In our review of the blazar phenomenon, we discuss blazar models, with a focus on the following issues: sub-parsec jets and their environment; energy dissipation and particle acceleration; and radiative processes.

The LIGO (Laser Interferometer Gravitational-Wave Observatory) experiment consists of three Fabry-Perot interferometers designed to measure the infinitesimal perfurbations of the curvature of spacetime due to the motion of massive astronomical bodies. The interferometers are sensitive to strains of h ∼ 10 in a frequency range from 40 Hz to 1 kHz. Sources of astronomical interest include binary ...