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Previous Ku-band (15 GHz) imaging with data obtained from the Very LongBaseline Array (VLBA) had shown two compact, sub-pc components at the locationof a presumed kpc-scale radio core in the Seyfert galaxy NGC 7674. It was thenpresumed that these two unresolved and compact components were dual radio corescorresponding to two supermassive black holes (SMBHs) accreting surrounding gasand launching radio-bright relativistic jets. However, utilizing the originalVLBA dataset used to claim the detection of a binary SMBH, in addition to latermulti-epoch/multi-frequency datatsets obtained from both the VLBA and theEuropean VLBI Network, we find no evidence to support the presence of a binarySMBH. We place stringent upper limits to the flux densities of any sub-pc-scaleradio cores which are at least an order of magnitude lower than the originalVLBI radio-core detections, directly challenging the original binary SMBHdetection claim. With this in mind, we discuss the possible reasons for thenon-detection of any VLBI radio cores in our imaging, the possibility of abinary SMBH still residing in NGC 7674, and the prospect of future observationsshedding further light on the true nature of this active galactic nucleus.

Deep VLBI Observations Challenge Previous Evidence of a Binary Supermassive Black Hole Residing in the Seyfert Galaxy NGC 7674