Maser Effects in Recombination Lines: the case of Eta Carinae

Abstract

Population of high quantum number states can differ from their LTE values at high densities (Ne ~106− 108cm−3) and temperatures of the order of 104K. In this case, the intensity of recombination lines can be strongly amplified. The amount of amplification depends on density and temperature, and it is different for different quantum numbers, allowing the determination of the physical and kinematic conditions of the emitting region through the observation of recombination lines of different quantum numbers. This…