infill for the Ground Array Study muon component of showers Good variable to check hadronic models

Auger North Colorado, USA Increase the statistics of very high energy events 200 events/year above 55 EeV 4000 tanks over 21 000 km2 39 FD telescopes in 5 stations Enables full-sky exposure

Conclusions Auger South is completed and has already given important results GZK like suppression Highest energy events are anisotropic Puzzling scenario: composition change or new physics Further improvements will come from higher statistics and a better control of systematics Auger North will provide a full sky coverage and an important increase on statistics for the highest energy events

Thank you!!

Backup slides

Pierre Auger Observatory The Auger Observatory is a "hybrid detector," employing two independent methods to detect and study high-energy cosmic rays: Surface detector (SD) 3000 km2 in the Pampa Argentina 1600 pure water tanks 1.5 km spacing Flourescence Detector (FD) 4 “eyes” 6 telescopes in each viewing 30o x 30o 4 weather stations (with LIDARs) 2 Laser Facilities FD SD Auger is now completed Very high statistics up to 50 EeV Above 50 EeV we get 30 events per year

Event Reconstruction Surface Detector Fluorescence Detector Tank hit time gives shower direction Energy is obtained using Nch( distance to the shower core ) Evolution in camera gives the shower geometry Energy is calculated by integrating a universal longitudinal profile

Hybrid Technique Better reconstruction geometry Higher Xmax resolution Better energy reconstruction Calibration of SD with FD Reduce systematics Good correlation between SD and FD SD FD

Auger North Expands Auger aperture eight-fold for E>55 EeV 4000 tanks 2.28 km spacing 20 000 km2 Enables full-sky exposure 200 events/year instead of 25 events/year Enables Xmax studies above 55 EeV 39 FD telescopes in 5 stations