ApJ 623 (2005 April 10) 164-170 doi: 10.1086/428570
Search for Point Sources of Ultra-High-Energy Cosmic Rays above 4.0 × 1019 eV Using a Maximum Likelihood Ratio Test
R. U. Abbasi1, T. Abu-Zayyad1, J. F. Amann2, G. Archbold1, R. Atkins1, J. A. Bellido3, K. Belov1, J. W. Belz4, S. Y. Ben-Zvi5, D. R. Bergman6, J. H. Boyer5, G. W. Burt1, Z. Cao1, R. W. Clay3, B. M. Connolly5, B. R. Dawson3, W. Deng1, G. R. Farrar7, Y. Fedorova1, J. Findlay1, C. B. Finley5, W. F. Hanlon1, C. M. Hoffman2, M. H. Holzscheiter2, G. A. Hughes6, P. Hüntemeyer1, C. C. H. Jui1, K. Kim1, M. A. Kirn4, B. C. Knapp5, E. C. Loh1, M. M. Maestas1, N. Manago8, E. J. Mannel5, L. J. Marek2, K. Martens1, J. A. J. Matthews9, J. N. Matthews1, A. O'Neill5, C. A. Painter2, L. Perera6, K. Reil1, R. Riehle1, M. D. Roberts9, M. Sasaki8, S. R. Schnetzer6, M. Seman5, K. M. Simpson3, G. Sinnis2, J. D. Smith1, R. Snow1, P. Sokolsky1, C. Song5, R. W. Springer1, B. T. Stokes1, J. R. Thomas1, S. B. Thomas1, G. B. Thomson6, D. Tupa2, S. Westerhoff5, L. R. Wiencke1 and A. Zech6
1 Department of Physics and High Energy Astrophysics Institute, University of Utah, Salt Lake City, UT 84112
2 Los Alamos National Laboratory, P.O. Box 1663, Los Alamos, NM 87545
3 Department of Physics, University of Adelaide, Adelaide, SA 5005, Australia
4 Department of Physics and Astronomy, University of Montana, Missoula, MT 59812
5 Department of Physics and Nevis Laboratories, Columbia University, New York, NY 10027
6 Department of Physics and Astronomy, Rutgers, State University of New Jersey, Piscataway, NJ 08854
7 Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, NY 10003
8 University of Tokyo, Institute for Cosmic Ray Research, Kashiwa City, Chiba 277-8582, Japan
9 Department of Physics and Astronomy, University of New Mexico, Albuquerque, NM 87131
E-mail: finley@physics.columbia.edu, westerhoff@nevis.columbia.edu and gf25@nyu.eduABSTRACT.
We present the results of a search for cosmic-ray point sources at energies in excess of 4.0 × 1019 eV in the combined data sets recorded by the Akeno Giant Air Shower Array and High Resolution Fly's Eye stereo experiments. The analysis is based on a maximum likelihood ratio test using the probability density function for each event rather than requiring an a priori choice of a fixed angular bin size. No statistically significant clustering of events consistent with a point source is found.
Subject headings:
acceleration of particles; cosmic rays; large-scale structure of universe
Print publication: Issue 1 (2005 April 10)Received 9 November 2004, accepted for publication 23 December 2004
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