Beams crossing a galactic halo-intergalactic medium interface and the size of extragalactic radio sources

Numerical simulations of extragalactic jets which penetrate the boundary between a power-law galactic halo and a hotter intergalactic medium are carried out using a boundary-following code. Comparisons of these models are made with both simplified analytical models and observations of powerful radio sources. Good agreement is obtained with regard to the relationships between the overall linear size of such radio sources and both the cosmological redshift (at fixed power) and the total radio power (at fixed redshift). These computations support the basic idea that the interaction between jets and a cosmologically significant intergalactic medium is very important. 41 references