Document Type
Article
Publication Date
1-1-2008
Abstract
A method is developed to search for air showers initiated by photons using data recorded by the surface detector of the Auger Observatory. The approach is based on observables sensitive to the longitudinal shower development, the signal risetime and the curvature of the shower front. Applying this method to the data, upper limits on the flux of photons of 3.8 × 10- 3, 2.5 × 10- 3, and 2.2 × 10- 3 km- 2 sr- 1 yr- 1 above 1019 eV, 2 × 1019 eV, and 4 × 1019 eV are derived, with corresponding limits on the fraction of photons being 2.0%, 5.1%, and 31% (all limits at 95% c.l.). These photon limits disfavor certain exotic models of sources of cosmic rays. The results also show that the approach adopted by the Auger Observatory to calibrate the shower energy is not strongly biased by a contamination from photons. © 2008 Elsevier B.V. All rights reserved.
Publication Source (Journal or Book title)
Astroparticle Physics
First Page
243
Last Page
256
Recommended Citation
Abraham, J., Abreu, P., Aglietta, M., Aguirre, C., Allard, D., Allekotte, I., Allen, J., Allison, P., Alvarez-Muñiz, J., Ambrosio, M., Anchordoqui, L., Andringa, S., Anzalone, A., Aramo, C., Argirò, S., Arisaka, K., Armengaud, E., Arneodo, F., Arqueros, F., Asch, T., Asorey, H., Assis, P., Atulugama, B., Aublin, J., Ave, M., Avila, G., Bäcker, T., Badagnani, D., Barbosa, A., Barnhill, D., Barroso, S., Bauleo, P., & Beatty, J. (2008). Upper limit on the cosmic-ray photon flux above 1019 eV using the surface detector of the Pierre Auger Observatory. Astroparticle Physics, 29 (4), 243-256. https://doi.org/10.1016/j.astropartphys.2008.01.003