Speaker
Description
Gamma-ray binaries are unique laboratories for studying the interplay between relativistic outflows and dense stellar winds, producing variable non-thermal emission radio to very-high-energy (TeV) gamma rays. Resolving the spatial structure and evolution of the radio-emitting regions is essential for understanding the mechanisms driving particle acceleration and non-thermal emission in these systems. Howeevr, so far we only know nine of these systems and they have not been studied in detail at low frequencies. The synergy between LOFAR-VLBI, with its unprecedented sensitivity and sub-arcsecond resolution at the lowest radio frequencies, and the European VLBI Network (EVN), which provides high-resolution imaging at higher frequencies, enables a comprehensive multi-frequency investigation of gamma-ray binaries. This combined approach allows for tracing the morphology and evolution of the shocked material formed at the interaction zones between the relativistic wind of the young non-accreting neutron star and the stellar wind of the massive (O or B spectral type) companion. By mapping the extended and compact radio emission across a wide frequency range, we can trace the origin of the radio emission and its connection to the high-energy processes, ultimately advancing our understanding of particle acceleration and energy dissipation in these extreme binary systems. In this talk I summarize the first initiatives in this direction and how potential LOFAR+EVN observations would resolve the current unknowns from these particular sources.
