Scientific activities at IRA in the field of VLBI are mostly focused on the exploitation of the extremely high angular resolution that no other technique can achieve.

The main area is the study of relativistic jets from the vicinity of supermassive black holes at the center of Active Galactic Nuclei. We study these regions with VLBI in combination with other tools, such as high energy observations. Typically, we observe various kinds of systems at various stages of evolution: radio quiet or radio loud AGNs; young or evolved radio galaxies; with jets pointed towards the observers (gamma-ray blazars) or misaligned (radio galaxies). We carry out both projects focused on highly detailed studies of individual sources and on "snapshot" observations of large samples. With the former approach, we can investigate with high accuracy the physical properties (energetics, magnetic field, composition) of relativistic jets in the best astrophysical laboratories (such as the blazar Mrk421 or the radio galaxies M87 and 3C84); in the latter, we can carry out a statistical analysis, which is also a fundamental tool in understanding the AGN population.

Furthermore, we also use the VLBI technique in studies of galactic systems, such as novae and microquasars.