Since the AGILE and Fermi launch, the synergy between gamma-ray experiments and other space- and ground-based observatories has been the key to carry out multi-wavelength campaign aimed at understanding the physical mechanisms responsible for the observed gamma-ray emission in astrophysical sources. Blazars are the best examples of astrophysical sources where this strategy has been applied. The big efforts put in place for blazars to obtain coordinated observations with a broad coverage of the electromagnetic spectrum are providing new diagnostics of the physical processes at work in these sources, raising a lot of challenges for the theoretical interpretation. These could be partially solved through further observations with ground- and space-based facilities, therefore requiring new advances in technology and mission profile design. We will discuss how the lessons learned from current \(\gamma\)-ray observatories represent an important heritage for future missions expected to play a crucial role in the understanding of extreme phenomena in the high-energy domain.
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S.V. acknowledges financial contribution from the Grant ASI I/028/12/0 and the agreement ASI-INAF no. 2017-14-H.0.
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Conflict of interest
The authors declare that they have no conflict of interest.
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