Jets in quasars, microquasars and gamma-ray bursts

Relativistic outflows are common in accreting and forming black holes. Despite the enormous differences in scale, stellar-mass black holes in X-ray binaries and supermassive black holes in Galactic Nuclei produce jets with analogous properties. In both are observed two types of relativistic outflows: 1) quasi-steady compact jets with flat-spectrum, and 2) episodic large-scale ejections with steep-spectrum and apparent superluminal motions. Because of the short time scale of the phenomena in black hole binaries, the formation of synchrotron jets is associated to changes in the X-ray thermal emission from the accretion disk. Besides, the most common class of gamma-ray bursts can be conceived as extreme microquasars, since they are afterglows from ultra-relativistic jets associated to the formation of black holes at cosmological distances.