1 / 37

The Pierre Auger Observatory

The Pierre Auger Observatory. Hunting the Highest Energy Cosmic Rays I – High Energy Cosmic Rays and Extensive Air Showers. Discovery of Cosmic Rays. Altitude variation of ionisation detected by Hess and Kohlhoster and Pfotzer. The Cosmic Ray Spectrum. Outstanding Issues.

fburch
Download Presentation

The Pierre Auger Observatory

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The Pierre Auger Observatory Hunting the Highest Energy Cosmic Rays I – High Energy Cosmic Rays and Extensive Air Showers E.Menichetti - Villa Gualino, March 2007

  2. Discovery of Cosmic Rays Altitude variation of ionisation detected by Hess and Kohlhoster and Pfotzer E.Menichetti - Villa Gualino, March 2007

  3. The Cosmic Ray Spectrum E.Menichetti - Villa Gualino, March 2007

  4. Outstanding Issues Acceleration Mechanism GZK Composition Point Sources E.Menichetti - Villa Gualino, March 2007

  5. The Magnetic Mirror Energy exchange Drift ↔ Revolution Inhomogeneous B field Spiral trajectories around field lines High gradient regions acting like walls E.Menichetti - Villa Gualino, March 2007

  6. Fermi Mechanism - 2nd Order Scattering by B-field Stochastic process: DE2E Expect: Slow, inefficient E.Menichetti - Villa Gualino, March 2007

  7. Fermi Mechanism - 1st Order As before, scattering by B -field irregularities Momentum gain: Expect: fast, efficient Speed=U1 >Speed=U2 Shock compression ratio E.Menichetti - Villa Gualino, March 2007

  8. Maximum Energy Simple estimate of max. energy (Hillas): b: plasma speed B: mag field L: source size E.Menichetti - Villa Gualino, March 2007

  9. Spectral Index, Time Constant Power law spectrum Fermi 2nd order: tacc>108 yr! KO Fermi 1st order: tacc~1 month! OK E.Menichetti - Villa Gualino, March 2007

  10. Compact sources Just meaning: non electromagnetic acceleration Various mechanisms proposed: Black hole accretion disks Gamma ray bursts Topological defects (monopoles, cosmic strings, ..) UHE n’s from decays of high mass particles E.Menichetti - Villa Gualino, March 2007

  11. Cosmic Microwave Background Penzias, Wilson & the Antenna The CMB spectrum (by FIRAS) E.Menichetti - Villa Gualino, March 2007

  12. CMB Photons Peak energy  kBT= 0.6 meV Density  400 cm-3 Possible CR interactions: ,A ,A E.Menichetti - Villa Gualino, March 2007

  13. G(reisen),Z(atepsin),K(uz’min) (G, Z&K - 1965) The moral: CR’s above threshold bound to lose energy E.Menichetti - Villa Gualino, March 2007

  14. The GZK Cutoff So UHECR’s just can’t propagate beyond, say, 50 Mpc! Then we should find a suitable source just ‘round the corner’. But where? E.Menichetti - Villa Gualino, March 2007

  15. The High End of the CR spectrum ~ x 2 effect ~ 2-3 s issue.. E.Menichetti - Villa Gualino, March 2007

  16. Composition Issues Spectrum Depth of Shower Maximum in Air vs. E Galactic? Extra-Galactic? E.Menichetti - Villa Gualino, March 2007

  17. More on Composition Proton/Iron Discrimination tied to Intra/Extra-Galactic origin E.Menichetti - Villa Gualino, March 2007

  18. Opening a New Window? Effect of Extra-Galactic Magnetic Field on CR trajectories –Simulation E = 1018 eV E = 1020 eV Clearly, around 1020 eV a new astronomy is feasible… …if Cosmic Rays of that energy are actually observed E.Menichetti - Villa Gualino, March 2007

  19. The Known Matter (< 21 Mpc) E.Menichetti - Villa Gualino, March 2007

  20. Anisotropies, Point Sources? AGASA Controversial results… Issues at stake: Detection Technique Angular Resolution Statistics! > 6 Clusters observed HIRES No cluster E.Menichetti - Villa Gualino, March 2007 E.Menichetti – SIF 2006

  21. Cosmic Rays Detection Direct detection - Up to 1014 eV Main limitation: Flux Usually performed by balloons, satellites, … Extensive Air Showers – Above 1014 eV Primary particle interaction in upper atmosphere Developing shower detected by different techniques E.Menichetti - Villa Gualino, March 2007

  22. EAS Development • Primary interaction in the high atmosphere • Hadronic Shower • Charged mesons Muons • Neutral mesons Photons • Muon component • + • EM Shower ~10 km E.Menichetti - Villa Gualino, March 2007

  23. EAS – Cross Section E.Menichetti - Villa Gualino, March 2007

  24. EAS – EAS development Next ~6 slides from R.Engel’s simulations See for example: R.Engel EAS Lectures given at ISAPP 2005 Summer School http://www.isapp2005.to.infn.it/ E.Menichetti - Villa Gualino, March 2007

  25. EAS-I E.Menichetti - Villa Gualino, March 2007

  26. EAS-II E.Menichetti - Villa Gualino, March 2007

  27. EAS-III E.Menichetti - Villa Gualino, March 2007

  28. EAS-IV E.Menichetti - Villa Gualino, March 2007

  29. EAS-V E.Menichetti - Villa Gualino, March 2007

  30. EAS - Profiles Longitudinal Lateral E.Menichetti - Villa Gualino, March 2007

  31. EAS - Electron Lateral Distribution E.Menichetti - Villa Gualino, March 2007

  32. EAS - Muons vs Electrons E.Menichetti - Villa Gualino, March 2007

  33. EAS- Elongation Rate E.Menichetti - Villa Gualino, March 2007

  34. EAS Detectors Long history, dating back to the ’60s Volcano Ranch (USA) – Sampling Haverah Park (UK) – Sampling SUGAR (Australia) - Sampling Yakutsk (Russia) - Sampling Fly’s Eye (USA) – Fluorescence AGASA HiRes E.Menichetti - Villa Gualino, March 2007

  35. AGASA Akeno Giant Air Shower Array 111 scintillators + 27 muon det. Akeno, Japan 11 Super-GZK events Small Scale Clustering Constraints on Composition:  protons at UHEs. (“Classical” analysis based on Ne vs Nm) E.Menichetti - Villa Gualino, March 2007

  36. HiResHigh Resolution Fly’s Eye Pioneers of FluorescenceTechnique Air fluorescence detectors HiRes 1 - 21 mirrors HiRes 2 - 42 mirrors Dugway, Utah, USA No Super-GZK flux No Small Scale Clustering Composition Change E.Menichetti - Villa Gualino, March 2007

  37. EAS – The Movie E.Menichetti - Villa Gualino, March 2007

More Related