Colloquium Abstract - Li - 2024Feb02

February 2, 2024

11:00am Mountain

Hui Li (LANL)

 

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

 

Abstract

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 stellar mass BBHs. In this talk, we focus on the scenario where stellar BBHs are embedded inside an AGN disk – the so-called AGN channel for LIGO sources. Through detailed multi-dimensional simulations, we address several basic questions related to this scenario: How BBHs form inside an AGN disk? Will they harden their binary orbit after becoming a binary? How will accretion unto individual black holes and their feedback impact the flow around BBHs? Perhaps more importantly, will there be any electromagnetic signatures associated with such BBH mergers that can be observed?  We will use high-resolution 2D and 3D hydrodynamical and magnetohydrodynamic (MHD) simulations to examine the physical processes that regulate their formation and 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.  In addition, general relativistic MHD simulations are used to investigate the accretion and outflow, from which we calculate the expected power of jet/outflows. Implications for possible observational signatures will be discussed as well.


Local Host: Frank Schinzel

Connect with NRAO

The National Radio Astronomy Observatory and Green Bank Observatory are facilities of the U.S. National Science Foundation operated under cooperative agreement by Associated Universities, Inc.

Founded in 1956, the NRAO provides state-of-the-art radio telescope facilities for use by the international scientific community. NRAO telescopes are open to all astronomers regardless of institutional or national affiliation. Observing time on NRAO telescopes is available on a competitive basis to qualified scientists after evaluation of research proposals on the basis of scientific merit, the capability of the instruments to do the work, and the availability of the telescope during the requested time. NRAO also provides both formal and informal programs in education and public outreach for teachers, students, the general public, and the media.

The National Science Foundation (NSF) is an independent federal agency created by Congress in 1950 "to promote the progress of science; to advance the national health, prosperity, and welfare; to secure the national defense..."

AUI collaborates with the scientific community and research sponsors to plan, build, and operate cutting-edge facilities. We cultivate excellence, deliver value, enhance education, and engage the public.