Department of Physics & Astronomy
University of New Mexico

Center for Astrophysics Research and Technologies Seminar Series

Binary Stellar Mass Black Holes in AGN Disks as Possible LIGO Sources

Presented by Hui Li (Los Alamos National Laboratory)

The recent GW190521 event – an 85 Msun and a 66 Msun black hole (BH) coalescing to a 142 Msun BH – the heaviest binary black hole (BBH) merger to date has opened up new discussions on the formation channels of BBHs. In this talk, we focus on the scenario where BBHs are embedded inside an AGN disk (disk around a supermassive black hole at the center of a galaxy). We will present simulations on how stellar mass black hole binaries could form in AGN disks. We will also use high-resolution 2D and 3D hydrodynamical and magnetohydrodynamic simulations to examine the physical processes that regulate their orbital evolution. We demonstrate that there is a hierarchy of disk structures in such an embedded BBH, including the circum-single disk (CSD) and the circum-binary disk (CBD), both of which play an essential role in regulating the angular momentum evolution. We discuss the parameter spaces that will cause the BBH to contract or expand. Lastly, we explore the likely electromagnetic signatures from such events. Implications for possible observational signatures for the upcoming Observing Cycle 4 by LIGO/Virgo/KAGRA will be discussed as well.

2:00 pm, Thursday, September 14, 2023

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