Beaming and precession in the inner jet of 3C 273 II. The central engine

The quasar 3C 273 is a well-known superluminal source. More than 10 radio c omponents have been detected moving away from the nucleus with different su perluminal speeds and position angles. The pattern of ejection suggests the existence of a precessing inner jet, whose kinematics has been discussed b y Abraham & Romero (1999). We now present a binary black hole model for the central engine of 3C 273 where the rapid precession is tidally induced in the primary accretion disk inner region by a secondary black hole in a non- coplanar orbit. Using gamma- and X-ray data we estimate upper limits for th e mass of the primary, and then we compute the relevant parameters of the s ystem for a variety of disk models. We also discuss some of the implication s of the model for the electromagnetic and gravitational radiation from 3C 273.