Landing page for project EM163

Past decade has been revolutionized by the discovery of stellar-mass black hole binary mergers via gravitational wave events. Mergers of supermassive black holes are expected due to the number of observed galaxy mergers, and fast changes in the spin-axis of AGN observed in several galaxies. SDSS J1430+2303 is the first candidate of a potential merger of two supermassive black holes (SMBBHs). Its optical and X-ray emission show a decay in both the period and amplitude of the signal that resembles the one expected from a merging SMBBH. The end point of the oscillations converge within the next ~100 days to ~3 years. We request a first exploratory EVN+eMERLIN observation to characterize the pre-merger system. We aim to obtain an accurate astrometric position of the SMBBH, and a detailed image of the expected jet/lobe emission. These data would allow us to determine, together with future observations the post-merger, dramatic spin-axis changes expected in the jet of these systems. This would represent the first time that such a change is observed in real time. The data would also allow us to trace and characterize the relativistic outflows expected during and after the merger.

This data is part of the archive of VLBI data maintained by JIVE on behalf of the EVN, a network of radio telescopes located primarily in Europe and Asia, with additional antennas in South Africa. The EVN archive itself has the DOI https://doi.org/10.17616/R3Z197