Distribution of M_*, M_•, sSFR, f_Edd, redshift and q for the overall population of numerical BH mergers (in blue) and for the sub-sample of AGN-dominated mergers (in crimson), and observable mergers (in green) in the X-rays. The integrals of all distribution functions are normalised to unity. X-ray-observable merger remnants accrete faster and are more massive with respect to the general merger remnant population. They occur at lower redshifts and are hosted in more massive galaxies with lower sSFR.