A limit to the rate of ultra high energy γ-rays in the primary cosmic radiation

M. Aglietta, B. Alessandro, P. Antonioli, F. Arneodo, L. Bergamasco, M. Bertaina, A. Campos Fauth, C. Castagnoli, A. Castellina, A. Chiavassa, G. Cini Castagnoli, B. D'Ettorre Piazzoli, G. Di Sciascio, W. Fulgione, P. Galeotti, P. L. Ghia, R. Granella, M. Iacovacci, A. Lima De Godoi, G. MannocchiC. Melagrana, N. Mengotti Silva, C. Morello, G. Navarra, H. Nogima, L. Riccati, O. Saavedra, G. C. Trinchero, P. Vallania, S. Vernetto, C. Vigorito

Research output: Contribution to journalArticlepeer-review


An upper limit to the flux of Ultra High Energy (UHE) γ-rays in the primary cosmic radiation is obtained through the data of the electromagnetic and the muon detectors of the EAS-TOP Extensive Air Shower array (Campo Imperatore, National Gran Sasso Laboratories, atmospheric depth 810g cm-2). The search is performed by selecting Extensive Air Showers (EAS) with low muon content. For EAS electron sizes Ne > 6.3 · 105, no showers are observed with the core located inside a fiducial area and no muons recorded in the 140 m2 muon detector, during a live time of 8440 h. The 90% c.l. upper limit to the relative intensity of γ-ray with respect to cosmic ray (c.r.) primaries is Iγ/Ic.r. < 7.3 · 10-5, at primary energy E0 ≥ 1015 eV: this limit is lower than reported in previous measurements.

Original languageEnglish (US)
Pages (from-to)71-75
Number of pages5
JournalAstroparticle Physics
Issue number1
StatePublished - Dec 1996


  • Cosmic rays
  • Gamma rays

ASJC Scopus subject areas

  • Astronomy and Astrophysics


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