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TeV gamma-rays and neutrinos from photo-disintegration of nuclei in Cygnus OB2

Luis A. Anchordoqui·John F. Beacom·Haim Goldberg·Sergio Palomares-Ruiz·Thomas J. Weiler
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Abstract

TeV gamma-rays may provide significant information about high energy astrophysical accelerators. Such gamma-rays can result from the photo-de-excitation of PeV nuclei after their parents have undergone photo-disintegration in an environment of ultraviolet photons. This process is proposed as a candidate explanation of the recently discovered HEGRA source at the edge of the Cygnus OB2 association. The Lyman-alpha background is provided by the rich O and B stellar environment. It is found that (1) the HEGRA flux can be obtained if there is efficient acceleration at the source of lower energy nuclei; (2) the requirement that the Lorentz-boosted ultraviolet photons can excite the Giant Dipole resonance implies a strong suppression of the gamma-ray spectrum compared to an E_γ^{-2} behavior at energies \alt 1 TeV (some of these energies will be probed by the upcoming GLAST mission); (3) a TeV neutrino counterpart from neutron decay following helium photo-disintegration will be observed at IceCube only if a major proportion of the kinetic energy budget of the Cygnus OB2 association is expended in accelerating nuclei.

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Luis A. Anchordoqui, John F. Beacom, Haim Goldberg, Sergio Palomares-Ruiz, Thomas J. Weiler. 2007-02-05. TeV gamma-rays and neutrinos from photo-disintegration of nuclei in Cygnus OB2. https://doi.org/10.1103/physrevd.75.063001

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