Four dual AGN candidates observed with the VLBA

Understand

According to hierarchical structure formation models, merging galaxies are expected to be seen in different stages of their coalescence.

• However, currently there are no straightforward observational methods neither to select nor to confirm a large number of dual active galactic nuclei (AGN) candidates.
• Most attempts involve the better understanding of double-peaked narrow emission line sources, to distinguish the objects where the emission lines originate from narrow-line kinematics or jet-driven outflows from those which might harbour dual AGN.
• We observed four such candidate sources with the Very Long Baseline Array (VLBA) at 1.5 GHz with $\sim$ 10 milli-arcsecond angular resolution where spectral profiles of AGN optical emission suggested the existence of dual AGN.