Relativistic outflows from X-ray binaries (a.k.a. `Microquasars')

Abstract

In this review I summarise the observational connections between accretion and relativistic outflows -- jets -- in X-ray binaries. I argue that jets are likely to be a fairly ubiquitous property of X-ray binaries as a whole, an assertion which can be tested by further observations of the Atoll-type X-ray binaries. I discuss broad patterns that are emerging from these observational studies, such as a correlation between `hard' X-ray states and the presence of radio emission, and the related anti-correlation between jet strength and mass-accretion rate as inferred from X-ray studies alone. I briefly discuss possible future directions for research and compare X-ray binary jets to those from Active Galactic Nuclei and Gamma Ray Bursts.