Related papers: Abundance Determinations from Gamma Ray Spectrosco…
Solar flare observations are used to demonstrate the new technique of abundance determination based on gamma ray line emission produced by accelerated particle bombardment. Some of the implications of similar gamma ray line emission…
We review the wide range of astrophysical observations of gamma ray emission lines and we discuss their implications. We consider line emission from solar flares, the Orion molecular cloud complex, supernovae 1987A and 1991T, the supernova…
We consider $\gamma$-ray emission from heavy nuclei that are accelerated in the shocks of stellar winds and are excited in interactions with the ambient matter in the Orion complex. We show that the recent detection of $\gamma$-ray lines in…
The total cosmic-ray luminosity of the Galaxy is an important constraint on models of cosmic-ray generation. The diffuse high energy $\gamma$-ray and radio-synchrotron emissions of the Milky Way are used to derive this luminosity. The…
Clusters of galaxies and the large scale filaments that connect neighboring clusters are expected to be sites of acceleration of charged particles and sources of non-thermal radiation from radio frequencies to gamma rays. Gamma rays are…
The rate of ionization by cosmic rays in interstellar gas directly associated with gamma-ray emitting supernova remnants is for the first time calculated to be several orders of magnitude larger than the Galactic average. Analysis of…
Gamma-ray line observations provide a versatile tool for studies of nucleosynthesis processes and supernova physics. In particular, the observation of radioactive species in the interstellar medium probes recent nucleosynthesis activity on…
Cosmic rays fill up the entire volume of galaxies, providing an important source of heating and ionisation of the interstellar medium, and may play a significant role in the regulation of star formation and galactic evolution. Diffuse…
Gamma-ray emission from large structures is useful for tracing the propagation and distribution of cosmic rays throughout our Galaxy. For example, the search for gamma-ray emission from Giant Molecular Clouds may allow us to probe the flux…
Galactic cosmic rays are commonly believed to be accelerated at supernova remnants via diffusive shock acceleration. Despite the popularity of this idea, a conclusive proof for its validity is still missing. Gamma-ray astronomy provides us…
Gamma rays constitute a privileged point of view for the study of the extreme Universe. Unlike charged cosmic rays, which are thought to have a common origin, gamma rays are not deflected by galactic and intergalactic magnetic fields. This…
Evidence for the existence of low energy cosmic rays in the Galaxy comes from the COMPTEL observations of gamma ray line emission from Orion, and also from light element abundance data which seem to suggest a low energy rather than a…
The study of the gamma-ray radiation produced by cosmic rays that escape their accelerators is of paramount importance for (at least) two reasons: first, the detection of those gamma-ray photons can serve to identify the sources of cosmic…
Blazar emission of gamma rays and cosmic ray production of gamma rays in gas-rich clusters have been proposed recently as alternative sources of the high energy extragalactic diffuse gamma ray background radiation. We show that these…
Gamma rays in the band from 30 MeV to 300 GeV, used in combination with direct measurements and with data from radio and X-ray bands, provide a powerful tool for studying the origin of Galactic cosmic rays. Gamma-ray Large Area Space…
Gamma rays from young pulsars and milli-second pulsars are expected to contribute to the diffuse gamma-ray emission measured by the {\it Fermi} Large Area Telescope (LAT) at high latitudes. We derive the contribution of the pulsars…
The study of Galactic diffuse $\gamma$ radiation combined with the knowledge of the distribution of the molecular hydrogen in the Galaxy offers a unique tool to probe the cosmic ray flux in the Galaxy. A methodology to study the level of…
We will review the main channels of gamma ray emission due to the acceleration and propagation of cosmic rays, discussing the cases of both galactic and extra-galactic cosmic rays and their connection with gamma rays observations.
Continuum gamma-ray emission produced by interactions of cosmic rays with interstellar matter and radiation fields is a probe of non-thermal particle populations in galaxies. After decades of continuous improvements in experimental…
Highly relativistic jets from merger and accretion induced collapse of compact stellar objects, which may produce the cosmological gamma ray bursts (GRBs), are also very efficient and powerful cosmic ray accelerators. The expected…