Ultra high energy cosmic rays: present status and recent results

L. Villaseñor

Institute of Physics and Mathematics, University of Michoacan, Morelia, Michoacan, 58040, Mexico, e–mail: villasen@ifm.umich.mx

Recibido el 1 de mayo de 2006
Aceptado el 1 de noviembre de 2006

Abstract

Cosmic rays with energies above 10²⁰ eV are the highest–energy particles ever observed in the Universe. Their flux is so small that up to now only about two dozen such particles have been detected by past and present observatories. Their nature, the location of their sources and the mechanisms by which they are produced or accelerated constitute still a mystery worth of investigating by gathering much higher statistical samples of such events. The Pierre Auger Observatory is a large–area hybrid detector that is under construction to study such ultra high energy cosmic rays. At present the southern site is near completion and it already constitutes the largest scientific observatory ever built to study cosmic rays. In this paper we describe the latest status of ultra high energy cosmic ray research with an emphasis on the Pierre Auger Observatory.

Keywords: Cosmic rays.

Resumen

Los rayos cósmicos con energías de 10²⁰ eV representan las partículas con mayor energía jamás observadas en el Universo. Su flujo es tan bajo que hasta ahora sólo se han detectado unas dos docenas de estas partículas con observatorios pasados y presentes. Su naturaleza, la localización de sus fuentes, y los mecanismos por los que son producidas o aceleradas continúan siendo un misterio que vale la pena investigar obteniendo muestras estadísticas mucho mayores de dichos eventos. El Observatorio Pierre Auger es un detector híbrido de gran área que se encuentra actualmente en construcción y que se dedicará a la observación de rayos cósmico de alta energía. En este momento, el observatorio en el sur esta prácticamente terminado y ya constituye el mayor observatorio de rayos cósmicos jamás construido. En este artículo se describe el estado actual de la investigación de rayos cósmicos de ultra alta energía haciendo énfasis en el papel del observatorio Pierre Auger.

Descriptores: Rayos cósmicos.

PACS: 95.55.Vj; 95.85.Ry; 98.70.Sa

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Acknowledgments

The author thanks the organizers of this Workshop for the invitation to give this talk and the Coordination of Scientific Research from University of Michoacan for supporting this project.

References

1. K. Greisen, Phys. Rev. Lett. 16 (1966) 798.        [ Links ]

2. G. Zatsepin and V. Kuzmin, JETP Lett. 4 (1966) 78.        [ Links ]

3. P.P. Kronberg, Rep. Prog. Phys. 57 (1994) 325.        [ Links ]

4. P.L. Biermann, Observing Ultra High Energy Cosmic Rays From Space and Earth, eds. H. Salazar, L. Villaseñor, and A. Zepeda, AIP Conf. Proc. 566 (2001) 37.        [ Links ]

5. A.M. Hillas, Ann. Rev. Astron. Astrophys. 22 (1984) 425.        [ Links ]

6. C.T. Hill, D.N. Schramm, and T.P Walker, Phys. Rev. D 36 (1987) 1007.        [ Links ]

7. L. Masperi, Observing Ultra High Energy Cosmic Rays From Space and Earth, eds. H. Salazar, L. Villaseñor, and A. Zepeda, AIP Conf. Proc. 566 (2001) 284.        [ Links ]

8. M.A. Lawrence et al., J. Phys. G 17 (1991) 773.        [ Links ]

9. B.N. Afanasiev et al., Proc. 24th. ICRC 2 (1995) 756.        [ Links ]

10. M. Teshima et al., Proc. 28th. Intl. Cosmic Ray Conf. 1 (2003) 437.        [ Links ]

11. C.B. Finley et al., Proc. 28th. Intl. Cosmic Ray Conf. 1 (2003) 433.        [ Links ]

12. D.J. Bird et al., Ap. J. Phys. 424 (1994) 491.        [ Links ]

13. S. Yoshida et al., Astrop. Phys. 3 (1995) 105.        [ Links ]

14. Pierre Auger Collaboration, Nucl. Instr. and Meth. in Phys. Res. A. 523 (2004) 50.        [ Links ]

15. Proc. 29th. Intl. Cosmic Ray Conf. (India), (2006) in press.        [ Links ]

16. B.A. Khrenov et al., Observing Ultra High Energy Cosmic Rays From Space and Earth, eds. H. Salazar, L. Villaseñor, and A. Zepeda, AIP Conf. Proc. 566 (2001) 57.        [ Links ]

17. L. Scarsi, Observing Ultra High Energy Cosmic Rays From Space and Earth, eds. H. Salazar, L. Villaseñor, and A. Zepeda, AIP Conf. Proc. 566 (2001) 113.        [ Links ]

18. Xavier Bertou for the collaboration, FERMILAB–CONF–05–267–E–TD, Jul 2005. 4pp. Presented at 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, 3–11 Aug 2005. e–Print Archive: astro–ph/0508466.        [ Links ]

19. Pierre Auger Collaboration (M. Aglietta et al.), FERMILAB–PUB–06–241–A–TD, Jul 2006. e–Print Archive: astro–ph/0607382.        [ Links ]

20. N. Hayashida et al. (AGASA Collaboration), Proc. Intl. Cosmic Ray Conf, Salt Lake City, 1999, OG.1.3.04, (astro–ph/9906056).        [ Links ]

21. J.A. Bellido et al., Astropart. Phys. 15 (2001) 167, (astro–ph/0009039).        [ Links ]

22. Pierre Auger Collaboration (J. Abraham et al.), FERMILAB–PUB–06–210–A, Jun 2006. 29pp. Submitted to Astropart. Phys., astro–ph/0606619.        [ Links ]

23. C. Bonifazi for the Auger Collaboration, Presented at 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, 3–11 Aug 2005.        [ Links ]

24. P. Ghia for the Auger Collaboration, 29th ICRC Pune (2005), in press.        [ Links ]

25. P. Sommers for the Pierre Auger Collaboration, Presented at 29th International Cosmic Ray Conference (ICRC 2005), Pune, India, 3–11 Aug 2005.        [ Links ]