Biography:

In the past F.A. Aharonian has collaborated on articles with L.O’C. Drury. One of their most recent publications is Very high energy gamma-ray astronomy and the origin of cosmic rays. Which was published in journal Nuclear Physics B - Proceedings Supplements.

More information about F.A. Aharonian research including statistics on their citations can be found on their Copernicus Academic profile page.

F.A. Aharonian's Articles: (3)

Very high energy gamma-ray astronomy and the origin of cosmic rays

The paper highlights the status and motivations of very high energy (E ≥ 100 GeV) γ-ray astronomy in the era of the Compton GRO. I discuss the potential of future ground-based γ-ray observations with emphasis on objectives connected with the general problem of the origin of galactic cosmic rays.

The puzzling MILAGRO hot spots

AbstractWe discuss the reported detection by the MILAGRO experiment of localised hot spots in the cosmic ray arrival distribution and the difficulty of interpreting these observations. A model based on secondary neutron production in the heliotail is shown to fail. An alternative model based on loss-cone leakage through a magnetic trap from a local source region is proposed.

TeV gamma rays from BL Lac objects due to synchrotron radiation of extremely high energy protons

AbstractOne of remarkable features of the gamma-ray blazar Markarian 501 is the reported shape of the TeV spectrum, which during strong flares of the source remains essentially stable despite dramatic variations of the absolute γ-ray flux. I argue that this unusual behavior of the source could be explained assuming that the TeV emission is a result of synchrotron radiation of extremely high energy (E≥1019 eV) protons in highly magnetized (B∼30–100 G) compact regions of the jet with typical size R∼1015–1016 cm and Doppler factor δj≃10–30. It is shown that if protons are accelerated at the maximum possible rate, i.e. tacc=η(rg/c) with so-called gyro-factor η∼1, the synchrotron cooling of protons could not only dominate over other radiative and non-radiative losses, but could also provide good fits (within uncertainties introduced by extragalactic γ-ray extinction) to the γ-radiation of two firmly established TeV blazars — Markarian 501 and Markarian 421. Remarkably, if the proton acceleration takes place in the regime dominated by synchrotron losses, the spectral shape of the Doppler-boosted γ-radiation in the observer's frame is determined essentially by the self-regulated “synchrotron cutoff” at ϵ0≃0.3δjη−1 TeV. The hypothesis of the proton-synchrotron origin of TeV flares of BL Lac objects inevitably implies that the energy contained in the form of magnetic field in the γ-ray emitting region exceeds the kinetic energy of accelerated protons.

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