RADIO QUASARS AND THE LINK WITH GAIA

ABSTRACT. Modeling VLBI ejections of nuclei of extragalactic radio sources, indicates that theirnuclei contain a binary black hole system. One can derive the distance and the positions of the two blackholes in the plane of the sky. We can also use the RMS of the time series of the ICRF2 survey to obtainan estimate of the structure and the size of the nuclei. We will discuss the possible problems to link VLBIobservations and GAIA optical observations of radio quasars if they contain a binary black hole system. 1. STRUCTURE OF COMPACT RADIO SOURCES MODELING VLBI EJECTIONS VLBI observations of compact radio sources show that the ejection of VLBI components does notfollow a straight line but undulates. These observations suggests a precession of the accretion disk. Toexplain the precession of the accretion disk, we will assume that the nucleus of radio sources contains abinary black hole system (BBH system) .A BBH system produces 2 main perturbations of the VLBI ejection due to:1. the precession of the accretion disk and2. the motion of the two black holes around the gravity center of the BBH system.Figure 1: Using the MOJAVE data (Lister & al 2009), we plot the trajectories of C5 and C10. ComponentC10 is ejected by the VLBI core and component C5 is ejected with a large o set from the VLBI core.Components C5 and C10 follow two di erent trajectories and are ejected from di erent origins, indicatingthat the nucleus of 3C 279 contains a BBH system (Roland & al. 2013).The presence of a BBH system, induces several consequences, which are:1. the 2 black holes can have accretion disks with di erent angles with the plane of rotation of theBBH system and can eject VLBI components; in that case we will observe two di erent families oftrajectories, a good example of a source showing 2 families of trajectories is 3C 279 (see Figure 1),1