DOI

https://doi.org/10.48717/x0bc-a096

Project

EV023

Title

e-EVN: EN010A, EV023, EA065A, EM156A

Abstract

Supermassive black hole binaries (SBHB) are formed as a consequence of galaxy mergers. 3C66B is a nearby radio galaxy that became enigmatic when a SBHB was proposed based on the elliptical motion of the radio core, observed in phase-referenced VLBI experiments in 2003. Follow-up observations with high astrometric precision are required to confirm the elliptical motion of the core, and quantify any evolution of the orbit. This proposal requests preparatory observations that will precede a more rigorous astrometric monitoring campaign. Ultimately, our hope is to observe this source at high cadence (every 30 days for two years) at 1.6 GHz to carry out astrometry over at least two orbits of the binary. However, before we propose those observations, we must test whether we will be able to reach sufficient (<30microarcsec) astrometric precision by identifying usable compact, in-beam phase-calibrators. In addition to the known (variable) phase calibrator 3C66A, there are two sources in the field that may provide suitable cross-referencing to ensure astrometry stability over time. Here we propose to test for the presence of bright, unresolved components in these sources. We request 4h of e-EVN time at18 cm.