The Search for Supermassive Black Holes in WF VLBI data

Many, if not all, galaxies are believed to host a supermassive black hole (SMBH) which is thought to form an integral ingredient in the evolution of the host galaxies through feedback mechanisms. In this scenario, the host and SMBH is expected to grow symbiotically and one of the favoured scenarios comes from major mergers of galaxies where the SMBHs are expected to merge. To this date, very little is known about these elusive systems. The great time scales of their lives as well as their mysterious nature calls on many studies to be able to intricately observe their properties as well as to gain insight into their formation and the overall role they play in their host galaxy’s evolution. In this scenario, we expect that there would be a plethora of evidence for binary SMBHs (B-SMBHs), however, confirming their existence, especially at parsec scales is often difficult. One possible method comes from Very Long Baseline Interferometry, whose milliarcsecond resolving power, allows us to resolve the B-SMBHs at parsec scales. In this presentation, I shall talk about a potential B-SMBH found in a wide-field VLBI survey of the GOODS-N data. Using ancillary Hubble Space Telescope spectra, we find that this object, has a high chance of being a B-SMBH, thus providing a proof-of-concept for this method of B-SMBH detections. Finally, I shall introduce our initial findings and estimates from a new survey of B-SMBHs using a new commensal wide-field VLBI survey which covers many degrees of the sky.