This paper considers a population process where individuals reproduce according to an age-dependent branching process and immigrants enter the population at the event epochs of an ergodic point process. A limit theorem is proven for what corresponds to the supercritical case, and the limit...

A number of limit theorems for the integral of a non-supercritical age-dependent branching process with immigration are found. Some results are given for the subcritical case without immigration, but conditioned to stay positive. Finally a central limit theorem is given for the population size...

Some limit theorems are obtained for the population size of a critical Bienaymé-Galton-Watson process allowing immigration and where the variance of the offspring distribution is infinite. An application is given to a limit theorem for the situation where the immigration does not occur but the...