Skip to main navigation Skip to search Skip to main content

Cangaroo-III search for TeV gamma rays from two clusters of galaxies

  • R. Kiuchi*
  • , M. Mori
  • , G. V. Bicknell
  • , R. W. Clay
  • , P. G. Edwards
  • , R. Enomoto
  • , S. Gunji
  • , S. Hara
  • , T. Hara
  • , T. Hattori
  • , S. Hayashi
  • , Y. Higashi
  • , Y. Hirai
  • , K. Inoue
  • , C. Itoh
  • , S. Kabuki
  • , F. Kajino
  • , H. Katagiri
  • , A. Kawachi
  • , T. Kifune
  • H. Kubo, J. Kushida, Y. Matsubara, T. Mizukami, Y. Mizumoto, R. Mizuniwa, H. Muraishi, Y. Muraki, T. Naito, T. Nakamori, S. Nakano, D. Nishida, K. Nishijima, M. Ohishi, Y. Sakamoto, A. Seki, V. Stamatescu, T. Suzuki, D. L. Swaby, T. Tanimori, G. Thornton, F. Tokanai, K. Tsuchiya, S. Watanabe, Y. Yamada, E. Yamazaki, S. Yanagita, T. Yoshida, T. Yoshikoshi, Y. Yukawa
*Corresponding author for this work

    Research output: Contribution to journalArticlepeer-review

    21 Citations (Scopus)

    Abstract

    Because accretion and merger shocks in clusters of galaxies may accelerate particles to high energies, clusters are candidate sites for the origin of ultra-high-energy (UHE) cosmic rays. A prediction was presented for gamma-ray emission from a cluster of galaxies at a detectable level with the current generation of imaging atmospheric Cherenkov telescopes. The gamma-ray emission was produced via inverse Compton upscattering of cosmic microwave background photons by electron-positron pairs generated by collisions of UHE cosmic rays in the cluster. We observed two clusters of galaxies, Abell 3667 and Abell 4038, searching for very high energy gamma-ray emission with the CANGAROO-III atmospheric Cherenkov telescope system in 2006. The analysis showed no significant excess around these clusters, yielding upper limits on the gamma-ray emission. From a comparison of the upper limit for the northwest radio relic region of Abell 3667 with a model prediction, we derive a lower limit for the magnetic field of the region of ∼0.1 μG. This shows the potential of gamma-ray observations in studies of the cluster environment. We also discuss the flux upper limit from cluster center regions using a model of gamma-ray emission from neutral pions produced in hadronic collisions of cosmic-ray protons with the intracluster medium. The derived upper limit of the cosmic-ray energy density within this framework is an order of magnitude higher than that of our Galaxy.

    Original languageEnglish
    Pages (from-to)240-246
    Number of pages7
    JournalAstrophysical Journal
    Volume704
    Issue number1
    DOIs
    Publication statusPublished - 2009

    Fingerprint

    Dive into the research topics of 'Cangaroo-III search for TeV gamma rays from two clusters of galaxies'. Together they form a unique fingerprint.

    Cite this