Gamma rays are the most energetic part of the spectrum. They have the shortest wavelengths and highest frequencies. These characteristics make them extremely hazardous to life, but they also tell astronomers alotabout the objects that emit them in the universe. Gamma-rays do occur on Earth, creat...
Cosmic rays: The interaction between cosmic rays and matter releases gamma rays from bremsstrahlung or pair-production. Gamma rays bursts: Intense bursts of gamma radiation may be produced when neutron stars collide or when a neutron star interacts with a black hole. Other astronomical sources: Astr...
Key words: Gamma rays: bursts − ISM: jets and out- flows − stars: mass loss − shock waves 1. Introduction Since the discovery of the GRB 970228 afterglow by BeppoSAX, research on gamma-ray bursts (GRBs) has evolved. Now we know that GRBs are one of the most en- ergetic...
Gamma ray, electromagnetic radiation of the shortest wavelength and highest energy. Gamma rays are produced in the disintegration of radioactive atomic nuclei and in the decay of certain subatomic particles. It includes some overlap with X-rays in the el
Radioactivity - Gamma Decay, Radiation, Particles: A third type of radiation, gamma radiation, usually accompanies alpha or beta decay. Gamma rays are photons and are without rest mass or charge. Alpha or beta decay may simply proceed directly to the gro
relativistic jet; gamma-rays; X-rays; optical; radio; emission mechanism; Seyfert galaxy; super-massive black hole; host galaxy 1. Introduction Only a small percentage of active galactic nuclei (AGN) is radio-loud, and this characteristic is commonly ascribed to the presence of a relativistic ...
relativistic jet; gamma-rays; X-rays; optical; radio; emission mechanism; Seyfert galaxy; super-massive black hole; host galaxy 1. Introduction Only a small percentage of active galactic nuclei (AGN) is radio-loud, and this characteristic is commonly ascribed to the presence of a relativistic ...
The presence of a BLR could produce a spectral absorption feature due to pair production, which may either suppress all 𝛾γ-rays above a few GeV, or manifest as a harder spectrum towards the VHE regime. The geometry of the BLR does not affect the possible detection at VHE because the ...
However, the first gamma-rays from the short GRB could not be explained. To overcome this drawback, different scenarios have been proposed. The production of the gamma-rays is attributed to the collapse of this long-lived object to a BH, which happens after the production of the X-ray ...