We consider the sound radiation from an acoustic point-like source moving
along a supersonic ("space-like") trajectory in a fluid at rest. We call it an
acoustic "tachyonic" source. We describe the radiation emitted by this
supersonic source. After quantizing the acoustic perturbations, we present the
distribution of phonons generated by this classical tachyonic source and the
classical wave interference pattern.Comment: 14 pages, 5 figures, accepted for publication in Mod. Phys. Lett.