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PSO J334.2028+1.4075 (PSO J334) is a luminous quasar located at redshiftz=2.06. The source gained attention when periodic flux density variations werediscovered in its optical light curve. These variations were initiallyinterpreted as the variability due to the orbital motion of a supermassiveblack hole binary (SMBHB) residing in a single circumbinary accretion disk.However, subsequent multiwavelength observations provided evidence against thebinary hypothesis as no optical periodicity was found on extended timebaselines. On the other hand, detailed radio analysis with the Karl G. JanskyVery Large Array (VLA) and the Very Long Baseline Array (VLBA) revealed alobe-dominated quasar at kpc scales, and possibly a precessing jet, which couldretain PSO J334 as a binary SMBH candidate. We aim to study both the large- andsmall-scale radio structures in PSO J334 to provide additional evidence for oragainst the binary scenario. We observed the source at 1.7 GHz with theEuropean Very Long Baseline Interferometry Network (EVN), and at 1.5 and 6.2GHz with the VLA, at frequencies that complement the previous radiointerferometric study. Our images reveal a single component at parsec scalesslightly resolved in the southeast-northwest direction and a lobe-dominatedquasar at kiloparsec scales with a complex structure. The source morphology andpolarization in our VLA maps suggest that the jet is interacting with denseclumps of the ambient medium. While we also observe a misalignment between theinner jet and the outer lobes, we suggest that this is due to the restartednature of the radio jet activity and the possible presence of a warpedaccretion disk rather than due to the perturbing effects of a companion SMBH.Our analysis suggests that PSO J334 is most likely a jetted AGN with a singleSMBH, and there is no clear evidence of a binary SMBH system in its centralengine.

From binary to singular: the AGN PSO J334.2028+1.4075 under the high-resolution scope