  Merging binaries of compact relativistic objects (neutron stars and black
holes) are thought to be progenitors of short gamma-ray bursts and sources of
gravitational waves, hence their study is of great importance for astrophysics.
Because of the strong magnetic field of one or both binary members and high
orbital frequencies, these binaries are strong sources of energy in the form of
Poynting flux (e.g., magnetic-field-dominated outflows, relativistic leptonic
winds, electromagnetic and plasma waves). The steady injection of energy by the
binary forms a bubble (or a cavity) filled with matter with the relativistic
equation of state, which pushes on the surrounding plasma and can drive a shock
wave in it. Unlike the Sedov-von Neumann-Taylor blast wave solution for a
point-like explosion, the shock wave here is continuously driven by the
ever-increasing pressure inside the bubble. We calculate from the first
principles the dynamics and evolution of the bubble and the shock surrounding
it and predict that such systems can be observed as radio sources a few hours
before and after the merger. At much later times, the shock is expected to
settle onto the Sedov-von Neumann-Taylor solution, thus resembling an
explosion.
