Workshop "Steady Jets and Transient Jets"

Jets are a common phenomenon in accreting compact objects, both Galactic and extragalactic, and results of the last years show that there exist two types of jets with completely different characteristics. The first type of jet is a result of magneto-rotational processes within an optically thick (flat or inverted spectrum) radio core region, from which emerges a quasi-steady slowly moving jet, with Kelvin-Helmholtz instabilities dominating its morphology and dynamics that are best seen in AGNs. The second type of jet is a result of internal shocks, producing a transient jet which features a sequence of bright and typically optically thin regions that move at superluminal speeds, embedded in the structural patterns produced by instabilities in the underlying flow. These two types are called "steady" vs "transient" jet in the microquasar community and "underlying" vs "shocked" jet in the AGN community. X-ray observations of microquasars show that the steady jet is taking place in the 'low / hard' X-ray state and the transient jet in the 'steep power-law' X-ray state. That means that the two radio states correspond to two different X-ray states. The connection, if any, between the two types of jets continues to challenge observers and theoreticians. Latest results show a possible relationship: internal shocks form when an event like a disk instability or magnetic reconnection creates a faster jet that catches up with the previously generated slowly moving steady jet.

The aim of this workshop is to review the current status of the knowledge about steady and transient jets in various environments, like  microquasars, AGN and gamma-ray bursts and to spotlight existing discrepancies/analogies in a fruitful interchange between the  members of the different communities. An important goal is to identify the connection between steady jets and transient jets.

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