Black Hole States: Accretion and Jet Ejection

The complex spectral and timing properties of the high-energy emission from the accretion flow in black-hole binaries, together with their strong connection to the ejection of powerful relativistic jets from the system, can be simplified and reduced to four basic states: hard, hard-intermediate, soft-intermediate and soft. Unlike other classifications, these states are based on the presence of sharp state transitions. I summarize this classification and discuss the relation between these states and the physical components contributing to the emitted flux.