The National Science FoundationThe Kavli Foundation Mapping the Ultra-high--energy Cosmic-ray Sky with the Pierre Auger Observatory Vasiliki Pavlidou for Group U. Chicago: M. Ave, L. Cazon, J. Cronin, J. de Mello Neto, F. Ionita, A. Olinto, V. Pavlidou, B. Siffert, F. Schmidt, T. Venters

The National Science FoundationThe Kavli Foundation Outline Alternative messengers: the final mapping frontier Ultra-high--energy cosmic ray astronomy The Pierre Auger Observatory Astronomy with Auger Outlook

The National Science FoundationThe Kavli Foundation Alternative Messengers: the Final Frontier Humanity: a pre-warp civilization Cartography: a messenger- based enterprise Conventional messengers: photons Alternative messengers: –Neutrinos –Gravitational waves –Charged nuclei (cosmic rays) not yet available…

The National Science FoundationThe Kavli Foundation Charged Particle Astronomy Difficult! Deflections in B-field Only at highest energies could deflections be small Still… –At highest energies source fluxes extremely low –Very hard to obtain adequate statistics to resolve sources if fighting against isotropic background R gyro = 0.11 Mpc E 20 /ZB  G E~10 20 eV B<10nG R>11Mpc Low-energy cosmic ray sky S. Swordy

The National Science FoundationThe Kavli Foundation Charged Particle Astronomy II Hope: isotropic background goes away at highest energies –At highest energies E~10 20 eV : GZK  horizon  only nearby sources accessible  strong deviations form isotropy? E. Armengaud sims by A. Kravtsov D. Allard

The National Science FoundationThe Kavli Foundation Charged Particle Astronomy II Hope: isotropic background goes away at highest energies –At highest energies E~10 20 eV : GZK  horizon  only nearby sources accessible  strong deviations from isotropy? Horizon necessary but not sufficient to see anisotropies –Intergalactic B-field has to be sufficiently small! –Expectations from theory not clear-cut: Dolag et al. (2004): Deflections small (  few degrees), expect strong anisotropies Sigl et al (2004): Deflections large (  tens of degrees), anisotropies smeared

The National Science FoundationThe Kavli Foundation UHECRs: the questions Highest energy particles (> eV) –Spectrum? – Protons, heavier nuclei, photons? – Top-down or bottom-up? – Local or cosmological? – Sources?

The National Science FoundationThe Kavli Foundation Detecting UHECRs Credit: Cosmus team ( )

The National Science FoundationThe Kavli Foundation The Pierre Auger Observatory of Ultra-high Energy Cosmic Rays ~400 scientists from ~70 Institutions and 17 countries 1554 deployed 1509 filled 1464 taking data AIM: 1600 tanks, 3,000km 2

The National Science FoundationThe Kavli Foundation Astronomy with Auger Hybrid experiment (fluorescence telescopes + surface detector array) –better energy determination –better exposure determination –better arrival direction reconstruction (typically <1°) Credit: Cosmus team ( )

The National Science FoundationThe Kavli Foundation The highest-energy Auger spectrum Residuals from a standard spectrum ± ± ± 0.4 Pierre Auger Collaboration

The National Science FoundationThe Kavli Foundation What would we look for? GZK  No background  event  nearby source Very few events –Does the sky look isotropic? –With very few events, very easy to get compatibility with isotropy –If incompatibility with isotropy, signal must be strong –On the other hand: with very few events, every realization of isotropy special –The Auger Collaboration anisotropies policy

The National Science FoundationThe Kavli Foundation Auger Highest-energy Sky Map The Pierre Auger Collaboration

The National Science FoundationThe Kavli Foundation Is The Map Anisotropic? The search: using data between 01Jan 2004 and 26 May 2006 –Correlation of E>E min events with VC catalog AGN of z<z max within  degrees. Optimize (E min, z max,  ) to maximize deviation from isotropy The prescription: –FIX test parameters: E min = 56EeV, z max =0.018,  =3.1degrees – accumulate new data. Terminate test when probability of isotropy to have yielded new data < 1% The confirmation: –Data collected between 27 May 2006 and 31 August 2007 –Signal so strong it only required 8 new events to fulfill prescription –From 8 new events 6 correlate, probability to get from isotropy <1% Combining old + new data, accounting for “trials” over the 3 parameters: –False positives occur only once every 10 5 isotropic realizations

The National Science FoundationThe Kavli Foundation What does this mean? The highest-energy cosmic-ray sky is anisotropic! (sources still unclear) Intergalactic B-field small, cosmic rays good messengers for mapping the nearby universe Astrophysics! –UHECR source identification, study –Timely concurrent operation with gamma-ray, neutrino, and low-energy photon observatories –UHECR astronomy possible: time to build a bigger telescope!  Auger North

The National Science FoundationThe Kavli Foundation Auger North Planned location in Colorado, US Full-sky coverage Optimized for operation in energies where arrival directions are anisotropic Sufficient exposure to: –Detect individual sources –Calculate fluxes, spectra –Answer fundamental questions about nature’s most powerful accelerators, their physics, and their energy sources –Map the Galactic/intergalactic magnetic field! B. Siffert

The National Science FoundationThe Kavli Foundation Conclusions Highest-energy CR sky anisotropic Auger South results proof-of-concept for charged particle astronomy More data + Auger North = individual source detection, individual source fluxes, spectra…

The National Science FoundationThe Kavli Foundation BONUS: sampling the sky with few events

The National Science FoundationThe Kavli Foundation

The National Science FoundationThe Kavli Foundation

The National Science FoundationThe Kavli Foundation