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Astrophysics at Very High Energies: Saas-Fee Advanced Course by Felix Aharonian, Lars Bergström, Charles Dermer, Roland

By Felix Aharonian, Lars Bergström, Charles Dermer, Roland Walter, Marc Türler

With the good fortune of Cherenkov Astronomy and extra lately with the release of NASA’s Fermi project, very-high-energy astrophysics has passed through a revolution within the final years. This publication presents 3 finished and up to date studies of the hot advances in gamma-ray astrophysics and of multi-messenger astronomy. Felix Aharonian and Charles Dermer tackle our present wisdom at the resources of GeV and TeV photons, gleaned from the perfect measurements made by means of the recent instrumentation. Lars Bergström provides the demanding situations and customers of astro-particle physics with a selected emphasis at the detection of darkish topic applicants. the subjects lined through the fortieth Saas-Fee path current the services of present instrumentation and the physics at play in resources of very-high-energy radiation to scholars and researchers alike. This e-book will motivate and get ready readers for utilizing house and ground-based gamma-ray observatories, in addition to neutrino and different multi-messenger detectors.

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Extra resources for Astrophysics at Very High Energies: Saas-Fee Advanced Course 40. Swiss Society for Astrophysics and Astronomy

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15). Figure 16 shows the spectra of secondary gamma-ray, electrons and neutrinos obtained for the proton distribution given in the form N (E) = A E −α exp − E E0 β , (18) with α = 2, β = 1, and E 0 = 1000 TeV. The constant A is set from the condition that the energy density of protons w = E N (E)d E = 1 erg/cm3 . It should be noted that, the spectrum of gamma-rays deviates, in contrast to commonly used assumptions, from the power-law form of the parent proton spectrum even at energies well below the cut-off energy and well above the threshold of π 0 production.

However, this symmetry can be violated in environments with high gas or radiation densities. In certain conditions, the characteristic time for inelastic interactions of charged pions with nucleons or photons could be shorter than the decay time, so the energy of pions degrades before they decay. At very high energies this would result in significantly smaller fluxes of neutrinos compared to gamma-rays. 5 MeV, independent of the energy distribution of π 0 mesons, and m π c2 /2 consequently of the parent protons.

19), with E = E e or E = E γ depending on the process. Figure 19 shows the total cross sections σsynchr and σ p as a function of χ. These 1, are obtained integrating Eqs. (34) and (35) over E γ and E e , respectively. For χ the probability of synchrotron radiation is approximately constant, but the probability Gamma Rays at Very High Energies 41 Fig. 19 Interaction probabilities of synchrotron radiation and magnetic pair production as a function of χ Fig. 20 Differential interaction probabilities (differential cross sections) of synchrotron radiation (left panel) and pair production in a magnetic field (right panel).

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