Aims: We suggest an explanation for the high-frequency power excess surrounding active regions known as seismic halos. Methods: We use numerical simulations of magneto-acoustic wave propagation in a magnetostatic sunspot model. Results: We propose that seismic halos can be caused by the additional energy injected by high-frequency fast mode waves

Here we present two-dimensional hydrodynamic calculations of free expanding supergalactic winds, taking into consideration strong radiative cooling. Our main premise is that supergalactic winds are powered by collections of super-star clusters, each of which is a source of a high-metallicity supersonic diverging outflow. The interaction of winds

IAUC 5131 available at Central Bureau for Astronomical Telegrams. IAUC 5131 available at Central Bureau for Astronomical Telegrams.

IAUC 8430 available at Central Bureau for Astronomical Telegrams.

IAUC 7745 available at Central Bureau for Astronomical Telegrams.