Supermassive black hole binaries: a neat multi-messenger source

Luciano Combi (Perimeter Institute/University of Guelph)

February 13, 2023

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Abstract: Supermassive black hole binaries (SMBHBs) are natural products of galaxy mergers and promising gravitational wave sources. Living in the gas-rich center of galaxies, these systems might accrete plasma and emit copious amounts of electromagnetic radiation. But how do we distinguish a binary from a single black hole in active galactic nuclei? Because we cannot spatially resolve these sources, we need to build precise models to identify them in the electromagnetic spectrum. The complex interplay between the magnetized plasma and the dynamical spacetime can only be fully solved using accurate general relativistic magneto-hydro (GRMHD) simulations that span a broad range of scales, from the black hole horizon to the disk around the binary. In this talk, I will present our recent work on modeling accretion disks and their emission around SMBHB using a combination of 3D GRMHD simulations, ray-tracing, and semi-analytical techniques. In particular, I will focus on electromagnetic signatures we might observe when the black holes are spinning; in this case, the system can launch powerful double jets and the emission from the disk can be brighter.