Annihilation Fountain in the Galactic Center Region

摘要

A starburst episode within the inner few hundred parsecs of our Galaxy would drive hot pair- laden gas into the halo, with the one-sidedness pointing to the site of initial pressure release at the onset of the starburst activity. Positrons lose energy and annihilate as they are convected upward with the gas flow, and we calculate high-latitude annihilation patterns and fluxes in accord with the observations. Changes in the ionization state when the escaping gas cools could give annihilation radiation substructure. The fountain of hot (～10~610~7 K) gas rising into the Galactic halowould be seen through its enhanced dispersion measure, thermal emission, and recombination radiation.