Physics of accretion and matter ejection
The investigation of accretion onto compact objects and the emergence of relativistic jets can be sub-divided into three areas. The first concerns blazars, in which the jet dominates the system, the second is "non-beamed" X-ray binaries and AGN (Active Galactic Nuclei) where the properties of accretion and jet are closely linked, and the third are binaries containing compact objects. In these fields Italy plays a leading role thanks both to the "Agenzia Spaziale Italiana" satellite AGILE, whose scientific component is represented by INAF and INFN, and collaboration with NASA's FERMI satellite and the Cherenkov telescope MAGIC. Italy also provides an important theoretical and interpretative contribution.
Italy then has a centre-stage role in the study of extragalactic jets, and particularly blazars. From an observational standpoint, the multi-frequency studies of blazars (especially in the radio, optical, X- and gamma-ray bands) are particularly relevant and involve various INAF sites and universities (Insubria, Perugia). Italy has a leadership position in optical monitoring, playing a leading role in the consortium of medium to small telescopes, GASP-WEBT. The studies conducted with AGILE and REM (completely Italian) and the one hand, and with Swift, Fermi and MAGIC (with an essential Italian contribution) on the other, are of particular importance. The qualified involvement of INAF in these latter instruments is assured by the presence of several researchers in the relevant international collaborations.
From the theoretical and interpretative point of view, Italy's position is excellent, especially in the case of blazar modeling (and more in general extragalactic jets) and in the numerical simulation of the formation and dynamics of relativistic jets. As far as radio-quiet AGN are concerned, the Italian contribution has been first rate. Italy has an important role also in the study of compact binaries with white dwarfs, benefiting from projects with Italian leaders and co-Is involving X-ray observations with Chandra, XMM-Newton, Swift and INTEGRAL, and in the optical band with both Italian and ESO telescopes.
These studies make use of X-ray satellites such as Swift, Chandra, XMM-Newton, Suzaku and RossiXTE; those for gamma-ray astronomy such as INTEGRAL, AGILE and Fermi; the ground-based Cherenkov telescope MAGIC; the infrared and optical telescopes VLT, TNG and REM, and the radio telescopes of LOFAR.
In the same field, various projects with an Italian involvement are in the design or development phase, like, for example, the Cherenkov Telescope Array (CTA).