Speaker
Description
Active galactic nuclei (AGN) present rapid variability across the electromagnetic spectrum. In most cases, this can be explained with relativistic boosting along the line of sight. A very valuable approach to probe the nature of these objects is to study their radio morphology at the highest resolution available at present, provided by very-long-baseline interferometry (VLBI). While high-energy photons can be explained via inverse Compton scattering of soft photons, radio photons are mostly produced by synchrotron emission from the relativistic outflows powered from the super massive black holes at the centre of AGN. These jets display high variability and traveling features reaching apparent superluminal motions. VLBI monitoring at different wavelengths and including polarisation reaches sub-parsec scales (beyond the milliarsecond) and provides essential, complementary information to the multi-messenger studies of these highly energetic objects. I will present an overview of recent and ongoing VLBI projects devoted to AGN monitoring.
